Porous capillary monolithic column coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry for fast and effective separation and determination of estrogens

To establish a method for determination of 15 pesticides residue in edible fungi by multiplug filtration clean-up(m-PFC) pretreatment technique with ultra-high performance liquid chromatography-tandem triple quadruple mass spectrometry(UPLC-MS/MS). The interferences of edible fungus samples were removed by extracting with acetonitrile and filtration type extraction column, which were fat, carbohydrates, water-soluble vitamins. Samples were separated with column of Waters ACQUITY UPLC®HSS T3(2.1 mm×100 mm, 1.8 μm), and were scanned by multiple reaction monitoring mode(MRM). Samples were quantified with matrix matching standard curve external standard method. The recoveries of 15 target compounds at the spiked levels of 10, 20, 50 μg/kg were 82.5%-118.5%, and the relative standard deviations were between 6.1% and 23.1%(n=6). The detection limit of 15 target compounds was 1-3 μg/kg, and the limit of quantification was 3-10 μg/kg. This method improves the efficiency of pretreatment, has good stability and high sensitivity, and could be used for the detection of 15 pesticides in edible fungi.

Development of an aptamer-functionalized capillary monolithic column for the highly-selective and highly-efficient recognition of patulin

We attempted an analysis of naturally occurring polyprenol and dolichol using a monolithic silica capillary column in HPLC. First, the separation of the polyprenol mixture alone was performed using a 250 x 0.2 mm inner diameter (ID) octadecylsilyl (ODS)-monolithic silica capillary column. The resolution of the separation between octadecaprenol (prenol 18) and nonadecaprenol (prenol 19) exceeded by >or=2-fold the level recorded when using a conventional ODS-silica particle-packed column (250 x 4.6 mm ID) under the same elution conditions. Next, the mixture of the prenol type (polyprenol) and dolichol type (dihydropolyprenol) was subjected to this capillary HPLC system, and the separation of each homolog was successfully achieved. During the analysis of polyprenol fraction derived from Eucommia ulmoides leaves, dolichols were found as a single peak, including all-trans-polyprenol and cis-polyprenol previously identified. This sensitive high-resolution system is very useful for the analysis of compounds that are structurally close to polyprenols and dolichols and that have a low content.

Pre-column dilution large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of multi-class pesticides in cabbages

The concentration of antibiotic residues in water and animal-derived foods is low and the matrix is complex, and effective extraction of antibiotic residues in them is a key factor for accurate quantification. It is important to establish a rapid and effective method for the analytical determination of antibiotics in water and foods. In this study, a type of novel magnetic COF (Fe3O4@SiO2@PDE-TAPB-COF) was synthesized and characterized. Moreover, Fe3O4@SiO2@PDE-TAPB-COF combined with ultra-high performance liquid chromatography-tandem mass spectrometry was used to determine the 11 sulfonamide antibiotics (SAs) in water and food. The parameters including pH, adsorption amount, adsorption time, type of elution solvent and elution time were optimized. Under the optimal conditions, the standard curves of 11 SAs showed good linearity (R 2 > 0.999) in their respective concentration ranges and had lower detection and quantification limits. The spiked recoveries of the developed MSPE-UPLC-MS/MS method for the 11 SAs in water and foods were 74.3-107.2% and 75.1-102.5%, respectively. And the relative standard deviations (RSDs) were less than 9.56% (n = 7). The results indicated that the method can be used for the determination of SAs in foods and water with low detection limits and high sensitivity.

Determination of restricted dyes in textile raw material solid wastes by ultra-high performance liquid chromatography-tandem mass spectrometry

Flower-like calix[6]arene-based covalent organic framework for membrane extraction of sulfonamides in animal-derived food through host-guest interaction prior to determination with ultra-high performance liquid chromatography-tandem mass spectrometry

A novel method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was developed for ultra-preconcentration of 10 antibiotics in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry detection. The optimized results were obtained as follows: after being adjusted to pH 4.0, the water sample was firstly passed through PEP-2 column at 10 mL min(-1), and then methanol was used to elute the target analytes for the following steps. Dichloromethane was selected as extraction solvent, and methanol/acetonitrile (1:1, v/v) as dispersive solvent. Under optimal conditions, the calibration curves were linear in the range of 1-1000 ng mL(-1) (sulfamethoxazole, cefuroxime axetil), 5-1000 ng mL(-1) (tinidazole), 10-1000 ng mL(-1) (chloramphenicol), 2-1000 ng mL(-1) (levofloxacin oxytetracycline, doxycycline, tetracycline, and ciprofloxacin) and 1-400 ng mL(-1) (sulfadiazine) with a good precision. The LOD and LOQ of the method were at very low levels, below 1.67 and 5.57 ng mL(-1), respectively. The relative recoveries of the target analytes were in the range from 64.16% to 99.80% with relative standard deviations between 0.7 and 8.4%. The matrix effect of this method showed a great decrease compared with solid-phase extraction and a significant value of enrichment factor (EF) compared with dispersive liquid-liquid microextraction. The developed method was successfully applied to the extraction and analysis of antibiotics in different water samples with satisfactory results.

A novel aptamer-modified magnetic mesoporous carbon was prepared to develop a specific and sensitive magnetic solid-phase extraction method through combination with ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis chloramphenicol in complex samples. More specifically, the chloramphenicol aptamer-modified Mg/Al layered double hydroxide magnetic mesoporous carbon was employed as a novel magnetic solid-phase extraction sorbent for analyte enrichment and sample clean-up. The extraction solvent, extraction time, desorption solvent, and desorption time were investigated. It was found that the mesoporous structure and aptamer-based affinity interactions resulted in acceptable selective recognition and a good chemical stability toward trace amounts of chloramphenicol. Upon combination with the ultra-high performance liquid chromatography-tandem mass spectrometry technique, a specific and sensitive recognition method was developed with a low limit of detection (0.94pmol/L, S/N=3) for chloramphenicol analysis. The developed method was successfully employed for the determination of chloramphenicol in complex serum, milk powders, fish and chicken samples, giving recoveries of 87.0-107% with relative standard deviations of 3.1-9.7%.

Liquid chromatographic determination of per- and polyfluoroalkyl substances in environmental river water samples

Simultaneous determination of quaternary phosphonium compounds and phosphine oxides in environmental water and solid samples by ultrahigh performance liquid chromatography–tandem mass spectrometry

Determination of fluoroquinolones in dried plasma spots by using microwave-assisted extraction coupled to ultra-high performance liquid chromatography-tandem mass spectrometry for therapeutic drug monitoring

Analysis of neurotransmitters in brain tissue is useful for mechanistic studies of the central nervous system. Isotope dilution coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of glutamic acid, γ-amino butyric acid, acetylcholine, dopamine, and serotonin in the hippocampus tissue. A 2% (v/v) acetic acid in water-methanol (9:1, v/v) solution was used to prepare the standards and re-dissolute samples after nitrogen drying. An Ultimate AQ-C18 column (150 mm×4.6 mm, 3 μm) was used as the analytical column and 0.1% (v/v) formic acid in water and methanol were used as the mobile phase. Gradient elution was performed and all target compounds were eluted over 3 min at 28℃. Vitamin C spiked during the sample pretreatment and storage periods significantly retarded the oxidation of dopamine and serotonin and improved the neurotransmitter stability. The developed method showed good linearities (correlation coefficient (R2)>0.998), low detection limits (0.15-1.0 μg/L), good inter-and intra-day precisions (relative standard deviations:0.39%-13.6%), good accuracy (92.9%-119%), low carry-over, and excellent stability. Moreover, the method was successfully applied and validated in the determination of rat hippocampus exposed to bisphenol A.

基于阳离子型金属有机骨架膜材料，建立了一种分散膜萃取（DME）与超高效液相色谱-串联质谱（UHPLC-MS/MS）相结合的分析方法，用于同时检测海水中8种全氟及多氟烷基化合物（PFASs）。优化的色谱-质谱条件如下：ACQUITY UPLC BEH C18色谱柱（100 mm×2.1 mm， 1.7 μm），进样体积为10 μL，柱温保持在40 ℃，流速为0.4 mL/min，采用1.0 mmol/L乙酸铵水溶液和乙腈为流动相进行梯度洗脱；在负离子模式下，通过电喷雾离子源（离子源电压-2 500 V，离子源温度300 ℃）进行质谱检测，并使用多反应监测模式采集化合物质谱信息。在最优条件下，8种PFASs在各自的浓度范围内线性关系良好，相关系数均≥0.990 7，方法的检出限为0.07~0.49 ng/L，定量限为0.22~1.63 ng/L。在10、50和100 ng/L加标水平下PFASs的回收率为50.4%~116.4%，日内和日间相对标准偏差分别为1.0%~19.2%和2.2%~19.5%。将该方法应用于胶州湾表层海水中8种PFASs的检测，共检出7种PFASs。其中，全氟-11-氯-3-氧杂十一烷磺酸检出浓度最高，平均质量浓度为17.11 ng/L。与2018年胶州湾表层海水中PFASs的检出结果对比，全氟辛酸的平均质量浓度水平明显降低。同时新型PFASs中全氟-9-氯-3-氧杂壬烷磺酸钾在胶州湾表层海水中被检出，可能与近些年PFASs的生产转型有关。新型PFASs的广泛使用可能带来与传统PFASs类似的环境风险，需引起人们高度关注。综上所述，本方法操作简便、快速且灵敏度高，适用于海水中8种PFASs的分析。

Multi-class determination of around 50 pharmaceuticals, including 26 antibiotics, in environmental and wastewater samples by ultra-high performance liquid chromatography–tandem mass spectrometry