Determination of nitroimidazole antibiotics based on dispersive solid-phase extraction combined with capillary electrophoresis

For a long time, the detection of nitroimidazole antibiotics (NIABs) has been a research focus in environmental analytical chemistry. In this work, a novel technique for the analysis of nitroimidazoles was established based on capillary electrophoresis (CE). UiO-66, synthesized using a solvothermal method, was utilized as an adsorbent in the dispersive solid-phase extraction (DSPE) of five different NIABs. The separation and detection of NIABs in environmental water samples were accomplished using the CE diode array detection method. The optimal extraction conditions were obtained after systematically studying the effects of adsorption time, the amount of extractant, and elution solvent on extraction efficiency. According to the results of the study, the limit of detections of the five NIABs were between 16 and 97 ng/mL, the relative standard deviations were between 0.32% and 0.55%, and the spike recoveries were between 87.43% and 104.8%. This study presents a novel technique for measuring NIABs in complex water samples.     

Miniaturized ternary deep eutectic solvent-based matrix solid-phase dispersion: A green sample preparation method for the determination of chlorophenols in river sediment

New ternary deep eutectic solvents were prepared and applied as efficient green dispersing solvents in miniaturized matrix solid-phase dispersion to extract chlorophenols from river sediments for the first time. High-performance liquid chromatography coupled with a photodiode array detector was used to analyze the target analytes. The significant factors affecting the extraction were optimized as follows: dispersant (100 mg), sample (100 mg), ternary eutectic solvents (150 μl), grinding for 1 min, 450 μl of acetonitrile as the elution solvent, and vortex mixing for 20 s. Under the optimal conditions, the method exhibited excellent linearity (correlation coefficient > 0.9980), low limits of detection between 1.039–2.478 μg/g, and extraction recoveries between 93.9% and 99.2%. Furthermore, the method demonstrated excellent precision in the intra- and inter-day analysis with a relative standard deviation below 6%. When compared to conventional extraction techniques, the miniaturized matrix solid-phase dispersion considerably reduced samples and solvent usag, offering important environmental benefits. The green profile of the method was assessed using the complementary green analytical procedure index tool confirming its eco-friendship. The technique was finally employed to evaluate sediment samples from three distinct locations along the Zuibaiji River, indicating its applicability for monitoring environmental samples.     

Application of matrix solid-phase dispersion to the determination of amitrole and urazole residues in apples by capillary electrophoresis with electrochemical detection

A new method based on matrix solid-phase dispersion (MSPD) extraction was studied for the extraction of amitrole (3-amino-1,2,4-triazole), and its metabolite urazole (3,5-dihydroxy-1,2,4-triazole), in apple samples. The influence of experimental conditions on the yield of the extraction process and on the efficiency of the cleanup step was evaluated. Determination was carried out by capillary electrophoresis (CE) with electrochemical detection, demonstrating the compatibility between MSPD and CE techniques. The method has been successfully applied to different apple varieties. Recoveries in samples spiked at 1.6 and 1.7 μg g⁻¹ for amitrole and urazole were 88 and 82%, respectively. The limits of detection were 0.4 μg g⁻¹ for both compounds using electrochemical detection.     

固相萃取法与基质固相分散法在橙子中有机磷农药残留分析中的应用

建立了固相萃取(SPE)-反相高效液相色谱(RP-HPLC)同时测定橙子中痕量辛硫磷、二嗪农有机磷农药残留量的方法。样品经甲醇超声提取、C18固相萃取柱净化后,采用液相色谱柱分离,以乙腈-水(体积比为85∶15)为流动相等度洗脱,于254 nm下紫外检测。结果表明:在0.1～10.0 mg/L和0.4～10.0 mg/L范围内,辛硫磷、二嗪农的质量浓度与峰面积呈良好的线性关系;样品的加标平均回收率为87.3%～102.7%,相对标准偏差(RSD)为0.9%～4.9%。将该分析结果与用基质固相分散法(MSPD)处理样品所得的结果相比较,发现SPE对二嗪农的提取效果较好,而MSPD对辛硫磷的提取效果较好,但两种方法都能较好地净化样品,均能满足残留量的分析要求。     

分子印迹基质固相分散-液相色谱法测定牛奶中的氯霉素残留

以对模板分子具有较强识别特性的分子印迹聚合物为基质固相分散吸附剂, 提取牛奶中痕量氯霉素, 最后用HPLC法测定. 研究了氯霉素分子印迹聚合物对样品中氯霉素的提取和净化效果, 在优化条件下, 方法的检出限为0.15 ng/mL, 定量限为0.50 ng/mL. 不同氯霉素添加量的回收率大于93.2%, RSD＜5.9%. 方法适用于牛奶中氯霉素残留的测定.     

Molecularly imprinted matrix solid-phase dispersion combined with dispersive liquid-liquid microextraction for the determination of four Sudan dyes in egg yolk

A new kind of aniline-naphthol molecularly imprinted microsphere (MIM) synthesized by aqueous suspension polymerization was applied as a selective sorbent of miniaturized matrix solid-phase dispersion combining with dispersive liquid-liquid microextraction (MSPD-DLLME) for the simultaneous determination of four Sudans in egg yolk samples. The solid sample was directly blended with MIM in MSPD procedure and the eluent of MSPD was used as the dispersive solvent of the followed DLLME for further purification and enrichment of the analytes before HPLC analysis. Good linearity for all the Sudan dyes was ranged from 0.02 μg g(-1) to 2.0 μg g(-1) (r(2)≥0.9990) and their recoveries at three spiked levels were ranged from 87.2% to 103.5% with RSD less than 6.1% (n=3). The presented MIM-MSPD-DLLME method combined the advantages of MIM, MSPD and DLLME, and could be applied for the determination of Sudans in complicated food samples.     

Surfactant‐assisted dispersive liquid–liquid microextraction combined with field‐amplified sample stacking in capillary electrophoresis for the determination of mexiletine and lidocaine

A sensitive method for the determination of mexiletine and lidocaine using surfactant‐assisted dispersive liquid–liquid microextraction coupled with capillary electrophoresis was developed. Triton X‐100 and dichloromethane were used as the dispersive agent and extraction solvent, respectively. After the extraction, mexiletine and lidocaine were analyzed using capillary electrophoresis with ultraviolet detection. The detection sensitivity was further enhanced through the use of field‐amplified sample stacking. Under optimal extraction and stacking conditions, the calibration curves were linear over a concentration range of 0.05–1.00 μM for mexiletine and 0.03–1.00 μM for lidocaine. The limits of detection (signal‐to‐noise ratio of 3) were 0.01 and 0.01 μM for mexiletine and lidocaine, respectively. An approximately 1141‐ to 1250‐fold improvement in sensitivity was observed for the two analytes compared with the injection of a standard solution without the surfactant‐assisted dispersive liquid–liquid microextraction and field‐amplified sample stacking procedures. This developed method was successfully applied to the determination of mexiletine and lidocaine in human urine and serum samples. Both precision and accuracy for urine and serum samples were less than 8.7 and 6.7%, respectively. The recoveries of the two analytes from urine and serum samples were 54.7–64.9% and 16.1–56.5%, respectively.