Analysis of Water Samples for Anions & Cations using Ion Chromatography & ICP-OES

September 2005
Faculty of Science
School of Chemical and Pharmaceutical Sciences
MSc in Analytical Chemistry
Identification & Validation of
method(s) for the analysis of
water samples for Anions &
cations, utilising Ion
Chromatography and ICP-OES
by Darren Horton

Darren Horton MSc in Analytical Chemistry September 2005
Page 1 of 89
Content
PAGE
Table of Contents 1 - 2
Abstract 3
Introduction 4 - 5
Diagram 1 – Ion Chromatographic Instrument Schematic
Diagram 2 – Schematic diagram of the mechanism of suppression
Method & Experimental 6
Instrumentation
General Laboratory Equipment
DI Waters Systems
IC Analysis
ICP Analysis
Reagents 6 - 7
Table 1 & 2
Water Sample details
Anion Analysis 7 - 14
Analysis 1 – Investigating Method
Analysis 2 – Developing Method
Analysis 3 – Investigating Method 2
Analysis 4 – Linearity / Determination of LOD/LOQ
Analysis 5 – Repeat Linearity / Determination of LOD-LOQ
Analysis 6 – 7 Day Stability
Analysis 7 – Accuracy
Analysis 8 – 7 Day Stability & Accuracy
Analysis 9 – Method Reproducibility
Analysis 10 – Sample Analysis
Cation Analysis 14 - 17
ICP Analysis 18
pH Measurement 19
Discussion
Anion Analysis 20 - 53
Diagram 3
Analysis 2 – Developing Method
Diagram 4
Analysis 3 – Investigating Method 2
Diagram 5
Chart 1 to 14 & Table 3
Analysis 5 – Repeat Linearity / Determination of LOD-LOQ
Analysis 6 – 7 Day Stability
Chart 29
Analysis 7 – Accuracy
Table 5
Table 6 & Chart 30 to 44
Table 7

Page 2 of 89
Cation Analysis 54 - 74
Diagram 6
Table 10 & Chart 64
pH Analysis 74
ICP Analysis 74 - 84
Conclusion 85 - 86
Bibliography 87
Appendices 88 - 89

Page 3 of 89
Abstract
As with any pharmaceutical site which manufacturer’s chemicals and raw materials large
quantities of water are in the process, and hence, discharged back into the water system. To enable
the determination of the levels of ions within the water discharge an Ion Chromatographic method
was required. This method would also allow the determination of the ion levels in deionised & bottled
water used within the laboratory for LC, and hence establish whether problems with poor gradient
elution could be shown to be due to levels of a particular ion.
Utilising two different Dionex Ion Chromatographic systems, methods for the determination
of Anions and Cations were found via literature searches. Both methods were developed by Dionex,
and were shown to work with anion and cation columns Dionex provided. When both methods had
been run on the two systems and show to work satisfactorily, the work of validating then was started.
This entailed running several analyses for each method determining the following properties;
(i) Whether the method is linear over the sample range to be determined
(ii) The limit of detection (LOD) for each method
(iii) The limit of quantification (LOQ) for each method
(iv) The stability of the standard solutions prepared for the method
(v) The method accuracy determining spike levels in samples
(vi) Whether the method is reproducible via method transfer between systems
When both methods had been shown to be accurate, linear, reproducible, fairly stable and
had LOD’s for most ions of 0.1 to 0.2 mg/L, several water samples were analysed. Utilising several
standard solutions of different concentration, the level of the seven anions and six cations were
determined, showing values for the different water samples of the expected levels.
The values obtained were also compared with the values measured via an Inductively
Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) instrument. The ICP-OES was used to
determine the results not just of the anions and cations under investigation, but also levels of heavy
metals in the samples. When the comparison was carried out the results obtained from the ICP were
seen to be within 1 to 2 mg/L for all cations, apart from Calcium, which had levels determined using
IC to be almost twice those seen with the ICP. The comparison of the results obtained for the anions
via the ICP was of little use as responses seen with the ICP for the anions was very small, and hence
the results generated had little meaning.
The pH of the water samples was also measured although these showed no link between pH
and high ion content, whether anion or cation.
From the analysis carried out methods for determining of the levels of anions and cations at
low level has been validated, and shown to work. They have also been shown to give comparative
results for those obtained via ICP, and have shown to have better LOD/LOQ values than those
obtained via ICP. However, further work is required to determine the stability of the standard and
sample solutions, as the stable data obtained was unclear, and affected by external factors.

Page 4 of 89
Introduction
Water covers 70 to 75% of the earth’s surface, is a vital component of life for millions of
plants and animals which inhibit it, and is a vital part of the world’s ecosystem. The human body
required one to seven litres of water per day, and while planet is comprised of 70-75% water, only
0.6% of that is usable for human consumption. In the developing world water purity and sanitation is
an everyday concern, where waterborne diseases such as cholera, hepatitis A and typhoid fever can
caused debilitating illness and may prove fatal.
The developed nations of the world, having no need to worry about such bacterial diseases,
consume 89 billion litres of bottled water a year, as a total cost of $22 billion per annum. The bottled
water business is, as with other industries, are highly depend on pleasing the customer, who chose a
particular brand depending on its taste and mineral content. The level of these minerals, such as
heavy metals & alkali earth metals, along with micro-organisms, are tightly controlled, whether the
water is bottled or straight out of a tap, and as a result are tested and monitored continuously.
Water is also an important component of any laboratory, as it is the primary solvent fro 75%
of all solids reagents and drug substances. As a result, the purity of the water in use in an analytical
laboratory can be important if any component present in the water can interfere or react with the
dissolved product/reagent. To minimise this, most laboratories utilise deionising water systems which
remove these ions via either reverse osmosis or ionic exchange column, Reverse Osmosis works by
removing the ions from the water as it passes through a semi-permeable reverse osmosis membrane,
while ion exchange removes the same ions as they pass down the column and absorb onto either the
anode or the cathode. In both cases the removed ions and microbes are passed to waste, while highly
pure water is stored in a tank for subsequent use. However, in order to check that the water has been
filtered and cleaned as described above the water must be analysed for ion content.
There are several groups of components which are analysed to determine their levels or to
determine that they are not present in solution. These groups include bacteria, heavy metals and the
group that is of interest in this project, trace ions. These trace ions include fluoride, Calcium and
magnesium which are ions present in treated or untreated water, and in the case of fluoride, is added
to the water course.
There are many techniques for analysing these trace ions, and they are excitation techniques
such as Atomic Absorption (AA) and Inductively Coupled Plasma -Optical Emission Spectroscopy (ICP-
OES), and ion exchange which is a component of Ion Chromatography (IC). ICP-OES is a technique that
can measure these trace ions down to ppb levels, and is largely replacing the older and less flexible
AA. However, ICP-OES is a technique which has trouble identifying and quantifying negatively charged
ions such as fluoride, hence it is primarily used for the identification and quantification of heavy
metals and positively charged ions such as calcium, lithium, sodium etc.
The technique which is primarily used for the identification and quantification of trace ions,
in solution is Ion Chromatography (IC). This technique was developed for the purpose of separating
negatively and positively charged ions, and injecting them onto a column where the ions are
separated according to their size and charge, as components are separated in Liquid Chromatography
(LC). Diagram 1 below shows a schematic diagram of an Ion Chromatographic system, with the main
differences to a LC system being the suppressor and detector cell. As these ions have no chromafore
to absorb UV radiation, which is the primary means of detection in LC, IC utilises the ions charge to
allow detection, hence it uses an electrochemical detector to determine the presence of a particular
ion in the cell.
The suppressor is the main part of an IC system as within the suppressor the mechanism by
which IC could not happen.
Diagram 1. Ion Chromatograph instrument schematic
Within the suppressor, the mechanism of suppression occurs, which entails the separate of the
reagent components into the anion and cation. The cation will be attracted to the cathode, which
will cause this separation. Taking diagram 2 as an example NaCl would be reaction in the following
way

Page 5 of 89
NaCl  Na+
+ Cl-
The separate components then react with
the anion and cation from water to form
Na+
+ OH-
 NaOH
Cl-
+ H+
 HCl
The NaOH is taken to waste while the HCl is
passed through the column. In this way the
anions in any solution can be separated by
forming HX compounds which will be
separated in the column.
Cations can be equally separated
whereby the water is replaced by MSA. This
acts as anion bonding to the cation in the
elution solution. Then when it enters the
suppressor, it separates from the cation
which bonds to the hydroxide ion and is
passed through to the column. In this way
the anions and cations contained in water
solutions can be separated and quantified,
down to levels of ppm (mg/L) to ppb
(цg/L).

Page 6 of 89
Method & Experimentation
Instrumentation
General Laboratory Equipment
2000ml Glass volumetric flask
250ml PMP volumetric flask
100ml Glass Beaker
50ml Glass Beaker
100ml PMP Beaker
50ml PMP Beaker
Analytical Balance Mettler AX205DR Inst. TABA01 S/N 1121300923
Anachem Electronic Pipette E3-10ML Inst. TEEP01 S/N I020177E
Anachem Electronic Pipette E3-2000 Inst. TEEP02 S/N K0200866E
Anachem Electronic Pipette E3-200 Inst. TEEP03 S/N G0200155E
Mettler Toledo MP220 pH Meter Inst. TEPH02 S/N 215123
DI Water Units
Millipore Milli-RX 20 Inst. TEWS02 S/N F5SM92192G
Millipore Elix-5 Inst. TEWS01 S/N F6MM19816D
Millipore Gradient A10 Inst. TEWS01 S/N F9BM51663F
IC Analysis
System TEIC01 (Initially named DX600)
Dionex EG40 Autosampler S/N 00050610
Dionex CD25 Conductivity Detector S/N 00070414
Dionex GP50-2 Gradient Pump S/N 00080590
Dionex AS50 Thermal Compartment S/N 00080813
Dionex AS50 TC Eluent Generator S/N 00090238
System TEIC02 (Initially named DX500)
Dionex AS3500 Autosampler S/N 017/06854
Dionex CD20 Conductivity Detector S/N 97010281
Dionex GP40 Gradient Pump S/N 93110161
Dionex LC20 Column Enclosure S/N 961020342
ICP Analysis
Varian CCD Simultaneous ICP-OES Inst. TEIP01 S/N 01114904
Reagents
Table 1 – List of General reagents
Reagent Grade Supplier Lot No Expiry
Sodium Fluoride AnalaR BDH (VWR) B923446 439 24 May 2008
Sodium Chloride AnalaR BDH (VWR) K3477433 512 05 May 2008
Sodium Nitrite AnalaR BDH (VWR) A463066 444 24 May 2008
Sodium Nitrate AnalaR BDH (VWR) A5717620429 24 May 2008
Sodium Bromide AnalaR BDH (VWR) K33152724 437 24 May 2008
Sodium Sulphate AnalaR BDH (VWR) A565797 438 24 May 2008

Page 7 of 89
Potassium Hydrogen Orthophosphate HiPerSolv BDH (VWR) A324924 239 24 May 2008
Ammonium Chloride AnalaR BDH (VWR) A598878 502 08 Jul 2008
Lithium Chloride AnalaR BDH (VWR) B471717 422 08 Jul 2008
Potassium Chloride AnalaR BDH (VWR) K34074529 504 08 Jul 2008
Calcium Chloride Dihydrate AnalaR BDH (VWR) TA5797321 140 13 Feb 2006
Magnesium Chloride Hexahydrate AnalaR BDH (VWR) A410133 447 08 Jul 2008
Sodium Bicarbonate AnalaR BDH (VWR) A576229 502 05 May 2008
Sodium Hydrogen Carbonate AnalaR BDH (VWR) K33644516 446 05 May 2008
46/48% Sodium Hydroxide Analytical 0449306
1.0N Sodium Hydroxide CONVOL BDH (VWR) OC516309 13 Jul 2006
Methylsulfonic Acid Merck S32938422 445 22 Jun 2006
Table 2 – List of ICP Standards
Ion Conc Supplier Lot No Expiry
Chloride 1000 mg/L BDH (VWR) B5055003-065 JUL 2006
Nitrate 1000 mg/L BDH (VWR) B4125033-065 JUL 2006
Sulphate 1000 mg/L BDH (VWR) B5015138-025 JUN 2006
Phosphate 1000 mg/L BDH (VWR) B5025069-025 APR 2006
Nitrite 1000 mg/L BDH (VWR) B5045089-065 JUN 2006
Bromide 1000 mg/L BDH (VWR) B4125012-065 JUN 2006
Copper 1000 mg/L BDH (VWR) B4075029-025 MAR 2008
Iron 1000 mg/L BDH (VWR) B4115174-025 APR 2008
Zinc 1000 mg/L BDH (VWR) B4095012-025 APR 2005
Lead 1000 mg/L SpexCertified 9-14PB 15 JUL 2003
Tin 1000 mg/L SpexCertified 10-32SN 15 SEP 2004
Magnesium 1000 mg/L SpexCertified 9-12MG 15 APR 2004
Potassium 1000 mg/L SpexCertified 10-135K 15 MAR 2004
Calcium 1000 mg/L SpexCertified 9-69CA 15 APR 2004
Sodium 1000 mg/L SpexCertified 10-46NA 15 MAR 2005
Lithium 1000 mg/L BDH (VWR) B3055003-015 JAN 2008
Waters Samples
HiPerSolv Water BDH (VWR) Lot No: OC350417
Normapur Water BDH (VWR) Lot No: 0501165
AlanaR Water BDH (VWR) Lot No: OC528289
Anion Analysis
ANALYSIS 1 – Investigating Method
Using the following Method as a guide – Dionex Application Note 140 – Fast Analysis of Anions in
Drinking Water by Ion Chromatography
Preparation of 10,000 mg/L Standard Solutions
10,000 mg/L standard solution of the following anions were prepared. The weights required to
produce 10,000 mg/L solutions of these anions was calculated using the following equation;
Weight Required = Concentration of Anion in Solution (in mg/L) x Mol. Mass
Conc of reagent in soln Fraction of Anion of Reagent
of conc 10,000 mg/L (in mg/L) in reagent
Reagent Anion M.W. Anion % Weight Weight
Required Taken
Sodium Fluoride F-
42.00 45.26 2.209g 2.1997g
Sodium Chloride Cl-
58.45 60.67 1.648g 1.6482g
Sodium Nitrite NO2
-
69.00 66.68 1.500g 1.5089g
Sodium Bromide Br-
102.91 77.66 1.288g 1.2858g
Sodium Nitrate NO3
-
85.01 72.96 1.371g 1.3759g

Page 8 of 89
Sodium Sulphate SO4
2-
142.06 83.82 1.193g 1.1928g
Pot. Phosphate PO4
-
136.09 71.27 1.403g 1.4068g
These reagents were weighed into 100ml volumetric flask and dissolved in deionised water.
Preparation of 100mg/L Standard Solutions
200цl of each 10,000mg/L solution was pipetted into individual 25ml vials, containing 1980цl of
deionised water. The solution was shaken well to mix
Preparation of 100mg/L Combined Standard Solution
1ml of each of the eight 10,000mg/L standard solutions was pipetted into a 100ml volumetric flask.
The solution was made to the mark with deionised water and shaken well.
Preparation of 0.8M Sodium Carbonate / 0.1M Sodium Bicarbonate Soln
16.80193g of Sodium Bicarbonate & 169.58761g of Sodium Hydrogen Carbonate were weighed into a
2lt volumetric flask, and dissolved via sonication, then diluted to the mark with deionised water.
Preparation of 8.0mM Sodium Carbonate / 1.0mM Sodium Bicarbonate Soln
20ml of the above solution was pipetted into 1980ml of deionised water, contained in a 2lt IC mobile
phase bottle. The solution was shaken then purged with helium for 190 mins prior to use.
IC Conditions
The 100mg/L individual and combined standards were analysed via the conditions below;
Column: IonPac AS11 Analytical, 4 x 250mm, P/N 44076 S/N 10092
IonPac AG11 Guard, 4 x 50mm, P/N 44076 S/N 8287
Suppressor: ASRS-ULTRA II 4-mm P/N 06156 S/N 22320
Eluent 8.0mM Sodium Carbonate / 1.0mM Sodium Bicarbonate
Flow Rate: 0.8ml/min
Temperature: 30°C
Run Time: 30mins
Injection Vol: 25цl
SRS Current: 100цS
System: TEIC02 (Formally DX500)
Sequence: Anion Run 2 24May 2005
Method: Anion Method 1
ANALYSIS 2 – Developing Method
Preparation of 0.8M Sodium Carbonate Solution
84.79g of Sodium Hydrogen Carbonate were weighed into a 1000ml volumetric flask, and dissolved via
sonication, then made to the mark with deionised water.
Preparation of 0.2M Sodium Bicarbonate Solution
16.80g of Sodium Bicarbonate were weighed into a 1000ml volumetric flask, and dissolved via
sonication, then made to the mark with deionised water.
Preparation of 8.0mM Sodium Carbonate / 2.0mM Sodium Bicarbonate Mobile Phase
20ml of the above solutions were pipetted into 1980ml of deionised water, contained in a 2lt IC
mobile phase bottle. The solution was shaken then purged with helium for 190 mins prior to use.
IC Conditions
The 100mg/L individual and combined standards prepared in ANALYSIS 1 were analysed via the
conditions below;
Column: IonPac AS11 Analytical, 4 x 250mm, P/N 44076 S/N 10092
Eluent 8.0mM Sodium Carbonate / 1.0mM Sodium Bicarbonate
Temperature: 30°C
Run Time: 30mins
SRS Current: 100цS
Sequence: Anion Run 4 01 July 2005

Page 9 of 89
Method: Anion Method 2 01 July 2005
ANALYSIS 3 – Developing Method
Using the following Method as a guide – IonPac AS11-HC Product Manual, Document No 031333-05 Page
18 of 41
Preparation of 1.0N Sodium Hydroxide
A 1.0N Sodium Hydroxide CONVOL was transferred with deionised water washings into a 1000ml
volumetric flask. This was made to the mark with deionised water and shaken.
Preparation of 25mM Sodium Hydroxide
50.0ml of the above solution was pipetted into 1950ml of water, contained in a 2lt IC Mobile Phase
bottle. The solution was shaken, and then purged with Helium for 10mins prior to use.
IC Conditions
The 100mg/L individual and combined standards prepared in ANALYSIS 1 were analysed via the
conditions below;
Column: IonPac AS11-HC Analytical, 4 x 250mm, P/N 052960 S/N 003763
Eluent 25mM Sodium Hydroxide
Temperature: Ambient
Run Time: 20mins
SRS Current: 100цS
Sequence: Anion Analysis 14 July 2005
Method: Anion Analysis 13 July 2005
ANALYSIS 4 – Linearity/Determination of LOD/LOQ
Preparation of Combined Standards
The following combined standard solution was prepared, taking the volumes of each 10,000mg/L
standard (See ANALYSIS 1 for preparation details) into individual volumetric flasks;
Concentration Volume Volumetric
Prepared / mg/L Taken Flask
100 1.0ml 100ml
50 0.5ml 100ml
40 0.4ml 100ml
30 0.3ml 100ml
20 0.2ml 100ml
Using the 100mg/L standard the following solutions were prepared;
10mg/L – 1.0ml in 10ml volumetric flask
All solutions were made to the mark with deionised water
50.0ml of the 1.0N Sodium Hydroxide solution was pipetted into 1950ml of deionised water, contained
in a 2lt IC mobile phase bottle. The solution was shaken, and the purged with helium for 10mins prior
to use.
IC Conditions
5 injections of each of the 100, 50, 40, 30, 20, 10, 5 & 2mg/L combined standards were analysed via
the conditions below;

Page 10 of 89
Run Time: 20mins
SRS Current: 100цS
Sequence: Anion Linearity 15 July 2005
Method: Anion Method 15 July 2005
ANALYSIS 4 – Repeat Linearity/Determination of LOD/LOQ
The following combined standard solution was prepared, taking the volumes of each 10,000mg/L
100 1.0ml 100ml
50 0.5ml 100ml
40 0.4ml 100ml
30 0.3ml 100ml
20 0.2ml 100ml
to use.
IC Conditions
5 injections of each of the 100, 50, 40, 30, 20, 10, 5 & 2mg/L combined standards were analysed via
the conditions below;
Run Time: 20mins
SRS Current: 100цS
Sequence: Anion Linearity 15 July 2005
ANALYSIS 6 – 7 Day Stability
Preparation of 10mg/L Combined Standard
250цl of each of the seven 10,000mg/L standards (See ANALYSIS 1 for preparation details) were
pipetted into a 250ml glass volumetric flask. The solution was made to the mark with deionised
water.
to use.

Page 11 of 89
IC Conditions
Injections of the 10mg/L Combined Standard were made at 1Hr, 2Hr, 3Hr, 4Hr, 5Hr, 6Hr, 9Hr & 12Hr;
Run Time: 20mins
SRS Current: 100цS
Sequence: Analysis 25 July 2005
ANALYSIS 7 – Accuracy
Preparation of 1000mg/L Standards
250цl of each of the 10,000mg/L Standards (See ANALYSIS 1 for preparation) were pipetted into
individual 25ml vials containing 18ml of deionised water
Preparation of 10mg/L Combined Standards
2.5ml of each of the 1,000mg/L Standards prepared above were pipetted into a 250ml glass
volumetric flask. The solution was made to volume with deionised water and shaken.
to use.
Preparation of Spike Solutions
10mg/L Spike - 100цl of each 1,000mg/L standard into individual 10ml glass volumetric flasks, made
to the mark with the 10mg/L combined standard.
5mg/L Spike - 100цl of each 1,000mg/L standard into individual 20ml glass volumetric flasks, made
to the mark with the 10mg/L combined standard.
IC Conditions
3 injections of each of the 10mg/L combined standard and the spike solutions were analysed under
the following conditions;
Run Time: 20mins
SRS Current: 100цS
Sequence: Anion Spike Analysis 26 July 2005
Method: Anion Analysis
ANALYSIS 8 – 7 Day Stability & Accuracy
10,000 mg/L standard solutions of the following anions were prepared in plastic PMP volumetric
flasks. The weights required to produce 10,000 mg/L solutions of these anions was calculated using
the following equation;
Weight Required = Concentration of Anion in Solution (in mg/L) x Mol. Mass
Conc of reagent in soln Fraction of Anion of Reagent
of conc 10,000 mg/L (in mg/L) in reagent

Page 12 of 89
Reagent Anion M.W. Anion % Weight Weight
Required Taken
Sodium Fluoride F-
42.00 45.26 2.209g 2.2058g
Sodium Chloride Cl-
58.45 60.67 1.648g 1.6483g
Sodium Nitrite NO2
-
69.00 66.68 1.500g 1.4981g
Sodium Bromide Br-
102.91 77.66 1.288g 1.2937g
Sodium Nitrate NO3
-
85.01 72.96 1.371g 1.4981g
(Incorrect weight taken. All subsequent standard solution conc. Will be adjusted accordingly)
Sodium Sulphate SO4
2-
142.06 83.82 1.193g 1.1954g
Pot. Phosphate PO4
-
136.09 71.27 1.403g 1.4038g
These reagents were weighed into 100ml volumetric flask and dissolved in deionised water.
Preparation of 1,000mg/L Standards
2ml of each 10,000mg/L standard was pipetted into a 25ml glass vial containing 18ml of deionised
water.
Preparation of 19mg/L Combined Stability Standard (2 preps)
250цl of each 10,000mg/L standard was pipetted into a 250ml PMP volumetric flask. The solution was
made up to the mark with deionised water. This solution was prepared in duplicate, with the two
solutions being mixed in a 1,000ml PMP beaker, and used to prepare the spike solutions. The
remaining solution was transferred back to the 250ml PMP volumetric flasks fro use over the 7 days of
the stability period.
10mg/L Spike - 250цl of each 1,000mg/L standard into individual 25ml PMP volumetric flasks, made
to the mark with the 10mg/L combined stability standard.
4.2g of 46/48% Sodium Hydroxide was weighed into a 2000ml of deionised water, contained in a 2lt
Mobile Phase bottle. The solution was shaken thoroughly and purged with helium for 10mins prior to
use.
Calculation of Mass 46/48% NaOH required;
Mass of Sodium Hydroxide: 39.997g/mole
Conc of 46/48% NaOH: 46.68%
Amount required = 39.997 x 0.025
0.4668 = 2.14g in 1lt or 4.28g in 2lt
IC Conditions
Injection of the 10mg/L Combined stability standard were made at 1Hr, 2Hr, 3Hr, 4Hr, 5Hr, 6Hr, 7Hr,
9Hr, 12Hr, 18Hr, 24Hr, 30Hr, 36Hr, then once a day up to 7 days, along with the spike solutions. All
analysed under the following conditions;
Run Time: 15mins
SRS Current: 100цS
Sequence: Stability & Spiking Analysis 11 Aug 2005
Stability Analysis 12 Aug 2005
Method: Anion Method
Anion Method 2
Anion Method 3
Anion Reduced Method

Page 13 of 89
ANALYSIS 9 – Repeatability
1ml of each of the 10,000mg/L standards (See ANALYSIS 7 for preparation details) were pipetted into
a 100ml PMP volumetric flask, and made up to the mark with deionised water.
The following combined solutions were then prepared, taking the following volumes of the 100mg/L
combined standard prepared above, into individual PMP volumetric flasks;
15 3.75ml 25ml
10 2.50ml 25ml
5 1.25ml 25ml
2 0.50ml 25ml
The solutions were then made to the mark with deionised water.
The mobile phase was produced using a KOH Eluent Generator S/N 040912263014
IC Conditions
3 injections of the combined standard solutions were analysed using the following conditions;
Produced using a KOH Eluent Generator S/N 040912263014
Run Time: 15mins
SRS Current: 100цS
Sequence: Anion Analysis 19 Aug 2005
Method: Anion Eluent Generator Method
ANALYSIS 10 – Sample Analysis
10 2.50ml 25ml
5 1.25ml 25ml
2 1.00ml 50ml
1 0.50ml 50ml
The mobile phase was produced using a KOH Eluent Generator S/N 040912263014
Water Samples
Sample 1 – K9 Lab 1 Tap Water
Sample 2 – K43 DI Water (Back Millipore Unit)
Sample 3 – K43 DI Water (Middle Millipore Unit)
Sample 4 – K43 Tap Water

Page 14 of 89
Sample 5 – QC Seve. Lab Egla System
Sample 6 – QC Raw Mat Lab. Elga System
Sample 7 – VWR HiPerSolv bottled water Lot No: OC350417
Sample 8 – VWR Normapur bottled water Lot No: 0501165
Sample 9 – VWR AnalaR bottled water Lot No: OC528289
IC Conditions
3 injections of the combined standard solutions along with the 9 water samples were analysed using
Produced using a KOH Eluent Generator S/N 040912263014
Run Time: 15mins
SRS Current: 100цS
Sequence: Sample Analysis 23 Aug 2005
Method: Anion Method
Cation Analysis
ANALYSIS 1 – Investigation of Method
Using the following Method as a guide – IonPac CS14 Product Manual, Document No 031333-05 Page 18
of 48 (METHOD 1 – Isocratic Method) & 36 of 48 (METHOD 2 – Gradient Method)
10,000 mg/L standard solution of the following cations were prepared. The weights required to
produce 10,000 mg/L solutions of these cations was calculated using the following equation;
Weight Required = Concentration of Cation in Solution (in mg/L) x Mol. Mass
Conc of reagent in soln x Fraction of Anion of Reagent
of conc 10,000 mg/L
(in mg/L) in reagent
Reagent Cation M.W. Cation % Weight Weight
Required Taken
Ammonium Chloride NH4
+
53.49 33.70 2.967g 2.9675g
Potassium Chloride K+
74.55 52.45 1.907g 1.9045g
Sodium Chloride Na+
58.44 39.34 2.542g 2.5395g
Lithium Chloride Li+
42.39 16.37 6.109g 6.1144g
Calcium Chloride Ca+
147.008 27.26 3.668g 3.6694g
(dehydrate)
Magnesium Chloride Mg+
203.30 11.95 8.368g 8.3567g
(hexahydrate)
These reagents were weighed into 100ml PMP volumetric flask and dissolved in deionised water.
Preparation of 1,000mg/L Standard Solutions
2ml of each 10,000mg/L standard solutions was pipetted into individual 25ml vials, containing 18ml of
deionised water. The solution was shaken well to mix
Preparation of 10mg/L Standards
500цl of each of the 1,000mg/L standard solutions was pipetted into individual 100ml PMP volumetric
flask. The solution was made to the mark with deionised water and shaken well.
Preparation of 10mM MSA
1.3ml of MSA (Methylsulphonic Acid) was pipetted into a 2000ml of deionised water, contained in a 2lt
IC Mobile Phase bottle. The solutions was shaken then purged with helium for 10mins prior to use.

Page 15 of 89
Calculation of Volume of MSA required;
Mass of MSA: 96.10g/mole
Conc of MSA: < 99%
Density of MSA: 1.48g/ml
Amount required for 10mM = 09610
1.48 = 0.65ml in 1lt or 1.30g in 2lt
IC Conditions
The 10mg/L individual standards were analysed via the conditions below;
Column: IonPac CS14 Analytical, 4 x 250mm, P/N 44123 S/N 3877
IonPac CS14 Guard, 4 x 50mm, P/N 44124 S/N 4643
Suppressor: CSRS-ULTRA II 4-mm P/N 061563 S/N 007073
Eluent 10mM MSA
Run Time: 20mins
SRS Current: 100цS
Sequence: Analysis 1 03 Aug 2005
Method: Cation Analysis Method 1 – METHOD 1
Cation Gradient Analysis – METHOD 2
Cation Analysis Method 2 – METHOD 1 with Eluent of 5mM MSA
The following combined standard solution were prepared, taking the volumes of each 10,000mg/L
100 1.0ml 100ml
30 150цl 50ml
25 125цl 50ml
20 100цl 50ml
15 75цl 50ml
10mg/L – 2.50ml in 25ml PMP volumetric flask
1.3ml of MSA was pipetted into a 2000ml of deionised water, contained in a 2lt IC Mobile Phase
bottle. The solutions was shaken then purged with helium for 10mins prior to use.
IC Conditions
3 Injections of each of the Combined standards were analysed under the following condtions;
Eluent 10mM MSA
Run Time: 20mins
SRS Current: 100цS

Page 16 of 89
Sequence: Linearity Analysis 1 08 Aug 2005
Method: Cation Analysis Method 1
Preparation of 10mg/L Combined Stability Standard
250цl of each of the 10,000mg/L standards (See ANALYSIS 1 for preparation details) were pipetted
into a 250ml PMP volumetric flask. The solution was made to the mark with deionised water. This
solution was prepared in duplicate, with the two solutions being mixed in a 1000ml PMP beaker, and
used to prepare the spike solutions. The remaining solution was transferred back into the 250ml PMP
volumetric flasks for use over the 7 days of the stability period.
bottle. The solutions was shaken then purged with helium for 10mins prior to use. The mobile phase
was prepared in duplicate in 2 x 2lt IC mobile phase bottles
IC Conditions
Injection of the 10mg/L Combined stability standard were made at 1Hr, 2Hr, 3Hr, 4Hr, 5Hr, 6Hr, 9Hr,
12Hr, 18Hr, 24Hr, 30Hr, 36Hr, then once a day up to 7 days, along with the spike solutions. All
analysed under the following conditions;
Eluent 10mM MSA
Run Time: 15mins
SRS Current: 100цS
Sequence: Stability and Spiking Analysis 12 Aug 2005
Method: Cation Analysis 1
ANALYSIS 4 – Repeatability
15 3.75ml 25ml
10 2.50ml 25ml
5 1.25ml 25ml
2 0.50ml 25ml
IC Conditions
3 injections of the combined standard solutions were analysed using the following conditions;

Page 17 of 89
Eluent 10mM MSA
Run Time: 15mins
SRS Current: 100цS
Sequence: Cation Analysis 19 Aug 2005
Method: Cation Analysis 19 Aug 2005
10 2.50ml 25ml
5 1.25ml 25ml
2 1.00ml 50ml
1 0.50ml 50ml
Water Samples
IC Conditions
3 injections of the combined standard solutions along with the 9 water samples were analysed using
Eluent 10mM MSA
Run Time: 15mins
SRS Current: 100цS
Sequence: Sample Analysis 23 Aug 2005
Method: Cation Method 19 Aug 2005

Page 18 of 89
ICP Analysis
Sample Anaysis
The Analysis of the various ions was split into three separate methods, with three different ion
groups. They were;
Method 1 - Cations (Lithium, Sodium, Potassium, Magnesium & Calcium)
Method 2 - Heavy Metals (Lead, Tin, Iron, Copper & Zinc)
Method 3 - Anions (Chloride, Bromide, Nitrate/Nitrite (looking for Nitrogen), Phosphate
(looking for Phosphorus) & Sulphate (looking for Sulphur)
The Ions shown above in the three methods were combined to make up four standards for each
method.
Taking the following volumes of the 1000mg/L ICP standards of the ion listed above, into individual
PMP volumetric flasks, the following standards were prepared;
10 250цl 25ml
5 125цl 25ml
2 100цl 50ml
1 50цl 50ml
Water Samples
ICP Conditions
Three ICP methods were set-up to run the standard and water samples listed above at the following
wavelengths;
Method 1
Calcium @ 396.85nm
Magnesium @ 279.55nm
Potassium @ 766.49nm
Sodium @ 588.99nm
Lithium @ 670.78nm
Method 2
Iron @ 238.20nm
Copper @ 324.75nm
Zinc @ 206.20nm & 213.86nm
Tin @ 283.99nm
Lead @ 220.35nm
Method 3
Chloride @ 774.49nm
Bromide @ 734.85nm
Nitrogen @ 174.21 & 174.47nm
(Back calculation will give the combined Nitrate/Nitrite levels)
Phosphorus @ 213.62nm
(Back calculation to give the Phosphate level)
Sulphur @ 181.97
(Back calculation to give the Sulphate level)

Page 19 of 89
pH Determination
pH measurement carried out using a glass electrode S/N 662-1759
The pH measurements for the nine water samples were;
SAMPLE pH
Sample 1 – K9 Lab 1 Tap Water 7.68
Sample 2 – K43 DI Water (Back Millipore Unit) 7.85
Sample 3 – K43 DI Water (Middle Millipore Unit) 7.34
Sample 4 – K43 Tap Water 7.69
Sample 5 – QC Seve. Lab Egla System 8.09
Sample 6 – QC Raw Mat Lab. Elga System 7.44
Sample 7 – VWR HiPerSolv bottled water Lot No: OC350417 8.62
Sample 8 – VWR Normapur bottled water Lot No: 0501165 7.26
Sample 9 – VWR AnalaR bottled water Lot No: OC528289 6.80

Page 20 of 89
Data Analysis & Discussion
Anion Analysis
ANALYSIS 1 – Investigation Method
Via literature searches the method selected for initial investigation was one developed by
Dionex for the analysis of the seven anions of interest. The method utilised an IonPac AS16 ion
chromatography column, but due to the absence of this particular column within the department and
the limit on what could be purchased for this method development, an AS16 column would not be
available. As the only anion columns within the department were IonPac AS11 & AS11-HC, the method
was tried out using an AS11 analytical & guard column combo, to see what sort of separation could be
achieved. The retention times and resolution for the seven ions was;
Ret Time Resolution
Fluoride 2.18mins 2.866
Chloride 2.70mins 1.331
Nitrite 2.96-3.00mins 4.195
Bromide 3.89min 0.508
Nitrate 4.11mins 5.708
Sulphate 5.84mins 3.841
Phosphate 7.07-7.15mins -
Diagram 3 – Chromatogram obtained with this method
As can be seen from the retention times and the chromatogram the separation of the
Chloride-Nitrite and Bromide-Nitrate peaks are not good, with resolution between the peaks of
concern far less then the 2.5, specified in most analytical methods. From the method it could
however be seen, that the anion column and system were working well, and that just the choice of
mobile phase was an issue. To investigate whether the method could be changed slightly in order for
the Chloride-Nitrite & Bromide-Nitrate peaks to have better separation, a slight change in the mobile
phase concentration would be investigated.
ANALYSIS 2 – Developing the Method
The method selected for the initial investigation was carried out as in Analysis 1, with the
only change being an increase in the concentration of the Sodium Bicarbonate in the mobile phase.
With the increase in the concentration of one of the components of the mobile phase it would be able
to see if the method could be adapted for use on an AS11 column or not.
The change in the concentration has the effect of increasing the retention times of the peaks
by between 0.3 and 3.0mins and as result, increasing the run time of the methods. The retention
times and resolution of the peaks were;
Ret Time Resolution
Nitrite 3.21mins 5.542

Page 21 of 89
Phosphate 10.46mins -
As seen with Analysis 1 the Chloride-Nitrite & Bromide-Nitrate peaks are still seen to be not
baseline resolving, with resolution’s of less then 2.5. As this change in concentration of the mobile
phase has done little to improve the peak resolution on the AS11 column, this method is deemed to
be not specify enough for the separation of the seven component anions. Another method will be
selected from the literature search, one that is developed for an AS11 or AS11-HC column.
ANALYSIS 3 – Investigating Method 2
The literature search for methods developed for use with AS11 or AS11-HC columns revealed
that the best source of methods for any Dionex IonPac column was the columns own column manual.
When reviewed a method was selected that gave good separation of the seven anions with a relative
short runtime, on an IonPac AS11-HC (High Capacity) column. The retention time & resolution for the
seven ions were;
Ret Time Resolution
Nitrite 3.82mins 7.641
Phosphate 13.46mins -

Page 22 of 89
As can be seen from the retention times and the chromatogram, the separation of the anions
is fairly good, with resolutions greatly improved from the previous method. There is a bit of overlap
of the bromide-nitrate peaks, but the chromatogram and peak shapes are good enough to give good
agreement between injections. As a result this method can be said to specific for the seven anions
and will be the method used for the determination of anions in the water samples. Accordingly, the
method will be validated t determine Accuracy, Stability & Reproducibility. The Limit of Detection
(LOD) & Limit of Quantification (LOQ) for the method, and the system will also be determined,
showing how good the method and system are.
The data when tabulated and averaged was used to calculate the linear regression equations
for area and height of the anion peaks. Further equations (see below) were used to calculate the
errors and LOD/LOQ’s for each of the seven anions
See table 14 through 23 for the tabulated data along with error/LOD/LOQ values calculated
using these equations, along with the charts below showing the linearity of the standard
concentrations for each ion.
Equations to calculate Linear Regression & Correlation
Correlation Coefficient r = ∑{xi – xm)(yi – ym)}
√{[∑(xi – xm)2
][∑(yi – ym)2
]}
b = ∑{(xi – xm}(yi – ym)}
∑{xi – xm)2
a = ym - bxm
where xm = x mean & ym = y mean
Equations to calculate the errors for Linear Regression & Correlation
Random errors in y-direction, sy/x = √∑(yi – yr)2
/(n - 2)
Standard deviation of intercept, sb = sy/x / √∑(xi – xm)2
Standard deviation of intercept, sa = sy/x√∑xi
2
/ (n∑(xi – xm)2
where yr = y residual and n = no of data points
Equations to calculate Limit of Detection and Limit of Quantification
Limit of Detection in the y-axis LOD = yB + 3SB where yB = a & SB = sa
Limit of Quantification in the y-axis LOQ = yB + 10SB

Page 23 of 89
CHART 1 – Fluoride Peak Area against Concentration
Chart 1 - Fluoride (Area) v Concentration
y = 0.0823x + 0.2520
R
2
= 0.9940
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
9.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 2 – Fluoride Peak Height against Concentration
Chart 2 - Fluoride (Height) v Concentration
y = 0.9371x + 4.9324
R
2
= 0.9857
0.000
20.000
40.000
60.000
80.000
100.000
120.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 24 of 89
CHART 3 – Chloride Peak Area against Concentration
Chart 3 - Chloride (Area) v Concentration
y = 0.0644x - 0.0178
R
2
= 0.9998
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 4 – Chloride Peak Height against Concentration
Chart 4 - Chloride (Height) v Concentration
y = 0.6509x - 0.1405
R
2
= 0.9998
0.000
10.000
20.000
30.000
40.000
50.000
60.000
70.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 25 of 89
CHART 5 – Nitrite Peak Area against Concentration
Chart 5 - Nitrite (Area) v Concentration
y = 0.0422x + 0.0345
R
2
= 0.9990
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 6 – Nitrite Peak Height against Concentration
Chart 6 - Nitrite (Height) v Concentration
y = 0.3437x + 0.6269
R
2
= 0.9971
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
40.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 26 of 89
CHART 7 – Sulphate Peak Area against Concentration
Chart 7 - Sulphate (Area) v Concentration
y = 0.0367x - 0.0125
R
2
= 0.9999
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 8 – Sulphate Peak Height against Concentration
Chart 8 - Sulphate (Height) v Concentration
y = 0.222x - 0.0364
R
2
= 0.9998
0.000
5.000
10.000
15.000
20.000
25.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 27 of 89
CHART 9 – Bromide Peak Area against Concentration
Chart 9 - Bromide (Area) v Concentration
y = 0.0268x - 0.0116
R
2
= 0.9999
0.000
0.500
1.000
1.500
2.000
2.500
3.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 10 – Bromide Peak Height against Concentration
Chart 10 - Bromide (Height) v Concentration
y = 0.1554x - 0.0977
R
2
= 0.9999
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 28 of 89
CHART 11 – Nitrate Peak Area against Concentration
Chart 11 - Nitrate (Area) v Concentration
y = 0.0352x - 0.0379
R
2
= 0.9990
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 12 – Nitrate Peak Height against Concentration
Chart 12 - Nitrate (Height) v Concentration
y = 0.177x - 0.0167
R
2
= 0.9996
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
20.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 29 of 89
CHART 13 – Phosphate Peak Area against Concentration
Chart 13 - Phosphate (Area) v Concentration
y = 0.0174x - 0.0229
R
2
= 0.9980
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
2.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
CHART 14 – Phosphate Peak Height against Concentration
Chart 14 - Phosphate (Height) v Concentration
y = 0.039x - 0.0472
R
2
= 0.9982
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 30 of 89
Table 3 – List of correlation coefficients & LOD/LOQ values for the seven anions
Correlation
Coefficient
(Area)
LOD
(Area)
LOQ
(Area)
Correlation
Coefficient
(Height)
LOD
(Height)
LOQ
(Height)
Fluoride 0.9970 3.64 12.12 0.9928 5.62 18.73
Chloride 0.9999 0.58 1.94 0.9999 0.63 2.09
Nitrite 0.9995 1.46 4.86 0.9986 2.51 8.37
Sulphate 0.9999 0.47 1.58 0.9999 0.60 1.99
Bromide 0.9999 0.57 1.90 0.9999 0.55 1.83
Nitrate 0.9995 1.44 4.81 0.9998 0.88 2.93
Phosphate 0.9990 2.06 6.86 0.9991 2.00 6.66
As can be seen from the table above, the correlation coefficients for all ions have correlation
coefficients of 0.99 or greater. All the ions appear to be linear over the standard concentration range
measured, however, the fluoride plot shows a slight non-linear and possibly poly-nominal relationship.
To investigate whether or not fluoride has a linear of poly-nominal correlation over this concentration
range the linearity analysis will be repeated.
The LOD/LOQ figures calculated from this analysis were far highly then expected. As is clear
from the chromatograms from the analysis, all the peaks for the seven anions are clearly visible and
easily integrated at the 2mg/L level. This would therefore suggest that an LOD of around 0.5mg/L or
less would have been applicable for the analysis.
To investigate the values of LOD & LOQ obtained, calculations were made to calculate LOD &
LOQ figures using the baseline signal to noise ratio (S/N). The values for S/N were taken from all the
standard injections between 15 & 20mins, averaged and the standard deviation calculated. These
values were then used to calculate a LOD/LOQ figure for the seven anions. However, because the
LOD/LOQ figures were calculated using the regression equation calculated from the peak areas and
heights, the values calculated were either negative values or higher values than those show above,
and therefore highly inaccurate figures.
As the analysis is to be repeated to check the linear relationship of the fluoride ion, it will
also be possible to compare values of LOD/LOQ. If as is seen here the LOD/LOQ values are on the high
side it maybe possible to surmise potential reason for this, and any methods of determining the true
value for Limit of Detection and Limit of Quantification of the method and system.
ANALYSIS 5 – Repeat Linearity/Determination of LOD/LOQ
As with the previous linearity analysis the data was tabulated and averaged, then used to
calculate the linear regression relationship for the areas and heights of the anions. Further
calculation were used to calculate the errors of the slope and intercept, and the LOD & LOQ for each
anion.
See tables 23 through 33 for the tabulated data for each anion, both for area and height
along with the errors and LOD/LOQ values. See below for the regression plots of the area and height
of the seven anions, along with there regression equations.

Page 31 of 89
y = 0.0677x + 0.2500
R
2
= 0.9923
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.8061x + 4.7185
R
2
= 0.9833
0.000
10.000
20.000
30.000
40.000
50.000
60.000
70.000
80.000
90.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 32 of 89
y = 0.0498x + 0.0412
R
2
= 0.9989
0.000
1.000
2.000
3.000
4.000
5.000
6.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.5108x + 0.5663
R
2
= 0.9984
0.000
10.000
20.000
30.000
40.000
50.000
60.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 33 of 89
y = 0.0341x + 0.0465
R
2
= 0.9981
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.2876x + 0.6246
R
2
= 0.996
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 34 of 89
y = 0.0285x + 0.0118
R
2
= 0.9996
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.1823x + 0.117
R
2
= 0.9993
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
20.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 35 of 89
y = 0.0203x - 0.0015
R
2
= 0.9997
0.000
0.500
1.000
1.500
2.000
2.500
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.1194x - 0.0189
R
2
= 0.9997
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 36 of 89
y = 0.0269x + 0.0024
R
2
= 0.9997
0.000
0.500
1.000
1.500
2.000
2.500
3.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.1364x + 0.1024
R
2
= 0.9988
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 37 of 89
y = 0.0121x - 0.0140
R
2
= 0.9973
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Area(us*min)
y = 0.0306x - 0.0478
R
2
= 0.9975
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
0.0 20.0 40.0 60.0 80.0 100.0 120.0
Concentration (ppm)
Height(us)

Page 38 of 89
Table 4 – List of Correlation Coefficients & LOD/LOQ values for the seven anions
Correlation
Coefficient
(Area)
LOD
(Area)
LOQ
(Area)
Correlation
Coefficient
(Height)
LOD
(Height)
LOQ
(Height)
Fluoride 0.9961 4.11 13.71 0.9916 6.08 20.27
Chloride 0.9994 1.58 5.28 0.9992 1.85 6.16
Nitrite 0.9990 2.05 6.82 0.9980 2.96 9.87
Sulphate 0.9998 0.95 3.17 0.9996 1.26 4.21
Bromide 0.9999 0.75 2.51 0.9998 0.82 2.73
Nitrate 0.9999 0.79 2.64 0.9994 1.61 5.36
Phosphate 0.9987 2.43 8.08 0.9987 2.34 7.81
As with the previous analysis the correlation coefficients for height and area for the seven
anions are 0.99 or greater. Again as per the previous analysis it can be said that all anions show a
linear relationship apart from Fluoride which again gives a slightly poly-nominal plot, rather than a
linear plot.
As with the previous linearity analysis the LOD/LOQ are higher then would be predicted, and
for this analysis a little higher then the previous one. Therefore, it can be said that the two linearity
experiments have not been giving the true values for LOD & LOQ, and that this analysis is slightly
worse then the previous. The higher values of LOD & LOQ along with the slightly worse values for
correlation coefficient, even through better then 0.99, shows a slightly poorer standard preparation
by the analyst.
Also as per the previous analysis the S/N ratio between 15 and 20mins, was measured and
used to calculate LOD/LOQ figures. Also as per previous analysis the figures were largely negative,
and therefore highly inaccurate.
The higher then expected values for Limit of Detection and Limit of Quantification could
possibly due to several factors which could be looked at in the following sets of analysis. They are;
i) A wide standard concentration range from 2mg/L to 100mg/L
ii) To many standards over this large concentration range
iii) Widely separated standard concentration values i.e. 50mg/L to 100mg/L
Therefore, during the next validation steps, the standard range could be reduced along with
the number of standards. This would result in 4 to 5 different standard concentrations being analysed,
over a shorter concentration range, such as 20 – 30mg/L. It is also possible that over the shorter
standard concentration ranges, the fluoride peak, both area and height, will give a more linear nature
rather then the poly-nominal one observed.
ANALYSIS 6 – 7 Day Stability
(See table 34 in appendices for the tabulated data)
The stability analysis was initially planned to run for 7 days with injections ever hour up to
6hrs, then ever 6hrs up to 36hrs and then one injection a day up to the 7 day limit. However, the
analysis was shopped after just 12hrs after a trend of increasing area & height was noted for all seven
anions. As can be seen from the trend plot below, table 34 (see appendices), or the chromatograms
themselves, the areas and heights of the peaks increase with every injection, even if taken from the
same vial. The effect is most noticeable for the Fluoride peak (the blue line on the trend plot below),
which has the largest area, and hence the largest increase.

Page 39 of 89
Chart 29 -Stability Plot of Peak Area over 12Hrs
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1 2 3 4 5 6 9 12
Hr
Area(us*min)
As this observed increase will have an effect on any and all analysis carried out, not just the
stability analysis, the factors causing it will be investigated, and hopefully eliminated. Those factors
may be;
(i) The use of glass volumetric flasks
(ii) The possible presence of residual detergent in the glassware
(iii) Carry over from the previous injections
(iv) Contamination of the system
The 7 day stability analysis will be repeated at a time when this problem has either been
solved or minimised.
ANALYSIS 7 – Accuracy
(See table 35 in appendices for the calculations & tabulated data)
Prior to the start of this analysis all glassware was rinsed with deionised water and 19% nitric
acid in order to remove any residual detergent from the interior walls. The IonPac AS11-HC column
and guard column had also been reversed and washed out with 10% methanol in water, in order to
wash any organic contaminate off the column. These two clean-up steps were to alleviate two of the
above factors, factor (ii) & (iv), which may have been causing the increasing area trend seen with the
7 day stability.
As can be seen from the results in table 5 below, the trend of increasing area and height per
injection has not been terminated. As the run has continued the area of the anions has increased,
with the effect of increasing percentage recovery when calculated using the areas of the standard
injections at the start of the run.
Table 5 – Determination of Method Accuracy via Spike Recovery
10mg/L Spike 5mg/L Spike
Fluoride 103.95% 109.70%
Chloride 118.02% 119.30%
Nitrite 124.31% 129.72%
Sulphate 126.27% 145.92%
Bromide 118.84% 125.75%
Nitrate 123.54% 123.83%
Phosphate 187.84% 218.92%
Although the results for the Fluoride and Chloride recoveries are slightly high but in the
expected range, as the run continues the percentage recovery increases. The effect is shown clearly

Page 40 of 89
for the phosphate peak, which because of its small size produces the highest percentage recovery at
219%.
Although two of the factors have seen to do little to change the trend of increasing peak
area, and factor (iii), carryover is unlikely, the first factor, the use of glassware may have a
significant effect. Therefore, the validation of the anion method will be stopped till plastic
volumetrics can be ordered, hence eliminating the use of glassware from the project.
(See table 36 in appendices for the calculations & tabulated data)
As can be seen from the experimental details, the stock 10,000mg/L solution and all
subsequent dilutions were re-prepared in PMP (Poly methyl Propylene) volumetric flasks. This should
hopefully eliminate the increasing area trend seen in previous analyses.
The results for the accuracy experiment seen in table 6 below show better results then seen
with the previous experiment, will all anions having expected recoveries within the 80 to 120% region.
The phosphate peak again has the highest percent recovery at 133 & 138%, but due to its extremely
small peak area these are acceptable results. Therefore, it can be said that the method is accurate
for all seven anions at the 10mg/L level.
Fluoride 84.24% 86.36%
Chloride 122.43% 112.15%
Nitrite 111.39% 113.92%
Sulphate 99.26% 83.70%
Bromide 110.34% 113.79%
Nitrate 110.72% 106.92%
Phosphate 133.33% 137.78%
See table 37 for tabulated stability data
From the stability trend plot below (Chart 30), as with the previous stability analysis, an
increase in peak area is seen with each new injection. However, in this case the area reaches a
constant value after 6 hours and was then stable up to 12hrs. After the 12hr injection the mobile
phase and the channel were changed, which as can be seen from the trend plot, has caused the area
for the 10mg/L standard top fall significantly.

Page 41 of 89
Chart 30 – Stability trend plot for the seven anions
Chart 30 -Stability Plot for 10ppm Standard
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
1 2 3 4 5 6 7 9 12 18 24 30 36 48 72 96 120 144 168
Hr
Area(us*min)
FLUORIDE
CHLORIDE
NITRITE
SULPHATE
BROMIDE
NITRATE
PHOSPHATE
The trend is repeated over the course of the next five days with the area rising until the
time when the mobile phase is changed and then the peak area falls. The mobile phase changes occur
at 12hr, 48hr & 120hr with the following injections area decreasing significantly, while all other
injections show an increase in area over the previous one. The increase over the five days may be due
to the system not being completely settled after the mobile phase change and the numerous reduced
phase injections prior to the standard injection.
Although the stability trend plot after the 12hr point is very inconsistent and shows
significant variation, the area for the final time point at 168hr has a peak area similar to that of those
at 5, 6, 7, 9 & 12 hours. While this is less then a perfect stable trend, because the last time point has
a similar peak area to those at the start when the trend plot was stable, it could be stated that the
10mg/L standard was stable over the 7 day period, and hence the solutions could be said to have a 7
day expiry.
ANALYSIS 9 – Reproducibility
See below the regression plots of area & height, for the seven anions run on an alternative system.

Page 42 of 89
y = 0.1049x + 0.0197
R
2
= 1.0000
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
y = 1.4118x + 0.5755
R
2
= 0.9998
0.000
5.000
10.000
15.000
20.000
25.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 43 of 89
y = 0.0652x + 0.0003
R
2
= 0.9999
0.000
0.200
0.400
0.600
0.800
1.000
1.200
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
y = 0.6678x + 0.0411
R
2
= 0.9999
0.000
2.000
4.000
6.000
8.000
10.000
12.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 44 of 89
y = 0.0474x + 0.0152
R
2
= 0.9999
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
y = 0.4162x + 0.0869
R
2
= 0.9999
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 45 of 89
y = 0.0385x + 0.0079
R
2
= 0.9998
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
y = 0.2569x + 0.056
R
2
= 0.9998
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 46 of 89
y = 0.0284x - 0.0044
R
2
= 0.9997
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
y = 0.164x - 0.026
R
2
= 0.9998
0.000
0.500
1.000
1.500
2.000
2.500
3.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 47 of 89
y = 0.0366x - 0.0055
R
2
= 0.9997
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0
Concentration (ppm)
Area(us*min)
y = 0.1901x - 0.0159
R
2
= 0.9998
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0
Concentration (ppm)
Height(us)

Page 48 of 89
y = 0.0204x + 0.0027
R
2
= 0.9999
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
y = 0.0529x - 0.0008
R
2
= 0.9999
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 49 of 89
In order to show reproducibility the standard solutions linearity was reanalysed on an
alternate Ion Chromatographic system. The data from the analysis of the standards on this alternate
system, when tabulated and averaged was again used to generate another set of linear regression
equations, along with the linear plots for each anion.
See tables 38 through 46 for the tabulated data for each anion, both for area and height
along with the errors and the LOD/LOQ values. Table 7 below has the correlation coefficient values
for each set of data along with the calculated values of LOD & LOQ.
Table 7 – List of Correlation Coefficients & LOD/LOQ values for the seven anions
Correlation
Coefficient
(Area)
LOD
(Area)
LOQ
(Area)
Correlation
Coefficient
(Height)
LOD
(Height)
LOQ
(Height)
Fluoride 1.0000 0.08 0.28 0.9999 0.21 0.71
Chloride 0.9999 0.16 0.54 0.9999 0.17 0.57
Nitrite 0.9999 0.15 0.51 1.0000 0.12 0.41
Sulphate 0.9999 0.19 0.63 0.9999 0.18 0.60
Bromide 0.9999 0.23 0.77 0.9999 0.22 0.73
Nitrate 0.9999 0.28 0.92 0.9999 0.19 0.63
Phosphate 0.9999 0.17 0.57 0.9999 0.17 0.55
The correlation coefficients obtained for all seven anions, both area and height, gave values
of 0.9999 or better. This showed that not only was the method reproducible on more then one
instrument, but that a smaller concentration range, than the previous analysis, better linearity was
obtained.
As stated earlier with the previous linearity analysis, more precise values for the LOD and
LOQ could be obtained if the standard concentration range was reduced, along with fewer standards.
This analysis was carried out with only four standard concentrations, with a range of 2 to 15mg/L.
The result of this is that the LOD values obtained are all of the order of 0.1 to 0.3mg/L, both for
height and area calculations. These values are fair better and lower than those seen previously and
hence can be deemed to be the closest to, if not the true values for the anions LOD & LOQ. It can
therefore be said that the anion method is not only precise, linear, stable, accurate & reproducible,
but also that it has a limit of detection of 0.1 to 0.3mg/L (100 to 300ppb), and a limit of
quantification of 0.3 to 0.9mg/L (300 to 900ppb).
As the method is now validated, water samples can be analysed to determine the levels of
the seven anions present.
See tables 47 through 54 for the tabulated data both standard and sample for each anion,
along with the linear regression errors and LOD/LOQ values. See below for the regression plots of the
standard areas for the seven anions, along with their regression equations.

Page 50 of 89
CHART 45 – Fluoride Peak Area against concentration
y = 0.0491x - 0.0155
R
2
= 0.9961
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
0.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
CHART 46 – Chloride Peak Area against concentration
y = 0.0312x - 0.0051
R
2
= 0.9997
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)

Page 51 of 89
CHART 47 – Nitrite Peak Area against concentration
y = 0.0230x - 0.0061
R
2
= 0.9995
0.000
0.050
0.100
0.150
0.200
0.250
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
CHART 48 – Sulphate Peak Area against concentration
y = 0.0180x + 0.0013
R
2
= 0.9998
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
0.200
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)

Page 52 of 89
CHART 49 – Bromide Peak Area against concentration
y = 0.0132x - 0.0043
R
2
= 0.9996
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
CHART 50 – Nitrate Peak Area against concentration
y = 0.0184x - 0.0049
R
2
= 0.9997
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
0.200
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)

Page 53 of 89
CHART 51 – Phosphate Peak Area against concentration
y = 0.0086x - 0.0017
R
2
= 0.9998
0.000
0.010
0.020
0.030
0.040
0.050
0.060
0.070
0.080
0.090
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
As can be seen from the regression plots above, the standards are linear for all seven anions,
with correlation coefficients of 0.99 or better. The regression calculations also gave values for the
analysis LOD of between 0.2 to 0.4mg/L for all, but fluoride which has a value of 1.1mg/L. Therefore,
values obtained above the LOD will be reported in the table below
Table 8 – Levels of Anions in the 9 water samples by IC
Sample Location/Type Fluoride Chloride Nitrite Sulphate Bromide Nitrate Phosphate
1 K9 Lab 1 Tap Water 0.83 46.99 0.39 256.6 ND 3.51 ND
2
K43 DI Water
(Back Millipore Unit)
ND 0.23 ND 0.37 ND ND ND
3
K43 DI Water
(Middle Millipore Unit)
4 K43 Tap Water 0.85 48.14 ND 258.13 ND 5.03 1.47
5
QC Sev. Lab Elga
System
6
QC Raw Mat. Lab Elga
System
7 VWR HiPerSolv Water ND 0.20 ND 0.15 ND ND ND
8 VWR Normapur Water ND 0.24 ND 0.15 ND ND ND
9 VWR AnalaR Water ND ND ND 0.15 ND ND ND
ND – Not Detected results in mg/L (ppm)
The levels of the anions seen in the water samples were as would be predicted, with very
little, if anything seen in the DI water (Samples 2, 3, 5 & 6) or in the purchased water samples
(Samples 7, 8 & 9), while large peaks were detected for Chloride and Sulphate in the tap water
(Sample 1 & 4). Small levels of Chloride and Sulphate were also seen in the DI and purchased water
samples, just about at the limit of quantification for the method.

Page 54 of 89
Cation Analysis
ANALYSIS 1 – Investigation of Method
As the only cation column present in the laboratory were IonPac CS14 IC columns, the
literature search was made for methods utilizing this guard and analytical column set. The literature
search revealed that the best separation of the six cations of interest would be to couple two
separate method together, both of which had been developed by Dionex and which were taken from
the CS14 product manual. The first method was a straight isocratic method giving good separation of
the Ammonium, Potassium, Magnesium & Calcium peaks, while the second method was a gradient
elution method, giving good separation of Lithium & Sodium peaks.
The two methods were tested separately and then combined to see which of the two or
combined would give the best separation. Unfortunately, although run, the gradient elution method
gave no definite peak shapes, due to the large increase in the baseline, due to the changing mobile
phase composition. The first method gave fairly good separation with a slight overlap of the lithium-
sodium peaks, as was predicted from the column product manual. The retention times and resolution
for the six cations from this method were:
Ret Time Resolution
Lithium 3.53mins 1.465
Sodium 3.85mins 2.190
Ammonium 4.50mins 2.814
Potassium 5.50min 7.362
Magnesium 9.01mins 2.324
Calcium 10.53mins -
Above is a chromatogram obtained using the isocratic method, and as can be seen from the
retention times and the chromatogram the separation of the peaks is fairly good with all the peaks
apart from Lithium having resolutions greater than 2.
In order of see if the separation of the Lithium-Sodium peak could be improved the mobile
phase composition was changed from 10mM MSA to 5mM MSA. This had the effect of increasing all the
retention times, such that calcium, the last peak had a retention time of approximately 27mins, and
was very close to the end of the chromatogram. The separation of the Lithium-Sodium peaks was very
slightly improved, but still gave a slight overlap. As this change in mobile phase composition only had
a slight change in the separation of these two peaks, but at the chose of doubling the run time, it was
decided that the separation with 10mM MSA, as seen above, was satisfactory for the method.
As the method parameters had been decided upon, it was now necessary to determine the
Accuracy, Specificity, Stability & Reproducibility of the method, along with the Limit of Detection
(LOD) and Limit of Quantification (LOQ).
ANALYSIS 2 – Linearity of Method
As the anion linearity has shown that the 2 to 100mg/L range of standard calibration gave
erroneous and untrue LOD and LOQ figures, the cation linearity calibration was carried out using the
range 2 to 30mg/L

Page 55 of 89
See tables 55 through 62 for the tabulated data along with errors/LOD/LOQ values calculated
using the below equations, along with the charts below showing the linearity of the standard
concentrations for each ion.
Equations to calculate Linear Regression & Correlation
Correlation Coefficient r = ∑{xi – xm)(yi – ym)}
√{[∑(xi – xm)2
][∑(yi – ym)2
]}
b = ∑{(xi – xm}(yi – ym)}
∑{xi – xm)2
a = ym - bxm
where xm = x mean & ym = y mean
Equations to calculate the errors for Linear Regression & Correlation
Random errors in y-direction, sy/x = √∑(yi – yr)2
/(n - 2)
Standard deviation of intercept, sb = sy/x / √∑(xi – xm)2
Standard deviation of intercept, sa = sy/x√∑xi
2
/ (n∑(xi – xm)2
where yr = y residual and n = no of data points
Equations to calculate Limit of Detection and Limit of Quantification
Limit of Detection in the y-axis LOD = yB + 3SB where yB = a & SB = sa
Limit of Quantification in the y-axis LOQ = yB + 10SB

Page 56 of 89
CHART 52 – Lithium Peak Area against Concentration
Chart 52 - Lithium (Area) v Concentration
y = 0.6834x - 0.8199
R
2
= 0.9989
0.000
5.000
10.000
15.000
20.000
25.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Area(us*min)
CHART 53 – Lithium Peak Height against Concentration
Chart 53 - Lithium (Height) v Concentration
y = 3.8939x + 1.371
R
2
= 0.9962
0.000
20.000
40.000
60.000
80.000
100.000
120.000
140.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Height(us)

Page 57 of 89
CHART 54 – Sodium Peak Area against Concentration
Chart 54 - Sodium (Area) v Concentration
y = 0.2397x - 0.0926
R
2
= 0.9995
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Area(us*min)
CHART 55 – Sodium Peak Height against Concentration
Chart 55 - Sodium (Height) v Concentration
y = 1.6366x - 0.5929
R
2
= 0.9994
0.000
10.000
20.000
30.000
40.000
50.000
60.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Height(us)

Page 58 of 89
CHART 56 – Ammonium Peak Area against Concentration
Chart 56 - Ammonium (Area) v Concentration
y = 0.1145x + 0.3378
R
2
= 0.9881
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Area(us*min)
CHART 57 – Ammonium Peak Height against Concentration
Chart 57 - Ammonium (Height) v Concentration
y = 0.3837x + 2.0444
R
2
= 0.9732
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Height(us)

Page 59 of 89
CHART 58 – Potassium Peak Area against Concentration
Chart 58 - Pottasium (Area) v Concentration
y = 0.1545x - 0.1392
R
2
= 0.9996
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
5.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Area(us*min)
CHART 59 – Potassium Peak Height against Concentration
Chart 59 - Potassium (Height) v Concentration
y = 0.6443x - 0.6627
R
2
= 0.9993
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
20.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Height(us)

Page 60 of 89
CHART 60 – Magnesium Peak Area against Concentration
Chart 60 - Magnesium (Area) v Concentration
y = 0.4164x - 0.4589
R
2
= 0.9991
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Area(us*min)
CHART 61 – Magnesium Peak Height against Concentration
Chart 61 - Magnesium (Height) v Concentration
y = 1.0347x - 0.8951
R
2
= 0.9998
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Height(us)

Page 61 of 89
CHART 62 – Calcium Peak Area against Concentration
Chart 62 - Calcium (Area) v Concentration
y = 0.2712x - 0.2981
R
2
= 0.9991
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
9.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Area(us*min)
CHART 63 – Calcium Peak Height against Concentration
Chart 63 - Calcium (Height) v Concentration
y = 0.5613x - 0.5175
R
2
= 0.9997
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Concentration (ppm)
Height(us)

Page 62 of 89
Table 9 – List of Correlation Coefficients & LOD/LOQ values for the sic cations
Correlation
Coefficient
(Area)
LOD
(Area)
LOQ
(Area)
Correlation
Coefficient
(Height)
LOD
(Height)
LOQ
(Height)
Lithium 0.9994 1.07 3.57 0.9981 1.97 6.58
Sodium 0.9998 0.69 2.29 0.9997 0.76 2.54
Ammonium 0.9941 3.49 11.64 0.9865 5.29 17.63
Potassium 0.9998 0.64 2.15 0.9997 0.84 2.79
Magnesium 0.9996 0.94 3.12 0.9999 0.40 1.33
Calcium 0.9995 0.96 3.20 0.9998 0.52 1.73
The correlation coefficients for the plots all had values of 0.99 or higher, apart from the plot
of peak height for the ammonium peak. A possible reason for this slightly lower value then the other
cations is that, like fluoride in the anion analysis, the ammonium peak has a slight non-linear plot,
which could be called poly-nominal in nature. As with Fluoride in the anion analysis, the linear
regression for the ammonium ion may be of a more linear nature when plotting four concentrations,
rather then the seven for this analysis.
The values obtained for the LOD & LOQ for each ion are slightly higher then expected, as
they were in the anion analysis, while the ammonium peak, due to its slight poly-nominal nature has
very high values.
Even through the ammonium plot could be poly-nominal, the plots for the cations have
shown that the cation method is linear over the range 2 to 30mg/L. The LOD and LOQ figures will be
recalculated from the standard areas used during the sample analysis, which should give more
accurate and truer values.
(See table 63 in appendices for the calculation & tabulated data)
In table 10 below are the percentage recovery results for the cation spiking experiment.
These show that for five of the six cations, the recovery percentage was within the 80 to 120% range
expected for this analysis. The only exception was the ammonium peak, which gave values of 61 &
58%. The reason for this lower then expected recovery is unclear, and may be due to the linear
relationship seen in the previous analysis
Of the six cations of interest, the less likely cation to be found in water samples would be
the ammonium ion. Therefore, although it would be nice to say that the method is accurate for all
ions, in this case, it can be stated that apart from ammonium, the cation method is accurate at the
10mg/L level.
Lithium 102.32% 111.36%
Sodium 90.37% 82.23%
Ammonium 61.69% 58.37%
Potassium 92.71% 91.77%
Magnesium 102.88% 101.22%
Calcium 107.60% 104.37%
The stability plot for the seven cations, over the seven day period, shows a downward trend
after the 12 hour time point. As ion the anion stability analysis, the 12 hr time point at which the
mobile phase and channel were changed, so as extend the run time. However unlike the anion
analysis, the peak area continues to fall, until the 36hr point, at which time the mobile phase was
changed again. This time the area went up and down over the next 5 days, as well as containing the
one further change of mobile phase.
(See table 64 in appendices for the tabulated stability data)

Page 63 of 89
CHART 64 – Stability Plot of Cation Standards
Chart 64 -Stability Plot of 10ppm Standard
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
9.000
1 2 3 4 5 6 9 12 18 24 30 36 48 72 97 121 144
Hr
Area(us*min)
LITHIUM
SODIUM
AMMONIUM
POTASSIUM
MAGNESIUM
CALCIUM
The mobile phase change appears to have a significant effect on the IC system, which as a
result, affects the peak area. The sharp decrease in peak area was also seen for the anion stability
analysis, but due to the increasing peak area trend seen for the anions, the peak area increased. No
such trend has been seen for the cations, hence a steady decrease was observed. As a result of this
observed decrease the last time point at 168 hours was not run, as there seemed little point adding
another point to, what seems to be a failing analysis.
From the trend data above it could be stated that the stability data for the cation standard
solutions would point to their degradation after 12 hours. However, because of the mobile phase
effect on the system and peak area, it is unclear whether or not the solutions are stable. As a result it
can be stated that the cation solutions are stable up to 12 hours, and to determine if they are stable
beyond this point, the analysis needs to be repeated in such a way as to eliminate the mobile phase
change effecting the system.
ANALYSIS 4 – Reproducibility
As with the anion method, the cation method and anion method were swapped from one
system to the other. The data from the analysis on this alternate system, when tabulated and
averaged was again used to generate another set of linear regression equations, along with the linear
plots for each cation.
See tables 65 through 72 for the tabulated data for each cation, and the regression plots
below for standard heights and areas of the six cations

Page 64 of 89
y = 0.6810x + 0.0003
R
2
= 0.9997
0.000
2.000
4.000
6.000
8.000
10.000
12.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
CHART 66 – Lithium Peak Height against Concentration
Chart 66 - Lithium (Height) v Concentration
y = 3.6753x + 0.1916
R
2
= 0.999
0.000
10.000
20.000
30.000
40.000
50.000
60.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 65 of 89
y = 0.2702x + 0.2004
R
2
= 0.9999
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
CHART 68 – Sodium Peak Height against Concentration
Chart 68 - Sodium (Height) v Concentration
y = 1.3486x + 0.6843
R
2
= 0.9999
0.000
5.000
10.000
15.000
20.000
25.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 66 of 89
y = 0.1402x + 0.2498
R
2
= 0.9919
0.000
0.500
1.000
1.500
2.000
2.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
CHART 70 – Ammonium Peak Height against Concentration
Chart 70 - Ammonium (Height) v Concentration
y = 0.3932x + 1.1225
R
2
= 0.9777
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 67 of 89
Chart 71 - Potassium (Area) v Concentration
y = 0.1572x + 0.0044
R
2
= 0.9994
0.000
0.500
1.000
1.500
2.000
2.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
CHART 72 – Potassium Peak Height against Concentration
Chart 72 - Potassium (Height) v Concentration
y = 0.4666x - 0.003
R
2
= 0.9996
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 68 of 89
y = 0.4199x - 0.0406
R
2
= 0.9993
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
CHART 74 – Magnesium Peak Height against Concentration
Chart 74 - Magnesium (Height) v Concentration
y = 0.7762x + 0.0841
R
2
= 0.9984
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 69 of 89
y = 0.2633x - 0.0641
R
2
= 0.9990
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Area(us*min)
CHART 75 – Calcium Peak Height against Concentration
Chart 76 - Calcium (Height) v Concentration
y = 0.4167x - 0.0325
R
2
= 0.9983
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Concentration (ppm)
Height(us)

Page 70 of 89
In table 11 below the values for the correlation coefficients and LOD/LOQ figures for the six
cations
Table 11 – List of correlation coefficients & LOD/LOQ values for the six cations
Correlation
Coefficient
(Area)
LOD
(Area)
LOQ
(Area)
Correlation
Coefficient
(Height)
LOD
(Height)
LOQ
(Height)
Lithium 0.9998 0.26 0.88 0.9995 0.45 1.49
Sodium 0.9999 0.15 0.51 0.9999 0.16 0.54
Ammonium 0.9960 1.27 4.23 0.9888 2.13 7.10
Potassium 0.9997 0.34 1.12 0.9998 0.27 0.89
Magnesium 0.9997 0.37 1.23 0.9992 0.57 1.90
Calcium 0.9995 0.44 1.48 0.9991 0.59 1.97
All the regression plots have correlation coefficients of 0.99 or greater, and the LOD values
for the peak areas are around 0.2 to 0.4mg/L, apart from Ammonium which has an LOD of 1.3mg/L.
As with the anion method, the more accurate and truer LOD values for each ion is calculated using
only four standard concentrations over a smaller concentration range, in this case 2 to 14mg/L.
From the analysis it can stated that the cation method is linear, specify and accurate (apart
from the Ammonium ion), reproducible and stable for 12 hours. Also the method LOD for five of the
six ions is around the 0.3mg/L, apart from the ammonium ion, which because of its slight poly-
nominal relationship, has a higher value.
As the cation method is now deemed to be validated, water samples can now be analysed
and quantified.
See tables 73 through 79 for the tabulated data for both standard and sample, along with the
linear regression errors and LOD/LOQ values. Below are the regression plots for the peak areas of the
six cations with their regression equations.

Page 71 of 89
y = 0.5871x - 0.0846
R
2
= 0.9997
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
y = 0.2198x + 0.1397
R
2
= 0.9966
0.000
0.500
1.000
1.500
2.000
2.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)

Page 72 of 89
y = 0.1440x + 0.0988
R
2
= 0.9963
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.800
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
Chart 80 - Potassium (Area) v Concentration
y = 0.1302x - 0.0201
R
2
= 0.9997
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)

Page 73 of 89
y = 0.3528x - 0.0950
R
2
= 0.9999
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)
y = 0.2174x - 0.0885
R
2
= 0.9999
0.000
0.500
1.000
1.500
2.000
2.500
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Concentration (ppm)
Area(us*min)

Analysis of Water Samples for Anions & Cations using Ion Chromatography & ICP-OES

Analysis of Water Samples for Anions & Cations using Ion Chromatography & ICP-OES

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