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. We found 8366 Articles
Using Autolab equipments on
environmental applications
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
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
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. 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
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)
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. Cd and Pb in sea water
Electrolyte: HCl + 10 mg/L Hg2+ + UV digestion
Cd
18.2 ng/L
Pb
487 ng/L
47. Ni and Co in sea water
Electrolyte: ammonia buffer + DMG
Ni
0.95 µg/L
Co
n.n.
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. 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. 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. 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. 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
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
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. 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
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. Mechanism of a Biosensors
Transducer
Receptor
Measurable
Signal
=Analyte
Solution
NO
Measurable
Signal
RECOGNITIONNO RECOGNITION
Thin selective
membrane
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. - 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. - 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. O - ring
Polycarbonate Membrane
Biocatalytic Membrane
Permeable Membrane
biosensors components
●
●
●
●
●
●
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. - 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)
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. Sugar catalysis by oxidoreductases
FADH2
FAD
O
CH2OH
HO
HO
OH O
OH
O
CH2OH
HO
HO
OH
H Glucose
Gluconolactone
2H+ + 2e-
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. 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. - Detection Elements -
3rd Generation Biosensors: the reaction
itself causes the response and no product or
mediator diffusion is directly involved.
S
P
e-
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
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. 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. 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. 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. 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. Some examples:
• Biosensors for Heavy Metals
• Modify screen print electrodes
• Sensors for organics elements
• Sensors in food applications
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. 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. 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. 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. 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. 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. 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. 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. 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. 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.
111. 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
112.
113. 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
114. 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 !!
115. 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.
116. 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.
118. 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.
119. 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.
120. 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).
121. 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
122. 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.
123. 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
