Quantitative determination of the herbicide paraquat in human plasma by gas chromatographic and mass spectrometric methods

Draffan, G. H.; Clare, R. A.; Davies, D. L.; Hawksworth, GM; Murray, Stephen A.; Davies, Donald S.

doi:10.1016/s0021-9673(00)89326-7

Cited by 66 publications

(23 citation statements)

References 7 publications

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“…The temperature used for the reaction (60 • C) was the same used by Arys et al [8]. Initially, it was known that alkaline medium is a favorable condition to occur the reduction reaction [8,19]. In our experiments, sample solution adjusted to pH 8.0 was found to be the optimal condition.…”

Section: Resultsmentioning

confidence: 75%

“…However, to the knowledge of the authors, very few papers have reported the determination of PQ and DQ using gas chromatography-mass spectrometry (GC-MS) [19,20]. In the present work, after chemical reduction of the herbicides with NaBH 4 in more volatile compounds, solid-phase extraction (SPE) was used as sample preparation technique and the analytes were detected and quantified using GC-MS. Ethyl paraquat (EPQ) was used as internal standard (IS) for the chromatographic analysis.…”

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Gas chromatographic–mass spectrometric method for the determination of the herbicides paraquat and diquat in plasma and urine samples

Almeida

Yonamine

2007

Journal of Chromatography B

105

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Section: Resultsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 96%

Gas chromatographic–mass spectrometric method for the determination of the herbicides paraquat and diquat in plasma and urine samples

Almeida

Yonamine

2007

Journal of Chromatography B

105

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“…The Environmental Protective Agency (EPA) established a maximum concentration of 3 µg L -1 in natural waters, 2 while the European Community established 0.1 µg L -1 for the same kind of sample. A large variety of analytical techniques have been proposed for determination of paraquat, such as molecular absorption spectrophotometry, 7,8 liquid chromatography with UV detection, 9,10 liquid and gas chromatography coupled to mass spectrometry detection, 11,12 gas chromatography with specific detector for nitrogen and phosphorus (NPD), 13 ELISA 14 as well as potentiometric and amperometric sensors. 15,16 More recently, capillary electrophoresis with ultraviolet (CE-UV) 17 or mass spectrometry (CE-MS) 18 detection was proposed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry

Oliveira¹,

Lichtig²,

Masini³

2004

J. Braz. Chem. Soc.

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Este trabalho apresenta uma avaliação de um eletrodo de carbono vítreo recoberto com filme de Nafion para a determinação de paraquat em águas de rio e urina por voltametria de pulso diferencial. O filme foi formado adicionando-se 4 µL de uma solução de Nafion 4% (m/v) na superfície do eletrodo, seguindo-se evaporação do solvente com luz infra-vermelha. A máxima relação sinal/ruído foi obtida em meio de tampão Britton-Robinson 40 mmol L -1 com pH 12 como eletrólito suporte. Utilizando-se um tempo de acumulação de 5 min em circuito aberto, o limite de detecção foi de 0,7 µg L -1 , enquanto o limite de quantificação foi de 1,0 µg L -1 , com uma faixa de resposta linear até 12 µg L -1 . Nestas condições, uma série de dez experimentos revelou um desvio padrão relativo de 2,2% para uma solução de paraquat 10 µg L -1 . A formação de par iônico em solução foi o principal fator de erro nas análises. Apesar do filme evitar a adsorção de espécies aniônicas na superfície do eletrodo, o paraquat sofre fortes associações em solução com substâncias húmicas, proteínas, argilas, surfactantes aniônicos, etc. Estas interações diminuem a acumulação do paraquat no filme de Nafion e, em conseqüência, diminuem a magnitude da corrente de pico de redução, requerendo que as quantificações sejam feitas por adição de padrão. Recuperações entre 87 e 106% foram obtidas para amostras de água de rio e urina enriquecidas aos níveis de 1,0 e 3,0 µg L -1 . This paper presents an evaluation of a Nafion coated glassy carbon electrode for determination of paraquat in river water and urine by differential pulse voltammetry. The film was formed applying 4 µL of a 1% (m/v) Nafion solution, which was evaporated under an infrared light. The maximum signal to noise ratio was obtained using a 40 mmol L -1 Britton-Robinson buffer at pH 12 as supporting electrolyte. For an accumulation time of 5.0 min in open circuit, the limit of detection was 0.7 µg L -1 , while the quantification limit was 1.0 µg L -1 , with a linear dynamic range up to 12 µg L -1 . In these conditions, a sequence of ten experiments lead to a relative standard deviation of peak current of 2.2% for a 10 µg L -1 paraquat solution. Ion pair formation in solution was the major factor of error in analysis. Despite the film to avoid adsorption of anionic species at the electrode surface, paraquat suffers strong association in solution with humic substances, proteins, clays, anionic surfactants, etc. These interactions decrease the accumulation of paraquat in the Nafion film and, as a consequence, the magnitude of the reduction peak, requiring that quantifications have to be made by standard addition. Recoveries between 87 and 106% were obtained for river waters and urine samples spiked with 1.0 and 3.0 µg L -1 paraquat.Keywords: paraquat determination, river water, urine, modified electrode, voltammetry, ion exchange IntroductionParaquat (1,1'-dimethyl-4,4'-bypiridilium ion), also known as methyl viologen, is a defoliant and desiccant agent used to control herbal growth in terrestrial and aquat...

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“…Sodium dithionite reaction allows qualitative detection of PQ and DQ in urine or gastric fluid (Berry and Grove, 1971;Yuen et al, 1967). For serum or urine spectrophotometric methods are used (Knepil, 1977;Tayama et al, 1991;Kesari et al, 1997) or derivated spectrophotometric methods (O'Haver, 1979;Fell et al, 1981;Jarvie et al, 1981;Fuke et al, 1992), chromatographic analysis-highperformance liquid chromatography (Miller et al, 1979;Gill et al, 1983;Nakagiri et al, 1989;Ito, 1993), gas chromatography (Martens and Heynfrickse, 1974;Kawase et al, 1984) or gas chromatography-mass spectrometric methods (Draflan et al, 1977), radioimmunologic assays (Levitt, 1979;Fatori and Hunter, 1980) and RMN 1 H (Imbenotte et al, 1999). Interest in capillary electrophoresis has greatly increased.…”

Section: Introductionmentioning

confidence: 99%

Separation and quantification of paraquat and diquat in serum and urine by capillary electrophoresis

Vinner

Stievenart

Humbert

et al. 2001

Biomedical Chromatography

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The use of capillary electrophoresis (CE) for simultaneous qualitative and quantitative detection of paraquat (PQ) and diquat (DQ) in both serum and urine was investigated. The two herbicides were extracted from biological fluids with liquefied phenol. Serum required a deproteinization with chloroform and ammonium sulfate as pretreatment. The extracts were hydrodynamically injected and the complete separation was carried out in 10 min, using a capillary tube (75 microm i.d., 500 mm) of fused silica containing 50 mM phosphate buffer (pH 2.50) as the carrier. UV absorbance detection at 200 nm was performed by an on-column detector. The analytes were characterized by their respective migration times. Analytical recoveries were 52.6% for PQ and 62.6% for DQ in serum, and 71.4% and 59.3%, respectively, in urine. The linearity was studied up to 4 mg/L and the limits of detection (LODs) were better than 5 pg/mL in serum or urine. The CE method described was applied to the characterization of two lethal poisonings and results were related.

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Quantitative determination of the herbicide paraquat in human plasma by gas chromatographic and mass spectrometric methods

Cited by 66 publications

References 7 publications

Gas chromatographic–mass spectrometric method for the determination of the herbicides paraquat and diquat in plasma and urine samples

Gas chromatographic–mass spectrometric method for the determination of the herbicides paraquat and diquat in plasma and urine samples

Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry

Separation and quantification of paraquat and diquat in serum and urine by capillary electrophoresis

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