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

Synthesis of weak cation exchange/C18 bifunctional magnetic polymers for pretreatment and determination of glufosinate and its two metabolites in plasma samples

This study focuses on the purification and detection of glufosinate (GLUF) and its metabolites N-acetyl GLUF and MPP in plasma samples. A Dikma Polyamino HILIC column was used for the effective retention and separation of GLUF and its metabolites, and the innovative addition of a low concentration of ammonium fluoride solution to the mobile phase effectively improved the detection sensitivity of the target analytes. Monodisperse core-shell weak cation exchange (WCX)/C18 bifunctional magnetic polymer composites (Fe3O4@WCX/C18) were prepared in a controllable manner, and their morphology and composition were fully characterized. The Fe3O4@WCX/C18 microspheres were used as a magnetic solid-phase extraction (MSPE) adsorbent for the sample purification and detection of GLUF and its metabolites in plasma samples combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purification conditions of Fe3O4@WCX/C18 microspheres for GLUF and its metabolites in spiked plasma samples were optimized to achieve the best MSPE efficiency. The purification mechanisms of the target analytes in plasma samples include electrostatic attraction and hydrophobic interactions. Furthermore, the effect of the molar ratio of the two functional monomers 4-VBA and 1-octadecene in the adsorbent was optimized and it shows that the bifunctional components WCX/C18 have a synergistic effect on the determination of GLUF and its metabolites in plasma samples. In addition, the present study compared the purification performance of the Fe3O4@WCX/C18 microsphere-based MSPE method with that of the commercial Oasis WCX SPE method, and the results showed that the Fe3O4@WCX/C18 microsphere-based MSPE method established in this work had a stronger ability to remove matrix interferences. Under optimal purification conditions, the recoveries of GLUF and its metabolites in plasma were 87.6-111 % with relative standard deviations (RSDs) ranging from 0.2 % to 4.8 %. The limits of detection (LODs, S/N≥3) and limits of quantification (LOQs, S/N≥10) were 0.10-0.18 μg/L and 0.30-0.54 μg/L, respectively. The MSPE-LC-MS/MS method developed in this study is fast, simple, accurate and sensitive and can be used to confirm GLUF intoxication based not only on the detection of the GLUF prototype but also on the detection of its two metabolites.

Determination of pesticide residues in urine by chromatography-mass spectrometry: methods and applications

Introduction

Pollution has emerged as a significant threat to humanity, necessitating a thorough evaluation of its impacts. As a result, various methods for human biomonitoring have been proposed as vital tools for assessing, managing, and mitigating exposure risks. Among these methods, urine stands out as the most commonly analyzed biological sample and the primary matrix for biomonitoring studies.

Objectives

This review concentrates on exploring the literature concerning residual pesticide determination in urine, utilizing liquid and gas chromatography coupled with mass spectrometry, and its practical applications.

Method

The examination focused on methods developed since 2010. Additionally, applications reported between 2015 and 2022 were thoroughly reviewed, utilizing Web of Science as a primary resource.

Synthesis

Recent advancements in chromatography-mass spectrometry technology have significantly enhanced the development of multi-residue methods. These determinations are now capable of simultaneously detecting numerous pesticide residues from various chemical and use classes. Furthermore, these methods encompass analytes from a variety of environmental contaminants, offering a comprehensive approach to biomonitoring. These methodologies have been employed across diverse perspectives, including toxicological studies, assessing pesticide exposure in the general population, occupational exposure among farmers, pest control workers, horticulturists, and florists, as well as investigating consequences during pregnancy and childhood, neurodevelopmental impacts, and reproductive disorders.

Future directions

Such strategies were essential in examining the health risks associated with exposure to complex mixtures, including pesticides and other relevant compounds, thereby painting a broader and more accurate picture of human exposure. Moreover, the implementation of integrated strategies, involving international research initiatives and biomonitoring programs, is crucial to optimize resource utilization, enhancing efficiency in health risk assessment.

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 determination of glyphosate and glufosinate in human blood by probe electrospray ionization tandem mass spectrometry

In forensic science, glyphosate (GLYP) and glufosinate (GLUF), a class of non-selective broad-spectrum herbicides, have been frequently encountered in many fatal poisoning and suicide cases due to their widespread availability. Therefore, it is essential to develop an effective method for detecting these compounds. Some conventional methods, such as gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS), have been reported to detect these compounds. However, these methods are not ideal for their time-consuming and non-sensitive feature. Herein, probe electrospray ionization (PESI) tandem mass spectrometry (MS/MS), a fast and sensitive technique, was applied for the determination of GLYP and GLUF in human blood, which can obtain analytical results within 0.5 min without derivatization and chromatographic separation. After protein precipitation of blood samples, the supernatant was mixed with isopropanol and ultra-pure water (1:1 v/v). Then, 8 μL of the mixture was introduced into the plastic sample plate for PESI-MS/MS analysis. The limits of detection (LODs) of the method were 0.50 μg/mL and 0.25 μg/mL for two analytes, and the limits of quantitation (LOQs) were both 1.00 μg/mL, which are higher than the concentration of reported poisoning and fatal cases. In the linear range of 1-500 μg/mL, the regression coefficients (r2) for GLYP and GLUF were over 0.99. The matrix effects ranged from 94.8 % to 119.5 %, and the biases were below 4.3 %. The recoveries ranged between 84.8 % and 107.4 %, and the biases were below 7.6 %. Meanwhile, the method was effectively utilized to detect and quantify the blood, urine, and other samples. Consequently, the results suggest that PESI-MS/MS is a straightforward, fast, and sensitive method for detecting GLUF and GLYP in forensics. In the future, PESI-MS/MS will become an indispensable technique for polar substances in grassroots units of public security where rapid detection is essential.

Simultaneous determination of diquat, paraquat, glufosinate, and glyphosate in plasma by liquid chromatography/tandem mass spectrometry: from method development to clinical application

Diquat (DQ), paraquat (PQ), glufosinate (GLU), and glyphosate (GLYP) are commonly used herbicides that have been confirmed to be toxic to humans. Rapid and accurate measurements of these toxicants in clinical practice are beneficial for the correct diagnosis and timely treatment of herbicide-poisoned patients. The present study aimed to establish an efficient, convenient, and reliable method to achieve the simultaneous quantification of DQ, PQ, GLU, and GLYP in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) without using derivatization or ion-pairing reagents. DQ, PQ, GLU, and GLYP were extracted by the rapid protein precipitation and liquid-liquid extraction method and then separated and detected by LC-MS/MS. Subsequently, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, extraction recovery, matrix effect, dilution integrity, and stability were evaluated to validate the method based on the FDA criteria. Finally, the validated method was applied to real plasma samples collected from 166 Chinese patients with herbicide poisoning. The results showed satisfactory linearity with low LOD (1 ng/mL for DQ and PQ, 5 ng/mL for GLU, and 10 ng/mL for GLYP, respectively) and low LOQ (5 ng/mL for DQ and PQ, 25 ng/mL for GLU and GLYP, respectively). In addition, the precision, accuracy, extraction recovery, and stability of the method were acceptable. The matrix effect was not observed in the analyzed samples. Moreover, the developed method was successfully applied to determine the target compounds in real plasma samples. These data provided reliable evidence for the application of this LC-MS/MS method for clinical poisoning detection.

Biomonitoring of glyphosate and aminomethylphosphonic acid: Current insights and future perspectives

Glyphosate is one of the most widely used herbicides globally, raising concerns about its potential impact on human health. Biomonitoring studies play a crucial role in assessing human exposure to glyphosate and providing valuable insights into its distribution and metabolism in the body. This review aims to summarize the current trends and future perspectives in biomonitoring of glyphosate and its major degradation product of aminomethylphosphonic acid (AMPA). A comprehensive literature search was conducted, focusing on studies published between January 2000 and December 2022. The findings demonstrated that glyphosate and AMPA have been reported in different human specimens with urine as the dominance. Sample pretreatment techniques of solid-phase and liquid-liquid extractions coupled with liquid/gas chromatography-tandem mass spectrometry have achieved matrix elimination and accurate analysis. We also examined and compared the exposure characteristics of these compounds among different regions and various populations, with significantly higher levels of glyphosate and AMPA observed in Asian populations and among occupational groups. The median urinary concentration of glyphosate in children was 0.54 ng/mL, which was relatively higher than those in women (0.28 ng/mL) and adults (0.12 ng/mL). It is worth noting that children may exhibit increased susceptibility to glyphosate exposure or have different exposure patterns compared to women and adults. A number of important perspectives were proposed in order to further facilitate the understanding of health effects of glyphosate and AMPA, which include, but are not limited to, method standardization, combined exposure assessment, attention for vulnerable populations, long-term exposure effects and risk communication and public awareness.

Quantitation of glyphosate, glufosinate, and AMPA in drinking water and surface waters using direct injection and charged-surface ultra-high performance liquid chromatography-tandem mass spectrometry

Herbicides glyphosate (N-(phosphonomethyl)glycine) and glufosinate (2-amino-4-(hydroxymethylphosphinyl)butanoic acid) and the main transformation product of glyphosate, aminomethanephosphonic acid (AMPA), are challenging to analyze for in environmental samples. The quantitative method developed by this study adapts previously standardized dechlorination procedures coupled to a novel charged surface C18 column, ultra-high performance liquid chromatography-tandem mass spectrometry, polarity switching, and direct injection. The method was applied to chlorinated tap water, as well as river samples, collected in the City of Winnipeg and rural Manitoba, Canada. Using only syringe filtration without derivatization, the validated method resulted in good accuracies in both tap and surface water, at both 2 and 20 μg L-1. Method limits of detection (MLD) and quantification (MLQ) ranged from 0.022/0.074 to 0.11/0.36 μg L-1, with precisions of 0.46-2.2% (intraday) and 1.3-7.3% (interday). The mean (SEM) of the pesticides in μg L-1 for tap water were 0.11 (0.007) (AMPA), glufosinate and glyphosate < MLDs; and for Red River water were 0.56 (0.045) (AMPA), glufosinate < MLQ, and glyphosate 0.40 (0.072). For the smaller tributaries, glufosinate was >MLD but < MLQ once and that was for Shannon Creek at 0.2 μg L-1. For the remaining rivers, the mean concentrations ranged from 0.31 to 3.1 μg L-1 for AMPA, and 0.087-0.53 μg L-1 for glyphosate. The method will be ideal for supporting monitoring and risk assessment programs that require high throughput sampling and quantitative methods capable of producing robust results that leverages chromatographic and mass spectrometric paradigms instead of being extraction technology focused.

Surface multi-walled carbon nanotube modified quaternary amine-functionalized polymers for purification and determination of glyphosate and its four metabolites in plasma samples

The present study focused on the pretreatment and detection of GLY and its four metabolites AMPA, N-acetyl AMPA, N-methyl GLY and N-acetyl GLY in plasma samples. Multi-walled carbon nanotube-modified quaternary amine-functionalized polymers (QA-PDNV@MWCNTs) were synthesized in a controlled manner by self-assembly, and its morphology and composition were extensively characterized. The QA-PDNV@MWCNTs microspheres were then used as an SPE adsorbent for the preparation and rapid determination of GLY and its four metabolites in plasma samples combined with ultra-performance liquid chromatography-high resolution mass spectrometry (UPLCHRMS). The SPE conditions based on QA-PDNV@MWCNTs were optimized for GLY and its metabolites to obtain the best purification efficiency. The experimental results show that when the adsorbent contains 8% MWCNTs, it can balance the adsorption of target analytes and the purification performance of the adsorbent for impurities. In addition, this study compared the QA-PDNV@MWCNTs based SPE method with the commercial Waters Oasis MAX SPE cartridge and the results showed that the developed method in this study has better resistance to matrix interference. Under optimal conditions, the recoveries of GLY and its metabolites spiked in plasma were 82.6-99.4 % with relative standard deviations (RSDs) of 1.0-7.8 %. The limits of detection (LODs, S/N ≥ 3) and limits of quantification (LOQs, S/N ≥ 9) of the method were 0.05-0.33 μg/L and 0.15-1.00 μg/L, respectively. Finally, the developed QA-PDNV@MWCNTs based SPE-UPLCHRMS method was used to confirm GLY poisoning not only on the basis of the detection of the GLY prototype, but also on the basis of its four metabolites.

Highly sensitive determination of multiple pesticide residues in foods by supercritical fluid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry

This experiment aimed to establish a green, simple and highly sensitive method (supercritical fluid chromatography (SFC) coupled with ion mobility quadrupole time-of-flight mass spectrometry (IM-Q-TOF/MS)) for the detection of multiple pesticides in foods. During the experiments, several important SFC parameters, such as stationary phase, modifier, make-up solution, back-temperature and back-pressure were optimized. Here, single-field collision cross section (CCS) values and multifield CCS values of 20 pesticides were examined by IM-Q-TOF/MS as highly specific parameters with excellent experimental precision. In addition, based on accurate mass matching and fragment ion comparison, mass fragments were obtained by IM-Q-TOF/MS, which elucidated the regularities of compound structure and characteristic fragment ions. Under the optimized conditions, satisfactory linearity (R2 ≥ 0.9989) and recoveries (79.60 % to 112.97 %) were obtained. The intra- and interday precisions were favorable, with RSDs lower than 4.91 and 7.65 %, respectively. Additionally, the method showed low limits of detection (0.1-8.8 ng/mL). The proposed method has been successfully applied to the highly sensitive detection of phenylurea herbicide, triazine herbicides, organophosphorus pesticide, pyrethroid insecticide and acaricide in yam and potato.

Simultaneous determination of water-soluble herbicides using hydrophilic interaction liquid chromatography-mass spectrometry

PURPOSE

The analysis of water-soluble herbicides, including glyphosate (Glyp), glufosinate (Gluf), paraquat (PQ), and diquat (DQ), is time-consuming and expensive because they cannot be analyzed using general toxicological screening methods. Thus, this study aimed to develop a simple and rapid method to simultaneously analyze these compounds without any derivatization nor ion-pairing reagents.

METHODS

The analytes were separated using hydrophilic interaction liquid chromatography and detected using tandem mass spectrometry. The developed method was applied to plant and biological samples assuming criminal damage and poisoning cases, respectively.

RESULTS

All analytes were separated well and detected with good peak shapes. For plant samples, the herbicides were specifically detected from withered leaves using a simple extraction method. For biological samples, quantitative analysis was successfully validated, and the limit of quantification values of Glyp and Gluf were 0.2 µg/mL, and those of PQ and DQ were 1 ng/mL.

CONCLUSION

The developed method had sufficient performance for practical forensic applications including poisoning cases and malicious uses to damage commercial crops.

Study on the therapeutic effect of glucocorticoids on acute kidney injury in rats exposed to diquat

AIMS

To preliminarily explore, whether glucocorticoids have a therapeutic effect on diquat-induced acute kidney injury in rats.

METHOD

150 Wistar rats were randomly divided into six groups: exposure model group (DQ group), dexamethasone control group (GC group), blank control group (Ctrl group), dexamethasone 2.1 mg/kg dose group (DQ+L-GC group), dexamethasone 4.2 mg/kg dose group (DQ+M-GC group), and dexamethasone 8.4 mg/kg dose group (DQ+H-GC group), with 25 rats in each group. Each group was further divided into five subgroups, 24 h, 3 d, 7 d, 14 d, and 21 d after exposure, according to the feeding time and the course of treatment, with five animals in each subgroup. The rats in DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups were administered 115.5 mg/kg diquat by gavage, respectively. Moreover, 30 min after gavage, rats in DQ+L-GC group, DQ+M-GC group, DQ+H-GC group and GC group were intragastric administered dexamethasone 2.1 mg/kg, 4.2 mg/kg, 8.4 mg/kg and 8.4 mg/kg, respectively. After 7 days, the intraperitoneal injection of dexamethasone was changed to 6.3 mg/kg prednisone by intragastric administration. Subsequently, 7 days later, it was changed to 3.15 mg/kg prednisone by intragastric administration until the end of the experiment on 21 days. After the start of the experiment, changes in the conditions of the rats in each group were observed at a fixed time every day, changes in the body weight of the rats were monitored at the same time, and the death of the rats was recorded at 24 h, 3 d, 7 d, 14 d, and 21 d after exposure. The rats were sacrificed by an intraperitoneal injection of 100 mg/kg sodium pentobarbital overdose. Blood was collected by puncture of the inferior vena cava, used to determine Cr and BUN. The upper segment of the left kidney was collected for histopathological examination. Elisa was used to detect neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in the lower segment of left kidney. TLR4, Myd88, and NF-κB were detected in the right kidney.

RESULTS

(1) After exposure, most rats in DQ group, DQ+L-GC group, DQ+M-GC group and DQ+H-GC group showed shortness of breath, oliguria, diarrhea, yellow hair and other symptoms. No symptoms and related signs were observed in Ctrl group and GC group. (2) The weight of rats in the Ctrl group and the GC group increased slowly during the test. the body weight of the rats in the DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups continued to decrease after self-infection. Body weight dropped to the lowest point at approximately 7 d, and gradually increased from 7 d to 21 d. (3) A small amount of capillary congestion in the medulla was observed after 7 days in the GC group. The DQ group showed tubular atrophy, edema of the epithelial cells, and over time, the tubules were seen dilated and became irregular in shape; large amount of capillary congestion was also observed in the renal cortex and medulla. The renal injury in the DQ+L-GC group was less than that in the DQ group. DQ+H-GC group had no obvious injury before 7 d, but more renal tubules were seen in the DQ+H-GC group from 7 d to 14 d. (4) Compared with the DQ group, there was no difference before 14 d, and at 14 d-21 d, DQ+L-GC group, DQ+M-GC group, DQ+H-GC group all had different degrees of decline. NGAL content: Compared with the DQ group, the content of NGAL and KIM-1 in kidney tissue of the DQ+L-GC, DQ+M-GC, and DQ+H-GC groups decreased compared with the DQ group at each time node. (5) Compared with the Ctrl group, the expression of TNF-α, TLR4, MyD88, NF-κB in the DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups at each time node increased in the renal tissue. The content of TNF-α, TLR4, MyD88, NF-κB in kidney tissue of the DQ+L-GC, DQ+M-GC, and DQ+H-GC groups at each time node was lower than that in the DQ group.

CONCLUSION

(1) Diquat can cause kidney damage in rats, mainly manifested as renal tubular atrophy, epithelial cell edema, capillary congestion and dilation, and the renal function damage indicators have been improved to varying degrees. (2) Glucocorticoids have therapeutic effects on acute kidney injury in rats exposed to diquat. During the treatment, the efficacy of glucocorticoids did not increase with increasing doses after reaching a dose of 4.2 mg/kg. (3) TLR4 receptor-mediated TLR4/Myd88/NF-κB signaling pathway is involved in the inflammatory response of acute kidney injury in diquat poisoning rats. Glucocorticoids can inhibit the inflammatory response, thereby affecting the expression of TLR4/Myd88/NF-κB signaling pathway-related proteins.

Surface-enhanced Raman scattering of a gold core-silver shell-sponge substrate for detection of thiram and diquat

Aiming at the difficulty of traditional pesticide sampling, a low-cost and convenient flexible surface enhanced Raman scattering (SERS) gold core-silver shell-sponge (Au-Ag-sponge) substrate was synthesized by chemical reduction. The SERS substrate consisted of Au-AgNPs and a melamine sponge. The sponge had a rich open pore structure, which could well "capture" Au-AgNPs, generating a large number of "hot spots". The SERS enhancement activity of the flexible substrate was characterized with rhodamine 6G (R6G) Raman probe molecules. The substrate showed good activity to 10-12 M rhodamine 6G with an enhancement factor (EF) of 7.72 × 106. Applying this substrate to the qualitative and quantitative detection of pesticide residues, the results showed that the Raman intensity was well related to the concentration of pesticide solution with the range of 0.1-10 mg L-1 of thiram and 1-10 mg L-1 of diquat. Furthermore, the substrate was analyzed by finite difference time domain (FDTD) simulation and the results were in good agreement with the experimental results. The reason for the difference in Raman signals of pesticide molecules on the same substrate was the different binding modes of Au-AgNPs on the sponge. Finally, we pointed out the advantages of flexible substrates in the field of pesticide residues, as well as future opportunities and challenges.

Methods and Strategies for Biomonitoring in Occupational Exposure to Plant Protection Products Containing Glyphosate

Glyphosate, and the ever growing reliance on its use in agriculture, has been a point of contention for many years. There have been debates regarding the risk and safety of using glyphosate-based herbicides as well as the effects of occupational, accidental, or systematic. Although there have been a number of studies conducted, the biomonitoring of glyphosate poses a series of challenges. Researchers attempting to determine the occupational exposure face questions regarding the most appropriate analytical techniques and sampling procedures. The present review aims to summarize and synthetize the analytical methodologies available and suitable for the purpose of glyphosate biomonitoring studies as well as discuss the advantages and disadvantages of each analytical technique, from the most modern to more well-established and older ones. The most relevant publications that have described analytical methods and published within the last 12 years were studied. Methods were compared, and the advantages and disadvantages of each methods were discussed. A total of 35 manuscripts describing analytical methods for glyphosate determination were summarized and discussed, with the most relevant one being compared. For methods that were not intended for biological samples, we discussed if they could be used for biomonitoring and approaches to adapt these methods for this purpose.

Pesticides monitoring in biological fluids: Mapping the gaps in analytical strategies

Pesticides play a key-role in the development of the agrifood sector allowing controlling pest growth and, thus, improving the production rates. Pesticides chemical stability is responsible of their persistency in environmental matrices leading to bioaccumulation in animal tissues and hazardous several effects on living organisms. The studies regarding long-term effects of pesticides exposure and their toxicity are still limited to few studies focusing on over-exposed populations, but no extensive dataset is currently available. Pesticides biomonitoring relies mainly on chromatographic techniques coupled with mass spectrometry, whose large-scale application is often limited by feasibility constraints (costs, time, etc.). On the contrary, chemical sensors allow rapid, in-situ screening. Several sensors were designed for the detection of pesticides in environmental matrices, but their application in biological fluids needs to be further explored. Aiming at contributing to the implementation of pesticides biomonitoring methods, we mapped the main gaps between screening and chromatographic methods. Our overview focuses on the recent advances (2016-2021) in analytical methods for the determination of commercial pesticides in human biological fluids and provides guidelines for their application.

Negligible Toxicokinetic Differences of Glyphosate by Different Vehicles in Rats

Glyphosate is a non-selective herbicide. Although glyphosate is not acutely toxic, the intake of glyphosate-based herbicides has caused many accidents. Some studies have suggested that surfactants might be the cause. The purpose of this study was to compare the toxicokinetic (TK) properties of glyphosate according to different vehicles in rats. Glyphosate (1%) was dissolved in distilled water (DW), polyoxyethylene tallow amine (POEA), and Tween 20. After a single oral treatment of glyphosate (50 mg/kg), blood was collected at time intervals, and glyphosate concentrations in the target organ (liver and kidney) were determined 24 h after final blood collection. All samples were analyzed using LC-MS/MS. The TK parameters of glyphosate were similar in the DW and Tween 20 groups. However, there were significant differences in Tmax and volume of distribution (Vd) between the DW and POEA group (p < 0.05). Glyphosate was absorbed about 10 times faster in POEA group rather than DW, and exhibited a higher distribution. However, other important TK parameters of T1/2, AUC, and Cmax were not statistically different among the different vehicle groups. Although glyphosate concentration in the liver was significantly higher in the POEA group than in the DW group, there was no significant difference in the kidney. These results indicate that the toxicokinetics of glyphosate are not significantly affected by POEA. It can be concluded that POEA toxicity itself can be attributed to the acute toxicity of glyphosate-containing products.

Paraquat and Diquat: Recent Updates on Their Pretreatment and Analysis Methods since 2010 in Biological Samples

Paraquat (PQ) and diquat (DQ) are quaternary ammonium herbicides which have been used worldwide for controlling the growth of weeds on land and in water. However, PQ and DQ are well known to be toxic. PQ is especially toxic to humans. Moreover, there is no specific antidote for PQ poisoning. The main treatment for PQ poisoning is hemoperfusion to reduce the PQ concentration in blood. Therefore, it is essential to be able to detect PQ and DQ concentrations in biological samples. This critical review summarizes the articles published from 2010 to 2022 and can help researchers to understand the development of the sample treatment and analytical methods for the determination of PQ and DQ in various types of biological samples. The sample preparation includes liquid-liquid extraction, solid-phase extraction based on different novel materials, microextration methods, and other methods. Analytical methods for quantifying PQ and DQ, such as different chromatography and spectroscopy methods, electrochemical methods, and immunological methods, are illustrated and compared. We focus on the latest advances in PQ and DQ treatment and the application of new technologies for these analyses. In our opinion, tandem mass spectrometry is a good choice for the determination of PQ and DQ, due to its high sensitivity, high selectivity, and high accuracy. As far as we are concerned, the best LOD of 4 pg/mL for PQ in serum can be obtained.

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.

[Determination of paraquat and diquat residues in urine samples based on solid-phase extraction and ultra performance liquid chromatography-high resolution mass spectrometry]

Determining the presence of paraquat (PQ) and diquat (DQ) in urine samples through physical and chemical testing is challenging. As PQ and DQ have characteristics such as high molecular polarity and good water solubility, they are difficult to be retained by conventional reversed-phase columns. Most of the methods in the literature use hydrophilic interaction chromatography (HILIC) for the retention of PQ and DQ, but they often require high concentrations of buffer salts as the mobile phase, which increase the contamination of the mass spectrometer. In view of the above problems, a rapid and accurate analysis method was developed for the determination of PQ and DQ residuals in urine samples based on weak cation exchange (WCX) solid-phase extraction (SPE) and ultra performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) in this study. Urine samples were first diluted with phosphate buffer (pH=6.86) and pretreated using the WCX SPE method. Chromatographic separation was performed on a Syncronis HILIC column (100 mm×2.1 mm, 1.7 μm). An electrospray ion source in the positive (ESI⁺) mode and full mass-data dependent MS² (full mass-ddMS²) mode was used for quantification by matrix-matched external standard method. In this study, the concentration of ammonium formate in the mobile phase in the HILIC mode was effectively reduced to 10 mmol/L by the continuous optimization of the chromatographic conditions. MS optimization results indicated that the molecular ion (M^+·) of PQ and DQ had the strongest response. In addition, sample pretreatment conditions were also optimized. The obtained results indicated that the hydrophobic polytetrafluoroethylene (PTFE) filter membrane, acetonitrile-water (1∶1, v/v) as a fixing solution, and polypropylene vials were suitable for PQ and DQ analysis. Under the optimal conditions, the linearity of PQ and DQ was good with correlation coefficients (r²) greater than 0.998. The limits of detection (LODs, S/N≥3) and limits of quantification (LOQs, S/N≥10) were 0.2 μg/L and 0.6 μg/L, respectively. Mean spiked recoveries of PQ and DQ at the four spiked levels (1.0, 20.0, 100.0, and 200.0 μg/L) were in the range of 85.8%-101% and 80.3%-86.9%, with the RSDs of 0.8%-5.1% and 0.9%-4.2%. The established method was employed for the analysis and confirmation of PQ and DQ for clinical poisoning cases. In one case, a 23-year-old male who had taken approximately 20 mL of pesticide orally was confirmed as DQ poisoning by the developed method. DQ concentration monitoring of the urine samples was conducted for this case during the clinical treatment process. The patient was successfully discharged from the hospital after five times of blood perfusion and other treatments until the DQ concentration was low in the urine samples. In conclusion, the method developed in this study based on WCX SPE-UPLC-HRMS can be used for the confirmation of poisoning cases and concentration monitoring during clinical treatment, providing strong technical support for clinical precision treatment. The method is rapid, simple, sensitive, and accurate, and it is suitable for the detection of PQ and DQ in urine samples.

Glyphosate exposure in early pregnancy and reduced fetal growth: a prospective observational study of high-risk pregnancies

BACKGROUND

Prenatal glyphosate (GLY) exposure is associated with adverse reproductive outcomes in animal studies. Little is known about the effects of GLY exposure during pregnancy in the human population. This study aims to establish baseline urine GLY levels in a high-risk and racially diverse pregnancy cohort and to assess the relationship between prenatal GLY exposure and fetal development and birth outcomes.

METHODS

Random first trimester urine specimens were collected from high risk pregnant women between 2013 and 2016 as part of the Indiana Pregnancy Environmental Exposures Study (PEES). Demographic and clinical data were abstracted from mother and infant medical records. Urine glyphosate levels were measured as a proxy for GLY exposure and quantified using liquid chromatography-tandem mass spectrometry. Primary outcome variables included gestation-adjusted birth weight percentile (BWT%ile) and neonatal intensive care unit (NICU) admission. Relationships between primary outcome variables and GLY exposure were assessed using univariate and multivariate linear and logistic regression models.

RESULTS

Urine GLY levels above the limit of detection (0.1 ng/mL) were found in 186 of 187 (99%) pregnant women. Further analyses were limited to 155 pregnant women with singleton live births. The mean age of participants was 29 years, and the majority were non-Hispanic white (70%) or non-Hispanic Black (21%). The mean (± SD) urine GLY level was 3.33 ± 1.67 ng/mL. Newborn BWT%iles were negatively related to GLY (adjusted slope ± SE = -0.032 + 0.014, p = 0.023). Infants born to women living outside of Indiana's large central metropolitan area were more likely to have a lower BWT%ile associated with mother's first trimester GLY levels (slope ± SE = -0.064 ± 0.024, p = 0.007). The adjusted odds ratio for NICU admission and maternal GLY levels was 1.16 (95% CI: 0.90, 1.67, p = 0.233).

CONCLUSION

GLY was found in 99% of pregnant women in this Midwestern cohort. Higher maternal GLY levels in the first trimester were associated with lower BWT%iles and higher NICU admission risk. The results warrant further investigation on the effects of GLY exposure in human pregnancies in larger population studies.

A Method for the Analysis of Glyphosate, Aminomethylphosphonic Acid, and Glufosinate in Human Urine Using Liquid Chromatography-Tandem Mass Spectrometry

The extensive use of herbicides, such as glyphosate and glufosinate, in crop production during recent decades has raised concerns about human exposure. Nevertheless, analysis of trace levels of these herbicides in human biospecimens has been challenging. Here, we describe a method for the determination of urinary glyphosate, its degradation product aminomethylphosphonic acid (AMPA), and glufosinate using liquid chromatography-tandem mass spectrometry (LC−MS/MS). The method was optimized using isotopically labelled internal standards (13C2, 15N-glyphosate, 13C, 15N, D2-AMPA, and D3-glufosinate) and solid-phase extraction (SPE) with cation-exchange and anion-exchange cartridges. The method provides excellent chromatographic retention, resolution and peak shape of target analytes without the need for strong acidic mobile phases and derivatization steps. The instrument linearity was in the range of 0.1−100 ng/mL, with R > 0.99 in the matrix for all analytes. The method detection limits (MDLs) and the method quantification limits (MQLs) were in the ranges of 0.12 (AMPA and glufosinate)−0.14 (glyphosate) ng/mL and 0.40 (AMPA)−0.48 (glyphosate) ng/mL, respectively. The recoveries of analytes spiked into urine matrix ranged from 79.1% to 119%, with coefficients of variation (CVs) of 4−10%. Repeated analysis of samples for over 2 weeks showed intra-day and inter-day analytical variations of 3.13−10.8% and 5.93−12.9%, respectively. The matrix effects for glyphosate, AMPA, and glufosinate spiked into urine matrix averaged −14.4%, 13.2%, and 22.2%, respectively. The method was further validated through the analysis of external quality assurance proficiency test (PT) urine samples. The method offers optimal sensitivity, accuracy, and precision for the urine-based assessment of human exposure to glyphosate, AMPA, and glufosinate.

Fast, sensitive and selective simultaneous determination of paraquat and glyphosate herbicides in water samples using a compact electrochemical sensor

We report a new ready-to-use sensor for simultaneous determination of paraquat (PQ) and glyphosate (GLY) based on a graphite screen-printed electrode modified with a dual-molecularly imprinted polymer coated on a mesoporous silica-platinum core. Amino-mesoporous silica nanoparticles (MSN-NH2) were first synthesized by a simple co-condensation method using tetraethyl orthosilicate and 3-aminopropyltrimethoxysilane. PtNPs were then decorated on the surface of MSN-NH2 by chemical reduction. Finally, the dual-MIP was successfully coated on the MSN-PtNP core. This 3D-surface-imprinting strategy enhances the conductivity and monodispersity of the MSN-PtNPs@d-MIP. Quantitative analysis was performed by differential pulse voltammetry with an oxidation current appearing at -0.95 V for PQ and +0.97 V for GLY. The dual-MIP sensor shows good linear calibration curves in the range of 0.025-500 μM for both analytes with detection limits of 3.1 nM and 4.0 nM for PQ and GLY, respectively. The dual-MIP sensor shows high selectivity and specificity, attributed to the increased affinity of the imprinted cavities formed on the polymer film for the target PQ and GLY molecules. The proposed dual-MIP sensor was successfully applied to detect PQ and GLY concentrations simultaneously in water samples. The ready-to-use dual-MIP sensor is well suited for water-quality control and on-site applications without sophisticated instrumentation.

Simultaneous determination of diquat and its two primary metabolites in rat plasma by ultraperformance liquid chromatography-tandem mass spectrometry and its application to the toxicokinetic study

PURPOSE

This study aimed to develop and validate an ultraperformance liquid chromatography-tandem mass spectrometry to simultaneously determine diquat (DQ) and its two primary metabolites in rat plasma and its application to the toxicokinetic study.

METHOD

The chromatographic separation of DQ and its two primary metabolites was performed with hydrophilic interaction chromatography column by adding formic acid and ammonium acetate in mobile phase in stepwise elution mode. DQ and its two primary metabolites were detected by liquid chromatography-tandem mass spectrometry in positive mode.

RESULTS

The lower limit of quantification ranging from 0.3 to 3.0 ng/mL for DQ and its two primary metabolites was achieved by using only 50 μL of rat plasma. The maximum concentration (C_max) was 977 ng/mL, half-life (t_1/2) was 13.1 h, and area under the plasma concentration-time curve (AUC_0-t) was 2770 h*ng/mL for DQ, C_max was 47.1 ng/mL, t_1/2 was 25.1 h, and AUC_0-t was 180 h·ng/mL for diquat monopyridone (DQ-M) and C_max was 246 ng/mL, t_1/2 was 8.2 h, and AUC_0-t was 2430 h·ng/mL for diquat dipyridone (DQ-D), respectively.

CONCLUSIONS

The validated method was shown to be suitable for simultaneous determination of diquat and its two primary metabolites in rat plasma. This study is the first to study the toxicokinetics of DQ and its two primary metabolites.

Ethanol-extraction SERS strategy for highly sensitive detection of poisons in oily matrix

The sensitive detection and identification of toxicants in oily matrices have suffered from difficulty in poisoning incidents, therefore it is necessary to develop the rapid and efficient analytical method to realize the on-site screening and analyzing. In this report, the surface-enhanced Raman spectroscopy (SERS) method was used to detect paraquat and diquat poisons in various oily matrix coupled with solvent extraction. The solvent extraction not only remove interfering impurities of oily substrates, but also can enrich and separate the poisons from oily matrix. It was demonstrated that the ethanol as the extractant was suitable for the rapid separation of poisons such as paraquat (PQ) and diquat (DQ) in oily matrix (soy sauce, pasta sauce, sesame oil, chili oil). Moreover, combined with a handheld Raman spectrometer, the entire detection process was completed within 8 min with the level of 10 ppb PQ and 100 ppb DQ. Furthermore, double-blind experiments verify the reliability of this method. The results demonstrate that this rapid and convenient method could be used for the effective enrichment and sensitive detection of poisons in several oily matrix and has the grate potential application in emergency response and public safety.

Determination of twenty herbicides in blood by ultrapressure liquid chromatography-tandem mass spectrometry

A sensitive and rapid method for the simultaneous determination of twenty herbicides (aclonifen, lactofen, terbutryn, butylate, carbetamide, fluazifop-P-butyl, propanil, prometryn, isoproturon, terbumeton, pretilachlor, pendimethalin, cycloxydim, tri-allate, metolachlor, diuron, alloxydim, prosulfuron, triflusulfuron-methyl, and acetochlor) in human blood is reported herein. Liquid-liquid extraction coupled with ultra-pressure liquid chromatography-tandem mass spectrometry was employed for the simultaneous analysis of all compounds in 15 min. Validation parameters were studied through the estimation of the limits of detection and quantification, calibration curves, sensitivity, spiked recovery and precision. The limits of detection ranged from 0.1 to 1.0 ng/mL. The limits of quantification ranged from 0.5 to 2.0 ng/mL. Good linearity was obtained for all compounds with R²> 0.99 in all cases. Furthermore, interday precision (< 15%) and intraday precision (< 15%) were shown to be satisfactory. Recoveries in spiked blood samples were evaluated, and acceptable values (88.0%~108.8%) were found. Finally, this method was successfully applied to the determination of fluazifop-P-butyl, isoproturon and acetochlor in blood samples from real forensic cases. These results suggest that this method is reliable for rapid forensic and clinical diagnosis.

Effective removal of the herbicide glyphosate by the kelp Saccharina japonica female gametophytes from saline waters and its mechanism elucidation

Glyphosate has been widely and extensively used for weed control because of its excellent herbicidal profile and low costs. However, more than 750 glyphosate products are on the market and are increasingly regarded as water pollutants as they cause adverse effects on aquatic life. Dry cell weight and photosynthesis of Saccharina japonica female gametophytes increased when glyphosate was used as the sole phosphorus source at the concentration of less than 20 mg L-1. Nuclear magnetic resonance (NMR) analysis unambiguously confirmed that female gametophytes of the brown alga Saccharina japonica have the capability of breaking the C-P bond of glyphosate to orthophosphate, which finds the enormous potential of the most common seaweed to degrade the most widely used herbicide in the world. Furthermore, this is the first report on the use of glyphosate as the sole phosphorus source for the growth of eukaryotic cells. Because of the wide distribution and relatively easy cultivation of the fast-growing brown alga Saccharina japonica on the coast, our results set a promising stage for developing large macroalgae-based biotechnologies that can be applied for the remediation of contaminated seawater, which is greener and more cost-effective than conventional treatment methods.

Analysis of glyphosate, aminomethylphosphonic acid, and glufosinate from human urine by HRAM LC-MS

Aminomethylphosphonic acid (AMPA) is the main metabolite of glyphosate (GLYP) and phosphonic acids in detergents. GLYP is a synthetic herbicide frequently used worldwide alone or together with its analog glufosinate (GLUF). The general public can be exposed to these potentially harmful chemicals; thus, sensitive methods to monitor them in humans are urgently required to evaluate health risks. We attempted to simultaneously detect GLYP, AMPA, and GLUF in human urine by high-resolution accurate-mass liquid chromatography mass spectrometry (HRAM LC-MS) before and after derivatization with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) or 1-methylimidazole-sulfonyl chloride (ImS-Cl) with several urine pre-treatment and solid phase extraction (SPE) steps. Fmoc-Cl derivatization achieved the best combination of method sensitivity (limit of detection; LOD) and accuracy for all compounds compared to underivatized urine or ImS-Cl-derivatized urine. Before derivatization, the best steps for GLYP involved 0.4 mM ethylenediaminetetraacetic acid (EDTA) pre-treatment followed by SPE pre-cleanup (LOD 37 pg/mL), for AMPA involved no EDTA pre-treatment and no SPE pre-cleanup (LOD 20 pg/mL) or 0.2-0.4 mM EDTA pre-treatment with no SPE pre-cleanup (LOD 19-21 pg/mL), and for GLUF involved 0.4 mM EDTA pre-treatment and no SPE pre-cleanup (LOD 7 pg/mL). However, for these methods, accuracy was sufficient only for AMPA (101-105%), while being modest for GLYP (61%) and GLUF (63%). Different EDTA and SPE treatments prior to Fmoc-Cl derivatization resulted in high sensitivity for all analytes but satisfactory accuracy only for AMPA. Thus, we conclude that our HRAM LC-MS method is suited for urinary AMPA analysis in cross-sectional studies.

Micelle-dominated distribution strategy for non-matrix matched calibration without an internal standard: "Extract-and-shoot" approach for analyzing hydrophilic targets in blood and cell samples

The analysis of trace hydrophilic targets in complex aqueous-rich matrices is considerably challenging, generally requiring matrix-matched calibration, internal standard, or time-and-labor-intensive sample preparation. To address this analytical bottleneck, a non-matrix-matched calibration strategy without using internal standard was reported for the first time to analyze complicated biosamples such as whole blood, plasma, serum, and cell samples. This strategy, termed micelle-dominated distribution, also aimed at realizing the simple "extract-and-shoot" analytical process for such complex matrices. The micelle-matrix interaction was found to efficiently eliminate the matrix effect by dominating phase separation and analyte distribution between the extraction and matrix phases. Thus, calibration linear curves prepared in water were applicable to the analysis of all the above-mentioned sample types. Rapid distribution equilibrium within 4 min was achieved. This strategy could tolerate direct large volume injection, thereby providing two-order-of-magnitude enhancement in the sensitivity of ion-pair chromatography. The analytical method integrated cell rupture, matrix cleanup, analyte extraction, and on-column preconcentration into a fast and high-throughput operation. The successful application to the determination of exogenous pesticides and endogenous glutathione exhibited low limits of detection (0.0085-0.015 μg mL^-1 for pesticides; 0.52 μg mL^-1 for glutathione), wide linear ranges (0.028-50 μg mL^-1 and 0.049-50 μg mL^-1 for pesticides; 1.7-1000 μg mL^-1 for glutathione), good linearies (R² = 0.9994-0.9999), excellent accuracy (recoveries of 91.3-105.2%), and good precision (0.7-6.2% at the levels of 0.028 (or 0.049), 0.1, 0.5, and 50 μg mL^-1 for pesticides; 0.5-8.7% at 1.7, 500, and 1000 μg mL^-1 for glutathione).

Robust and highly sensitive micro liquid chromatography-tandem mass spectrometry method for analyses of polar pesticides (glyphosate, aminomethylphosfonic acid, N-acetyl glyphosate and N-acetyl aminomethylphosfonic acid) in multiple biological matrices

Glyphosate is the most used herbicide in agriculture. To monitor glyphosate exposure, analytical methods have to fulfill requirements with regard to sensitivity, reproducibility, ease of handling/high-throughput and applicability to multiple biological matrices. Furthermore, the methods have to include the degradation product of glyphosate, aminomethylphosfonic acid (AMPA) and preferably metabolites of glyphosate and AMPA, N-acetyl AMPA and N-acetyl glyphosate. Majority of the published methods for glyphosate and AMPA require derivatization to be able to achieve high sensitivity. In this work, we present highly sensitive microLC-MS/MS method for simultaneous quantification of glyphosate, AMPA, N-acetyl AMPA and N-acetyl glyphosate in multiple biological matrices without derivatization. The combination of simple sample clean-up procedures for simultaneous handling of 96 sample and short chromatographic run of only 3.4 min, meets the requirements for high-throughput methods. Simple mobile phase of water containing formic and medronic acids and isocratic run provided robust chromatographic separation on hypercarb column. The use of micro-flow system decreased the background noise, increasing the sensitivity. Achieved Low Limits of Quantification (LOQs) for liquid samples (plasma/serum/urine) were 0.00005 mg L-1 and 0.0001 mg kg-1 for solid samples (grain and soybean based feed/stomach/gizzard/intestinal content), which is more than 100 time more sensitive compared to QuPPe-Method. The method was validated in representative matrices with minimum of five fortification levels, six measurements per spiked concentration and three batches. All the samples were spiked with corresponding internal standards for all four analytes before sample clean-up procedures, ensuring high accuracy and precision. Recoveries for plasma/serum ranged between 86-108%, urine 93-120%, feed 91-115% and stomach/gizzard/intestinal content 92-110% with precision below 20%. The method's applicability was tested on 2000 samples measured during one year period.

A simple liquid chromatography-high resolution mass spectrometry method for the determination of glyphosate and aminomethylphosphonic acid in human urine using cold-induced phase separation and hydrophilic pipette tip solid-phase extraction

Recently, the phenomenon of acute poisoning events caused by glyphosate (GLY) had frequently occurred all over the world. The present work reported a simple liquid chromatography-high resolution mass spectrometry (LC-HRMS) method for direct determination of GLY and its metabolite aminomethylphosphonic acid (AMPA) in human urine by combining cold-induced phase separation (CIPS) with hydrophilic pipette tip solid-phase extraction (PTSPE). First, a urine sample was mixed with acetonitrile at a 80% concentration to precipitate proteins. After centrifugation, the mixture was performed a CIPS at -20 °C to enrich GLY and AMPA (six-fold) in the lower water phase which was further performed PTSPE procedure. PTSPE as a miniaturized procedure of SPE, combined with a manual accu-jet® Pro Pipette Controller, was used to extract GLY and AMPA, in which a new type of hydrophilic adsorbent (HILIC powder) based on amide-modified silica was selected as the adsorption of GLY and AMPA. The key factors including the type and the amount of adsorbent, the loading extraction solution, the type and volume of eluent, and the number of aspirating/dispensing cycles were investigated in detail. Meanwhile, the selectivity and sensitivity of GLY and AMPA analysis were improved by the use of LC-HRMS based on targeted single ion monitoring (tSIM) mode without tedious derivatization. This method made a full use of the advantages of these techniques by combining efficient enrichment, effective extraction and selective separation in a simple way. Finally, a comprehensive validation of the method was rigorously executed and the results indicated that the validated method afforded desired linearity, precision, accuracy, and sensitivity.

High throughput residue analysis of paraquat and diquat involving hydrophilic interaction liquid chromatographic separation and mass spectrometric determination

A selective, sensitive and robust LC-MS/MS method is reported for the determination of the residues of paraquat and diquat in various fruit matrices, including grape, apple and pomegranate. The extraction with acidified water (0.1 M HCl) at 80°C (15 min) offered superior recoveries for both analytes with a significantly lower matrix effects as compared to the extraction with acidified methanol by the methods reported in the existing literature. The optimised HPLC conditions on hydrophilic interaction liquid chromatography (HILIC) columns, when coupled with electrospray ionisation-tandem mass spectrometry, offered their limit of quantification at 0.01 mg kg^-1. The analysis on an XBridge HILIC column required a thorough optimisation of the gradient programme to induce chromatographic separation and minimise matrix effects. This was not necessary when a CORTECS HILIC column was used, which provided selective and sensitive analysis within 5 min runtime using isocratic flow. Isotopically labelled internal standards corrected the recoveries of both analytes within 70-120% (RSD < 20%). For the first time, the applications of high resolution accurate mass analysis in the 'time of flight - multiple reaction monitoring' mode have been demonstrated as a complementary means of targeted screening of these compounds at 0.01 mg kg^-1 level. The method has a strong potential for applications in both official control and by those involved in food production for checking compliance with the EU MRLs.

A facile fluorescent "turn-off" method for sensing paraquat based on pyranine-paraquat interaction

Development of a technically simple yet effective method for paraquat (PQ) detection is of great importance due to its high clinical and environmental relevance. In this study, we developed a pyranine-based fluorescent "turn-off" method for PQ sensing based on pyranine-PQ interaction. We investigated the dependence of analytical performance of this method on the experimental conditions, such as the ion strength, medium pH, and so on. Under the optimized conditions, the method is sensitive and selective, and could be used for PQ detection in real-world sample. This study essentially provides a readily accessible fluorescent system for PQ sensing which is cheap, robust, and technically simple, and it is envisaged to find more interesting clinical and environmental applications.

Paraquat Exposure of Pregnant Women and Neonates in Agricultural Areas in Thailand

This study aimed to assess paraquat concentrations in the urine of women at 28 weeks of pregnancy, delivery and 2 months postpartum and in the meconium of neonates. In all, 79 pregnant women were recruited from three hospitals located in agricultural areas in Thailand. The subjects were interviewed about personal characteristics, agricultural activities and pesticide use patterns. Paraquat was analyzed in urine and meconium using high performance liquid chromatography equipped with a fluorescence detector. The geometric mean (GSD) of urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum were 2.04 (4.22), 2.06 (5.04) and 2.42 (5.33) ng/mL, respectively. The urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum between agriculturist and non-agriculturist were not significantly different (p = 0.632, p = 0.915, p = 0.57, respectively). The geometric mean (GSD) of paraquat concentration in the meconium was 33.31 (4.59) ng/g. The factors predicting paraquat exposures among pregnant women and neonates included working outside, living near farmland, having family members who work on a farm, drinking well water and using herbicides or paraquat.

Glyphosate exposure in pregnancy and shortened gestational length: a prospective Indiana birth cohort study

BACKGROUND

Glyphosate (GLY) is the most heavily used herbicide worldwide but the extent of exposure in human pregnancy remains unknown. Its residues are found in the environment, major crops, and food items that humans, including pregnant women, consume daily. Since GLY exposure in pregnancy may also increase fetal exposure risk, we designed a birth-cohort study to determine exposure frequency, potential exposure pathways, and associations with fetal growth indicators and pregnancy length.

METHOD

Urine and residential drinking water samples were obtained from 71 women with singleton pregnancies living in Central Indiana while they received routine prenatal care. GLY measurements were performed using liquid chromatography-tandem mass spectrometry. Demographic and survey information relating to food and water consumption, stress, and residence were obtained by questionnaire. Maternal risk factors and neonatal outcomes were abstracted from medical records. Correlation analyses were used to assess relationships of urine GLY levels with fetal growth indicators and gestational length.

RESULTS

The mean age of participants was 29 years, and the majority were Caucasian. Ninety three percent of the pregnant women had GLY levels above the limit of detection (0.1 ng/mL). Mean urinary GLY was 3.40 ng/mL (range 0.5-7.20 ng/mL). Higher GLY levels were found in women who lived in rural areas (p = 0.02), and in those who consumed > 24 oz. of caffeinated beverages per day (p = 0.004). None of the drinking water samples had detectable GLY levels. We observed no correlations with fetal growth indicators such as birth weight percentile and head circumference. However, higher GLY urine levels were significantly correlated with shortened gestational lengths (r = - 0.28, p = 0.02).

CONCLUSIONS

This is the first study of GLY exposure in US pregnant women using urine specimens as a direct measure of exposure. We found that > 90% of pregnant women had detectable GLY levels and that these levels correlated significantly with shortened pregnancy lengths. Although our study cohort was small and regional and had limited racial/ethnic diversity, it provides direct evidence of maternal GLY exposure and a significant correlation with shortened pregnancy. Further investigations in a more geographically and racially diverse cohort would be necessary before these findings could be generalized.