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

This study aims to identify and analyze the metabolites of imperatorin in rats by UHPLC-Q-Exactive Orbitrap MS. Specifically, after rats were treated(ig) with imperatorin, the plasma, urine, and feces were collected, and the samples were processed by solid phase extraction. Then, UHPLC-Q-Exactive Orbitrap MS was performed. In MS, 0.1% formic acid water(A)-acetonitrile(B) was applied as mobile phase for gradient elution and the data of MS in both positive and negative ion modes were collected. The metabolites of imperatorin in blood, urine, and feces of rats were analyzed to explore the metabolic pathways of imperatorin in rats. According to accurate molecular weight, multistage MS data, MS fragmentation rule of the standard substance, and previous reports, a total of 51 metabolites were identified, with 35, 40, and 16 from plasma, urine, and feces, separately. The main metabolic pathways were oxidization, glucuronidation, isopentenyl removal, sulphation, carboxylation, among others. The conclusion in this study is expected to serve as a reference for the further development and the further pharmacodynamics study of imperatorin.
Animals ; Chromatography, High Pressure Liquid ; Feces ; Furocoumarins ; Plasma ; Rats ; 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*

Objective: To establish a method for rapid determination of bongkrekic acid (BA) in plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods: In November 2020, plasma samples were extracted by methanol and acetonitrile (1∶1) and purified directly. The samples were separated by C18 column. Gradient elution was carried out with 5 mmol/L ammonium acetate water acetonitrile solution as mobile phase. Under the optimized instrument conditions, the electrospray ionization multiple reaction monitoring (MRM) mode was used, and the external standard method was used for quantitative analysis. Results: The linear relationship of BA in plasma was good in the concentration range of 2-100 μg/L, the correlation coefficient was 0.9998, the average recovery was 83.7%-112.0%, the relative standard deviation within and between batches was less than 10%, the detection limit of the method was 0.7 μg/L and the lower limit of quantification was 2.0 μg/L. Conclusion: The method is simple, rapid, accurate and sensitive, and can meet the requirements for the determination of BA in blood samples of poisoning patients.
Bongkrekic Acid ; Chromatography, High Pressure Liquid ; Humans ; Solid Phase Extraction ; Tandem Mass Spectrometry

Objective: A method for the determination of acetochlor and its metabolites in urine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established. Methods: After cleaned-up by a HLB extraction cartridges, the urine was eluted with 1% acetic acid acetonitrile solution. The target compounds were separated by ACQUITY UPLC®HSS T3 Column (2.1 mm×100 mm×1.8 μm) by using 1% formic acid solution and acetonitrile as mobile phase with gradient elution program, and analyzed in positive electrospray ionization mode by liquid chromatography tandem mass spectrometry. Results: All the target compounds showed good linear relationships in the range of 1-50 μg/L, and the correlation coefficients (r) were higher than 0.997. The recoveries rates at three different spiked levels for all target compounds in blank matrices were 107.6%-129.1%, and the relative standard deviations (RSD) were 1.5%-9.9% (n=6) . The limits of detection and quantitation of the method were 0.04-0.11 μg/L and 0.15-0.42 μg/L, respectively, and target substances were detected in all urine samples from occupational exposure workers to acetochlor. Conclusion: This method is suitable for rapid screening and analysis of acetochlor and metabolites in urine with the advantages of accuracy, rapidity, simplicity, high sensitivity and good specificity.
Acetonitriles ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Humans ; Solid Phase Extraction ; Tandem Mass Spectrometry ; Toluidines

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*

A method of ultra-high performance liquid chromatography coupled with quadrupole/electrostatic field Obitrap high-resolution mass spectrometry(UHPLC-Q-Exactive MS) was established to comprehensively identify the metabolites of carnosic acid in rats. After oral gavage of carnosic acid CMC-Na suspension in rats, urine, plasma and feces samples were collected and pretreated by solid phase extraction(SPE). Acquity UPLC BEH C_(18 )column(2.1 mm×100 mm, 1.7 μm) was used with 0.1% formic acid solution(A)-acetonitrile(B) as the mobile phase for the gradient elution. Biological samples were analyzed by quadrupole/electrostatic field Obitrap high-resolution mass spectrometry in positive and negative ion mode. Based on the accurate molecular mass, fragment ion information, and related literature reports, a total of 28 compounds(including carnosic acid) were finally identified in rat samples. As a result, the main metabolic pathways of carnosic acid in rats are oxidation, hydroxylation, methylation, glucuronide conjugation, sulfate conjugation, S-cysteine conjugation, glutathione conjugation, demethylation, decarbonylation and their composite reactions. The study showed that the metabolism of carnosic acid in rats could be efficiently and comprehensively clarified by using UHPLC-Q-Exactive MS, providing a reference for clarifying the material basis and metabolic mechanism of carnosic acid.
Abietanes ; Animals ; Chromatography, High Pressure Liquid ; Mass Spectrometry ; Rats ; Solid Phase Extraction

Objective To establish a method for determination of escitalopram in biological samples by ultrasound-assisted ionic liquid-dispersive liquid-liquid microextraction combined with gas chromatography-tandem mass spectrometry （GC-MS/MS） and provide evidences for forensic determination of cases related to escitalopram. Methods The 1-hexyl-3-methylimidazolium hexafluorophosphate （[C₆MIM][PF₆]） was selected as an extract solvent to process biological samples. Ultrasound-assisted extraction was used on the samples. Then the samples were detected by GC-MS/MS. Results The linear range of escitalopram in blood and liver were 5.56-1 111.10 ng/mL and 0.025-5.00 mg/g, respectively. The correlation coefficient （r） were greater than 0.999, limit of detection （LOD） were 4.00 ng/mL and 2.00 μg/g, limit of quantitation （LOQ） were 14.00 ng/mL and 6.00 μg/g, respectively. The extraction recovery rates were all greater than 50%, the interday and intraday precision were less than 20%. Escitalopram was detected in blood and liver samples from the actual poisoning case by this method with a content of 1.26 μg/mL and 0.44 mg/g, respectively. Conclusion The ultrasound-assisted ionic liquid-dispersive liquid-liquid microextraction combined with GC-MS/MS is environment friendly, rapid, has good enriching effect and consumes less organic solvent and can be used for forensic determination of escitalopram related cases.
Citalopram ; Gas Chromatography-Mass Spectrometry ; Limit of Detection ; Liquid Phase Microextraction ; Tandem Mass Spectrometry

Currently, the main sample pretreatment methods for forensic toxic analysis are liquid-liquid extraction （LLE） and solid-phase extraction （SPE）. As a simple, convenient, and low-cost LLE method, dispersion liquid-liquid microextraction （DLLME） has high enrichment factor and good extraction efficiency, and therefore has attracted the attention of many researchers in the field of toxicology analysis in recent years. As a multi-functional microextraction method, DLLME has been widely used in the analysis of pesticides, sleeping sedatives, drugs and heavy metal poisons in forensic toxic analysis. Meanwhile, it can also be used in combination with such a variety of analytical instruments as gas chromatography-electron capture detectors （GC-ECD）, high performance liquid chromatography-diode array detectors （HPLC-DAD）. As a sample pretreatment method, DLLME has the advantages of simple operation, less use of organic solvent, reliable results and good reproducibility, thus can meet the requirements of modern court toxic analysis.
Forensic Toxicology ; Liquid Phase Microextraction ; Reproducibility of Results ; Solid Phase Extraction ; Solvents

Objective To investigate the maximum allowable deviation of ion abundance ratios of characteristic fragment ions in common drugs （poisons） in blood by gas chromatography-mass spectrometry （GC-MS） method. Methods Four common drugs （poisons） （dichlorvos, phorate, diazepam and estazolam） were detected by GC-MS full scan mode after liquid-liquid extraction in two laboratories and under three chromatographic conditions. The deviations of ion abundance ratios of the four common drugs （poisons） in marked blood samples with concentrations of 0.5, 1.0, 2.0, 5.0 and 10.0 μg/mL were analyzed. At the same time, the false negative rates of ion abundance ratios were analyzed when the mass concentration was limit of detection （LOD）, 2LOD, limit of quantitation （LOQ） and 2LOQ, and the false positive rates of ion abundance ratios were analyzed with blank blood samples. Results Under the two laboratories, four common drugs （poisons） and three kinds of chromatography conditions, the differences in deviations of the ion abundance ratios of marked blood samples were not statistically significant （P>0.05）. More than 95% of the absolute deviations of the ion abundance ratios of the marked blood samples were within the range of ±10%, and more than 95% of the relative deviations were within the range of ±25%. In cases of low concentration （concentration less than 2LOQ） or low signal to noise ratio （3-15）, the false negative rate was less than 5% and the false positive rate was 0% when the relative deviation was greater than 50%. Conclusion The absolute deviations of ion abundance ratios of four common drugs （poisons） in marked blood samples are advised to have a determination range within ±10%, and the determination range of relative deviations within ±25%.
Gas Chromatography-Mass Spectrometry ; Humans ; Ions/chemistry* ; Limit of Detection ; Liquid-Liquid Extraction ; Poisons/blood*