BACKGROUND: Icaridin and DEET are common insect repellents widely used on human skin and clothing (skin-insect repellents [skin-IR]) to repel common pests, such as mosquitoes and biting flies. Novel analytical methods for urinary skin-IR exposure biomarkers that can be effectively applied in epidemiological studies and provide strong evidence related to risk assessment associated with daily exposure are required. In this study, we aimed to develop a method for analyzing the concentrations of icaridin, DEET, and two DEET metabolites N,N-diethyl-3-(hydroxymethyl) benzamide and 3-(diethylcarbamoyl) benzoic acid in human urine. METHODS: In this analysis, after formic acid-induced acidification of the urine sample, exposure biomarkers were extracted using solid-phase extraction composed of a modified polystyrenedivinylbenzene polymer for reversed phase (hydrophobic) retention. Subsequently, high-performance liquid chromatography-tandem mass spectrometry was performed within 10 min for a separation analysis. The present method was applied to five Japanese adults (aged 20-43 years) who used icaridin or DEET-containing products within a week. RESULTS: Limits of detection were 0.06-0.11 µg/L. Extraction recoveries were 74%-88%. The intraday and interday variations were 1.5-17.5 and 0.9-15.8% relative standard deviation, respectively. All exposure biomarkers were successfully detected in all five adults. Urinary concentrations of exposure biomarkers reached their maximum values within 15 h after starting to use skin-IR. CONCLUSIONS This method was successful in measuring urinary exposure biomarkers of skin-IR, including icaridin and DEET. Moreover, this study presents the first application of biomonitoring of urinary icaridin concentrations after using a commercial product.
Humans ; Solid Phase Extraction/methods* ; Tandem Mass Spectrometry/methods* ; Adult ; Insect Repellents/urine* ; DEET/urine* ; Young Adult ; Male ; Japan ; Female ; Chromatography, Liquid ; Biomarkers/urine* ; Chromatography, High Pressure Liquid ; East Asian People

OBJECTIVES: To establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: The blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18, 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol (V_acetonitrile∶V_methanol=2∶3) were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring. RESULTS: The linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients (r) greater than 0.995 6. The limits of detection were 3.00, 0.40 and 1.30 ng/mL, respectively. The limit of quantitation were 8.00, 1.00 and 5.00 ng/mL, respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL, respectively. CONCLUSIONS This method has high sensitivity and good selectivity, which is suitable for the detection of carbamazepine and its metabolites in blood samples, and can be used for carbamazepine-related forensic identifications.
Chromatography, Liquid/methods* ; Tandem Mass Spectrometry ; Methanol ; Carbamazepine/analysis* ; Benzodiazepines/analysis* ; Solvents ; Chromatography, High Pressure Liquid ; Solid Phase Extraction

Objective: A method to determine chlorobenzene metabolite-p-chlorophenol in urine by solid phase extraction-gas chromatography was established. Methods: In May 2021, the urine sample was hydrolyzed at 100 ℃ for 1.5 h with 2 ml concentrated hydrochloric acid. After cooling and filtering, the sample was enriched and purified by Oasis(®)MAX 6cc SPE column. Drip washing with 0.01 mol/L hydrochloric acid solution and elution with acetonitrile, the eluent was volumized to 5 ml with acetonitrile and determined by gas chromatography, and quantify by standard curve method. Results: Calibration curve of the method was linear within the range of 1.61-80.30 μg/ml and showed good linearity with r=0.9997, the regression equation was y=1.51602x-0.10234. The determination limit was 0.17 μg/ml, and the limit of quantitation was 0.55 μg/ml. Recovery rates were between 89.3%-104.4%, the relative standard deviation (RSD) of intra-day measurements ranged from 4.3% to 6.7%, and the RSD of inter-day measurements ranged from 4.5% to 6.7%. Conclusion: This method could optimize sample pretreatment, and eliminate the interference of impurities, which is sensitive, efficient and accurate for the determination of chlorobenzene metabolite-p-chlorophenol in urine.
Acetonitriles ; Chlorophenols ; Chromatography, Gas ; Chromatography, High Pressure Liquid ; Hydrochloric Acid ; Solid Phase Extraction/methods*

BACKGROUND: Glyphosate and its salt formulations are nonselective herbicides that have been extensively used worldwide, both for residential and agricultural purposes. The possible carcinogenicity and teratogenicity of glyphosate remain to be elucidated. We developed a sensitive and high-throughput analytical method for urinary glyphosate using liquid chromatography-tandem mass spectrometry with the aim of contributing to glyphosate exposure assessment in epidemiological studies. METHODS: After urine dilution (creatinine matching dilution to 0.05 g creatinine/L), glyphosate was extracted using two types of solid phase extraction columns (SCX and NH2) with automated sample preparation instruments. The eluate was dried and dissolved in the mobile phase, followed by liquid chromatography-tandem mass spectrometry analysis. The optimized method was applied to urine samples obtained from 54 Japanese adults and children. RESULTS: The results from the validation study demonstrated good recoveries (91.0-99.6%), within- and between-run precisions (< 15%), low detection limits (0.1 μg/L), and lower limit of quantification (0.3 μg/L). The detection frequency and median concentration of the urinary glyphosate in Japanese subjects were 59% and 0.25 μg/L (0.34 μg/g creatinine). CONCLUSIONS Our reliable determination method was successful in measuring urinary glyphosate concentration. Moreover, this is the first biomonitoring report of urinary glyphosate levels in the Japanese general population.
Adult ; Aged ; Chromatography, Liquid/methods* ; Female ; Glycine/urine* ; Humans ; Male ; Middle Aged ; Solid Phase Extraction/methods* ; Tandem Mass Spectrometry/methods*

Positron emission tomography (PET) is a powerful non-invasive molecular imaging technique for the early detection, characterization, and "real-time" monitoring of disease, and for investigating the efficacy of drugs (Phelps, 2000; Ametamey et al., 2008). The development of molecular probes bearing short-lived positron-emitting radionuclides, such as ¹⁸F (half-life 110 min) or ¹¹C (half-life 20 min), is crucial for PET imaging to collect in vivo metabolic information in a time-efficient manner (Deng et al., 2019). In this regard, one of the main challenges is rapid synthesis of radiolabeled probes by introducing the radionuclides into pharmaceuticals as soon as possible before injection for a PET scan. Although many potential PET probes have been discovered, only a handful can satisfy the demand for a highly efficient synthesis procedure that achieves radiolabeling and delivery for imaging within 1-2 radioisotope half-lives. Only a few probes, such as 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) and [¹⁸F]fluorodopa, are routinely produced on a commercial scale for daily clinical diagnosis (Grayson et al., 2018; Carollo et al., 2019).
Lab-On-A-Chip Devices ; Positron-Emission Tomography/methods* ; Radioisotopes/chemistry* ; Radiopharmaceuticals/chemical synthesis* ; Solid Phase Extraction

OBJECTIVE: To establish the solid phase extraction (SPE) with GC/MS technology for fish poisoning cases to determine five pesticides in fishpond. METHODS: By three solid phase extraction column including Oasis HLB cartridge, Bond Elut C18 and SampliQ C18, the recovery rate was compared to extract and purify five pesticides in fishpond. The effects of different kinds and dosages of eluents on extract rate were also reviewed. RESULTS Using Bond Elut C18 as solid phase extraction column and 3 mL benzene as eluent, the linear range of mass concentration of five pesticides in fishpond was 1-50 μg/mL, and the correlation coefficient was 0.996 2-0.999 6. The limit of detection was 3.4-26 μg/L and the recovery was 61.49%-102.48%. The relative standard deviations was less than or equal to 3.01%. CONCLU-SION: With high sensitivity, good accuracy and precision, SPE-GC/MS has simple and quick operation and less solvent. It can be applied to determination of five pesticides in fishpond.
Gas Chromatography-Mass Spectrometry/methods* ; Pesticides/isolation & purification* ; Solid Phase Extraction ; Solvents ; Water Pollutants, Chemical/isolation & purification*

A method was developed for the determination of ochratoxin A (OTA) in human urine by HPLC-FLD after molecularly imprinted polymer solid phase extraction (MIP-SPE) column. After the pH being adjusted to 2.5 with 0.1 mol x L(-1) HC1, sample was cleaned up with MIP-SPE column for ochratoxin A, the analyte was analyzed by high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD), and finally all the positive results were confirmed by LC-MS/MS. Recoveries from urine samples spiked with OTA at levels ranging from 2 to 20 ng x mL(-1) were 90.6%-101.9%, and RSDs were 0.1%-1.6%. Sixty-five volunteers living in Beijing took part in the study, of which 5 were found containing OTA in their urine and the highest value was 0.091 ng x mL(-1). The MIP-SPE column was firstly applied to purify and concentrate OTA in human urine, this method is simple, rapid and reliable and can be used to determine the contents of OTA in human urine.
Chromatography, High Pressure Liquid ; methods ; Female ; Humans ; Male ; Molecular Imprinting ; Ochratoxins ; urine ; Polymers ; Reproducibility of Results ; Sensitivity and Specificity ; Solid Phase Extraction

Suitable pretreatment of biological samples can truly reflect the role of law of the measured components played in the body and will provide experimental evidence for the studies on metabolic process, material basis of efficacy, mechanism of action, pharmacology, toxicology and the others. Biological samples include blood, urine, hair, tears, etc. There are also many samples processing methods, such as the direct protein precipitation, liquid-liquid extraction and solid phase extraction and so on. These methods could be used alone or combined.
Animals ; Body Fluids ; chemistry ; Chemical Precipitation ; Chemistry Techniques, Analytical ; methods ; Humans ; Liquid-Liquid Extraction ; Proteins ; isolation & purification ; Solid Phase Extraction

OBJECTIVEWe aimed to establish a sensitive quantified method for the simultaneous determination of melamine and cyanuric acid residues in water and urine by hydrophilic interaction liquid chromatography coupled with electrospray tandem mass spectrometry (HILIC-ESI-MS/MS) with the pretreatment of hydrophilic functional silica gel and cation exchange resin mixed solid phase extraction column(MCT), and to investigate the melamine and cyanuric acid residues in 501 water and 216 urine from several province and city.

METHODSAbout 100 ml water (or 10 ml urine) was adjusted to pH 3.0 with concentrated hydrochloric acid, and then mixed with the internal standard solution((15)N3-melamine and (15)N3-(13)C3 -cyanuric acid) and 100 ml acetonitrile (10 ml for urine). The solution was cleaned with MCT solid-phase extraction column, and eluted once by 3 ml methanol and twice by 2.5 ml methanol (containing 5% ammonia water). The effluent was collected and dried by N2 flow at 40 °C, and then diluted to 2 mmol/L ammonium acetate containing 90% volume fraction acetonitrile. The completely dissolved solution was then filtered with 0.22 µm organic membrane; and the filtrate was detected by high performance liquid chromatography-tandem mass spectrometry and quantified with internal standards. The repeatability and sensitivity of the assay were evaluated. Then we detected the melamine and cyanuric acid residues in 501 water and 216 urine samples collected from several province and city.

RESULTSBy the quantification of internal standard (15)N3-melamine and (15)N3-(13)C3-cyanuric acid, the melamine and cyanuric acid were linear in the range of 2.0-1000.0 µg/L with correlation coefficient of 0.9998 and 0.9997. The detection limits of the method were separately 0.4 ng/L (melamine) and 0.3 ng/L (cyanuric acid) for water, and 4.0 ng/L (melamine) and 3.0 ng/L (cyanuric acid) for urine. The average recovery rate was around 95.3%-100.1% with the relative standard deviation (RSD) was <4.02%. Out of the 501 water samples, melamine was detected out in 19.9% (100/501) and cyanuric acid was detected out in 5.2% (26/501). The content was around 0.03-5.00 g/L. Melamine or cyanuric acid was detected out in 24.5% of the urine samples (53/216), with the content around 0.01-1.00 g/L.

CONCLUSIONThe established method of solid phase extraction-hydrophilic interaction liquid chromatography-electrospray tandem mass spectrometry can satisfy the requirement for detection of melamine and cyanuric acid residues in all sorts of water and urine. Meanwhile, the two substances widely existed in water and Chinese population.

Chromatography, Liquid ; methods ; Environmental Monitoring ; methods ; Humans ; Mass Spectrometry ; Solid Phase Extraction ; methods ; Triazines ; analysis ; urine ; Urinalysis ; methods

OBJECTIVETo develop an analytical method for simultaneous determination of 6 pesticides, namely bentazone, 2,4-dichlorophenoxyacetic acid,carbofuran, carbaryl, atrazine and pentachlorophenol, in drinking water by high performance liquid chromatography-tandem mass spectrometry, and thereby to provide a reference to revise the Health Standards for Drinking Water (GB/T 5750-2006). Meanwhile, to evaluate the content of the above 6 pesticides in the drinking water samples supplied by 12 centralized water plants in Jiangsu province.

METHODSThe 10 ml water sample was acidized by hydrochloric acid to pH ≤ 2, and then concentrated by solid phase extraction cartridge and eluted with acetone. The solvent was changed into methanol after drying by nitrogen blow. The target compounds were separated by C18 column using methanol/water as mobile phase, and detected by mass spectrometry with multi-reaction-monitoring(MRM) mode. The repeatability and sensitivity of the assay were evaluated. The drinking water samples from the 12 water plants were then detected.

RESULTSIn this experimental method, the minimum detectable concentration were around 0.02-0.41 µg/L, with the recovery rate at 75%-115%, and the RSD between 2% and 10%. Under the experimental condition, there were no pesticides detected in the drinking water samples from the 12 centralized water plants.

CONCLUSIONThe method is efficient and environment-friendly, with little discharge of effluent, which could meet the requirement of the drinking water monitor.

Drinking Water ; analysis ; Pesticides ; analysis ; Solid Phase Extraction ; methods ; Tandem Mass Spectrometry ; methods ; Water Pollutants, Chemical ; analysis