Determination of paraquat in blood and urine by liquid chromatography-electrospray-mass spectrometry

Paraquat (PQ) is a toxic quaternary ammonium compound widely used in agriculture. Numerous cases of paraquat intoxication have been reported either accidentally or intentionally as suicidal attempts. A method for the determination of the herbicide PQ in blood and urine samples was developed using liquid chromatography-(electrospray ionization) mass spectrometry (LCESI-MS), following extraction with Oasis® WCX solid-phase cartridges. Chromatographic separation was achieved using an Atlantis® HILIC silica column, eluted isocratically with acetonitrile and ammonium formate (200mM) buffer, pH 3.8, at a 300 µL/min flow rate. Quantitation was achieved by the addition of ethyl paraquat as internal standard (IS). The compounds were detected monitoring two ions for PQ (m/z 185 and m/z 171) and m/z 213 for the IS. The method was applied to determine PQ in two cases: a non fatal case, a 42-year-old female with 0.13 µg/mL PQ concentration in blood and 6.29 µg/mL in urine and a lethal case, a 51-year-old male with 0.27 µg/ mL PQ concentration in blood. The authors developed a specific, sensitive and rapid assay for the identification and quantification of PQ, very important for monitoring suspected paraquat intoxications in hospitals and subsequently help in the treatment of these patients

Elastin Degradation and Lung Function Deterioration with Remote Secondhand Tobacco Smoke Exposure in Never-smokers.

BackgroundProlonged past exposure to secondhand tobacco smoke (SHS) in never-smokers is associated with abnormal lung function and reduced diffusing capacity suggestive of an associated lung tissue injury and damage. The mechanisms by which past SHS exposure may contribute to lung tissue damage are unknown. Elastin is a major constituent of extracellular matrix in lung parenchyma.ObjectiveTo determine whether past exposure to SHS is associated with ongoing lung tissue damage as indicated by elevated elastin degradation products that are linked to lung function.MethodsWe measured the plasma levels of elastin degradation markers (EDM) from 193 never-smoking flight attendants with a history of remote SHS exposure in aircraft cabins and 103 nonsmoking flight attendants or sea-level control participants without such history of cabin SHS exposure and examined those levels versus their lung function with adjustment for covariates. The cabin SHS exposure was estimated based on airline employment history and years of the smoking ban enactment.ResultsThe median [interquartile range] plasma EDM level for all participants was 0.30 [0.24-0.36] ng/mL with a total range of 0.16-0.65 ng/mL. Plasma EDM levels were elevated in those with a history of exposure to cabin SHS compared to those not exposed (0.33±0.08 versus 0.26±0.06 ng/mL; age- and sex-adjusted P<0.001). In those with a history of cabin SHS exposure, higher EDM levels were associated with a lower diffusing capacity (parameter estimate [PE] 95% [confidence interval(CI)]=4.2 [0.4-8.0] %predicted decrease per 0.1 ng/mL increase in EDM; P=0.030). Furthermore, EDM levels were inversely associated with forced expiratory volume in 1 second (FEV1), FEV1 to forced vital capacity (FVC) ratio , and forced expiratory flow rate between 25% and 75% ( FEF25%-75%) (PE [95%CI]=5.8 [2.1-9.4], 4.0 [2.2-5.7], and 12.5 [5.8-19.2] %predicted decrease per 0.1 ng/mL increase in EDM, respectively; P<0.001). Plasma EDM mediated a substantial fraction of the association of SHS with FEV1, FVC, and FEF25%-75% (P<0.05).ConclusionsLong after past exposure to SHS, there is ongoing elastin degradation beyond what is expected from the aging process, which likely contributes to lower lung function and a reduced pulmonary capillary bed as seen in chronic obstructive pulmonary disease (COPD)