This document provides an outline and overview of standard methods for laboratory analysis. It discusses topics such as statistics, quality assurance, data quality, sample collection and preservation, analytical laboratory techniques, reagent water requirements, and health and safety practices. Specific statistical concepts covered include normal distribution, confidence intervals, outliers, and quality control calculations. The document also describes methods for evaluating data quality, measurement uncertainty, detection limits, and checking the correctness of analyses. Safety protocols for hazardous chemicals, emergency equipment, and waste disposal are also outlined.

1. CHAPTER 1
STANDARD METHODS
Katie Indarawis

2. TABLE OF CONTENTS (OUTLINE)
 Statistics
 Quality Assurance (Quality Control and Quality
assessment)
 Data Quality
 Method Development and Evaluation
 Expression of results
 Collection and preservation of samples
 Reagent Water
 Health and Safety
 Waste minimization and disposal

3. STATISTICS
 Normal Distribution
 Standard Normal Curve
 Confidence Interval
 Standard error
 Relative standard deviation or Coefficient of
variation
 Outliers

4. STATISTICS: CONFIDENCE INTERVALS
 Typically small sample sizes, so confidence intervals
of the mean are expressed as:
 Where t has the following values for 95% confidence
limits:
1010 B

5. STATISTICS: NORMAL DISTRIBUTION
 Standard Deviation – spread of the distribution
1010 B

6. STATISTICS: RELATIVE ST. DEV. (CV)
 Relative Standard Deviation (or coefficient of
variation) – expressed as a percentage
 Normalizes the standard deviation
 Measure of variability
1010 B

7. STATISTICS: OUTLIERS
 Outliers
 Compare the value of T to a t-test table at either a 1% or
5% level of significance (if T is larger than t-test
statistic, then the value is an outlier).
1010 B

8. TABLE 1010:I

9. QUALITY ASSURANCE
 A set of operating rules:
 Standard operating procedures (SOP)
 Training requirements
 Number of analyses required
 Equipment preventative maintenance procedures
 Calibration procedures, corrective actions, internal quality
control activities, performance audits, and data
assessments for bias and precision.
1020 A

10. QUALITY CONTROL
 Certification of operator competence
 Recovery of known additions
 Analysis of externally supplied standards
 Analysis of reagent blanks
 Calibration with standards
 Analysis of duplicates
 Maintenance of control charts
1020 B

11. QUALITY CONTROL (QC) CALCULATIONS
 Initial calibrations:

12. QC CALCULATIONS
 Calibration verification

13. QC CALCULATIONS
 Duplicate sample:

14. CONTROL CHARTS

15. QUALITY ASSESSMENT
 Using internal and external quality control measures
 Includes:
 Laboratory check samples
 Laboratory intercomparison samples
 Compliance audits
 Internal QC described previously
 Applied to test the recovery, bias, precision, detection
limit, and adherence to SOP requirements
1020 C

16. DATA QUALITY
 Indicators of data quality are bias and precision (when
combined, express its accuracy)
1030 A

17. BIAS VS PRECISION
 Bias – A measure of systematic error (part from the
method, part from the lab’s use of the method)
 Precision –
Measure of the
closeness with
which multiple
analysis of a given
sample agree with
one another. OR,
random error.
1030 A

18. MEASUREMENT UNCERTAINTY
 Biases that can occur in the system of analysis:
 Weighing a sample
 Result produced by the analytical instrument
 Changes in quality of reagents
 Incomplete extraction
 Generally the instrumental and extraction biases (B) are
the greatest, so the equation simplifies to:
 To express with 95% confidence:
1030 B

19. MEASUREMENT UNCERTAINTY
 Combined concepts of repeatability and
reproducibility (Gage R&R):
1030 B

20. METHOD DETECTION LIMIT
 The smallest amount that can be detected above
the noise in a procedure and within a stated
confidence limit is a detection limit.
 The confidence limits are set to reduce Type I and
Type II errors.
 Instrument Detection Limit (IDL)
 Lower Limit of Detection (LLD)
 Method Detection Limit (MDL)
 Limit of Quantitation (LOQ)
1030 C

21. DATA QUALITY OBJECTIVES
 Stating the issue
 Reason for performing analysis
 Identifying possible decisions and actions
 Specific to the research questions
 Identifying inputs
 Identify what information is needed
 Identifying study limits
 Logistical issues, time frame, geographical location, etc.
 Developing a decision rule
 Define the parameter, threshold values, criteria for action
 Specifying limits on decision errors
 Sample design errors, measurement errors – Use hypothesis
testing
 Optimizing the design for collection
 Identify the most resource-effective design for the study
1030 D

22. CHECKING CORRECTNESS OF ANALYSES
 Anion-Cation Balance (electrically neutral)
 Measured TDS = Calculated TDS
 Acceptable ratio:
 Measured EC = Calculated EC
 Acceptable ratio:
 Measured EC and Ion Sums
 100 * anion (or cation) sum, meq/L = (0.9-1.1) EC
 Calculated TDS to EC Ratio
 Calculated TDS/conductivity = 0.55-0.7
 Measured TDS to EC Ratio
 Acceptable ratio is from 0.55-0.7
1030 F

23. UNITS
 Record only the significant figures
 In solid samples and liquid wastes of high specific
gravity, make a correction if the results are
expressed as ppm or % by weight:
1050 A

24. SIGNIFICANT FIGURES
 Ambiguous zeros
 If a buret is read as “23.60 mL”, the zero should not be
dropped b/c the analyst took the trouble to estimate the
second decimal place.
 Standard deviation
 Round off data points based off of the standard deviation
 Calculations
 When multiplying or adding numbers, round to the number that
limits the accuracy of the number the most (the “weakest link
in the chain”)…the one with the least number of significant
figures
1050 B

25. COLLECTION/PRESERVATION OF SAMPLES
 Rinse bottle 2-3 times before filling (unless there is a
preservative or dechloronating agent)
 Leave 1% air space if shipping, etc.
 Do not remove suspended solids from the sample, but
treat them appropriately
 Lakes and reservoirs are subject to considerable
variations – choose location, depth, and frequency with
care
 Avoid turbulent sampling locations
1060 A

26. COLLECTION/PRESERVATION OF SAMPLES
 General precautions
 Safety considerations (beware of toxic substances)
 Types of samples
 Grab samples
 Composite samples
 Integrated samples
 Sampling Methods
 Manual sampling
 Automatic sampling
 Sorbent sampling
 Sample containers
1060 A

27. TYPES OF SAMPLES
 Grab – use when a source is known to be constant in
composition over a considerable period of time or over a
substantial distance in all directions
 Composite samples (time composite) – most useful for
determining average concentrations, usually over a 24 hr
period.
 Integrated samples – most useful when you need a
maxima and minima
1060 B

28. NUMBER OF SAMPLES
Where:
N = number of samples
t = Student-t statistic for a
given confidence level
s = overall standard
deviation
U = acceptable level of
uncertainty
1060 B

29. SAMPLE PRESERVATION
 Nature of sample changes
 Know your sample and how it interacts with its environment
 Time interval between collection and analysis
 For composite samples, use the end of the composite
collection as sample time
 Depends on the character of the sample, the analysis to be
made, and the conditions of storage
 Preservation techniques
 Most of the time, storage at 4ᴼC is recommended
 Refer to Table 1060:I
1060 C

30. LABORATORY APPARATUS
 Refer to Table 1060:I to make sure you are using the
appropriate material for storage
 For general lab use, borosilicate glass is most suitable
 Use class A volumetric glassware for accurate work
 Dry all anhydrous reagent chemicals in an oven at 105-
110ᴼC for at least 24 hrs (preferably overnight) and cool
in a desiccator
 “1 + 9 HCl” denotes that 1 volume of concentrated HCL is
to be diluted with 9 volumes of DI
1060 A-C

31. LABORATORY TECHNIQUES
 Ion Exchange
 Colorimetric Determinations
 Other methods
 Atomic absorption spectrometry
 Flame photometry
 Inductively coupled plasma (ICP)
 Potentiometric titration
 Selective ion electrodes
 Gas chromatography (GC) or GC-mass spec (GCMS)
 Continuous-flow analysis
 Ion chromatography
1070 D

32. REAGENT-GRADE WATER
 Reverse osmosis, distillation, and deionization in
various combinations can produce reagent-grade
water
 Ultrafiltration and/or UV treatment may also be
used as part of the process
 High – Use in test methods requiring min
interference and bias and max precision
 Medium – The presence of bacteria can be
tolerated. Used for the preparation of
dyes, reagents, and staining.
 Low – Used for glassware washing, etc.
1080 A-C

33. SAFETY EQUIPMENT
LAB EQUIPMENT: PERSONAL
PROTECTIVE
 Fire extinguishers
 Fire blankets
EQUIPMENT:
 Safety showers • Clothing
 Eye washes
• Gloves
 Safety Shields
 Safety containers
• Safety shoes
 Storage facilities • Safety glasses
 Laboratory fume hoods • Respirators
 Chemical spill kits
 Safety wall chart
1090 B

34. LABORATORY HAZARDS
 Prohibit eating, drinking and smoking
 Avoid floor clutter so escape routes and fire extinguishers
aren’t blocked
 Chemical Hazards (next slide)
 Biological Hazards (properly dispose of pipette tips, clean
tabletops, autoclave for sterilization, etc.)
 Radiation Hazards (shield UV lights)
 Physical Hazards (electrical, mechanical, & compressed
gases)
1090 C

35. CHEMICAL HAZARDS
 Avoid splashing or container spills
 Inorganic acids and bases
 Store acids and bases separately
 Do everything in the fume hood
 Add acids/bases to water (not vice versa)
 Leather will hold acids/bases & continue to burn if reworn
 Flush eyes for 15 min, if eye contact occurs
 Metals and inorganic compounds
 In general, consider all lab chemicals as hazardous and use
only as prescribed
 Organic solvents and reagents
1090 C

36. HAZARD MANAGEMENT PRACTICES
 Properly label hazardous waste containers
 Provide fire protected storage
 Use metal safety cans for waste solvents and
segregating incompatible materials
 Check the MSDS before using new chemicals
1090 D

37. QUESTIONS?