charles university in prague silver amalgam electrodes in electroanalysis of selected agrochemicals

56 Pages·2012·0.93 MB·English

by  Aleš Daňhel

CHARLES UNIVERSITY IN PRAGUE

FACULTY OF SCIENCE

Department of Analytical Chemistry

SILVER AMALGAM ELECTRODES
IN ELECTROANALYSIS OF SELECTED
AGROCHEMICALS

A Thesis Submitted as the Basis for the Award of the Ph.D. Degree

Prague 2012 Mgr. Aleš Daňhel
I declare that all the results which are used and published in this Ph.D. Thesis have been
obtained by my own experimental work and that all the ideas taken from work of others are
properly referred to in the text and the literature survey. I am conscious that the prospective
use of the results, published in this Ph.D. Thesis, outside the Charles University in Prague is
possible only with a written agreement of this university.
I also declare that neither this Ph.D. Thesis, nor its significant part, has been submitted
in any form for another degree or diploma at any university or other institution of tertiary
education.

In Prague, 16.11.2011 ..........................................................
Mgr. Aleš Daňhel
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This Ph.D. Thesis was experimentally carried-out in the period from 2006 till 2011 at
the Charles University in Prague, Faculty of Science, Department of Analytical Chemistry,
UNESCO Laboratory of Environmental Electrochemistry. During this period, a research visits
at Hong Kong Baptist University, Hong Kong S.A.R and CESTEH/ENSP/FIOCRUZ, Rio de
Janeiro, Brazil, supervised by Associated Professor Kwok Keung Shiu and Professor Josino
Costa Moreira, respectively, were completed. Some parts of experiments were also carried out
in cooperation with Ing. Bogdan Yosypchuk, Ph.D., Ing. Tomáš Navrátil, and
Ing. Pavel Janda, CSc. from J. Heyrovský Institute of Physical Chemistry, v.v.i. of the
Academy of Sciences of the Czech Republic.
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Acknowledgment

I would like to express acknowledgements to all who have supported my research
efforts during this time. Special thanks go to Prof. RNDr. Jiří Barek, CSc., my supervisor at
the Department of Analytical Chemistry, Charles University in Prague, for his kind leading
during my doctoral studies and his support during the exchange research visits. Further,
I would like to thank members of the Department, particularly to Prof. RNDr. Jiří Zima, CSc.,
RNDr. Karolina Pecková, Ph.D., RNDr. Karel Čížek, Ph.D., RNDr. Jan Fischer, Ph.D., and
RNDr. Vlastimil Vyskočil, Ph.D., and all colleagues from our research group, for their
extensive help and support. Additional thanks go to Mgr. Jana Tvrdíková from the
Department for experimental helping with supplementary voltammetric and amperometric
measurements and her cooperation with grant (GAUK, project No. 89710), to members of the
J. Heyrovský Institute of Physical Chemistry, namely Ing. Bogdan Yosypchuk, Ph.D. and
Ing. Tomáš Navrátil for their valuable remarks and comments and to Ing. Pavel Janda, CSc.
and Mgr. Věra Mansfeldová for AFM measurements. I would like to thank also Silvana do
Couto Jacob and Josino Costa Moreira for their kind supervision, care during my research
visit at FIOCRUZ in Rio de Janeiro, Brazil, and challenging my experiences not only in field
of science and RNDr. Ivo Daňhel and RNDr. Jana Daňhelová who supported and inspired me
a lot.
Last, but not least, I thank my parents, brothers, girlfriend Markéta Benešová, my
friends, particularly Ing. Onřej Kundrát, Ph.D., Mgr. Jan Bílý and Mgr. Jaroslav Žádný, for
their support, patience and fun during my graduate studies.

Financial support from Ministry of Education, Youth and Sports of the Czech Republic
(projects LC 06035, MSM 0021620857 and RP 14/63), Grant Agency of Charles University
(project 89710/2011/B-Ch/PrF) and project SVV 2011-263204 is gratefully acknowledged.
Special thanks go to Croucher Fondation, Hong Kong S.A.R., Mobility Foundation of Charles
University, Brazilian National Research Council and Josef, Marie and Zdenka Hlavkovi
Talent Foundation participated on financing of international research programs and
conferences.
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Abstract

Development and testing of novel non-toxic electrode materials, detection arrangements
and analytical methods applicable in determination of selected agrochemicals is the main aim
of this Ph.D. Thesis.
New working electrodes based on silver solid amalgam paste (AgSA-PE) with organic
pasting liquid and other based on crystallic silver amalgam (CAgAE) were developed, their
electrochemical behaviour investigated and further used in voltammetric determination of
widespread and toxic environmental pollutant 4-nitrophenol (4-NP). This analyte could be
determined by DPV at AgSA-PE with limit of detection (L ) 1×10−6 mol l−1 and using
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CAgAE with L 4×10−7 mol l−1, both in 0.2 mol l−1 acetate buffer pH 4.8. Attempts to
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decrease L s by utilization of adsorptive stripping voltammetry were not successful in either
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case. Crystallic silver amalgam was also successfully used for construction of microcylindric
flow-through cell and tested for amperometric determination of nitrophenol mixture in HPLC-
ED system. Both novel electrodes were found to be suitable alternatives to toxic mercury
electrodes and the CAgAE seems to be promising working electrode for flowing systems.
Method for sample preparation and voltammetric determination of broad-spectrum
herbicide Glyphosate in contaminated soil samples was also observed. However, it was
unfortunately found out that application of the silver solid amalgam electrode can not be used
in this case. It's narrower potential window prevented it's use and hanging mercury drop
electrode had to be utilized. This fact still demonstrated usefulness of the mercury electrodes
and its irreplaceability in some special cases. Sample extraction, cleaning and pre-
concentration steps were proceeded before the determination using DPV of derivatised
Glyphosate to N-nitrosoglyphosate with L about 1×10−5 mol l−1 in the soil samples with three
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different organic matter contents. Apparently, higher content of the organic matter facilitated
the recovery of the GP from the soils, supposing being easier to remove the GP associate with
organics than adsorbed in inorganic soil matter.
Furthermore, application of the silver solid amalgam for construction of amperometric
detectors was verified. Polished silver solid amalgam electrodes were used in thin layer and
wall jet arrangements utilizable in detection of selected nitrophenol derivatives
using HPLC-ED. Both detection systems were successfully used for determination of selected
nitrophenols, mainly contained in commercially available plant growth stimulators,
with L s from 5 to 10×10−6 mol l−1 using thin layer detector and from 10 to 25×10−6 mol l−1
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using wall jet arrangement coupled with HPLC.
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Contents

Abstract.................................................................................................................. 5
List of Symbols and Abbreviations............................................................................ 8
1. INTRODUCTION............................................................................................... 12
1.1 References........................................................................................................ 14
2. NITROPHENOLS AND GLYPHOSATE BASED AGROCHEMICALS................... 15
2.1 Sources, Formation, Occurrence and Biological Effects................................. 15
2.1.1 Nitrophenols............................................................................................... 15
2.1.2 Glyphosate.................................................................................................. 19
2.2 Analytical Methods for Determination of Selected Nitrophenols and
Glyphosate........................................................................................................ 21
2.3 References........................................................................................................ 26
3. THE USE OF SILVER AMALGAM IN ELECTROANALYSIS.............................. 31
3.1 Amalgams as an Electrode Material................................................................ 31
3.2 Voltammetric Sensors Based on Silver Amalgam........................................... 33
3.3 Amperometric Detectors.................................................................................. 36
3.4 References........................................................................................................ 38
4. RESULTS AND DISCUSSION............................................................................ 40
4.1 Voltammetric Determination of 4-nitrophenol at Silver Solid Amalgam
Paste Electrode................................................................................................. 40
4.2 Voltammetric Determination of 4-nitrophenol at Crystallic Silver Amalgam
Electrode.......................................................................................................... 42
4.3 Voltammetric Determination of Derivatised Glyphosate in Soil..................... 45
4.4 Amperometric Determination of Nitrophenol Mixture Using HPLC-ED....... 46
4.5 Amalgam Electrodes in Organic Electroanalysis............................................. 47
4.6 References........................................................................................................ 48
5. CONCLUSION.................................................................................................. 49
6. APPENDIX I..................................................................................................... 51
A novel paste electrode based on a silver solid amalgam and an organic pasting
liquid

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7. APPENDIX II ................................................................................................... 56
Crystallic silver amalgam – a novel electrode material
8. APPENDIX III.................................................................................................. 63
Influence of the soil organic matter content on voltammetric determination of
derivatised Glyphosate in herbicide contaminated soils
9. APPENDIX IV.................................................................................................. 76
The Use of Silver Solid Amalgam Working Electrode for Determination of
Nitrophenols by HPLC with Electrochemical Detection
10. APPENDIX V.................................................................................................... 82
Amalgam electrodes in organic electrochemistry
11. APPENDIX VI – CONFIRMATION OF PARTICIPATION.................................. 95
12. APPENDIX VII – LIST OF PUBLICATIONS, ORAL AND POSTER
PRESENTATIONS............................................................................................. 96
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List of Symbols and Abbreviations

2,4-DNP 2,4-dinitrophenol
2-NP 2-nitrophenol
4-NP 4-nitrophenol
4-NP-G 4-nitrophenyl-beta-D-glucuronide
4-NP-S 4-nitrophenyl-sulfate
5-NG 5-nitroguaiacol
AD amperometric detection
AdSDPV adsorptive stripping differential pulse voltammetry
AdSSWV adsorptive stripping square wave voltammetry
AdSV adsorptive stripping voltammetry
AdTSV adsorptive transfer stripping voltammetry
A-ESP anion-exchange sorptive pre-concentration
AgA-PE silver amalgam paste electrode
AgSA-CE silver solid amalgam composite electrode
AgSAE silver solid amalgam electrode
AgSA-PE silver solid amalgam paste electrode
AMPA aminomethylphosphonic acid
APCI atmospheric pressure chemical ionization
ASV anodic stripping voltammetry
AuE golden electrode
BDDE boron-doped diamond film electrode
BiBE bismuth bulk electrode
BiFE bismuth film electrode
BMIMPF6 1-butyl-3-methylimidazolium hexafluorophosphate (a ionic liquid)
C(4)D capacitively coupled contactless conductivity detection
CAgAE crystallic silver amalgam electrode
CPE carbon paste electrode
CPSA chronopotentiometric stripping analysis
CSV cathodic stripping voltammetry
CuE copper electrode
CuPc cupper phtalocyanine
CuTSPc copper(II)tetrasulfonated phthalocyanine
CV cyclic voltammetry
CZE capillary zone electrophoresis
DAD diode array detector
DCV direct current voltammetry
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DDT dichlorodiphenyltrichloroethane
DED dual electrode detection
derDCV derivative direct current voltammetry
DME dropping mercury electrode
DNA deoxyribonucleic acid
DP differential pulse
DPP differential pulse polarography
DPV differential pulse voltammetry
DRS diffuse reflectance spectroscopy
ECD electron capture detector
ED electrochemical detector
ESI electron spray ionization
EU European Union
EVLS elimination voltammetry with linear scan
F-ELISA flow-enzyme linked immunosorbent assay
FeT4MPyP iron(III) tetra(N-methyl-4-pyridyl)-porphyrin
FIA flow injection analysis
FID flame ionization detection
FLD fluorescent detector
GC gas chromatography
GCE glassy carbon electrode
GC-MS gas chromatography-mass spectrometry
GCPE glassy carbon paste electrode
GP Glyphosate (N-(phosphonomethyl)glycine)
HAP hydroxyapatite
HAP-NP hydroxyapatite nanopowder
HCH hexachlorocyclohexane
HMDE hanging mercury drop electrode
HPLC high performance liquid chromatography
HPLC-ED high performance liquid chromatography with electrochemical detection
HRP horseradish peroxidase
HS-SPMEx headspace solid-phase microextraction
HTLC hydrotalcite-like clay
ICP-MS inductively coupled plasma-mass spectrometry
iFLD indirect fluorescent detection
IP-HPLC ion-pair high performance liquid chromatography
IT-MS ion trap mass spectrometry
LC liquid chromatography
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LC-MS liquid chromatography-mass spectrometry
L limit of determination
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L-EC ligand-exchange chromatography
LiTCNE lithium tetracyanoethylenide
LLEx liquid-liquid extraction
LLLMEx liquid-liquid-liquid micro-extraction
LOV lab on valve
m-AgSAE mercury meniscus modified silver solid amalgam electrode
MF-AgSAE mercury film modified silver solid amalgam electrode
MF-AuE mercury film modified gold electrode
MFE mercury film electrode
MF-GCE mercury film modified glassy carbon electrode
MIP molecularly imprinted polymer
MLR–SPA multivariate linear regression and successive projections algorithm
MS mass spectrometry
MSFIA multi-syringe flow injection analysis
MS-MS tandem mass spectrometry
muCZE capillary zone electrophoresis on microchip
MWNT multiwall carbon nanotubes
NAD+ nicotinamide adenine dinucleotide
NADH nicotinamide adenine dinucleotide hydrate
NADP+ nicotinamide adenine dinucleotide phosphate
NADPH nicotinamide adenine dinucleotide phosphate hydrate
nano-Au gold nanopaticles
Ni-Al-LDH nickel-aluminium layered double hydroxide
NICI-MS negative-ion chemical ionization mass spectrometry
NiE nickel electrode
NIRDRS near-infrared diffuse reflectance spectroscopy
NiTSPc nickel tetrasulfonated phtalocyanine
NO-GP N-nitrosoglyphosate
NPs nitrophenols
p-AgSACE polished silver solid amalgam composite electrode
p-AgSAE polished silver solid amalgam electrode
PANI polyaniline coted platinum wire
PDMA-PSS poly(2,5-dimethoxyaniline) doped with poly(4-styrenesulfonic acid)
pH negative of the base-10 logarithm of the activity of hydronium ions
POEA polyoxyethyleneamine
Poly-MG polymerized malachite green
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