Autolab Instruments
in Environmental Research
Environmental applications
• Determination of Heavy metals
• Determination of organics pollution elements
• Preparations o...
We found 8366 Articles
Using Autolab equipments on
environmental applications
Environmental applications
Methods Electrodes
Development
ImunosensorsBiosensors
• Differential pulse voltammetry
• Square wave voltammetry
• Cyclic Voltammetry
• Chrono amperometry
• Potentiometric stri...
• Mercury Electrode
• Solid state electrode: Graphite, Platinum,
• Special deposition/modification electrodes
• Screen pri...
• Biosensors: Chrono Amperometry, Flow injection, DP
amperometry
• Imunosensors: same as biosensors
• Screen print electro...
Heavy metals Organics elements
Determination
• Differential pulse voltammetry
• Square wave voltammetry
• Chrono amperomet...
Hardware
NON MODULAR INSTRUMENT
MODULAR INSTRUMENTS
PGSTAT 101 Autolab Type III/FRA2
PGSTAT302N / PGSTAT128N PGSTAT100
- Software -
Cyclic Voltammetry
Linear sweep voltammetry
Differential pulse voltammetry
Square wave voltammetry
Direct cur...
- Software -
FRA
GPES
All includes in NOVA
Alternative current voltammetry
Potentiometric stripping analysis
Multimode ele...
Voltammetric Analysis
SMDE
Stable surface
Needle
Capillary
Tapper
Hg drop
DME
Droplife
New Drop
Electrode types in Voltammetric Analysis
Voltamm...
Electrode types in Voltammetric Analysis
MME
Multi Mode Electrode
SMDE
DME
HMDE
GC
Au
Ag
Pt
UT
RDE
Rotating Disc Electrode
Multi Mode Electrode
Precise and safe control of the Hg
drop electrode
Multi Mode Electrode
• Hg drop
–DME
–SMDE
–HDME
Possibility of determinations with DP and SQW
• Sb 500 ppt
• As 100 ppt
• Pb 10 ppt
• Cd 10 ppt
• Cr 25 ppt
• Fe 200 ppt
• Co 50 ppt
• Cu 50 ppt
• Rh 0.1 ppt
• Hg 100 p...
Normal Pulse Voltammetry
Voltammetric Analysis
Normal Pulse Voltammetry
• Dropping Mercury Electrode (DME):
Improved sensitivity compared to classical DC
polarography
• ...
Normal Pulse Voltammetry
Cd2+ measurement in acetate/KCl solution pH=4.9
Voltammetric Analysis
Differential pulse voltammetry (DPV)
Voltammetric Analysis
Differential pulse voltammetry
current measurement
Current is the difference between 2 and 1
Voltammetric Analysis
W1/2
E0
Differential pulse voltammetry
Voltammetric Analysis
Differential pulse voltammetry
• Currents will only be measured close to E0
• W½ = 90.4/n mV if the pulse height is small
...
Differential pulse voltammetry
Voltammetric Analysis
measurement in acetate/KCl solution, pH=4.9
Differential pulse voltammetry
Voltammetric Analysis
measurement in acetate/KCl solution, pH=4.9
Differential pulse voltammetry
Voltammetric Analysis
measurement in acetate/KCl solution, pH=4.9
Square Wave Voltammetry
Square wave is applied on top of a DC scan
Voltammetric Analysis
Square wave voltammetry Measurement
•The displayed result is the difference between
a forward and backward current.
•Iforw...
Square Wave Voltammetry
The best choice for analytical purposes:
• Background current cancellation (same as DPV)
• Slightl...
Square Wave Voltammetry
Cd2+ measurement in acetate/KCl solution pH=4.9
Voltammetric Analysis
SQW Voltammetry
DP Voltammetry
Cd2+ measurement in acetate/KCl solution pH=4.9
Voltammetric Analysis comparison:
Differential Normal Pulse Voltammetry
Developed for measurement of neurotransmitters
F. Gonon et al. Analytical Chemistry ...
Environmental Analysis
• Sample matrices
–Water
–Effluent
–Soil
–Sludge
–Plants and derivates
–Animal tissue
–Animal produ...
Environmental
• Heavy Metals:
– Zn, Cd, Pb, Cu, Sb, Bi, Mn, Tl
– As, Hg, Se
– Ni, Co, Fe, V, Mo, U, Cr
– Rh, Pt
• Anions:
...
U (mV)
I(nA)
-600 -400 -200 0
0
20
40
60
80
100
120
Cd, Pb, Cu in Tap Water
• acetate buffer
U (mV)
I(nA)
-650 -600 -550 -...
Ni, Co in tap water
Electrolyte: ammonia buffer pH 9.5 + DMG
Ni
0.34 ppb
Co
0.21 ppb
U in tap water
electrolyte: 0.1 mmol/L chloranilic acid +
HNO3 pH 1.8
U (mV)
I(nA)
20 0 -20 -40 -60 -80 -100 -120
0
-2
-4
...
Hg in waste water
Electrolyte:HClO4 + EDTA + NaCl (UV digestion)
Hg 5.9 µg/L
U (mV)
I(µA)
350 400 450 500 550 600 650 700
...
Fe and Mn in tap water
Electrolyte for Mn: ammonia/borate buffer
Electrolyte for Fe: phosphate buffer + catechol
U (mV)
I(...
Rh, Pt in tap water
Electrolyte for Rh: HCl+ H2COH
Electrolyte for Pt: HCl + H2COH + hydrazine
U (V)
I(µA)
-1.1 -1.15 -1.2...
Substance: CrDPVR(**)
U (mV)
I(µA)
220 200 180 160 140 120 100 80 60
-0.6
-0.7
-0.8
-0.9
-1
-1.1
Cr in tap water
Electroly...
Substance: W VR(**)
U (mV)
I(µA)
-325 -300 -275 -250 -225 -200 -175 -150 -125
1.6
1.8
2
2.2
2.4
2.6
2.8
W Ultra Trace Elec...
U (mV)
I(µA)
0 -100 -200 -300 -400 -500
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
-0.8
-0.9
-1
-1.1
NTA, EDTA in waste water
Elec...
Cd and Pb in sea water
Electrolyte: HCl + 10 mg/L Hg2+ + UV digestion
Cd
18.2 ng/L
Pb
487 ng/L
Ni and Co in sea water
Electrolyte: ammonia buffer + DMG
Ni
0.95 µg/L
Co
n.n.
U in sea water
Electrolyte: 0.1 mmol/L chloranilic acid +
HNO3 pH 2.5
U (mV)
I(nA)
-80 -100 -120 -140 -160 -180 -200
-10
-...
Official Methods
• HMSO Blue Book Method - Metal ions in
water: Zn,Cd,Pb,Cu,V,Ni,Co,U,Al,Fe
• EPA 7472 Hg in aqueous sampl...
CrIII and CrVI in sea water
Electrolyte: DTPA + acetate buffer + NaNO2
• CrVI measuring after reaction time
• Crtotal dire...
Substance: Arsenic VR(**)
U (mV)
I(µA)
-50 0 50 100 150 200
0.6
0.8
1
1.2
1.4
1.6
1.8
AsIII and Astotal in mineral water
A...
Substance: Selenium VR(**)
U (mV)
I(nA)
-600 -650 -700 -750
-5
-10
-15
-20
-25
-30
Substance: Selenium VR(**)
U (mV)
I(nA)...
Cyclic
Voltammetry
Cyclic Voltammetry
Potential applied
Cyclic Voltammetry
1st vertex
2nd vertexone scan
1st vertex
2nd vertex
59/n mV
(reversible system)
Ip ~ v1/2Current Response
Cyclic Voltammetry
Rapid quantitative technique
•Reversible or irreversible (Ep as a function of v)
•Number of electrons (Peak separation: 59...
Potential and Current step methods
• Chrono-amperometry
- Kinetic measurements
- Electrolysis
• Chrono-potentiometry
- Battery charging/discharging
- Coulome...
Multi Mode Electrochemical Detection
CE
REWE
Flow cell
IC Or HPLC Pump
WE = GCE Glassy Carbon Electrode
UTGE Ultra Trace Graphite Electrode
Carbon Paste Electrode
Metal Electrodes (Pt, Ag, Au)
...
DC AMPEROMETRY
One potential level
MULTIPULSE AMPEROMETRY
Up to 10 potential levels
DIFFERENCIAL PULSE AMPEROMETRY
Up to 1...
0.1 mM(20 ul) AANADOPAC 5-HIAA
ChromSpher C18,partsize 5um
0 50.0 100.0 150.0 200.0 250.0 300.0 350.0
0
-6
0.100x10
-6
0.2...
• AROMATIC HYDROXY COMPOUNDS
- antioxidants, flavones, phenols, tocopherols
• AROMATIC AMINES
- anilines, benzidines
• IND...
Thin layer Flow Cell
Amperometric with Flow Injection
Analysis
Time (s)
400 600 800
Current(A)
Pump
InjectorEC Detector
Environmental applications
Heavy metals Organics elements
Determination
• Differential pulse voltammetry
• Square wave vol...
Environmental applications
Heavy metals Organics elements
Determination
• Mercury Electrode (DP SQW)
• Solid state electro...
What is Biosensor?
BIOSENSOR
SAMPLE
Aquisition
ELABORATIONBIORECEPTOR
- Enzymes
- Microorganisms
- Antibodies
- Plant / animal tissues
TRANSD...
Mechanism of a Biosensors
Transducer
Receptor
Measurable
Signal
=Analyte
Solution
NO
Measurable
Signal
RECOGNITIONNO RECOG...
- Uses of Biosensors -
• Quality assurance in agriculture, food and pharma
industries
ex determination of E.Coli, Salmonel...
- Classes of Biosensors -
A)Catalytic biosensors:
Kinetics devices that measure steady-state
concentration of a transducer...
- Classes of Biosensors -
B)Affinity biosensors:
Devices in which receptor molecules bind analyte
molecules “irreversibly”...
O - ring
Polycarbonate Membrane
Biocatalytic Membrane
Permeable Membrane
biosensors components
●
●
●
●
●
●
1) To the amplifier
2) Body of the sensor
3) Ag/AgCl Electrode
4) Pt Electrode
5) Removing cap
6) O2 or H2O2 permeable mem...
- Detection Elements -
Catalysis strategies: enzimes most common
Glucose oxidase, urease, alcohol oxidase, etc.
Commercial...
Oxygen Electrode:
Anode: Ag/AgCl (reference electrode)
Cathode Pt (working electrode)
E= -700 mV
Hydrogen peroxide sensor
...
- Detection Elements -
1st Generation Biosensors: base on direct
determination of one of the reaction product
or consume o...
Sugar catalysis by oxidoreductases
FADH2
FAD
O
CH2OH
HO
HO
OH O
OH
O
CH2OH
HO
HO
OH
H Glucose
Gluconolactone
2H+ + 2e-
- Detection Elements -
2nd Generation Biosensors: involve specific
'mediators' between the reaction and the
transducer in ...
CV catalytic reaction
oxidase enzyme
mediate with
carboxylferrocene
(0.5mM).
a)No substrate
b)Substrate 2.5 mM
c)Substrate...
- Detection Elements -
3rd Generation Biosensors: the reaction
itself causes the response and no product or
mediator diffu...
- Transducers -
Electrochemical: translate a chemical event to
an electrical event by measuring current
passed (amperometr...
- Transducers -
Piezoelectric: translate a mass change from a
chemical adsorption event to electrical signal
- Transducers -
Piezoelectric: translate a mass change from a
chemical adsorption event to electrical signal
Ideal Biosensors characteristics
• Sensitivity high ΔSignal/ Δconcentration
analyte
• Simple calibration (with standards)
...
Ideal Biosensors characteristics
• Selectivity: response only to changes in target
analyte concentration
• Long term stabi...
WHY ELECTROCHEMICAL BIOSENSORS ?
ELECTROCHEMICAL
BIOSENSORS
High selectivity
Disposable,
reusable sensor
Small amount of
s...
Future directions on applications:
• Multi analyte capability (proteins, biowarfare
agents, pathogens, etc.)
• Integration...
Future directions on basic research:
• Development of tools for basic research and
investigation of new biosensors:
Spectr...
Some examples:
• Biosensors for Heavy Metals
• Modify screen print electrodes
• Sensors for organics elements
• Sensors in...
Disposable electrochemical sensor for
rapid determination of heavy metals in
herbal drugs
• I. Palchettia, M. Mascini , , ...
Ca10(PO4)6(OH)2-modified carbon-paste
electrode for the determination of trace
lead(II) by square-wave voltammetry
• M.A. ...
A mercury-free electrochemical sensor
for the determination of thallium(I)
based on the rotating-disc bismuth
film electro...
Determination of nitrite in food
samples by anodic voltammetry using
a modified electrode
• Wilney J.R. Santosa, Phabyanno...
Cadmium, zinc and copper biosorption
mediated by Pseudomonas veronii 2E
Diana L. Vullo , a, , Helena M. Cerettia, María Al...
Detection of pesticide by polymeric
enzyme electrodes
K. Duttaa, D. Bhattacharyaya, A. Mukherjeeb, S.J. Setfordc, A.P.F.
T...
Determination of selenium in Italian
rices by differential pulse cathodic
stripping voltammetry
Monica Panigatia, , , Luig...
Determination of fenthion and
fenthion-sulfoxide, in olive oil and in
river water, by square-wave
adsorptive-stripping vol...
Development of urease and glutamic
dehydrogenase amperometric assay for
heavy metals screening in polluted
samples
Belen B...
Determination of heavy metals in honey
by potentiometric stripping analysis and
using a continuous flow methodology
• Emma...
Screen print electrodes
Carbon
SPE
Gold
SPE
Platinum
SPE
Screen print electrodes
Disk electrodes in any material
Al, Ag, Au, Cu, Fe, Hf, Nb, Ni,
Pb, Pd, Pt, Ta, Ti, Sn, Zn, Zr, Y
Preparation of electronic tongue / EQCM
- EQCM -
EQCM application – Metal UPD
• UPD stands for Under-Potential Deposition
– UPD leads to the electrolytic formation a
metal...
2
2
25.5987Hz
m 314.094ng/ cm
0.0815Hz/ ng/ cm
  
f(Hz) 25.5987Hz 
EQCM application – Pb UPD / Au
• Data analysis
– A...
  2
QCMm 314.094ng/ cm
2Pb
Pb Pb
Q
m M 324.54 ng/ cm
2F
  
• Data analysis
– Required charge for Pb UPD on Au
2
PbQ 3...
EIS multianalyte sensing with an
automated SIA system
An electronic tongue employing the
impedimetric signal
Montserrat Co...
Amperometric sensors based on
poly(3,4-ethylenedioxythiophene)-
modified electrodes:
Discrimination of white wines
L. Piga...
Electrochemical elimination of contaminants
Electrochemical dissolution of contaminants
High Potential
High current applications
Autolab Booster 20A
Foto do sistema u...
Kinetics of the oxidation of formaldehyde
in a flow electrochemical reactor with
TiO2/RuO2 anode
Mara Terumi Fukunagaa, Jo...
Oxidation of pesticides by in situ
electrogenerated hydrogen peroxide:
Study for the degradation of 2,4-
dichlorophenoxyac...
Electrochemical dissolution of contaminants
0.0 0.5 1.0 1.5 2.0
0
5
10
15
20
0,033 M Na2
SO4
0,10 M NaCl
0,10 M NaNO3
0,10...
Electrochemical deposition of silver and
gold from cyanide leaching solutions
• Reyes-Cruz, Victor, Ponce de Leon, Carlos,...
Electrochemical environmental applications
Determination of Heavy metals
Determination of organics pollution elements
P...
21   applications analytical -biosensors - environmental 2012
21   applications analytical -biosensors - environmental 2012
21   applications analytical -biosensors - environmental 2012
21   applications analytical -biosensors - environmental 2012
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21 applications analytical -biosensors - environmental 2012

  1. 1. Autolab Instruments in Environmental Research
  2. 2. Environmental applications • Determination of Heavy metals • Determination of organics pollution elements • Preparations of Sensors, biosensors, imunosensors • Preparation of electronic tongue EQCM • Electrochemical elimination of contaminants
  3. 3. We found 8366 Articles Using Autolab equipments on environmental applications
  4. 4. Environmental applications Methods Electrodes Development ImunosensorsBiosensors
  5. 5. • Differential pulse voltammetry • Square wave voltammetry • Cyclic Voltammetry • Chrono amperometry • Potentiometric stripping analysis • Flow injection multimode electrochemical detections • Electrochemical Impedance Spectroscopy • (Electrochemical Surface Plasmon Resonance) Environmental applications Methods Electrodes Development ImunosensorsBiosensors
  6. 6. • Mercury Electrode • Solid state electrode: Graphite, Platinum, • Special deposition/modification electrodes • Screen printed electrodes Environmental applications Methods Electrodes Development ImunosensorsBiosensors
  7. 7. • Biosensors: Chrono Amperometry, Flow injection, DP amperometry • Imunosensors: same as biosensors • Screen print electrodes • self assembled monolayer Environmental applications Methods Electrodes Development ImunosensorsBiosensors
  8. 8. Heavy metals Organics elements Determination • Differential pulse voltammetry • Square wave voltammetry • Chrono amperometry • Potentiometric stripping analysis • Flow injection multimode electrochemical detections Electrochemical Techniques Environmental applications
  9. 9. Hardware NON MODULAR INSTRUMENT MODULAR INSTRUMENTS PGSTAT 101 Autolab Type III/FRA2 PGSTAT302N / PGSTAT128N PGSTAT100
  10. 10. - Software - Cyclic Voltammetry Linear sweep voltammetry Differential pulse voltammetry Square wave voltammetry Direct current voltammetry Normal pulse voltammetry Differential normal pulse voltammetry Chrono methods Electrochemical noise Impedance techniques
  11. 11. - Software - FRA GPES All includes in NOVA Alternative current voltammetry Potentiometric stripping analysis Multimode electrochemical detection
  12. 12. Voltammetric Analysis
  13. 13. SMDE Stable surface Needle Capillary Tapper Hg drop DME Droplife New Drop Electrode types in Voltammetric Analysis Voltammetric Analysis
  14. 14. Electrode types in Voltammetric Analysis MME Multi Mode Electrode SMDE DME HMDE GC Au Ag Pt UT RDE Rotating Disc Electrode
  15. 15. Multi Mode Electrode Precise and safe control of the Hg drop electrode
  16. 16. Multi Mode Electrode • Hg drop –DME –SMDE –HDME
  17. 17. Possibility of determinations with DP and SQW
  18. 18. • Sb 500 ppt • As 100 ppt • Pb 10 ppt • Cd 10 ppt • Cr 25 ppt • Fe 200 ppt • Co 50 ppt • Cu 50 ppt • Rh 0.1 ppt • Hg 100 ppt • Mo 10 ppt • Ni 50 ppt • Pt 0.1 ppt • Tl 50 ppt • U 25 ppt • Bi 500 ppt • Se 300 ppt • W 200 ppt Possibility of determinations with DP and SQW Ultra trace analysis:
  19. 19. Normal Pulse Voltammetry Voltammetric Analysis
  20. 20. Normal Pulse Voltammetry • Dropping Mercury Electrode (DME): Improved sensitivity compared to classical DC polarography • Static Mercury Drop Electrode (SMDE): No charging current --> lower background current No slope in background current --> Improved precision Smaller drop times --> faster measurements. Voltammetric Analysis
  21. 21. Normal Pulse Voltammetry Cd2+ measurement in acetate/KCl solution pH=4.9 Voltammetric Analysis
  22. 22. Differential pulse voltammetry (DPV) Voltammetric Analysis
  23. 23. Differential pulse voltammetry current measurement Current is the difference between 2 and 1 Voltammetric Analysis
  24. 24. W1/2 E0 Differential pulse voltammetry Voltammetric Analysis
  25. 25. Differential pulse voltammetry • Currents will only be measured close to E0 • W½ = 90.4/n mV if the pulse height is small • Advantages over Normal Pulse Voltammetry 1. Cancellation of capacitive currents 2. Ability to distinguish close/overlapping peaks 3. Higher currents and higher selectivity Voltammetric Analysis
  26. 26. Differential pulse voltammetry Voltammetric Analysis measurement in acetate/KCl solution, pH=4.9
  27. 27. Differential pulse voltammetry Voltammetric Analysis measurement in acetate/KCl solution, pH=4.9
  28. 28. Differential pulse voltammetry Voltammetric Analysis measurement in acetate/KCl solution, pH=4.9
  29. 29. Square Wave Voltammetry Square wave is applied on top of a DC scan Voltammetric Analysis
  30. 30. Square wave voltammetry Measurement •The displayed result is the difference between a forward and backward current. •Iforward and Ibackward can be saved as well. •Square wave period: 0.5 ms – 125 ms (f:8 Hz-2000 Hz) Voltammetric Analysis
  31. 31. Square Wave Voltammetry The best choice for analytical purposes: • Background current cancellation (same as DPV) • Slightly more sensitive than DPV • Faster scan rates • Less Hg consumed Voltammetric Analysis
  32. 32. Square Wave Voltammetry Cd2+ measurement in acetate/KCl solution pH=4.9 Voltammetric Analysis
  33. 33. SQW Voltammetry DP Voltammetry Cd2+ measurement in acetate/KCl solution pH=4.9 Voltammetric Analysis comparison:
  34. 34. Differential Normal Pulse Voltammetry Developed for measurement of neurotransmitters F. Gonon et al. Analytical Chemistry 56, 573-575 (1984) Voltammetric Analysis t1 t2 I = I(t2)-I(t1)
  35. 35. Environmental Analysis • Sample matrices –Water –Effluent –Soil –Sludge –Plants and derivates –Animal tissue –Animal products
  36. 36. Environmental • Heavy Metals: – Zn, Cd, Pb, Cu, Sb, Bi, Mn, Tl – As, Hg, Se – Ni, Co, Fe, V, Mo, U, Cr – Rh, Pt • Anions: – Sulphide, Sulphite, Cyanide • Complexing Agents – NTA, EDTA • Speciation – Free / complexed metals
  37. 37. U (mV) I(nA) -600 -400 -200 0 0 20 40 60 80 100 120 Cd, Pb, Cu in Tap Water • acetate buffer U (mV) I(nA) -650 -600 -550 -500 -450 0 1 2 U (mV) I(nA) -450 -400 -350 -300 -250 0 2.5 5 7.5 10 12.5 15 Cd 0.07 ppb U (mV) I(nA) -250 -200 -150 -100 -50 0 50 25 50 75 100 Pb 1.7 ppb Cu 38 ppb
  38. 38. Ni, Co in tap water Electrolyte: ammonia buffer pH 9.5 + DMG Ni 0.34 ppb Co 0.21 ppb
  39. 39. U in tap water electrolyte: 0.1 mmol/L chloranilic acid + HNO3 pH 1.8 U (mV) I(nA) 20 0 -20 -40 -60 -80 -100 -120 0 -2 -4 -6 -8 -10 -12 -14 U(VI) 1 ppb
  40. 40. Hg in waste water Electrolyte:HClO4 + EDTA + NaCl (UV digestion) Hg 5.9 µg/L U (mV) I(µA) 350 400 450 500 550 600 650 700 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7
  41. 41. Fe and Mn in tap water Electrolyte for Mn: ammonia/borate buffer Electrolyte for Fe: phosphate buffer + catechol U (mV) I(nA) -300 -350 -400 -450 -2.5 -5 -7.5 -10 -12.5 -15 -17.5 -20 -22.5 -25 -27.5 U (V) I(nA) -1.55 -1.5 -1.45 -1.4 -1.35 -10 -20 -30 -40 -50 -60 -70 Mn 21 µg/L Fe 50 µg/L
  42. 42. Rh, Pt in tap water Electrolyte for Rh: HCl+ H2COH Electrolyte for Pt: HCl + H2COH + hydrazine U (V) I(µA) -1.1 -1.15 -1.2 -0.2 -0.4 -0.6 -0.8 -1 U (V) I(nA) -0.7 -0.75 -0.8 -0.85 -0.9 -0.95 -50 -100 -150 -200 -250 Rh 2.4 ng/L Pt 3.5 ng/L
  43. 43. Substance: CrDPVR(**) U (mV) I(µA) 220 200 180 160 140 120 100 80 60 -0.6 -0.7 -0.8 -0.9 -1 -1.1 Cr in tap water Electrolyte:H2SO4 + diphenylcarbazide UV digestion for oxidation of CrIII to CrVI Crtotal 4.7 µg/L
  44. 44. Substance: W VR(**) U (mV) I(µA) -325 -300 -275 -250 -225 -200 -175 -150 -125 1.6 1.8 2 2.2 2.4 2.6 2.8 W Ultra Trace Electrode • electrolyte: H2SO4 + NH4SCN + antipyrine + ascorbic acid + thiourea WVI 4.8 µg/L
  45. 45. U (mV) I(µA) 0 -100 -200 -300 -400 -500 -0.1 -0.2 -0.3 -0.4 -0.5 -0.6 -0.7 -0.8 -0.9 -1 -1.1 NTA, EDTA in waste water Electrolyte: HNO3 + ascorbic acid + Bi3+ NTA 2.3 mg/L EDTA 0.65 mg/L Bi3+ EDTA NTA
  46. 46. Cd and Pb in sea water Electrolyte: HCl + 10 mg/L Hg2+ + UV digestion Cd 18.2 ng/L Pb 487 ng/L
  47. 47. Ni and Co in sea water Electrolyte: ammonia buffer + DMG Ni 0.95 µg/L Co n.n.
  48. 48. U in sea water Electrolyte: 0.1 mmol/L chloranilic acid + HNO3 pH 2.5 U (mV) I(nA) -80 -100 -120 -140 -160 -180 -200 -10 -20 -30 -40 -50 -60 -70 -80 -90 UVI 3 ppm
  49. 49. Official Methods • HMSO Blue Book Method - Metal ions in water: Zn,Cd,Pb,Cu,V,Ni,Co,U,Al,Fe • EPA 7472 Hg in aqueous samples by ASV • EPA 7063 As in aqueous samples by ASV • EPA 970.53 Organophosphorous Residues • EPA 7198 Cr(VI) in water by polarography • DIN 38 406 - Zn,Cd,Pb,Cu,Ni,Co + Tl • DIN 38 413 EDTA , NTA in Waters • ASTM D3557 - 95 Cd in water • ASTM D3559 - 96 Pb in water
  50. 50. CrIII and CrVI in sea water Electrolyte: DTPA + acetate buffer + NaNO2 • CrVI measuring after reaction time • Crtotal direct measurement U (V) I(nA) -1.1 -1.2 -1.3 -20 -40 -60 -80 -100 -120 -140 -160 -180 U (V) I(nA) -1.1 -1.2 -1.3 -20 -40 -60 -80 -100 -120 -140 -160 -180 Crtotal 1.7 µg/L CrVI 0.47 µg/L
  51. 51. Substance: Arsenic VR(**) U (mV) I(µA) -50 0 50 100 150 200 0.6 0.8 1 1.2 1.4 1.6 1.8 AsIII and Astotal in mineral water AsIII deposition: 60 sec at -200 mV Astotal deposition: 120 sec at -1200 mV Astotal 1.9 µg/L AsIII 0.64 µg/L
  52. 52. Substance: Selenium VR(**) U (mV) I(nA) -600 -650 -700 -750 -5 -10 -15 -20 -25 -30 Substance: Selenium VR(**) U (mV) I(nA) -650 -700 -750 -2.5 -5 -7.5 -10 -12.5 -15 -17.5 -20 -22.5 -25 -27.5 SeIV and Setotal CSV in (NH4)SO4 + Cu + EDTA, pH 2.2 Setotal UV digestion at pH 7-9 SeIV 1.6 µg/L Setotal 2.1 µg/L SeIV no sample preparation
  53. 53. Cyclic Voltammetry
  54. 54. Cyclic Voltammetry
  55. 55. Potential applied Cyclic Voltammetry 1st vertex 2nd vertexone scan
  56. 56. 1st vertex 2nd vertex 59/n mV (reversible system) Ip ~ v1/2Current Response Cyclic Voltammetry
  57. 57. Rapid quantitative technique •Reversible or irreversible (Ep as a function of v) •Number of electrons (Peak separation: 59/n mV) •Diffusion coefficient •Faradaic (I~v1/2) vs Capacitive current (I~v) Cyclic Voltammetry
  58. 58. Potential and Current step methods
  59. 59. • Chrono-amperometry - Kinetic measurements - Electrolysis • Chrono-potentiometry - Battery charging/discharging - Coulometric titration - Measuring change in OCP (corrosion potential) over time Potential and Current step methods
  60. 60. Multi Mode Electrochemical Detection CE REWE Flow cell IC Or HPLC Pump
  61. 61. WE = GCE Glassy Carbon Electrode UTGE Ultra Trace Graphite Electrode Carbon Paste Electrode Metal Electrodes (Pt, Ag, Au) Amalgamated “home made” Electrodes CE =Au RE= Ag/AgCl ELECTRODE Multi Mode Electrochemical Detection
  62. 62. DC AMPEROMETRY One potential level MULTIPULSE AMPEROMETRY Up to 10 potential levels DIFFERENCIAL PULSE AMPEROMETRY Up to 10 potential levels with the possibility to choose which level subtract. Multi Mode Electrochemical Detection
  63. 63. 0.1 mM(20 ul) AANADOPAC 5-HIAA ChromSpher C18,partsize 5um 0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 0 -6 0.100x10 -6 0.200x10 -6 0.300x10 -6 0.400x10 -6 0.500x10 -6 0.600x10 -6 0.700x10 -6 0.800x10 t/s i/A 9 Potential levels HPLC column Determination of: AA (ascorbic Acid), NA DOPAC (3,4-dihydroxyphenylacetic acid) 5-HIAA (5-hydroxyindoleacetic acid)
  64. 64. • AROMATIC HYDROXY COMPOUNDS - antioxidants, flavones, phenols, tocopherols • AROMATIC AMINES - anilines, benzidines • INDOLS • PHENOLTHIAZINE • MERCAPTANES • VITAMIN A VITAMIN C VITAMIN K1 • NITRO COMPOUNDS - nitrophenols, nitroglicerin • INORGANICS ANIONS - NO2 -, SO3 -2, S2O3 -2, ClO2 -, SCN-, CN-
  65. 65. Thin layer Flow Cell
  66. 66. Amperometric with Flow Injection Analysis Time (s) 400 600 800 Current(A) Pump InjectorEC Detector
  67. 67. Environmental applications Heavy metals Organics elements Determination • Differential pulse voltammetry • Square wave voltammetry • Chrono amperometry • Potentiometric stripping analysis • Flow injection multimode electrochemical detections
  68. 68. Environmental applications Heavy metals Organics elements Determination • Mercury Electrode (DP SQW) • Solid state electrode: GC, Pt, Au (DP, SQW, PSA) • Biosensors: Chrono Amperometry, Flow injection, DP amperometry • Imunosensors: same as biosensors
  69. 69. What is Biosensor?
  70. 70. BIOSENSOR SAMPLE Aquisition ELABORATIONBIORECEPTOR - Enzymes - Microorganisms - Antibodies - Plant / animal tissues TRANSDUCER - Electrodes - FET - Thermistors - Optical fibers - Piezoelectric SIGNAL What is Biosensor? A self-contained integrated device which is capable of providing specific quantitative or semi- quantitative analytical information using a biological recognition element which is in direct spatial contact with a transducer element
  71. 71. Mechanism of a Biosensors Transducer Receptor Measurable Signal =Analyte Solution NO Measurable Signal RECOGNITIONNO RECOGNITION Thin selective membrane
  72. 72. - Uses of Biosensors - • Quality assurance in agriculture, food and pharma industries ex determination of E.Coli, Salmonella • Monitoring environmental pollutants & biological warfare agents ex determination pesticides, anthrax spores, Heavy metals • Medical diagnostic ex Glucose determination, PSA, Troponin T • Biological assays ex DNA microarrays
  73. 73. - Classes of Biosensors - A)Catalytic biosensors: Kinetics devices that measure steady-state concentration of a transducer-detectable species formed or lost due to a biocatalytic reaction • Monitored quantities:  rate of product formation  Disappearance of a reactant  Inhibition of a reaction • Biocatalysts used: • Enzymes, Microorganisms, Organelles, Tissue samples
  74. 74. - Classes of Biosensors - B)Affinity biosensors: Devices in which receptor molecules bind analyte molecules “irreversibly”, causing a physicochemical change that is detected • Receptor molecules:  Antibodies  Nucleic acids  Hormone receptors Biosensors today are most often used to detect molecules of biological origin, based on specific interactions
  75. 75. O - ring Polycarbonate Membrane Biocatalytic Membrane Permeable Membrane biosensors components ● ● ● ● ● ●
  76. 76. 1) To the amplifier 2) Body of the sensor 3) Ag/AgCl Electrode 4) Pt Electrode 5) Removing cap 6) O2 or H2O2 permeable membrane amperometric sensor
  77. 77. - Detection Elements - Catalysis strategies: enzimes most common Glucose oxidase, urease, alcohol oxidase, etc. Commercial example: glucose sensor using glucose oxidase (GOD) Commercially available Biosensors: Glucose, lactate, alcohol, sucrose, galactose, uric acid, alpha amylase, choline, L-Lysine (all amperometric based) Glucose + O2 + H2O  Gluconic acid + H2O2 Measurements routes: - pH Change (acid production) - O2 Consumption (fluorophore monitor) - H202 production (electrochemical)
  78. 78. Oxygen Electrode: Anode: Ag/AgCl (reference electrode) Cathode Pt (working electrode) E= -700 mV Hydrogen peroxide sensor Cathode Ag/AgCl (reference electrode) Anode Pt (working electrode) E= +700 mV - Detection Elements - H2O2  O2+ 2 H+ + 2e- 1/2O2+ 2 H+ + 2e-  H2O O2 + 4H+ + 4e-  2 H2O Ag  Ag+ + 1e-
  79. 79. - Detection Elements - 1st Generation Biosensors: base on direct determination of one of the reaction product or consume of Oxigen S P O2 H2O2 e-
  80. 80. Sugar catalysis by oxidoreductases FADH2 FAD O CH2OH HO HO OH O OH O CH2OH HO HO OH H Glucose Gluconolactone 2H+ + 2e-
  81. 81. - Detection Elements - 2nd Generation Biosensors: involve specific 'mediators' between the reaction and the transducer in order to generate improved response S P Mox Mred e- Substrate product Electrode Important points for the mediator: Low redox potential, reversible molecule, fast kinetic electron transfer, high stability
  82. 82. CV catalytic reaction oxidase enzyme mediate with carboxylferrocene (0.5mM). a)No substrate b)Substrate 2.5 mM c)Substrate 5 mM scanrate 5 mV/s
  83. 83. - Detection Elements - 3rd Generation Biosensors: the reaction itself causes the response and no product or mediator diffusion is directly involved. S P e-
  84. 84. - Transducers - Electrochemical: translate a chemical event to an electrical event by measuring current passed (amperometric detection is the most common), potential change between the electrodes, etc. Response measurements withcellobiose biosensor GC electrode 0 100 200 300 400 500 600 700 800 0 -5 0.10x10 -5 0.20x10 t/ s i/A
  85. 85. - Transducers - Piezoelectric: translate a mass change from a chemical adsorption event to electrical signal
  86. 86. - Transducers - Piezoelectric: translate a mass change from a chemical adsorption event to electrical signal
  87. 87. Ideal Biosensors characteristics • Sensitivity high ΔSignal/ Δconcentration analyte • Simple calibration (with standards) • Linear response : ΔSignal/ Δconc. Constant over large concentration range • Background signal: low noise • No hysteresis: signal independent of prior history of measurements
  88. 88. Ideal Biosensors characteristics • Selectivity: response only to changes in target analyte concentration • Long term stability: not subject of fouling poisoning oxide formation that interferes with the signal • Dynamic response: rapid response to variation in analyte concentration • Biocompatibility: minimize clotting platelet interactions, activation of complement
  89. 89. WHY ELECTROCHEMICAL BIOSENSORS ? ELECTROCHEMICAL BIOSENSORS High selectivity Disposable, reusable sensor Small amount of sample Sensitivity, accuracy and reproducibility Fast response time Screening and monitoring of real matrices Miniaturization
  90. 90. Future directions on applications: • Multi analyte capability (proteins, biowarfare agents, pathogens, etc.) • Integration – miniaturization (microfluidic “lab on a chip” devices) • Implantable devices (ex Medtronic: glucose sensor implant in major vein of the heart) • Living cells – tissue as biological element
  91. 91. Future directions on basic research: • Development of tools for basic research and investigation of new biosensors: Spectroelectrochemistry, surface modification (FRA), ESPR, EQCM • Production of more redox enzymes • Site directed mutagenesis • Development of applications with already existing biosensors
  92. 92. Some examples: • Biosensors for Heavy Metals • Modify screen print electrodes • Sensors for organics elements • Sensors in food applications
  93. 93. Disposable electrochemical sensor for rapid determination of heavy metals in herbal drugs • I. Palchettia, M. Mascini , , a, M. Minunnia, A. R. Biliab and F. F. Vincierib • a Dipartimento di Chimica, Università degli Studi di Firenze – Polo Scientifico, Via della Lastruccia 3, 50019, Firenze, Italy • b Dipartimento di Scienze Farmaceutiche, Via G. Capponi 9, 50100, Firenze, Italy • Abstract • Analysis of herbal drugs and extracts need rapid and affordable methods to assure the quality of products. The application of the electrochemical sensors in the field of quality control of herbal drugs, herbal drug preparations and herbal medicinal products appears very promising, advantageous and alternative to conventional methods due to their inherent specificity, simplicity and for the fast response obtained. This paper presents a proposal about the application of disposable electrochemical sensors associated with electroanalytical instrumentation for the detection of heavy metal analysis in herbal drugs. In particular samples of St. John's wort were analysed applying anodic stripping voltammetry. The content of Cd and Pb were evaluated.
  94. 94. Ca10(PO4)6(OH)2-modified carbon-paste electrode for the determination of trace lead(II) by square-wave voltammetry • M.A. El Mhammedia, , , M. Achakb and A. Chtainia • aEquipe d’Electrochimie et des Matériaux Inorganiques, Université Cadi Ayyad, Faculté des Sciences et Techniques, BP 523, 23000 de Beni- Mellal, Morocco • bLaboratoire d’Hydrobiologie et d’Algologie, Faculté des Sciences Semlalia, Université Cadi Ayyad, Marrakech, Morocco • Abstract • The analytical performance of hydroxyapatite Ca10(PO4)6(OH)2(HAp) screen-printed sensors designed for the detection of metals was evaluated. The suitable HAp-modified carbon-paste electrode (HAp- CPE) for the electrochemical determination of lead is illustrated in this work using cyclic and square-wave voltammetry in the potential range between −0.3 and −0.8 V. The voltammetric measurements were carried out using as working electrode HAp-CPE, and a platinum electrode and an SCE electrode as auxiliary and reference electrodes, respectively. Under the optimized working conditions, calibration graph is linear for 5 min of preconcentration time with the detection limit 7.68 × 10−10 mol L−1.
  95. 95. A mercury-free electrochemical sensor for the determination of thallium(I) based on the rotating-disc bismuth film electrode • E.O. Jorgea, M.M.M. Netoa, b, , and M.M. Rochaa • aDepartamento de Química e Bioquímica, Centro de Ciências Moleculares e Materiais, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal • bDepartamento de Química Agrícola e Ambiental, Instituto Superior de Agronomia, TULisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal • Abstract • A bismuth film electrode was tested and proposed as an environmentally friendly sensor for the determination of trace levels of Tl(I) in non- deoxygenated solutions. Determination of thallium was made by anodic stripping voltammetry at a rotating-disc bismuth film electrode plated in situ, using acetate buffer as the supporting electrolyte. The stripping step was carried out by a square wave potential-time excitation signal. Under the selected optimised conditions, a linear calibration plot was obtained in the submicromolar concentration range, allowing the electrochemical determination of thallium in trace amounts; the calculated detection limit was 10.8 nM and the relative standard deviation for 15 measurements of 0.1 μM Tl(I) was ±0.2%, for a 120 s accumulation time. Interference of other metals on the response of Tl(I) was investigated. Application to real environmental samples was tested.
  96. 96. Determination of nitrite in food samples by anodic voltammetry using a modified electrode • Wilney J.R. Santosa, Phabyanno R. Limaa, Auro A. Tanakab, Sônia M.C.N. Tanakab and Lauro T. Kubotaa, , • aDepartment of Analytical Chemistry, Institute of Chemistry, University of Campinas – UNICAMP, 13084-971 Campinas, SP, Brazil • bDepartment of Chemistry Technology, Center Technological, University Federal of Maranhão – UFMA, 65085-040 São Luís, MA, Brazil • Abstract • A glassy carbon (GC) electrode modified with alternated layers of iron(III) tetra-(N-methyl-4-pyridyl)-porphyrin (FeT4MPyP) and copper tetrasulfonated phthalocyanine (CuTSPc) was employed for nitrite determination by differential pulse voltammetry (DPV). This modified electrode showed excellent catalytic activity for the nitrite oxidation. After optimizing the operational conditions, a linear response range from 0.5 to 7.5 μmol l−1 with a low detection limit of 0.1 μmol l−1 was obtained. The proposed sensor was stable with a sensitivity of 20.0 μA, 1 μmol−1 and good repeatability, evaluated in terms of relative standard deviation (R.S.D. = 1.3%) for n = 10. Possible interferences from several common ions were evaluated. This sensor was applied for the voltammetric determination of nitrite in some food samples.
  97. 97. Cadmium, zinc and copper biosorption mediated by Pseudomonas veronii 2E Diana L. Vullo , a, , Helena M. Cerettia, María Alejandra Daniela, Silvana A.M. Ramíreza and Anita Zaltsa • aÁrea Química, Instituto de Ciencias, Universidad Nacional de General Sarmiento, J.M. Gutiérrez 1150, (B1613GSX) Los Polvorines, Buenos Aires, Argentina • Abstract • Adsorption properties of bacterial biomass were tested for Cd removal from liquid effluents. Experimental conditions (pH, time, cellular mass, volume, metal concentration) were studied to develop an efficient biosorption process with free or immobilised cells of Pseudomonas veronii 2E. Surface fixation was chosen to immobilise cells on inert surfaces including teflon membranes, silicone rubber and polyurethane foam. Biosorption experiments were carried out at 32 °C and controlled pH; maximal Cd(II) retention was observed at pH 7.5. The isotherm followed the Langmuir model (Kd = 0.17 mM and qmax = 0.48 mmol/g cell dry weight). Small changes in the surface negative charge of cells were observed by electrophoretic mobility experiments in presence of Cd(II). In addition, biosorption of 40% Cu(II) (pH 5 and 6.2) and 50% Zn(II) and 50% Cd(II) (pH 7.5) was observed from mixtures of Cu(II), Zn(II) and Cd(II) 0.5 mM each.
  98. 98. Detection of pesticide by polymeric enzyme electrodes K. Duttaa, D. Bhattacharyaya, A. Mukherjeeb, S.J. Setfordc, A.P.F. Turnerc and P. Sarkara, , • aDepartment of Polymer Science and Technology, University of Calcutta, 92 APC Road, Kolkata 700009, India • bDepartment of Chemical Engineering, Jadavpur University, Kolkata 700032, India • cCranfield Health, Cranfield University, Silsoe, BEDS., MK45 4DT, UK • Abstract • Screen-printed electrodes (SPEs) containing immobilized acetylcholine esterase (AChE) enzyme were used for the electrochemical determination of organophosphorous (OP) and carbamate pesticides. The extent of AChE deactivation by the pesticide was determined in the presence of acetylcholine (AChCl) substrate. The unique nature of this approach lies in the enzyme immobilization procedure in which AChE was attached to the SPE by in situ bulk polymerization of acrylamide to ensure efficient adherence within the membrane with minimal losses in enzyme activity. Responses were observed for the pesticides Monocrotophos, Malathion, Metasystox and Lannate over the concentration range 0–10 ppb (μg L−1).
  99. 99. Determination of selenium in Italian rices by differential pulse cathodic stripping voltammetry Monica Panigatia, , , Luigi Falciolab, Patrizia Mussinib, Giangiacomo Berettac and Roberto Maffei Facinoc • aDepartment of Inorganic, Metallorganic and Analytical Chemistry, Faculty of Pharmacy, University of Milano, Via Venezian 21, 20133 Milano, Italy • bDepartment of Physical Chemistry and Electrochemistry, Faculty of Science, University of Milano, Via Golgi 19, 20133 Milano, Italy • cInstitute of Pharmaceutical and Toxicological Chemical, Faculty of Pharmacy, University of Milano, Viale Abruzzi 42, 20131 Milano, Italy • Abstract • The total selenium content in white, black, red rice and white rice hull samples, grown in Northern Italy cultivars, has been determined using the differential pulse cathodic stripping voltammetry (DPCSV) on the hanging drop mercury electrode (HDME), in the presence of Cu(II). The digestion was performed in open vessel through a combination of wet acid/dry ashing with Mg(II) salts. The calibration curve was linear in the concentration range 0.15–8 ppb, the detection limit was estimated to be 0.07 ppb, and the recovery was in the range 85–102%. Reproducibility was from 1.9% to 9.0% (RSD, n = 4). The resulting selenium contents in different Italian rice varieties were: 20.1 ± 1.8 ppb (white), 3.0 ± 1.0 ppb (red), 26.7 ± 1.3 ppb (black), 45.3 ± 4.1 ppb (white rice hull).
  100. 100. Determination of fenthion and fenthion-sulfoxide, in olive oil and in river water, by square-wave adsorptive-stripping voltammetry T. Galeano Díaz , a, , A. Guiberteau Cabanillasa, M.D. López Sotoa and J.M. Ortiza • aDepartment of Analytical Chemistry, University of Extremadura, Avd. Elvas s/n 06071, Badajoz, Spain • Abstract Square-wave adsorptive-stripping voltammetry technique has been used to develop a method for the determination of fenthion in olive oil. Fenthion is isolated from olive oil by carrying out a solid–liquid extraction procedure using silica cartridge, followed by a liquid–liquid partitioning with acetonitrile. The detection limit in olive oil is 78.8 ng g−1 On the other hand, it has been developed a method for the simultaneous determination of fenthion and its metabolite fenthion-sulfoxide, in river water. The detection limits are 0.41 ng g−1 and 0.44 ng g−1, for fenthion and fenthion-sulfoxide, respectively. Recoveries for three levels of fortification are ranged from 96% to 103% for fenthion and 94% to 104% for fenthion-sulfoxide.
  101. 101. Development of urease and glutamic dehydrogenase amperometric assay for heavy metals screening in polluted samples Belen Bello Rodriguez , , John A. Bolbot and Ibtisam E. Tothill • Cranfield Biotechnology Centre, Institute of Bioscience, Cranfield University, Silsoe, Bedforshire, MK45 4DT, UKAbstract • The enzyme urease catalyses the hydrolysis of urea and the formation of NH4+ is determined using a NADH-glutamate dehydrogenase coupled reaction system. NADH consumption is monitored amperometrically using screen-printed three electrode configuration and its oxidation current is then correlated to urease activity. The linear range obtained for Hg(II) and Cu(II) was 10–100 μg l−1 with a detection limit of 7.2 μg l−1 and 8.5 μg l−1, respectively. Cd(II) and Zn(II) produced enzyme inhibition in the range 1–30 mg l−1, with limits of detection of 0.3 mg l−1 for Cd(II) and 0.2 mg l−1 for Zn(II).
  102. 102. Determination of heavy metals in honey by potentiometric stripping analysis and using a continuous flow methodology • Emma Muñoz , and Susana Palmero • Departamento de Química (Área de Química Analítica), Facultad de Ciencias, Universidad de Burgos, P/Misael Bañuelos s/n, 09001 Burgos, Spain • Abstract • A methodology for the determination of Zn(II), Cd(II) and Pb(II) directly in dissolved honey samples by potentiometric stripping analysis with a flow cell is proposed. Heavy metals in honey are of interest not only for quality control, but can be used also as an environmental indicator. In this work honey samples were collected in different places of Burgos (Spain). Lead (II) and cadmium (II) can be directly determined. The results were compared with inductively coupled mass plasma spectrometry as reference method.
  103. 103. Screen print electrodes Carbon SPE Gold SPE Platinum SPE
  104. 104. Screen print electrodes
  105. 105. Disk electrodes in any material Al, Ag, Au, Cu, Fe, Hf, Nb, Ni, Pb, Pd, Pt, Ta, Ti, Sn, Zn, Zr, Y
  106. 106. Preparation of electronic tongue / EQCM
  107. 107. - EQCM -
  108. 108. EQCM application – Metal UPD • UPD stands for Under-Potential Deposition – UPD leads to the electrolytic formation a metal layer at potentials > E • Interaction between substrate and metal ions – Deposition mode leads to a single monolayer of metal – Ideal system for EQCM validation
  109. 109. 2 2 25.5987Hz m 314.094ng/ cm 0.0815Hz/ ng/ cm    f(Hz) 25.5987Hz  EQCM application – Pb UPD / Au • Data analysis – Average f for the formation of Pb UPD on Au ff m C    2 fC 0.0815Hz/ ng/ cm
  110. 110.   2 QCMm 314.094ng/ cm 2Pb Pb Pb Q m M 324.54 ng/ cm 2F    • Data analysis – Required charge for Pb UPD on Au 2 PbQ 302 C/ cm  EQCM application – Pb UPD / Au Good agreement !!
  111. 111. EIS multianalyte sensing with an automated SIA system An electronic tongue employing the impedimetric signal Montserrat Cortina-Puiga, Xavier Muñoz-Berbelb, M. Asunción Alonso-Lomillob, Francisco J. Muñoz-Pascualb and Manuel del Vallea, , • aSensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, Barcelona E-08193, Spain • bNational Centre of Microelectronics (IMB-CNM), CSIC, Campus of Autonomous University of Barcelona, Barcelona E-08193, Spain • Abstract • In this work, the simultaneous quantification of three alkaline ions (potassium, sodium and ammonium) from a single impedance spectrum is presented. For this purpose, a generic ionophore – dibenzo-18-crown- 6 – was used as a recognition element, entrapped into a polymeric matrix of polypyrrole generated by electropolymerization. Electrochemical impedance spectroscopy (EIS) and artificial neural networks (ANNs) were employed to obtain and process the data, respectively. A sequential injection analysis (SIA) system was employed for operation and to automatically generate the information required for the training of the ANN.. Three commercial fertilizers were tested employing the proposed methodology on account of the high complexity of their matrix. The experimental results were compared with reference methods.
  112. 112. Amperometric sensors based on poly(3,4-ethylenedioxythiophene)- modified electrodes: Discrimination of white wines L. Pigania, G. Focab, K. Ionescua, V. Martinaa, A. Ulricib, F. Terzia, M. Vignalic, C. Zanardia and R. Seebera, , • bDipartimento di Scienze Agrarie e degli Alimenti, Università degli Studi di Modena e Reggio Emilia, Padiglione Besta, via Amendola 2, 42100 Reggio Emilia, Italy • aDipartimento di Chimica, Università di Modena e Reggio Emilia, via G.Campi 183, 41100 Modena, Italy • cVinicola San Nazaro, Via Gonzaga 12, 46020 Pegognaga (MN), Italy • Abstract • The voltammetric responses on selected white wines of different vintages and origins have been systematically collected by three different modified electrodes, in order to check their effectiveness in performing blind analysis of similar matrices. The electrode modifiers consist of a conducting polymer, namely poly(3,4-ethylenedioxythiophene) (PEDOT) and of composite materials of Au and Pt nanoparticles embedded in a PEDOT layer. Wine samples have been tested, without any prior treatments, with differential pulse voltammetry technique. The subsequent chemometric analysis has been carried out both separately on the signals of each sensor, and on the signals of two or even three sensors as a unique set of data, in order to check the possible complementarity of the information brought by the different electrodes. After a preliminary inspection by principal component analysis, classification models have been built and validated by partial least squares-discriminant analysis.
  113. 113. Electrochemical elimination of contaminants
  114. 114. Electrochemical dissolution of contaminants High Potential High current applications Autolab Booster 20A Foto do sistema utilizado para tratamento de chorume e representação esquemática do reator eletroquímico.
  115. 115. Kinetics of the oxidation of formaldehyde in a flow electrochemical reactor with TiO2/RuO2 anode Mara Terumi Fukunagaa, José Roberto Guimarãesa and Rodnei Bertazzolib, , • aDepartamento de Saneamento e Ambiente, Faculdade de Engenharia Civil, Arquitetura e Urbanismo, Universidade Estadual de Campinas, C.P. 6021, 13083-852 Campinas, SP, Brazil • bDepartamento de Engenharia de Materiais, Faculdade de Engenharia Mecânica, Universidade Estadual de Campinas, C.P. 6122, 13083-970 Campinas, SP, Brazil • Abstract • This paper reports the electrochemical degradation of solutions containing formaldehyde by means of an electrochemical tubular flow reactor with a titanium anode coated with metal oxides (Ti/Ru0.3Ti0.7O2). Due to the simplicity and low molecular weight of the compound it was possible to achieve high mineralization rates; the oxidation reaction of formaldehyde as well as TOC and COD removal were controlled by mass transfer. For solutions with 0.4 g L−1 of formaldehyde, electrodegradation followed a pseudo first-order kinetics, and the mass transport coefficients were calculated. After the experiments, a 97% reduction of TOC was observed, and the final formaldehyde and COD concentrations were below the detection limit threshold.
  116. 116. Oxidation of pesticides by in situ electrogenerated hydrogen peroxide: Study for the degradation of 2,4- dichlorophenoxyacetic acid Carla Badellinoa, Christiane Arruda Rodriguesa and Rodnei Bertazzoli , a, • aFaculty of Mechanical Engineering, Department of Materials Engineering, State University of Campinas, CP 6122, 13083-970 Campinas, Sao Paulo, Brazil • Abstract • This paper reports an investigation on the performance of the H2O2 electrogeneration process on a rotating RVC cylinder cathode, and the optimization of the O2 reduction rate relative to cell potential. A study for the simultaneous oxidation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) by the in situ electrogenerated H2O2 is also reported. First order apparent rate constants for 2,4-D degradation ranged from 0.9 to 6.3 × 10−5 m s−1, depending on the catalyst used (UV or UV + Fe(II)). TOC reduction was favored in acidic medium where a decreasing of 69% of the initial concentration was observed in the process catalyzed by UV + Fe(II).
  117. 117. Electrochemical dissolution of contaminants 0.0 0.5 1.0 1.5 2.0 0 5 10 15 20 0,033 M Na2 SO4 0,10 M NaCl 0,10 M NaNO3 0,10 M NaOH 0,10 M NaClO4 0,033 M H2 SO4 [atrazina]/mgL -1 t / h Electrolysis and Atrazina concentration (i = 40 mA cm-2) Artur de Jesus Motheo Dep. de Físico-Química Instituto de Química de São Carlos USP BR
  118. 118. Electrochemical deposition of silver and gold from cyanide leaching solutions • Reyes-Cruz, Victor, Ponce de Leon, Carlos, González, Ignacio and Oropeza, Mercedes.T. (2002) Electrochemical deposition of silver and gold from cyanide leaching solutions. Hydrometallurgy, 65, (2-3), 187-203. • Abstract • A systematic voltammetric study developed in this work allows the determination of the potential range at which the selective deposition of gold and silver is carried out in the presence of a high content of copper. Also, the voltammetric study of a cyanide solution containing low concentrations of Au(I) and Ag(I), free of and with high concentration of Cu(I) was carried out. The study shows the potential range at which Au(I) and Ag(I) are reduced despite the high concentration of the Cu(I) ions. The deposition of gold and silver was not interfered with by the high concentration of Cu(I) ions when the leaching solution was electrolyzed in a laboratory electrochemical reactor FM01-LC with a reticulated vitreous carbon (RVC) cathode.
  119. 119. Electrochemical environmental applications Determination of Heavy metals Determination of organics pollution elements Preparations of Sensors, biosensors, imunosensors Preparation of electronic tongue EQCM Electrochemical dissolution of contaminants

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