Analysis of paraquat formulations by liquid chromatography

Kawano, Yoshihiko; Audino, J B; Edlund, Melvin

doi:10.1016/s0021-9673(00)89052-4

Cited by 17 publications

(1 citation statement)

References 11 publications

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“…Paraquat (the 1,1‘-dimethyl-4,4‘-bipyridylium ion), also known as methyl viologen, has been widely used as a herbicide for more than 10 years. This herbicide is extremely toxic and is often encountered in cases of accidental and suicidal poisonings. , Various techniques have been reported for the determination of paraquat, such as spectrophotometry, − thin-layer chromatography, , gas chromatography, liquid chromatography, ,, polarography, and radioimmunoassay . However, these techniques suffer from either instability or the need for extensive sample pretreatment.…”

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Determination of Paraquat by Square-Wave Voltammetry at a Perfluorosulfonated Ionomer/Clay-Modified Electrode

1996

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A novel Nafion/clay-modified electrode (NCME) was developed for the determination of paraquat by square-wave cathodic stripping voltammetry. The clay that showed the best performance for the fabrication of the NCME is nontronite (SWa-1, ferruginous smectite). The electrochemical behavior of paraquat showed that the cathodic peak at -0.70 V vs Ag/AgCl permits adequate quantification of the analyte. Linear calibration curves are obtained over the 0-80 ppb range, with a detection limit of 0.5 ppb in pH 8 phosphate buffer solution for 4 min preconcentration time. Various factors influencing the determination of paraquat were thoroughly investigated in this study. The practical analytical utility is illustrated by selective measurements of paraquat in real water samples.

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Determination of Paraquat by Square-Wave Voltammetry at a Perfluorosulfonated Ionomer/Clay-Modified Electrode

1996

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Analytical method for the simultaneous determination of diquat and paraquat residues in potatoes by high‐pressure liquid chromatography

Worobey¹

1987

Pestic. Sci.

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A novel method was developed for the simultaneous determination of diquat and paraquat residues in potatoes. Potato tissues were spiked at several levels and extracted with acid using a micro‐reflux procedure with 5 g of sample; this was followed by adjusting the hydrolyzate pH to 9 to 10 and using a silica Sep‐Pak for rapid clean‐up and preconcentration. Aliquots of the final eluate were taken to dryness, dissolved in the h.p.l.c. mobile phase and analyzed as their heptanesulfonate ion‐pairs by u.v.‐h.p.l.c. (reverse phase column chromatography) at 254 and 313 nm for paraquat and diquat, respectively. A detection limit of approximately 0.05 mg kg−1 dication in a 5‐g sample of spiked potato (i.e. 0.25 μg ml−1 final extract) was achieved. Recoveries of 79.5 to 97.6% were obtained at spiking levels of 0.05 to 5.0 mg kg−1 for diquat and paraquat with coefficients of variation not greater than 8.27%. The method was developed and validated using 14C‐radiolabelled diquat and paraquat; u.v.‐h.p.l.c. recoveries were comparable with recoveries determined by radioassay. Several parameters affecting the extraction, adsorption and chromatography of diquat and paraquat were evaluated. The formula weights of diquat and paraquat were determined and their importance described; they were determined as mono‐ and tetra‐hydrates, respectively.

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Evaluation of paraquat concentrations in paraquat poisoning

Ikebuchi

1987

Arch Toxicol

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The toxicological significance of paraquat concentrations in paraquat poisonings was evaluated by means of multivariate analysis methods. Paraquat could be determined by a newly developed procedure, which involved thin-layer chromatography with flame ionization detector (TLC-FID) and solid-phase extraction with a disposable octadecylsilane cartridge. This new method proved to be simple, rapid and reliable for the analysis of paraquat in our seven cases of suicidal poisoning. The relationship between plasma paraquat concentration (C) and time from ingestion (T) could be best described by the following functions. The regression equation of fatal cases was ln[ln(C X 1000)] = 2.5453 - 0.2114 lnT. The regression equation of survivors was ln[ln(C X 1000)] = 2.1041 - 0.2826 lnT. The discriminant function (D) to separate the fatal and survival cases was D = 1.3114 - 0.1617 lnT - 0.5408 [ln(C X 1000)] (fatal cases: D less than 0, survivors: D greater than 0). The discriminant function was demonstrated to have a high reliability for the toxicological significance in our seven poisoned patients. The significant correlation between plasma paraquat concentration and urine paraquat concentration (C') in our cases was obtained. The regression equation was lnC' = 0.953 lnC + 1.409. This also indicated that urinary concentrations are 3.3 - 4.5 times greater than plasma concentrations. The multiple regression equation among plasma paraquat concentration, time from ingestion, and the ingested volume (V) of Gramoxone (trade name of paraquat), was lnC = 0.009V - 0.232T + 3.612. It is suggested that the determination of paraquat is of great value, and that these data are useful in assessing the severity and predicting the outcome of poisoning for forensic and clinical purposes.

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Analysis of paraquat formulations by liquid chromatography

Cited by 17 publications

References 11 publications

Determination of Paraquat by Square-Wave Voltammetry at a Perfluorosulfonated Ionomer/Clay-Modified Electrode

Determination of Paraquat by Square-Wave Voltammetry at a Perfluorosulfonated Ionomer/Clay-Modified Electrode

Analytical method for the simultaneous determination of diquat and paraquat residues in potatoes by high‐pressure liquid chromatography

Evaluation of paraquat concentrations in paraquat poisoning

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