Paraquat In Urine Research Articles

Liquid Chromatographic Method for Simultaneous Determination of Paraquat and Diquat in Plasma, Urine and Vitreous Humour

Abstract An HPLC method for the simultaneous determination of paraquat and diquat in aqueous solutions and biological fluids (plasma, urine and vitreous humour) was developed. This method is based on the initial ion-pair solvent extraction of both herbicides from plasma or urine. Vitreous humour samples required a protein precipitation and concentration process. Relatively small sample volumes (1 mL of plasma or urine, and 100 μL of vitreous humour) were enough to determine paraquat and diquat by the proposed technique. Chromatography was carried out using a LiChrospher(r) 100 RP-18 (5 μm) column for aqueous solutions and plasma and urine extracts, or a Nova-Pak C18 (3.9 × 150 mm) column for vitreous humour extracts. Two ultraviolet wavelengths were selected, 254 nm for paraquat and 310 nm for diquat. The calibration curves were linear in the concentration ranges 0.42–8.4 μg/mL for aqueous solutions, 0.1–2 μg/mL for plasma, 0.1–3 μg/mL for urine and 0.5–5 μg/mL for vitreous humour.

Quantitation of paraquat in serum by HPLC.

An HPLC method for the quantitation of paraquat in urine was applied to serum. Sample preparation consisted of ion-pair extraction on disposable cartridges of end-capped octadecyl silica. The paraquat thus extracted, was quantitated by HPLC using 1,1'-diethyl-4,4'-dipyridyl dichloride as an internal standard. Relatively small sample volumes (1 mL serum) were required. Within- and between-assay coefficients of variation for the HPLC technique were 2.9% and 4.0%, respectively, at low paraquat serum concentration (0.4 microgram/mL), and 2.4% and 3.2% at high paraquat serum concentration (4.0 micrograms/mL). The between-assay coefficient of variation for the total procedure, including the extraction, was 5.6% at low concentration (0.4 microgram/mL). Serum concentration levels down to 0.025 microgram/mL could be quantitated. The technique was checked for interference from muscle relaxants (pancuronium bromide and vecuronium bromide) and from anticoagulants (heparin and K2EDTA). No interference was observed.

Quantitation of paraquat in biological samples by radioimmunoassay using a monoclonal antibody

We have developed a sensitive and specific radioimmunoassay for the quantitative determination of paraquat in plasma, urine, and bronchoalveolar lavage fluid using a monoclonal antibody. The synthesis of the iodinated paraquat tracer is novel and less complicated than a previously reported method. Regardless of the type of biological sample analyzed, the sensitivity of the assay was 0.46 ng/ml in a 200-μl aliquot. The results correlated well with those of another assay performed in a separate laboratory. Paraquat concentrations were determined in plasma and in urine of a dog over several days after the intravenous administration of 7.48 mg paraquat cation/kg and in bronchoalveolar lavage fluid obtained 34 hr after the 2-hr infusion was discontinued. Concentrations of paraquat measured ranged from 14.1 to 0.03 μg/ml in plasma and 2034 to 0.36 μg/ml in urine. Concentrations of paraquat in plasma obtained at various times after the ingestion of paraquat by three patients ranged from 51.0 to 0.010 μg/ml.

Rapid determination of paraquat in urine with ion-pair extraction and spectrophotometry

Rapid determination of paraquat in urine with ion-pair extraction and spectrophotometry

Toxicokinetics of Paraquat in Humans

1. The toxicokinetics of paraquat were studied in 18 cases of acute human poisoning using a specific radioimmunoassay. Plasma paraquat concentration exhibited a mean distribution half-life (t1/2 alpha) of 5 h and a mean elimination half-life (t1/2 beta) of 84 h. Cardiovascular collapse supervened early during the course of the intoxication and was associated with the distribution phase. Death related to pulmonary fibrosis occurred late and was associated with the elimination phase. 2. Pharmacokinetic analysis of urine paraquat excretion confirmed the biphasic decline of paraquat. Moreover, renal paraquat and creatinine clearances were not correlated but renal paraquat clearance was never higher than the renal creatinine clearance. 3. Tissue paraquat distribution was ubiquitous with an apparent volume of distribution ranging from 1.2 to 1.6 l/kg. Muscle could represent an important reservoir explaining the long persistence of paraquat in plasma and urine for several weeks or months after poisoning.

Rapid quantification of paraquat and diquat in serum and urine using high-performance liquid chromatography with automated sample pretreatment

Rapid quantification of paraquat and diquat in serum and urine using high-performance liquid chromatography with automated sample pretreatment

A rapid and sensitive method for the determination of paraquat in plasma and urine by thin-layer chromatography with flame ionization detection.

A new method for the determination of paraquat in biological fluids has been developed. It involves thin-layer chromatography with flame ionization detection (TLC/FID) and simple solid-phase extraction with a disposable octadecylsilane column. This procedure allows direct loading of the samples on the disposable column. When Chromarod SII is used as the stationary phase and methanol-2N hydrochloric acid (2:3, v/v) as the mobile phase, recovery levels of paraquat in spiked materials are from 87.5 to 98.0%. This method can be used for samples of paraquat at levels as low as 50 ng.

A simple method for measuring paraquat in urine : Fukubayashi M, Harada Y, Suzuki K, et al. Jpn J Acute Med 1987;11(5):599–603

A simple method for measuring paraquat in urine : Fukubayashi M, Harada Y, Suzuki K, et al. Jpn J Acute Med 1987;11(5):599–603

An improved spot-test for the detection of paraquat and diquat in biological samples

herbicides which may be formulated or accidental ingestion may lead to intoxication and it is important to confirm whether these compounds are the cause of poisonings in which the toxicant has not been identified so that appropriate treatment can be given. A simple spot test for paraquat in urine involves the addition of alkali and sodium dithionite powder [1,2]: paraquat is converted to a blue radical ion and the sensitivity of the assay (by visual judgement) is approximately 1 mg/l. (We have recently confirmed unpublished observations by Japanese workers that ascorbic acid powder can be used in this test instead of sodium dithionite as the reducing agent.) The dithionite test is less sensitive for diquat which produces a green colour. Quantitative methods based on the dithionite reaction with a spectrophotometric end-point have also been described to determine paraquat and diquat in plasma [3-61. However no simple method has been published that will allow the distinction between cases involving formulations containing paraquat alone (e.g. Gramoxone), diquat alone (e.g. Reglone) and a mixture of the two compounds (e.g. Preeglox). Recently, a method was developed for extracting paraquat from urine and deproteinised blood using a ‘Sep-Pak’ C,, cartridge [7]. Paraquat is eluted from the cartridge with 0.1 mol/l HCl and the concentration determined spectrophotometritally after dithionite reduction. The maximum recommended sample size for satisfactory recovery of paraquat is 5 ml and the limit of detection for urine and blood 0.4 mg/l. This communication describes an improved version of this procedure in which a silica cartridge is used downstream from a C,, cartridge to adsorb any paraquat and

Determination of the herbicides paraquat and diquat in blood and urine by gas chromatography

A gas chromatographic method is described for determining paraquat (I) and diquat(II) in human blood and urine. I or II was readily precipitated as its reineckate complex (III and IV) by addition of Reinecke reagent, although blood required deproteination with 3.4%; perchloric acid or 10%; trichloroacetic acid. The precipitation is completed in 1 h at room temperature. III and IV were easily reduced by treatment with a mixture of sodium borohydride and nickel(II) chloride to afford corresponding perhydrogenated products, 1,1′-dimethyl-4,4′-bipiperidine (V) from III and trans- and cis-perhydrodipyrido[1,2- a:2′,1′- c] pyrazine (VI) from IV. The perhydrogenated products were determined by gas—liquid chromatography (GLC) without interference from the original components of the blood and urine. The GLC method (5%; potassium hydroxide solution with 5%; Apiezon L on Chromosorb W AW DMCS) is suitable for simultaneous determination with hydrogen flame-ionization detection in the range 1–70 > ml (0.7–50.7 > ml as I ion; 0.5–35.6 > ml as II ion) of I and II in blood and urine. The method could be applicable to the determination of the chemicals in postmortem tissue and as pollutants in soils.

High-performance liquid chromatography of paraquat and diquat in urine with rapid sample preparation involving ion-pair extraction on disposable cartridges of octadecyl-silica

A high-performance liquid chromatographic system is presented which separates the paraquat, diquat and 1,1′-diethyl-4,4′-bipyridyldiylium (internal standard) dications in under 7 min. An octadecyl-silica (ODS-silica) column is used with an eluent of 25 % methanol (v/v) containing sodium heptanesulphonate (0.01 M) and a diethylamine-orthophosphoric acid buffer. The method is suitable for the analysis of paraquat and diquat in commercial weedkillers and human urine samples following poisoning. A rapid procedure for the extraction of the herbicides from urine has been developed using disposable cartridges of ODS-silica pre-treated with sodium heptanesulphonate. The quaternary compounds are extracted as ion-pairs with the hydrophobic sulphonate anions.

Detection of paraquat in urine.

Detection of paraquat in urine.

The analysis of paraquat in urine by high-speed liquid chromatography

The paraquat content of urine can be directly determined by high-speed liquid chromatography using ultraviolet spectrophotometric detection. The method separates paraquat (and diquat) from the ultraviolet-absorbing components of urine and no extraction or pre-treatment of the sample is required prior to analysis. Concentrations down to 100 μg/l of paraquat in urine were determined. Quantitative results are in good agreement with those obtained by a colorimetric method. Diquat does not interfere with the analysis of paraquat, and it would also be possible to analyse diquat in paraquat-containing urine.

Paraquat disposition in rats, guinea pigs and monkeys

LD50 doses of 14C-labeled paraquat were administered to rats, guinea pigs and monkeys by gavage, and radioactivity was determined in excreta and tissues. Rat urine was analyzed for paraquat metabolites by thin-layer chromatography. [ 14C]Paraquat was absorbed from the gastrointestinal tract and reached highest serum values 0.5–1 hr after administration. Disappearance of [ 14C]paraquat from serum was characterized by a rapid initial decline followed by a prolonged slow decline. Tissue paraquat values were higher than serum values in rats and guinea pigs. Relative to other tissues, paraquat accumulated transiently in the lung and reached peak concentration 32 hr after administration. In rats a major portion of administered paraquat was not absorbed from the gastrointestinal tract. At 32 hr after paraquat, 52% of the administered dose remained in the gastrointestinal tract and 17 and 14% of the administered dose was excreted in the feces and urine, respectively. No radioactivity was recovered in expired air or flatus. Excretion of paraquat in urine and feces was prolonged in all species. In monkeys paraquat was measured in urine and feces 21 days after administration. Chromatography of urine from [ 14C]paraquat-treated rats revealed no metabolites. The primary pathologic changes induced by paraquat in the lung may be related to the transient uptake of the chemical by that organ.

The determination of paraquat (1,1′-dimethyl-4,4′-bipyridylium cation) in urine

Three methods of paraquat analysis have been examined and a suitable procedure for clinical laboratory use is recommended. The method is rapid and can determine down to 0.01 μg paraquation/ml in a 250-ml aliquot of urine. A rapid spot test with visual sensitivity of 1–1.5 μg ion/ml is also described. Some urine levels following oral ingestion of paraquat are reported, but it was not possible to correlate the levels found with severity of poisoning.

Rapid Detection and Determination of Paraquat and Diquat in Urine and Gastric Aspirate

Rapid Detection and Determination of Paraquat and Diquat in Urine and Gastric Aspirate