H-beta zeolite-based dispersive solid-phase strategy for the multi-residue determination of pesticides

Evaluation of the rotating disk sorptive extraction technique with polymeric sorbent for multiresidue determination of pesticides in water by ultra-high-performance liquid chromatography–tandem mass spectrometry

Spherical conjugated microporous polymers for solid phase microextraction of carbamate pesticides from water samples.

Vortex-assisted solid-phase extraction based on metal-organic framework/chitosan-functionalized hydrophilic sponge column for determination of triazine herbicides in environmental water by liquid chromatography-tandem mass spectrometry

Steroids can be injected to behave as therapeutic agents to promote muscle growth and strength. Areas of concern include synthetic steroids in consumer meat and milk products and the presence of anabolic steroids in athletes. Here we demonstrate a new ionization method for high sensitivity steroid analysis using liquid chromatography/mass spectrometry (LC/MS). Solvent-assisted inlet ionization (SAII) mass spectrometry was coupled directly to an infusion pump or to a liquid chromatograph to determine the limits of detection and quantitation for selected steroids. LC/MS/MS data was acquired on a quadrupole time-of-flight (QTOF) mass spectrometer and high resolution-accurate mass LC/MS data was obtained on an Orbitrap mass spectrometer. The SAII limit of detection for infusion into the Orbitrap using high mass resolution and accurate mass was shown, for the steroids studied, to be low ppqt and the limit of quantitation using LC/MS was low ppt. Low ppb levels were detected with high signal-to-noise from spiked urine using a simple Ziptip procedure without sample concentration. LC/SAII-MS is more sensitive than electrospray ionization (ESI) at similar mobile phase flow rates for the analysis of steroids. Previous studies have shown LC/SAII-MS to have high sensitivity for analysis of peptides. The combined results suggests this easy to implement ionization method may advantageously replace ESI for a wide range of analyses.

Objective To establish a method for measuring serum cotinine by isotope dilution liquid chromatography tandem mass spectrometry （ID-LC/MS/MS）and provide an assay that can be applied to the evaluation of the level of smoke exposure and to the risk analysis of smoking related diseases. Methods Blood samples were collected from 94 apparently healthy subjects from October to December in 2010 and centrifuged, and the sera were separated.Serum samples were mixed with ［D3］-cotinine (as the internal standard) and treated with acetonitriles to precipitate protein.After centrifugation, the supernatants were transferred and evaporated under a stream of nitrogen until dryness and reconstituted with mobile phase.Then the residuals were analyzed by LC/MS/MS system with multiple reaction monitor model; the concentration of cotinine were quantified by the isotope internal standard method and the stand curve was employed with a series of calibration.To estimate the precision of the method, five frozen serum pools were repeatedly analyzed in five runs, and every pool was analyzed in triplicate.In addition, the recovery rates were analyzed with the serum sample added with different levels of standard.The stability of cotinine in serum preserved at room temperature, 4 ℃ and -80 ℃, respectively.Finally, the levels of cotinine of94 healthy subjects were measured to evaluate the distribution of cotinine with different smoke statuses. Results Serum cotinine measured by ID-LC/MS/MS was separated well with few interferences.The correlation coefficients between the peak area ratios and cotinine concentrations were higher than 0.9993.The values of within-run coefficients of variation （CV） of five frozen serum pools (0.68, 48.42, 94.34, 250.95 and 287.04 μg/L) were 2.19%，0.78%，0.75%，0.65% and 0.67％, respectively.The values of total CV were 4.71%，1.40%，1.98%，1.10% and 1.03％, respectively.The limit of detection （LOD） and limit of quantitation （LOQ） were 0.013 and 0.050 μg/L, respectively.The analytical recoveries ranged from 99.22% to 102.67%.The samples could maintain stability within 2 d at room temperature, 7 d at 4 ℃ and 3 months at -80 ℃ resulting the accuracy of measurements from 99.28% to 100.87% and the CV<5%.The levels of cotinine of 94 healthy subjects were measured and shown skewed and leptokurtic distribution.The concentrations of twenty smokers, fourteen former smokers and sixty non-smokers were 116.40 (63.17-241.12), 0.67 (0.15-0.95) and 0.22 (0.15-0.42) μg/L, respectively. Furthermore, the level of cotinine of former smokers (Z=-2.12, P＜0.05) and smokers (Z=-6.67, P<0.001) were statistically higher than non-smokers. Conclusions An ID-LC/MS/MS method for serum cotinine detection has been established.It is hoped that the method will be applied to the assessment of smoke exposure and its association with the risks of smoking related diseases since it is simple, specific, precise, sensitive and accurate.（Chin J Lab Med, 2012, 35:333-338） Key words: Smoke; Cotinine; Isotope dilution mass spectrometry; Liquid chromatography tandem mass spectrometry

Cylindrospermopsin (CYN) is an emerging freshwater cyanobacterial toxin, and its reports on toxicity toward the human liver and kidney tissues has drawn a lot of attention. An appropriate analytical method is necessary to determine the presence of this emerging cyanobacterial toxin in water resources including drinking water; therefore, it is necessary to develop a sensitive analytical method for CYN detection. In this study, we developed a simple and sensitive analytical method for CYN detection using liquid chromatography-tandem mass spectrometry (LC-MS/MS) using direct injection. The method was validated for linearity of calibration, limit of detection, limit of quantitation, accuracy, and precision. The limit of detection and quantitation were in the range of 0.029 μg/L and 0.091 μg/L, respectively. Accuracy and precision were also obtained within an acceptable range. The optimized method was used to measure the concentrations of CYN in the surface water from each weir areas of the Geum River, Nakdong River. Additionally, this method was applied to samples of drinking water obtained from the treatment plants of the Geum River, Nakdong River for each process.

β-Methylamino-L-alanine (BMAA) is an emerging algal toxin that has drawn attention because it can cause neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease (AD). Therefore, it is necessary to develop a sensitive analytical method for BMAA, an emerging cyanobacterial toxin, to determine whether a trace amount is detected in the water resources and treated water. In this study, we developed a simple and sensitive analytical method for BMAA using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with direct injection. The method was validated for linearity of calibration, limit of detection, limit of quantitation, accuracy, and precision. The limits of detection and quantitation were in the range of 0.030 ?/L and 0.096 ?/L, respectively. The optimized method was used to measure the concentrations of BMAA in surface water from each weir point of the Geum River, Nakdong River. Sampling and analysis of drinking water treatment plants of the Geum River, Nakdong River were applied to samples for each process.

Facile preparation of nano-g-C3N4/UiO-66-NH2 composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis

Objective To investigate the maximum allowable deviations of retention time and ion abundance ratio of the 8 common drugs （poisons） from 3 categories, poisons （methamphetamine, morphine, ketamine）, benzodiazepines （estazolam, midazolam, diazepam, clonazepam） and barbiturates （phenobarbital） in blood, by liquid chromatography-tandem mass spectrometry （LC-MS/MS） in forensic toxicology analysis. Methods The deviations of retention time and ion abundance ratio at 7 low mass concentrations, limit of detection （LOD）, 2LOD, limit of quantitation （LOQ）, 1.5LOQ, 2LOQ, 4LOQ and 6LOQ, were tested by LC-MS/MS after liquid-liquid extraction under the conditions of two chromatographic columns and three chromatographs. Results The deviation of absolute retention time of 98.11% of 8 drugs （poisons） in the blood samples was within the range of ±0.05 min, and that of the relative retention time of 96.21% was within the range of ±0.4%. The maximum deviation of the ion abundance ratio was highly correlated with the mass concentration. When the mass concentration of drugs （poisons） was LOQ or above, more than 95% of the absolute deviation and relative deviation of the ion abundance ratio were in the range of ±25% and ±40%, respectively; when the mass concentration was below LOQ, the range could be expanded to ±35% and ±50%, respectively. Conclusion It is recommended for the determination range of the absolute retention time deviation of 8 common drugs （poisons） to be ±0.1 min and that of the relative retention time deviation to be ±1.0%. The determination range of absolute deviation of the ion abundance ratio should be ±25% when the mass concentration is LOQ or above, and the relative deviation should be ±40%. When the mass concentration is below LOQ, the deviation determination range can be expanded to ±35% and ±50%, respectively.

Occurrence of pesticides in surface water, pesticides removal efficiency in drinking water treatment plant and potential health risk to consumers in Tengi River Basin, Malaysia

Objective To establish a method for measuring blood phosphatidylethanol by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), which can be applied for objective and quantitative of alcohol intake. Methods Whole blood samples were treated with isopropanol to precipitate protein, and phosphopropanol (16∶0/16∶0) was used as the standard.After centrifugation, the supernatants were transferred and evaporated under a stream of nitrogen until dryness.Then the residuals were analyzed by LC-MS/MS.Various methodological parameters, including linearity, limit of detection (LOD), limit of quantitation (LOQ), recovery, and precision, were investigated.Finally, blood samples from 40 Chinese individuals with more than one year of regular drinking habits were analyzed, and distributions of phosphatidylethanol were evaluated. Results The correlation coefficients were higher than 0.9992.The LOD and LOQ were lower than 0.74 and 2.48 ng/ml, respectively.The inter- and total assay coefficient of variations were 0.77%-3.18% and 2.30%-6.95%, respectively, with recoveries ranged from 96.88% to 102.99%.The relationship between phosphatidylethanol level and self-reported alcohol consumption was significantly and positively correlated (r=0.769, P<0.001). Furthermore, Kruskal-Wallis analysis showed a significant difference in total phosphatidylethanol levels among individuals with different levels of alcohol intake (χ2=18.850, P<0.001). Conclusions An LC-MS/MS method for whole blood phosphatidylethanol detection has been developed. This method is simple, sensitive and accurate and can effectively reflect light, moderate and heavy alcohol intake. The method will be applied to the assessment of alcohol consumption and its association with the risks of drinking related diseases.(Chin J Lab Med, 2018, 41: 103-108) Key words: Glycerophospholipids; Chromatography, liquid; Tandem mass spectrometry; Alcohol drinking; Ethanol

Pesticides in livestock products must be measured to ensure food safety. We developed a single-sample preparation method followed by liquid chromatography–tandem mass spectrometry (LC-MS/MS) for simultaneous determination of fenpropimorph and fenpropimorph acid in six different livestock products. The extraction method was a modification of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and was validated according to the CODEX guidelines. The matrix-matched calibration curves for fenpropimorph and fenpropimorph acid exhibited good linearity, with coefficients of determination (R2 values) higher than 0.998. The limit of detection (LOD) and the limit of quantitation (LOQ) were 1.25 and 5.0 µg kg−1, respectively. The average recovery values ranged from 61.5% to 97.1% for samples fortified to the LOQ, 2 × LOQ, and 10 × LOQ. The method fully complied with the CODEX guidelines and was successfully applied to real samples obtained from domestic markets.

Objective: To establish an ultrahigh performance liquid chromatography tandem mass spectrometry method for the determination of creatinine (Cre) and 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: In October 2020, the end-of-shift urine samples of the monitored subjects were taken, and the filtrate was prepared by centrifugation. After separated by ultra high performance liquid chromatography C18 column, acetonitrile and 0.2% acetic acid aqueous solution were used as mobile phases for gradient elution, the three quadrupole tandem mass spectrometry adopted an electrospray ion source (ESI) , the ion source temperature was 500 ℃ , and the air curtain gas flow rate was 31.4 L/min, qualitative and quantitative analysis of Cre and TTCA were carried out under the multiple reaction monitoring mode. Results: The linear range of Cre was 1.0-1 000.0 μg/L, the linear equation was y=947.3x-1605.6, and the correlation coefficient was 0.9994. The detection limit and the limit of quantitation were 0.3, 1.0 μg/L. When the addition concentrations were 50.0, 150.0 and 450.0 μg/L, the recovery rates were 92.8%-94.6% , the intra assay precisions were 3.6%-5.7% , and the inter assay precisions were 3.4%-5.4%. The linear range of TTCA was 0.1-200.0 μg/L, the linear equation was y=1164.7x-2243.9, and the correlation coefficient was 0.9991. The detection limit and the limit of quantitation were 0.03, 0.1 μg/L. When the addition concentrations were 10.0, 40.0 and 160.0 μg/L, the recovery rates were 90.8%-93.6%, the intra assay precisions were 4.6%-7.4%, and the inter assay precisions were 4.4%-6.9%. Conclusion: The sample pretreatment process of the ultra high performance liquid chromatography tandem mass spectrometry method for the determination of Cre and TTCA in urine is simple, and the continuous determination of Cre and TTCA in urine can be realized only by switching mass spectrometry parameters under the same chromatographic conditions, which is accurate and efficient, and each performance index of the method meets the determination requirements.

Benzodiazepines are one of the most prescribed for therapeutic purposes and the most abused drugs. Therefore, liquid chromatography–tandem mass spectrometry–based methods that analyze several benzodiazepines simultaneously are required. In this study, we developed a simple, full validated in‐house method in a single‐triple quadrupole platform SCIEX QTRAP 4500 system for the simultaneous detection and quantification of the 10 most prescribed benzodiazepines within a 10‐min run time. The linear range was 12.5–500 ng/mL. All limits of detection were below 4.03 ng/mL and limits of quantitation below 12.22 ng/mL, except clobazam (7.27 and 22.04 ng/mL, respectively). Both the limit of detection and quantitation were lowest for diazepam (0.95 and 2.89 ng/mL, respectively). The method was evaluated for accuracy, precision, carry‐over, recovery, stability, and matrix effects, and all validation studies met internationally acceptable criteria. The applicability of the method was proven by analyzing authentic urine samples, internal, and third‐party external quality samples. This precise, accurate, shorter total run time and ease of urine sample analysis method is applicable in detecting most prescribed benzodiazepines and their metabolites even in glucuronide forms.

Solid phase extraction with high polarity Carb/PSA as composite fillers prior to UPLC-MS/MS to determine six bisphenols and alkylphenols in trace level hotpot seasoning