Paraquat In Urine Research Articles

Portable SERS-Based POCT Kit for Ultrafast and Sensitive Determining Paraquat in Human Gastric Juice and Urine.

Paraquat (PQ) poisoning poses a significant public health concern. Unfortunately, point-of-care testing (POCT) of PQ in biofluids remains challenging. This study developed a portable kit that enables swift and reliable identification and quantification of PQ in human urine and gastric juice. The approach employed the surface-enhanced Raman scattering (SERS) technique, leveraging gold-silver core-shell nanoparticles (Au@Ag NPs) as the substrate. The kit comprised a portable Raman spectrometer and three sealed tubes containing Au@Ag NPs colloid, KI solution, and MgSO4 solution. A discernible correlation was observed between signal intensity and the logarithmic concentration, spanning from 5 to 500 μg/L in urine and 10 μg/L to 1 mg/L in gastric juice. The detection limits, calculated from the characteristic peak at 1648 cm -1, were 1.36 and 4.05 μg/L in human urine and gastric juice, respectively. Notably, this POCT kit obviated the need for pretreatment procedures, and the detection process was accomplished within 1 min, yielding satisfactory recoveries. This expeditious time frame is crucial for clinical diagnosis and rescue operations. Compared to conventional methods, this kit demonstrated real-time determinations in nonlaboratory settings. The simplicity and practicality of this POCT assay suggest its significant potential as an innovative alternative for poisoning detection applications.

Rapid and highly sensitive determination of unexpected diquat and paraquat in biological fluids by electro-enhanced SPME-SERS

Poisoning with diquat (DQ) and paraquat (PQ) herbicides has been a public health problem. Unfortunately, rapid detection in biofluids remains challenging. Herein, a hyphenated approach of electro-enhanced adsorption, solid-phase microextraction, and surface-enhanced Raman spectroscopy (EE−SPME−SERS) was exploited for rapid and sensitive in situ analysis of DQ and PQ in human urine and plasma. A porous Ag fiber with an Au layer (p-Ag/Au fiber) was fabricated with multi-functions (SERS substrate, SPME sorbent, and working electrode). Clear trends could be observed between signal intensity and concentration of DQ or PQ with high reproducibility. The method detection limits (MDLs) calculated from the characteristic peak of DQ were 0.064 ppb and 0.65 ppb in urine and plasma, respectively. Corresponding MDLs for DQ and PQ in urine and plasma were 0.036 ppb and 0.35 ppb, respectively. The whole process of “extracting and detecting” was completed within 4 min with satisfactory recoveries. Notably, the EE−SPME−SERS technique could easily realize in situ analysis of DQ and PQ in biofluids with good selectivity, which is practical in clinical diagnosis. This EE−SPME−SERS method provides a potential avenue for efficient pretreatment and in situ poison detection in biological samples.

LC-MS/MS methods for the determination of 30 quaternary ammonium compounds including benzalkonium and paraquat in human serum and urine

Benzalkyldimethylammonium (or benzalkonium; BACs), alkyltrimethylammonium (ATMACs), and dialkyldimethylammonium compounds (DDACs) have been widely used for over six decades as disinfectants, especially during the COVID-19 pandemic. Here we describe methods for the determination of 7 BACs, 6 ATMACs, 6 DDACs, 8 BAC metabolites, and the structurally similar quaternary ammonium compound (QAC) herbicides diquat, paraquat, and difenzoquat in human serum and urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The methods were optimized using isotopically labelled internal standards and solid-phase extraction with weak cation-exchange cartridges. We separated diquat and paraquat chromatographically using a mixed-mode LC column, and BACs, ATMACs, DDACs, difenzoquat, and BAC metabolites using reversed-phase (C8 and C18) LC columns. Method limits of detection (MLODs) and quantification (MLOQs) were 0.002–0.42 and 0.006–1.40 ng/mL, respectively. Recoveries of all analytes fortified at 1, 5, and 20 ng/mL concentrations in serum and urine matrices were 61–129%, with standard deviations of 0–20%. Repeated analysis of similarly fortified serum and urine samples yielded intra-day and inter-day variations of 0.22–17.4% and 0.35–17.3%, respectively. Matrix effects for analytes spiked into serum and urine matrices ranged from –27% to 15.4%. Analysis of real urine and serum samples revealed the presence of several QACs in human serum. Although no parent BACs were found in urine, we detected, for the first time, several ω-hydroxy and ω-carboxylic acid metabolites of BACs at average concentrations in the range of 0.05–0.35 ng/mL. The developed method is suitable for application in large-scale biomonitoring of human exposure to QACs and their metabolites in human serum and urine.

Development and validation of a sensitive and high throughput UPLC-MS/MS method for determination of paraquat and diquat in human plasma and urine: application to poisoning cases at emergency departments of hospitals.

Paraquat and diquat are well-known toxic herbicides, at least responsible for hundreds of fatal poisoning events worldwide. However, the determination of diquat and paraquat in plasma and urine is very challenging because of their high polarity and double charge characteristics. In this study, we aim to develop a rapid and reliable method for the determination of paraquat and diquat in human plasma and urine by ultraperformance liquid chromatography-tandem mass spectrometry. The chromatographic separation of paraquat and diquat was tested with different chromatographic columns and different mobile phase conditions. The mass parameters were optimized by product ions, source gas flow, cone flow, desolvation temperature, and capillary voltage. The isocratic elution mode gave rapid appearance of peak of paraquat and diquat. The sharp peak shapes for paraquat and diquat were achieved with CORTECS® UPLC® HILIC (100× 2.1mm, 1.6μm) column by adding formic acid and ammonium acetate in mobile phase in isocratic elution mode. The lower limit of quantification of 1.0ng/mL for paraquat and diquat were achieved using only 50 μL of human plasma or urine. The running time for analysis of both paraquat and diquat was as short as 3.5min per sample. A rapid and reliable method for the determination of paraquat and diquat was developed and applied to 387 clinical poisoning cases and 22 poisoning cases were found to be paraquat or diquat poisoning.

Liquid chromatography-tandem mass spectrometry method for the determination of paraquat and diquat in plasma and urine

Objective: To establish a LC-MS/MS method for determination of paraquat and diquat in plasma and urine samples. Methods: Plasma is precipitated by acetonitrile then diluent with phosphate buffer (pH=7) , urine is diluent with phosphate buffer (pH=7) , then diluent samples extracted with Oasis WCX solid-phase extraction column. Samples were analyzed using LC-MS/MS in multiple reaction monitoring (MRM) mode. The analytical column was XBridge®BEH-HILIC (100 mm×2.1 mm×2.5 μm) and the mobile phase were 100 mmol ammonium formate add 0.5% formic acid and acetonitrile. Paraquat was quantified by internal standard method and diquat by external standard method. Results: The calibration curves of paraquat and diquat were linear in the concentration range of 10.0~120.0 μg/L, the correlation coefficient (r) were 0.9985~0.9994. The limit of detection of paraquat in plasma and urine were 1.98 μg/L and 1.00 μg/L, respectively, the recovery rate were 100.2%~107.3%, the RSD were 1.6%~3.3%. The limit of detection of diquat in plasma and urine were 1.80 μg/L and 2.77 μg/L, respectively, the recovery rate were 85.3%~93.1%, the RSD were 1.8%~5.5%. Conclusion: This method is sensitive and accurate, and can simultaneously determine paraquat and diquat in plasma and urine.

Clinical research of the differences between hematocrit and serum albumin for evaluating the severity of acute paraquat poisoning

To investigate the clinical values of the differences between hematocrit and serum albumin (HCT-ALB) for evaluating the severity of patients with acute paraquat (PQ) poisoning. Patients with acute PQ poisoning admitted to the Second People's Hospital of Yunnan Province from January 2018 to December 2019 were enrolled, and healthy voluteers during the same period were selected as the control. The general information, poisoning dose and poisoning time of patients, as well as the HCT and serum ALB levels before blood product infusion, intravenous infusion, or hemopurification at admission were collected, and the HCT-ALB was calculated. According to the results of rapid semiquantitative test of PQ in urine at admission, the patients were divided into PQ low concentration group (0-10 mg/L) and PQ high concentration group (30-100 mg/L). The relationship between poisoning time, poisoning dose, HCT-ALB and the degree of acute PQ poisoning were analyzed, and Spearman method was used to analyze the grade correlation. A total of 295 patients with acute PQ poisoning were enrolled, including 118 cases in PQ low concentration group and 177 cases in PQ high concentration group, and another 200 healthy persons matched with PQ patients in gender and age (healthy control group). The poisoning time of PQ low concentration group was significantly longer than that of PQ high concentration group [hours: 11.0 (6.0, 60.0) vs. 8.0 (5.0, 20.5), P < 0.01], but the poisoning dose was significantly lower than that of PQ high concentration group [mL: 10.0 (5.8, 15.0) vs. 40.0 (20.0, 80.0), P < 0.01]. The HCT and HCT-ALB in PQ low and high concentration groups were significantly higher than those of the healthy control group [HCT: (43.14±4.41)%, (43.54±5.40)% vs. (42.14±2.15)%, HCT-ALB: 3.59±6.26, 5.94±7.80 vs. -7.26±3.55, all P < 0.01], but ALB was significantly lower than that of the healthy control group (g/L: 39.54±5.74, 37.60±7.15 vs. 49.40±3.41, both P < 0.01). With the increase of urine PQ concentration, the HCT and HCT-ALB further increased, and ALB further decreased. There were significant differences between PQ high concentration group and PQ low concentration group [HCT: (43.54±5.40)% vs. (43.14±4.41)%, HCT-ALB: 5.94±7.80 vs. 3.59±6.26, ALB (g/L): 37.60±7.15 vs. 39.54±5.74, all P < 0.05]. The poisoning severity of patients with acute PQ poisoning were negatively correlated with poisoning time and ALB (r values were -0.195 and -0.695, respectively, both P < 0.01), there were positively correlated with poisoning dose, HCT, and HCT-ALB (r values were 0.650, 0.256, 0.737, respectively, all P < 0.01), and the correlation between HCT-ALB and poisoning severity was the strongest. The HCT-ALB can reflect the poisoning severity of patients with acute PQ poisoning and indirectly reveal the pathological changes of microvessels in patients with acute PQ poisoning.

A Paper-Based Analytical Device for Analysis of Paraquat in Urine and Its Validation with Optical-Based Approaches.

Paraquat is a highly toxic herbicide. Paraquat poisoning is often fatal and is an important public health threat in many places. The quick identification and timely initiation of treatment based on timely analysis of the paraquat concentration in urine/serum could improve the prognosis for patients. However, current paraquat concentration measurements are time-consuming and difficult to implement due to the expensive and bulky equipment required. To address these practical challenges, paper-based devices have emerged as alternative diagnostic tools for improving point-of-care testing. In this study, we demonstrate the successful use of a paper-based analytical device for the accurate detection of urine paraquat concentration. The developed paper-based analytical device employs colorimetric paraquat concentration measurements. The R2 value for the urine paraquat standard curve was 0.9989, with a dynamic range of 0–100 ppm. The limit of detection was 3.01 ppm. Two other optical-based approaches, Spectrochip and NanoDrop, were used for comparison. The results suggest that the developed paper-based analytical device is comparable to other colorimetric measurements, as determined by Bland–Altman analysis. The device was clinically validated using urine from six paraquat-poisoned patients. The results prove that the developed paper-based analytical device is accurate, easy-to-use, and efficient for urine paraquat concentration measurement, and may enable physicians to improve clinical management.

Simultaneous determination of paraquat and diquat in plasma and urine by ion chromatography-triple quadrupole mass spectrometry

Paraquat (PQ) and diquat (DQ) are widely used as non-selective contact herbicides. Several cases involving accidents, suicide, and homicide by PQ or DQ poisoning have been reported. Poising by PQ, which is mainly concentrated in the lungs, causes acute respiratory distress syndrome and leads to multiple organ toxicity. The toxic effects of DQ are similar to those of PQ but relatively less intense. The mortality rates in PQ and DQ poisoning are high. Simultaneous monitoring of the PQ and DQ concentrations in plasma and urine can provide valuable information for early clinical diagnosis and prognosis. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is the main analytical method used to detect PQ and DQ in plasma and urine. As both these compounds are highly polar and water soluble, they cannot be retained effectively on a reversed-phase column with conventional mobile phases. The separation of PQ and DQ by ion-pair chromatography or hydrophilic chromatography has been reported. The use of an ion-pairing reagent helps in improving the retention capabilities of PQ and DQ. However, the sensitivity of MS detection is noticeably decreased because of ion suppression caused by the ion-pairing reagent in the mobile phase; furthermore, ion-pairing reagents may contaminate the MS system. The separation of PQ and DQ by hydrophilic chromatography is easily affected by matrix components in the sample, and their retention times are not stable. Considering PQ and DQ are bicharged cation species in solution, they are more suitable for separation by cation-exchange chromatography. A method based on ion chromatography-triple quadrupole mass spectrometry was established for the determination of PQ and DQ in plasma and urine. The plasma and urine samples were diluted with water, and then purified on a solid-phase extraction column containing a polymer-reversed phase and weak ion-exchange mixed-mode adsorbent (Oasis WCX). PQ and DQ were separated on an IonPac CS 18 analytical column (250 mm×2.0 mm, 6.0 μm) with gradient elution using a methylsulfonic acid solution electrolytically generated from an on-line eluent generation cartridge. An in-line suppressor was used to remove methylsulfonate and other anions from the eluent before the eluent entered the mass spectrometer. Between the suppressor and the ion source in MS, the addition of 3% (v/v) formic acid in acetonitrile as an organic modifier (using an auxiliary pump and a T-piece) aided desolvation in the ion source, resulted in a one-or two-fold improvement of the response, and eliminated the residual effects of the adsorption of PQ and DQ caused by ion source. The analytes were detected by triple quadrupole tandem mass spectrometry using positive electrospray ionization in the multiple reaction monitoring (MRM) mode. PQ-d8 and DQ-d4 were used as internal standards. The calibration curves for PQ and DQ showed good linear relationships in the ranges of 1.0-150 μg/L and 0.5-75 μg/L, respectively, and the correlation coefficients were > 0.999. The average matrix effects of PQ and DQ in plasma were 84.2%-89.3% and 84.7%-91.1%, while the average matrix effects of PQ and DQ in urine were 50.3%-58.4% and 51.9%-59.4%. The average recoveries of PQ and DQ in plasma were 93.5%-117% and 91.7%-112%, respectively, with relative standard deviations (RSDs) of 3.4-16.7% and 2.8%-13.2%, and that in urine were 90.0%-118% and 99.2%-116%, with relative standard deviations of 5.6%-14.9% and 2.4%-17.3% (n=6). The limits of detection of PQ and DQ in plasma and urine were 0.3 μg/L and 0.2 μg/L, respectively, with the corresponding limits of quantification being 1.0 μg/L and 0.5 μg/L. This method is sensitive and accurate, and it can be used to determine PQ and DQ for clinical diagnosis and prognosis in patients.

A retrospective analysis reveals a predictor of survival for the patient with paraquat intoxication

Feasible and accurate predictors are urgently needed to evaluate the survival for patients with paraquat poisoning since the high mortality of paraquat poisoning always resulted in the loss of both life and money. Multiple predictors have been developed to predict prognosis of the patients with PQ poisoning, which however heavily depend on the time of admission to hospitals. Here we reported a feasible and accurate prognosis predictor for patients with paraquat poisoning that is independent of the time of admission to hospitals. Patients with paraquat poisoning were enrolled in this study according to the inclusion and exclusion criteria, which were grouped into survivors and non-survivors based on the 90-days follow-up investigation. The concentration of paraquat in serum and urine, and the baseline clinical parameters associated with the injuries of the liver, kidney, and lung were evaluated to predict the survival of these patients by using receiver operating characteristic curve (ROC) analysis, univariate and multivariate cox regression analyses. A total of 114 patients was included in this study with a survival rate of 54.4%. The median survival days of non-survivors were 6.0 (95%Cl: 4.0–7.8). A new predictor, namely paraquat concentration-associated multiorgan injury index (PCAMII), was established by integrating serum and urine paraquat concentration, serum creatinine, alanine aminotransferase, aspartate transaminase, total and direct bilirubin, at different weighting coefficients, with the accuracy of about 90%. The model to predict the survival probability by PCAMII was established with good fitness (R2 = 0.9325), providing the simulated survival rates comparable to the clinical data. PCAMII, which is independent of hospital admission time, is a feasible and accurate marker to predict the survival rate of patients with PQ poisoning.

Separation and Determination of Paraquat and Diquat in Human Plasma and Urine by Magnetic Dispersive Solid Phase Extraction Coupled with High-Performance Liquid Chromatography.

A magnetic dispersive solid phase extraction method coupled with high-performance liquid chromatography was proposed for the simultaneous separation and determination of paraquat (PQ) and diquat (DQ) in human plasma and urine samples. Based on the reduction of PQ and DQ to a blue radical and yellow-green radical by sodium dithionite in an alkaline medium, a fast colorimetric method was also developed for the fast detection of PQ or DQ. In this paper, CoFe2O4@SiO2 magnetic nanoparticles were used as the adsorbent for the magnetic dispersive solid phase extraction of paraquat and diquat, and these two analytes were found to be eluted directly from the adsorbent by NaOH solution. The main factors affecting the extraction efficiency including amount of extractant, extraction time, sample volume, sample solution pH, and elution volume were optimized. Under the optimized experimental conditions, the calibration curve was linear at a concentration range of 28.5–570.2 μg/L, and the correlation coefficient of paraquat and diquat was 0.9986 and 0.9980, respectively. The limits of detection of paraquat and diquat were 4.5 μg/L and 4.3 μg/L. The proposed MSPE-HPLC method was successfully applied to the detection of the paraquat and diquat in human plasma and urine with satisfied recoveries of PQ and DQ in the range of 87.5%–98.7%.

CT manifestations and prognosis of acute paraquat induced lung injury

Objective: To investigate the CT features of lung injury induced by paraquat poisoning and its relationship with prognosis, and to provide reference for the judgment of the condition and prognosis of paraquat poisoning. Methods: 146 cases of paraquat poisoning patients were treated in the Third People's Hospital of Xuzhou City from January 2013 to April 2016. The cases were divided into mild group, moderate-severe group and fulminant group according to the concentration of paraquat in urine. The clinical data and CT imaging findings were analyzed and reconstructed in three-dimensional reconstruction. The extent of the lesion was observed and the relationship between CT and prognosis was explored. Results: Paraquat lung injury has many manifestations on CT images, and it's performance can be intersecting at the same time. Early lesions lighter cases, late CT imaging lesions can be completely absorbed or residual fibrosis, the prognosis was good; the early lesion was pulmonary consolidation, pleural effusion cases, the late CT image was usually pleural thickening and bronchiectasis, the prognosis was relatively good; early lesions were large patches of ground glass opacity cases, finally, pulmonary fibrosis was common, the mortality rate of 56.57%. There were significant differences in the extent of lung injury between different groups (P<0.001) , and the difference in mortality was statistically significant when the lung injury was different (P<0.001) . Multivariate stepwise Logistic regression analysis showed that ground-glass opacity (OR value=2.013) , interstitial lung fibrosis (OR=3.779) and mediastinal emphysema (OR=33.118) were risk factors for death of lung injury caused by paraquat poisoning (P<0.05) . Conclusion: There were many manifestations on CT images of paraquat lung injury, and the manifestations of paraquat lung injury can be intersecting at the same time. The pulmonary manifestations and outcomes of different paraquat types were different. The CT manifestations of lung injury in paraquat poisoning were mainly exudative changes at early stage, and can be gradually absorbed or evolved into interstitial changes at later stage. The cumulative damage range can be used as a reference for evaluating the prognosis. Ground-glass opacity, interstitial pulmonary fibrosis and mediastinal emphysema are the risk factors for death of lung injury caused by paraquat poisoning.

Fabrication of benzenesulfonic acid groups modified magnetic microspheres as an MSPE adsorbent for fast determination of paraquat and diquat in human urine combined with UPLC-HRMS

In this study, novel benzenesulfonic acid groups modified magnetic microspheres (Fe3O4@SiO2@poly(4-VB)) were synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectrometry (FTIR), and vibrating sample magnetometer (VSM). The as-prepared Fe3O4@SiO2@poly(4-VB) was employed as a magnetic-phase extraction (MSPE) adsorbent for rapid determination of paraquat (PQ) and diquat (DQ) in human urine samples coupled with ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). Moreover, this paper had expounded systematically the mass spectrum cracking mechanisms of PQ and DQ. And a zwitterionic functionalized SIELC Obelisc R column was employed for separation and retention of the above two polar herbicides using 50 mmol/L ammonium formate (pH = 3.7)-acetonitrile as the mobile phase. Besides, the adsorption and desorption conditions of Fe3O4@SiO2@poly(4-VB) toward PQ and DQ were optimized in spiking urine samples to obtain the best adsorption and desorption efficiencies. And the adsorption mechanisms of Fe3O4@SiO2@poly(4-VB) toward PQ and DQ referred to synergetic effect of electrostatic attraction and π-π interaction. Under the optimal conditions, the inter-day and intra-day spiking recoveries of the proposed method were in the range of 86.7–109.9% with RSDs less than 10%. The limits of detection (LODs) were obtained by spiking in blank urine samples at a series of low concentrations and were found to be 0.12 μg/L and 0.14 μg/L for PQ and DQ, respectively, which were lower than the comparing literatures. The developed analytical method was proven to be simple, rapid, sensitive, and accurate for clinical poisoning analysis.

A simple and rapid method for determination of paraquat in human urine and plasma by improved solid adsorption using equipment built in-house

A simple and rapid method was developed for clinical naked-eye and quantitative detection of paraquat (PQ) in human plasma and urine samples using built-in-house analytical devices followed by visual colorimetric method and UV–Vis spectrophotometry. A quantitative spectrophotometric method for PQ was also developed based on device built in-house. Different factors influencing the recovery efficiency of PQ such as the pH of the sample solution, the amount of adsorbent, the type and volume of eluent, the extraction and desorption time, the adsorption capacity and sample volume were studied and optimized in detail. Under optimal conditions, the whole analysis time of the naked-eye method was less than 5 min and it provided the detection limit observed with naked eye of 0.2 μg/mL with the detection range between 0.5 and 5.0 μg/mL for paraquat determination. PQ could be detected as low as 6.21 × 10−3 μg/mL in urine and 0.119 μg/mL in plasma with this proposed quantitative spectrophotometric method, respectively. The method was applied in monitoring PQ levels in plasma and urine at different hemoperfusion numbers in local hospitals for patients exposed to PQ poisoning. The detection result could not only enable immediate medical intervention but also benefit patients’ survival.

The internal standard diquat-d4 causes errors in diquat analysis by LC–MS/MS

We report a more reliable method for determination of the herbicide diquat (DQ) in human biological samples using stable isotope dilution liquid chromatography–tandem mass spectrometry (LC–MS/MS). DQ-d8, a newly synthesized stable isotope was used as the internal standard (IS) for quantification of DQ instead of DQ-d4 typically used so far. The use of DQ-d8 could completely prevent errors like the misdetection of DQ and inaccurate quantification probably caused by using DQ-d4. Additionally, we developed a method for simultaneous determination of DQ and the similar herbicide paraquat (PQ) in urine, serum and whole blood by stable isotope dilution LC–MS/MS after solid-phase extraction. The stable isotopes DQ-d8 and PQ-d6 were synthesized and used as ISs. The DQ and PQ in the samples were extracted by solid-phase extraction using an EVOLUTE® WCX. The extracted DQ and PQ were separated and detected by LC–MSMS using a ZIC®-pHILIC column. The recovery rates ranged from 82.0 to 99.7%. Calibration curves showed good linearity in the 0.01–2 μg/mL. The intraday accuracy and intraday precision [% relative standard deviation (RSD)] ranged from 92.1 to 106% and from 0.4 to 4.7%, respectively. The interday precision (%RSD) ranged between 0.8 and 6.7%. The stable isotopes DQ-d8 and PQ-d6 allowed for accurate and precise quantification. Especially for analysis of DQ, the use of DQ-d8 could completely prevent errors caused by using DQ-d4. Therefore, the proposed method would be of great use in criminal investigations and emergency medicine.

The clinical value of combining early urine paraquat clearance rate with severity index of paraquat poisoning in predicting the prognosis for acute paraquat poisoning patients

Objective To investigate the clinical value of combining early urine paraquat early clearance rate(UPCR)with severity index of paraquat poisoning(SIPP)in predicting the prognosis for paraquat poisoning patients. Methods In this retrospective research, a total of 425 cases diagnosed with acute paraquat poisoning from March 2014 to March 2016 in Emergency Intensive Care Unit, First Affiliated Hospital of China Medical University were enrolled. The general data of patients, the results of rapid qualitative test of paraquat in blood and urine, the concentration of paraquat in blood / urine, the poisoning time, the concentration of blood lactic acid and the APACHE Ⅱscore were collected. The early UPCR and SIPP were measured at different time intervals, and the ratio of 6-SIPP and 12 h-UPCR were calculated. These patients were divided into death groups and survival groups according to the 28-day mortality. The relationship between these factors and the mortality were analyzed. Results Of all the 425 patients, 268 cases(63.1%)died, 157 cases(36.9%) survived; the blood concentration of paraquat, the lactate concentration, SIPP values and the APACHE Ⅱ scores were significant difference between the two groups(P 0.05). The 6 h-SIPP/12 h-UPCR value was (41.94±5.9)in death group, which was higher than that in survival group(5.27±3.6)(P<0.05). Conclusion The combined use of early UPCR and SIPP values is an effective indicator of the prognosis of patients with acute paraquat poisoning and is helpful for the early stratification. We should pay more attention to the patients whose rapid qualitative blood test is positive because of their high mortality risk; for the patients whose 12 h urinequalitative test was negative, the hemoperfusion therapy might be stopped because the toxin was completely excluded, and the medical resources can be saved reasonably. The UPCR might indicate the excretion of toxins, and SIPP might indicate the severity of poising. Key words: Urine paraquat early clearance rate; Severity index of paraquat poisoning; Blood paraquat rapid qualitative test; Urine paraquat rapid qualitative test; Prognosis

Magnetic Solid-Phase Extraction Using Fe3O4@SiO2 Magnetic Nanoparticles Followed by UV-Vis Spectrometry for Determination of Paraquat in Plasma and Urine Samples.

A rapid and simple method was optimized and validated for the separation and quantification of paraquat, a frequently used herbicide and a leading cause of fatal poisoning worldwide, at trace levels with UV-Vis spectrophotometry in plasma and urine samples by direct magnetic solid-phase extraction. Fe3O4@SiO2 nanoparticles (NPs) were used as the magnetic solid-phase extraction agents and the paraquat absorbed on NPs was eluted using NaOH and ascorbic acid. Upon optimization, paraquat could be extracted and concentrated from various samples by 35-fold. The linear range, limit of detection (LOD), correlation coefficient (R), and relative standard deviation (RSD) could reach 15.0–400.0 μg/L, 12.2 μg/L, 0.9987, and 0.65% (n = 5, c = 40.0 μg/L), respectively. The Fe3O4@SiO2 NPs could be reused up to five times. The method was successfully applied to the determination of paraquat in urine and plasma at different hemoperfusion numbers in a local hospital for the patient of paraquat poisoning. The experiment result could not only enable immediate medical intervention but also benefit patients' survival.

Optimization of solid phase microextraction procedure for determination of paraquat using reduction process

Headspace solid phase microextraction (HS-SPME) followed by gas chromatography–mass spectrometry was developed for the determination of paraquat in urine. The volatile product resulting from reduction of paraquat by sodium borohydride–nickel chloride was used for HS-SPME. The calibration curve was linear from 10–1000 ng/mL and the limit of detection was 0.1 ng/mL. The optimized methods were validated using 500 and 750 ng/mL concentrations of paraquat in the spiked urine samples. The recoveries obtained in this study were 98.2% for intra-day (n = 6) and 99.2% for inter-day (n = 6), respectively, with RSD lower than 1.1%.

Simultaneous Determination and Quantitation of Paraquat, Diquat, Glufosinate and Glyphosate in Postmortem Blood and Urine by LC-MS-MS.

A simple method, incorporating protein-precipitation/organic backwashing and liquid chromatography-tandem mass spectrometry (LC-MS-MS), has been successfully developed for the simultaneous analysis of four highly water-soluble and less volatile herbicides (paraquat, diquat, glufosinate and glyphosate) in ante- and postmortem blood, urine and gastric content samples. Respective isotopically labeled analogs of these analytes were adopted as internal standards. Acetonitrile and dichloromethane were used for protein precipitation and organic solvent backwashing, respectively, followed by injecting the upper aqueous phase into the LC-MS-MS system. Chromatographic separation was achieved using an Agilent Zorbax SB-Aq analytical column, with gradient elution of 15 mM heptafluorobutyric acid and acetonitrile. Mass spectrometric analysis was performed under electrospray ionization in positive-ion multiple reaction monitoringmode. The precursor ions and the two transition ions (m/z) adopted for each of these four analytes were paraquat (185; 169 and 115), diquat (183; 157 and 78), glufosinate (182; 136 and 119) and glyphosate (170; 88 and 60), respectively. Analyte-free blood and urine samples, fortified with the analytes of interest, were used for method development/validation and yielded acceptable recoveries of the analytes; interday and intraday precision and accuracy data; calibration linearity and limits of detection and quantitation. This method was successfully incorporated into an overall analytical scheme, designed for the analysis of a broad range of compounds present in postmortem samples, helpful to medical examiners' efforts to determine victims' causes of death.

Optimized ultra performance liquid chromatography tandem high resolution mass spectrometry method for the quantification of paraquat in plasma and urine.

A simple, sensitive and specific ultra performance liquid chromatography coupled to electrospray tandem high resolution mass spectrometry (UPLC-ESI-HRMS/MS) method has been developed and validated for quantification of paraquat in plasma and urine. The sample preparation was carried out by one-step protein precipitation with acetonitrile. The paraquat was separated with a HILIC column in 10min. Detection was performed using Q Exactive Orbitrap mass spectrometer by Targeted-MS/MS scan mode. Methodological parameters, such as ammonium formate concentration, formic acid concentration, spray voltage, capillary temperature, heater temperature and normalized collision energy were optimized to achieve the highest sensitivity. The calibration curve was linear over the concentration range of LOQ-1000ng/mL. LOD was 0.1 and 0.3ng/mL, LOQ was 0.3 and 0.8ng/mL for urine and plasma, respectively. The intra- and inter-day precisions were <7.97% and 4.78% for plasma and urine. The accuracies were within the range 93.51-100.90%. The plasma and urine matrices had negligible relative matrix effect in this study. This method was successfully applied to determine paraquat concentration in plasma samples with hemoperfusion from 5 suspected paraquat poisoning patients.

酸化法-液体クロマトグラフィー質量分析による生体試料中のパラコートおよびジクワットの分析

In this study, we developed a method for the detection of the herbicides paraquat (PQ) and diquat (DQ) in human urine and whole blood with an oxidative reaction followed by liquid chromatography/mass spectrometry (LC/MS). Prior to the oxidative reaction, urine samples were cleaned up by dispersive solid phase extraction with Oasis® WCX, and blood samples were deproteinized with sulfosalicylic acid. These pretreated samples were oxidized with 1 mg/mL potassium ferricyanide and 15 M sodium hydroxide. The oxidative products of PQ and DQ were extracted with high recovery rates by solid phase extraction with Oasis® MAX. These extracted oxidative products were successfully separated and detected by LC/MS using a semi micro C18 column in the gradient solvent system of 10 mM ammonium formate (pH 3) and methanol. Quantitative analyses for blood samples were carried out using PQ-d6 and ethyl PQ as internal standards. The calibration curves for PQ and DQ showed good linearity in the range of 10-5000 ng/mL. Precision (R.S.D.) was less than 5.8%, and accuracy was ranged from 99% to 112%.