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Exposure of agricultural workers in rice paddies to the insecticide chlorantraniliprole and its subsequent potential health risks were investigated during two scenarios (mixing/loading and hand-held spraying). The exposure factors, such as the outer dosimeter, inner dosimeter, gauze, and nitrile gloves, were calculated using whole-body dosimetry to measure dermal exposure. The inhalation exposure was determined using a fiberglass filter which is set with an Institute of Occupational Medicine (IOM) sampler. A recovery test was performed to evaluate the accuracy of the analytical method.The exposure amounts of various matrices were calculated from extraction volume and concentration of the target compound. The dermal exposure to chlorantraniliprole was 0.6 mg [0.001% of the total active ingredient (a.i.)] for mixing and loading, and 28.6 mg (0.066% of the total a.i.) for application. The inhalation exposure to chlorantraniliprole was 7.2 μg (1.3%, 1.2 × 10The risk assessment results demonstrated that the risk of chlorantraniliprole exposure in rice paddies was low during application than during mixing and loading. © 2022 Society of Chemical Industry.

Background: The efficacy and safety of equine cartilage as a competent xenograft material for rhinoplasty were evaluated and compared to the outcomes of rhinoplasty using silicone implants.Methods: We performed a multicenter, double-blind, non-inferiority, and randomized confirmatory study. Fifty-six patients were randomized 1:1 to the study group (using MegaCartilage-E) and control group (using silicone implants). The Rhinoplasty Outcome Evaluation (ROE) score, photo documentation, Global Aesthetic Improvement Scale (GAIS), and adverse event data were obtained until 12 months after surgery. The primary efficacy, which is the change in ROE score 6 months after surgery, was assessed in the modified intention-to-treat set. The secondary efficacy was evaluated in the per-protocol set by assessing the change in ROE score 6 and 12 months after surgery and nasofrontal angle, the height of the nasion, and GAIS 1, 6, and 12 months after surgery.Results: The change in ROE score of the study group was non-inferior to that of the control group; it increased by 24.26 ± 17.24 in the study group and 18.27 ± 17.60 in the control group (p = 0.213). In both groups, all secondary outcome measures increased, but there was no statistical difference. In the safety set, treatment-emergent adverse events occurred in 10 patients (35.71%) in the study group and six patients (21.43%) in the control group (p = 0.237). There were 13 adverse device events in the study group and six adverse device events in the control group (p = 0.515).Conclusion: Processed equine cartilage can be used effectively and safely as xenograft material for rhinoplasty.

In the present study, dermal and inhalation exposure of agricultural workers to insecticide, flubendiamide were determined during pesticide mixing/loading, and hand-held sprayer application in Kimchi cabbage fields, and the potential health risk was assessed. Dermal exposure amount during mixing/loading was 0.8 mg, whereas there was no inhalation exposure (0.0 µg) during similar procedures. Among several different body parts, the hands were the most prominent exposure area (84.5%), followed by the chest and stomach (10.1%). The protective role of PPE (personal protective equipment) during application was determined by comparative experiments with- and without-PPE. The dermal and inhalation exposure with PPE was 3.7 mg and 12.0 µg, respectively. The Forearms (29.6%) and pelvis (18.7%) showed the highest pesticide exposure, followed by the chest and stomach (18.4%). However, the exposure amount of without-PPE was 47.7 mg, and 22.9 µg, respectively, where shins were the most prominent exposure area (83.0%). For the risk assessment of the mixing/loading and application, the AOEL (acceptable operator exposure level) of flubendiamide was used as the reference dose to calculate that the RI (risk index) was much lower than 1 (mixing/loading:0.0, application with PPE:0.2), indicating that agricultural workers are at low risk of exposure to flubendiamide. On the other hand, in the case of an application without PPE, RI is higher than 1 (9.8), suggesting that it can be at risk.

Black pepper, dried green fruit of Piper nigrum L., is a household spice most popular in the world. Piperine, the pungency compound of black pepper, is proposed to partially arise from phenylpropanoid pathway. In the biosynthesis of piperine, 4-coumarate:CoA ligase (4CLs) must play a pivotal role in activating intermediate acids to corresponding CoA thioesters to serve as substrates. Based on transcriptome data, we isolated three P. nigrum 4CL isoforms (Pn4CL1, -2, and -3) from unripe peppercorn. These Pn4CLs were expressed in E. coli for in vitro enzyme assay with putative substrates, namely cinnamic, coumaric, ferulic, piperonylic, 3,4-methylenedioxycinnamic (3,4-MDCA), and piperic acids. Phylogenetic analysis and substrate usage study indicated that Pn4CL1, active towards coumaric and ferulic acids, belongs to class I 4CL for lignin synthesis. Pn4CL2 was a typical cinnamate-specific coumarate:CoA ligase-like (CLL) protein. The Pn4CL3, as class II enzyme, exhibited general 4CL activity towards coumaric and ferulic acids. However, Pn4CL3 was also active towards piperonylic acid, 3,4-MDCA, and piperic acid. Pn4CL3 possessed ∼2.6 times higher catalytic efficiency (kcat/KM) towards 3,4-MDCA and piperic acid than towards coumaric and ferulic acids, suggesting its specific role in piperine biosynthesis. Different substrate preference among the Pn4CL isoforms can be explained by 3-dimensional protein structure modeling, which demonstrated natural variants in amino acid residues of binding pocket to accommodate different substrates. Quantitative PCR analysis of these isoforms indicated that Pn4CL1 transcript level was highest in the roots whereas Pn4CL2 in the fruits and Pn4CL3 in the leaves.

The dissipation of ethoprophos and tricyclazole in soil and their translocation tendency to spinach were investigated. Prior to field trials, the analytical method for the determination of these pesticide residues was optimized and validated on soil and spinach. The field trial was conducted under greenhouse conditions for two different pretreatment periods with the pesticides. After treating with pesticides 30 (PBI-30) and 60 days (PBI-60) before seeding, soil samples were collected on different days for the dissipation study of soil. Spinach samples were harvested from the soil, and 50% and 100% mature spinach samples were collected. The initial amounts of ethoprophos residue in the PBI-60 and PBI-30 soils were 0.21 and 2.74 mg/kg, respectively, and these both decreased to less than 0.01 mg/kg on the day of spinach harvest. Similar initial residues of tricyclazole were observed in the PBI-60 (0.87 mg/kg) and PBI-30 soils (0.84 mg/kg), and these decreased to 0.44 and 0.34 mg/kg, respectively. The half-lives of ethoprophos in the soils were calculated as 7.6 and 4.8 days, respectively, while relatively long half-lives of 36.5 and 77.0 days were calculated for tricyclazole. According to the pesticide residue amounts in the spinach, the translocation rate from the soil to the spinach was determined. In the case of ethoprophos, the residual amount was already rapidly degraded in the soil, and the translocation rate could not be confirmed. On the other hand, for tricyclazole, it was confirmed that 1.19 to 1.61% of the residual amount in soil was transferred to spinach. According to these results, safe management guidelines for tricyclazole in soil were suggested considering the maximum residue limit on spinach.

The change in the existing business environment in the B2B enterprise is in response to customers’ requests. As customers need convey, the first change in the business environment is the uncertainty of demand while allowing the customer’s own industry stage strategy to turn into smooth progression, shorter product life cycles. The technological competition is really overwhelming. As a result, in this study, it is confirmed that the measurement items used in manufacturing industry can be applied to B2B companies, and further, it can contribute to the diffusion into service industries such as finance and public sectors. However, as a future suggestion, this study provides methodology approach according to the long-term and macroscopic dynamic concept applied with multiple techniques, unlike the existing correlation and the regression analysis in applying the methodologies between the service quality and the lower dimension (the economic quality, technical quality, processing quality, sympathy quality and the convenience quality).

The low temperature phase Mn55Bi45-xGax (x = 0, 1, 3, 5, and 10) alloys were prepared by induction melting process with subsequent low temperature annealing. The effects of Ga-doping on the crystal structure and magnetic properties of the alloys were systematically studied. The room temperature coercivities of Mn55Bi45-xGax after ball milling increased from 1.43 T for x = 0 to 1.66 T for x = 5, while the saturation magnetization decreased from 60.7 Am2/kg (x = 0) to 45.1 Am2/kg (x = 5). The maximum energy product (BH)max of Mn55Bi44Ga powders reached 7.87 MGOe. The Curie temperature of the Mn55Bi45-xGax alloys increased from 633 K to 658 K with increasing Ga concentration in the range of 0 ≤ x ≤ 5.

Tenebrio molitor larvae (mealworm) is an edible insect and is considered a future food. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a novel method for simultaneous analysis of 353 target analytes was developed and validated. Various sample preparation steps including &ldquo, quick, easy, cheap, effective, rugged, and safe&rdquo, (QuEChERS) extraction conditions, number of acetonitrile-hexane partitions, and dispersive-solid phase extraction (dSPE) sorbents were compared, and the optimal conditions were determined. In the established method, 5 g of homogenized mealworms was extracted with acetonitrile and treated with QuEChERS EN 15662 salts. The crude extract was subjected to three rounds of acetonitrile-hexane partitioning, and the acetonitrile layer was cleaned with C18 dSPE. The final solution was matrix-matched and injected into LC-MS/MS (2 &mu, L). For target analytes, the limits of quantitation (LOQs) were &le, 10 &mu, g/kg, and the correlation coefficient (r2) of calibration was &gt, 0.990. In recovery tests, more than 90% of the pesticides showed an excellent recovery range (70&ndash, 120%) with relative standard deviation (RSD) &le, 20%. For more than 94% of pesticides, a negligible matrix effect (within &plusmn, 20%) was observed. The analytical method was successfully applied and used for the detection of three urea pesticides in 4 of 11 mealworm samples.

Multiresidual pesticide analysis in hair can provide useful perspectives on the relationship between pesticides and human health. To establish a rapid and simultaneous analytical method using LC-MS/MS and GC-MS/MS, optimization of hair pulverization, extraction solvent and purification with dispersive SPE was performed for 300 pesticides. Hair pulverization was standardized with a ball mill, at 30 Hz for 20 min (10 min twice), using 3-mm diameter beads. For extraction, 0.1% formic acid in acetonitrile was selected, and PSA d-SPE was chosen for clean-up among three different types of solid phase extraction. The limits of quantitation (LOQs) in this method were between 2.5 and 7.5 pg mg-1. In recovery test, fifty milligrams of hair powder were extracted with 0.1% formic acid in acetonitrile, and incubated for three h at 40 ℃. The crude extract was treated using PSA-dSPE, dried under nitrogen gas, and reconstructed with acetonitrile. An aliquot was analyzed with LC- and GC-MS/MS. Recovery ranges were 22.7-131.1%, in LC-MS/MS analysis, and 81.1-151.8% in GC-MS/MS analysis. The validated analysis systems were applied to biomonitoring of ten agricultural workers, and residues of 28 target pesticides were detected in their hair.

Background Vitamin D deficiency has been often observed in obese persons. One of the mechanisms suggested for low vitamin D status in obesity was decreased bioavailability of vitamin D (VD) due to sequestration in adipose tissue. However, only few studies have investigated this mechanism via quantifying vitamin D levels from tissues from the obese. Methods Six-wk-old C57BL/6 mice were fed 10 or 45% kcal fat (CON or HFD) diets containing 50, 1000 or 25,000 IU vitamin D/kg diet (LVd, CVd or HVd) for 13 wks. Serum 25-hydroxyvitamin D (25(OH)D) levels were determined by radioimmunoassay and liver and adipose tissue cholecalciferol (VD) and 25-hydrocholecalciferol (25(OH)D) levels were measured by LC-MS/MS. mRNA levels of jejunal Mttp, Cd36, Sr-b1, Npc1l1, and Abca1 and liver and adipose tissue 25-hydroxylases (Cyp2r1 and Cyp27a1) were determined by real-time PCR. Results Serum 25(OH)D levels were affected by dietary vitamin D content but differential effects were observed between HFD and CON groups. When vitamin D intake was at a supplementary level, the HFD-HVd group had lower serum 25(OH)D levels than the CON-HVd group, while there was no significant difference between the HFD and CON groups fed LVd or CVd. Total amount of VD in liver and adipose tissue were significantly higher in HFD-HVd group compared with the CON-HVd group. However, no difference in total amount of tissue VD was observed between the CON and HFD groups fed CVd. In jejunum, mRNA levels of Mttp and Abca1 were significantly higher in HFD groups than CON groups. There was no difference in mRNA levels of liver 25-hydroxylases by both dietary fat amount and vitamin D content. Conclusion A significant amount of VD seemed to be stored in the liver and adipose tissue when dietary vitamin D is at a supplementation level; thus excess body adiposity could contribute to relatively low serum 25(OH)D level when vitamin D was supplemented.

We aimed to investigate the intestinal permeability and interaction of cyazofamid with clinically important transporters. The intestinal permeability of cyazofamid was low (0.21 ± 0.02 cm/s), and it is a substrate for P-glycoprotein (P-gp) with a Km value of 83.1 μM, indicated that P-gp in the intestinal lumen could serve as a protective barrier to this fungicide. Cyazofamid was not a substrate for clinically important transporters. However, cyazofamid inhibited organic cation transporter 3 (OCT3) and OAT1, with IC50 values of 1.54 and 17.3 μM, respectively, but could not result in OAT3- and OAT1-mediated cyazofamid-drug interactions because of its low plasma concentration. Cyazofamid poorly interacted with OCT1, OCT2, organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, P-gp, breast cancer resistance-related protein, and multidrug resistance-related protein 2. In conclusion, the interactions of cyazofamid with human drug transporters have been evaluated as part of the safety assessment. Given its low intestinal permeability and poor interaction with human drug transporters, cyazofamid might not cause serious toxicity or adverse events.

Doxorubicin, an anthracycline antitumor antibiotic, acts as a cancer treatment by interfering with the function of DNA. Herein, liquid chromatography-tandem mass spectrometry was for the first time developed and validated for the simultaneous determination of doxorubicin and its major metabolites doxorubicinol, doxorubicinone, doxorubicinolone, and 7-deoxydoxorubicinone in mouse plasma. The liquid&ndash, liquid extraction of a 10 &mu, L mouse plasma sample with chloroform:methanol (4:1, v/v) and use of the selected reaction monitoring mode led to less matrix effect and better sensitivity. The lower limits of quantification levels were 0.5 ng/mL for doxorubicin, 0.1 ng/mL for doxorubicinol, and 0.01 ng/mL for doxorubicinone, doxorubicinolone, and 7-deoxydoxorubicinone. The standard curves were linear over the range of 0.5&ndash, 200 ng/mL for doxorubicin, 0.1&ndash, 200 ng/mL for doxorubicinol, and 0.01&ndash, 50 ng/mL for doxorubicinone, doxorubicinolone, and 7-deoxydoxorubicinone in mouse plasma. The intra and inter-day relative standard deviation and relative errors for doxorubicin and its four metabolites at four quality control concentrations were 0.9&ndash, 13.6% and &ndash, 13.0% to 14.9%, respectively. This method was successfully applied to the pharmacokinetic study of doxorubicin and its metabolites after intravenous administration of doxorubicin at a dose of 1.3 mg/kg to female BALB/c nude mice.

Mertansine, a tubulin inhibitor, is used as the cytotoxic component of antibody&ndash, drug conjugates (ADCs) for cancer therapy. The effects of mertansine on uridine 5&prime, diphospho-glucuronosyltransferase (UGT) activities in human liver microsomes and its effects on the mRNA expression of cytochrome P450s (CYPs) and UGTs in human hepatocytes were evaluated to assess the potential for drug&ndash, drug interactions (DDIs). Mertansine potently inhibited UGT1A1-catalyzed SN-38 glucuronidation, UGT1A3-catalyzed chenodeoxycholic acid 24-acyl-&beta, glucuronidation, and UGT1A4-catalyzed trifluoperazine N-&beta, d-glucuronidation, with Ki values of 13.5 &micro, M, 4.3 &micro, M, and 21.2 &micro, M, respectively, but no inhibition of UGT1A6, UGT1A9, and UGT2B7 enzyme activities was observed in human liver microsomes. A 48 h treatment of mertansine (1.25&ndash, 2500 nM) in human hepatocytes resulted in the dose-dependent suppression of mRNA levels of CYP1A2, CYP2B6, CYP3A4, CYP2C8, CYP2C9, CYP2C19, UGT1A1, and UGT1A9, with IC50 values of 93.7 109.1, 36.8 18.3, 160.6 167.4, 32.1 14.9, 578.4 452.0, 539.5 233.4, 856.7 781.9, and 54.1 29.1 nM, respectively, and decreased the activities of CYP1A2-mediated phenacetin O-deethylase, CYP2B6-mediated bupropion hydroxylase, and CYP3A4-mediated midazolam 1-hydroxylase. These in vitro DDI potentials of mertansine with CYP1A2, CYP2B6, CYP2C8/9/19, CYP3A4, UGT1A1, and UGT1A9 substrates suggest that it is necessary to carefully characterize the DDI potentials of ADC candidates with mertansine as a payload in the clinic.

Since cannabis and amphetamine-type stimulants (ATS) are drugs of abuse used alone and concurrently worldwide, it is important to analyze them simultaneously. However, there are no reports of analytical method for the simultaneous extraction of these compounds and metabolites in hair samples of suspected drug abusers, due to the different chemical properties of acidic and lipophilic cannabinoids, and basic and hydrophilic ATS. We developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method for the quantification of cannabidiol (CBD), cannabinol (CBN), (-)-trans-Δ

Additional file 1.

In this study, we developed a multiresidue method for the analysis of 310 pesticides in representative agricultural produce (brown rice, orange, and spinach) using ultra high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) combined with a modified QuEChERS procedure. The optimal mobile phase composition (Methanol containing 5 mM ammonium formate and 0.1% formic acid) produced high sensitivity and reliable results. Also, the relationship between injection volume and repeatability of peak area was investigated. Most of the target pesticides had a limit of quantitation under 10 ng g−1, and correlation coefficients (r2) > 0.99 in matrix-matched standards within the range of 1–100 ng g−1. To validate the optimized method, recovery tests were performed with each of the crops at 10 and 50 ng g−1 spiking levels (n = 5). Satisfactory recoveries were achieved showing that 86.8–88.7% (at 10 ng g−1) and 91.9–96.1% (at 50 ng g−1) of the pesticides met the validation criteria (recoveries in the range of 70–120% and relative standard deviation ≤ 20%). Fifteen compounds were found to show a loss of recovery due to adsorption by primary and secondary amine or graphite carbon black. In the case of brown rice, 86.1% of pesticides showed an insignificant matrix effect (

A multiresidue analysis method for the simultaneous determination of 203 pesticides in soybean was developed using solid-phase extraction (SPE) and gas chromatography–tandem mass spectrometry (GC–MS/MS). Scheduled multiple reaction monitoring by GC–MS/MS was optimized in electron ionization mode. The target pesticides satisfied the method limit of quantitation below 0.01 mg/kg, and an excellent instrumental repeatability was obtained. The calibration curve correlation coefficients (r2) for 201 (99.0%) pesticides were ≥ 0.990. The Multiclass Pesticide Multiresidue Method (No. 2) of the Korea Food Code was scaled down and applied for efficient sample treatment. Soybean sample (10 g) was extracted with 20 mL acetonitrile. The sample was filtered, partitioned with sodium chloride, and centrifuged. The supernatant (8 mL) was subjected to cleanup with a florisil SPE cartridge (500 mg), and the final extract was subjected to GC–MS/MS analysis. To remove fat, further liquid–liquid partitioning with n-hexane/acetonitrile was conducted before the SPE cleanup, and this procedure was compared to the non-partitioning procedure. The percentage of pesticides satisfying the recovery range of 70–120% with a relative standard deviation ≤ 20% in the non-partitioning and partitioning procedures were 87.2% and 78.8% at 0.01 mg/kg and 88.2% and 76.8% at 0.05 mg/kg, respectively. The average matrix effect value (%) was 5.5%. This miniaturized analytical method can be successfully applied for rapid and sensitive monitoring of multiresidues in soybean and related agricultural products.

This study examined dermal and inhalation exposure of agricultural operators to kresoxim-methyl during pesticide mixing/loading and speed sprayer application (10 replicates, each of 3000 L of spray suspension) in an apple orchard and performed risk assessment. For the whole body dosimetry (WBD) exposure protocol, outer clothing, inner clothing, gauze, and nitrile gloves were examined to measure dermal exposure. In contrast, an IOM (institute of occupational medicine) sampler with a glass fiber filter was used to measure inhalation exposure. Analytical method accuracy in the exposure matrices was evaluated by a field recovery study. The dermal and inhalation exposure amounts for mixing/loading were 9.7 mg [0.002% of the total mixed/loaded active ingredient (a.i.)] and 1.2 µg (1.7 × 10−6% of the total mixed/loaded a.i.), respectively. The body parts more exposed were the forearms (35.5%), chest & stomach (30.2%), and hands (17.9%). During application, the dermal and inhalation exposure amounts were 66.5 mg (0.009% of the total applied a.i) and 34.8 µg (4.6 × 10−5% of the total applied a.i.), respectively. The shins (18.5%) and chest & stomach (16.0%) were exposed to higher proportion of pesticide, followed by the thighs (15.8%) and back (14.7%). Comparing the exposure pattern as assessed by the WBD method in the present study with the patch method as in our previous study, the ADE (actual dermal exposure) as measured by the WBD method was 25 times less than that measured by the patch method. The daily exposure amounts of ADE and AIE (actual inhalation exposure) for mixing/loading were 711.8 µg/day and 4.3 µg/day, respectively, whereas the amounts of ADE and AIE for application were 1825.8 µg/day and 116.1 µg/day. In risk assessment of the mixing/loading and application scenarios, the AOEL (acceptable operator exposure level) of kresoxim-methyl was used as the reference dose to show that the RI (risk index) was much lower than 1, indicating that agricultural operators are at low risk of exposure to kresoxim-methyl.

In this study, we performed the metabolism of endosulfan sulfate in human liver preparations (human liver microsomes, S9 fractions and hepatocytes) to identify new metabolites using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Endosulfan sulfate is a major oxidized metabolite of the organochlorine insecticide endosulfan, and it exhibits a similar toxicity to endosulfan. Six metabolites, including 5 novel metabolites of endosulfan sulfate, were identified in the three different human liver reaction mixtures and metabolic pathways of endosulfan sulfate were proposed. The phase I metabolites M1 and M2 were observed in human liver microsomes, S9 fractions and hepatocytes. M1 was suggested to be an endosulfan diol monosulfate and M2 was identified as (1,4,5,6,7,7-hexachloro-3-formylbicyclo[2,2,1]hept-5-en-2-yl)methyl hydrogen sulfate through the interpretation of the HRMS spectrum. The phase II metabolite M3 was produced as an endosulfan sulfate-GSH conjugate in those three liver preparations and transformed to M5 (dipeptide) in S9 fractions and hepatocytes. M3 was the most predominant metabolite identified in the three liver preparations. M4 was only detected in microsomes as an M2-GSH conjugate and was metabolized to M6 (monopeptide) in hepatocytes. These results are different from the metabolic pathway of endosulfan and suggest the possible detoxification metabolic reaction of endosulfan sulfate in living organisms.

Background This study described and analysed the features of powered mobility device (PMD)-related injuries and compared elderly and younger adult injuries. Methods Data from Korea Emergency Department-based Injury In-depth Surveillance (EDIIS) database involving eight emergency departments in 2011–2016 were analysed. The inclusion criteria were injuries sustained during the use of PMDs. The variables were compared between adults aged ≥ 65 years and younger adults. Primary and secondary outcomes were severe trauma and poor clinical course accordingly. The logistic regression analysis was used to identify risk factors for study outcomes. Results A total of 231 adults were enrolled, of whom 150 were ≥ 65 years of age. The total number of PMD-related injuries and the proportion of elderly injured patients increased annually, and most injuries occurred on the roadway and did not involve crash opponents. By multivariate analysis, patients aged ≥ 65 years had a higher injury severity score (adjusted odds ratio [AOR], 2.78; 95% confidence interval [CI], 1.50–5.40) and had a higher incidence of intensive care unit admissions, surgery, and death (AOR, 2.42; 95% CI, 1.16–5.28). Conclusion Given the higher number and severity of injuries sustained among elderly adults ≥ 65 years of age shown in this study, we recommend that safety educations, such as the use of protective equipment and the safe driving on the roadway, are considered for PMD users ≥ 65 years of age., Graphical Abstract

A screening method for simultaneous analysis of 379 pesticides in human serum was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Electrospray ionization with positive/negative switching mode of LC-MS/MS was adopted, and scheduled multiple reaction monitoring for each target compound was established. The limit of quantitation was 10 ng/mL for 94.5% of the total pesticides, and the correlation coefficients of calibration were ≥0.990 for 93.9% of the pesticides. For the sample preparation, scaled-down QuEChERS were used. Serum (100 μL) was extracted with acetonitrile (400 μL), partitioned with magnesium sulfate (40 mg) and sodium chloride (10 mg), and the upper layer was used for analysis without further cleanup steps. For the accuracy and precision tests, most of the pesticides showed excellent results in intra- and interday conditions. In the recovery tests at 10, 50, and 250 ng/mL, 85.8-91.8% of all target compounds satisfied the recovery range of 70-120% (relative standard deviation ≤20%).

Agricultural workers exposed to pesticides can experience adverse health impacts depending on toxicity and exposure amount. Whole-body dosimetry (WBD) is the most reliable, practical, and realistic method for measuring exposure. Since validation of analytical and experimental methodologies is critical for quantitative determination of exposure, we conducted a validation procedure to design an essential protocol for WBD exposure studies. Using the fungicide kresoxim-methyl, matrix-matched standards were prepared with various matrices including outer cloth, inner cloth, washing solution for gloves and hands, gauze, and glass fiber filter (IOM sampler) to determine the instrumental limit of quantitation for high-performance liquid chromatography (HPLC) (2 ng) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) (10 pg). Method limits of quantitation (MLOQ) were also set for HPLC (0.1 mg/L) and LC–MS/MS (0.005 mg/L). We observed good analysis repeatability (coefficient of variation 0.998) in the range of 0.001–10 mg/L in various matrices. Recovery tests were carried out at three levels of concentration (MLOQ, 10 MLOQ, and 100 MLOQ) and resulted in good recoveries (72.7–105.6%). We did not observe breakthrough of the compound in tests of holding capacity for glass fiber pesticide filters. The procedures established in the present study are applicable as an essential, comprehensive protocol for exposure assessment studies using WBD.