Determination of 12 additives in beverages by evaporation-assisted dispersive liquid-liquid microextraction based on the solidification of floating organic droplets combined with liquid chromatographyEI北大核心CSCD

An analytical method for the simultaneous determination of 12 additives in beverages was developed using evaporation-assisted dispersive liquid-liquid microextraction based on the solidification of floating organic droplets EVA-DLLME-SFOcombined with high performance liquid chromatography HPLC. The samples were extracted twice with 70%V/Vmethanol aqueous solution and extracted by EVA-DLLME-SFO method after the combination of the extractsand finally determined by HPLC. Extraction parameterssuch as types and amounts of extractantevaporant and heating agentthe concentration of saltand the extraction time were optimized. Under the optimized conditionsthere were good relationships in the ange of 0.25-50 μµg/mL with the limits of detection of 1.5 to 13.6 mg/kg and limits of quantification of 5.2 to 45.3 mg/kg. The recoveries at three spiked levels1025 and 50 mg/kgwere 76.8% to 101.2% with the relative standard deviations of 0.11% to 4.7%. The method can be used for rapid detection of 12 additives in beverages. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

石墨烯应用于样品前处理的研究进展

样品前处理技术在样品分析中发挥着越来越重要的作用,而对分析物的富集能力和对样品基体的净化程度主要取决于高效的样品前处理材料,所以发展高性能的样品前处理材料一直是该领域的前沿研究方向。近年来,各类先进材料已经被引入样品前处理领域,发展了多种高性能的萃取材料。由于独特的物理化学性质,石墨烯已在各个研究领域获得广泛关注,在样品前处理领域也发挥着重要作用。基于高的比表面积、大的π电子结构、优异的吸附性能、丰富的官能团和易于化学改性等优点,石墨烯和氧化石墨烯基萃取材料被成功应用于各种样品的前处理,对不同领域中多种类型分析物表现出优异的萃取性能。该论文总结和讨论了近3年来石墨烯材料(石墨烯、氧化石墨烯及其功能化材料)在柱固相萃取、分散固相萃取、磁性固相萃取、搅拌棒萃取、纤维固相微萃取和管内固相微萃取等方面的研究进展。基于多种萃取机理如π-π、静电、疏水、亲水、氢键等相互作用,石墨烯萃取材料能够高效萃取和选择性富集不同类别的目标分析物,如重金属离子、多环芳烃、塑化剂、雌激素、药物分子、农药残留、兽药残留等。基于新型石墨烯萃取材料的各种样品前处理技术与多种检测技术如色谱、质谱、原子吸收光谱等联用,广泛应用于环境监测、食品安全和生化分析等领域。最后,总结了石墨烯在样品前处理领域中存在的问题,并展望了未来的发展趋势。     

基于共价有机骨架材料的磁固相萃取-超高效液相色谱-串联质谱法测定水中4种杀菌剂

杀菌剂在环境中长期富集后会引起土壤和植物病害,并能借助雨水或灌溉渗透到深层土壤和地下水中,威胁水体环境和人体健康。因此针对水中杀菌剂开发简单快速、高效灵敏的分析方法至关重要。该研究通过原位合成法制备了磁性共价有机骨架材料Fe₃O₄@TpBD,将其作为萃取吸附剂,富集环境水体中苯并咪唑杀菌剂(噻菌灵、麦穗宁、多菌灵)和有机硫杀菌剂(稻瘟灵)。利用Fe₃O₄@TpBD与杀菌剂之间的π-π共轭、氢键和静电作用进行吸附,结合超高效液相色谱-串联质谱法(UHPLC-MS/MS)进行检测,建立了测定水中4种痕量杀菌剂的分析方法。通过透射电子显微镜、X射线衍射及傅里叶变换红外光谱等方式对Fe₃O₄@TpBD进行表征,以证明材料的成功合成。对萃取条件进行一系列的优化(Fe₃O₄@TpBD的磁性比例及用量、水样pH、吸附时间、洗脱液的种类及体积、洗脱时间、NaCl含量),确定了最佳萃取条件。4种杀菌剂在3~1200 ng/L的范围内线性关系良好,线性相关系数均大于0.998,方法的检出限和定量限分别为0.06~0.28 ng/L和0.20~0.92 ng/L。在15、150和600 ng/L 3个加标水平下进行加标回收试验,日内和日间精密度分别为2.8%~10.0%和4.4%~15.7%。将该方法用于实际水样的检测,4种杀菌剂的加标回收率为77.1%~119.1%,在水库水中检测出多菌灵,含量为27.5 ng/L。该方法灵敏度高,准确度和精密度良好,操作简单,耗时短。     

加速溶剂提取-同位素稀释-高分辨气相色谱-高分辨质谱法测定生物样品中82种多氯联苯

我国水产品中多氯联苯(PCBs)的检测方法,主要以6种指示性PCBs和12种二噁英类共平面PCBs为主,仅涵盖有限的PCBs。为更全面地获得生物体中PCBs的浓度水平,深入探讨PCBs在生物体内的代谢和富集特征,进而准确评价PCBs对人类的暴露水平及风险,以鱼和贝类作为生物样品代表,建立了加速溶剂提取-同位素稀释-高分辨气相色谱-高分辨质谱(ASE-ID-HRGC-HRMS)测定生物样品中82种PCBs的方法。比较了振荡提取和加速溶剂提取两种提取方式的回收率和重复性,最终采用正己烷-二氯甲烷(1∶1, v/v)对PCBs进行加速溶剂提取。考察了各流分淋洗液对PCBs的回收率,确定了样品提取液经8 g 44%酸性硅胶层析柱(内径15 mm), 90 mL正己烷洗脱的净化方式。样品提取液净化浓缩后进行HRGC-HRMS分析,色谱柱采用DB-5MS超低流失石英毛细管柱(60 m×0.25 mm×0.25 μm)。通过优化后的升温程序对化合物进行分离,以保留时间和两个特征离子精准定性,采用同位素内标法定量。结果表明,在0.1~200 μg/L范围内,平均相对响应因子(RRF)的相对标准偏差值(RSD, n=7)均≤20%,相关系数(r²)>0.99。生物样品中PCBs的方法检出限为0.02~3 pg/g;鱼类中PCBs平均加标回收率为71.3%~141%, RSD(n=7)为2.1%~14%;贝类中PCBs平均加标回收率为76.9%~143%, RSD为1.4%~11%。该方法灵敏、准确、可靠,可以更加全面具体地分析鱼和贝类等水产品受PCBs的污染情况,为国内外开展生物监测提供有效的技术支持,从而服务于相关生态环境管理及履行《斯德哥尔摩公约》。     

分散固相萃取-超高效液相色谱-串联质谱法测定水产品中5种硝基咪唑类和6种苯二氮卓类药物北大核心CSCD

建立了分散固相萃取-超高效液相色谱-串联质谱法同时测定水产品中5种硝基咪唑类和6种苯二氮卓类药物残留的方法。样品用1%(v/v)氨水乙腈提取,提取液经十八烷基键合硅胶(C18)和N-丙基乙二胺(PSA)吸附剂净化,在45℃下用氮气吹至近干,用1 mL甲醇-水(1∶9,v/v)溶液复溶,过0.22μm尼龙-66滤膜后用超高效液相色谱-串联质谱测定。目标化合物采用Kinetex F5色谱柱(100 mm×3.0 mm,2.6μm)分离,以0.1%(v/v)甲酸水溶液和甲醇作为流动相进行梯度洗脱,在电喷雾离子源(ESI)、正离子扫描和多反应监测(MRM)模式下进行测定,基质匹配外标法定量。结果表明,5种硝基咪唑类和6种苯二氮卓类药物在8.5 min内完成色谱分离分析,目标物在0.5~20μg/L范围内线性关系良好,相关系数均大于0.995,检出限和定量限分别为0.2~0.5μg/kg和0.5~1.0μg/kg。以草鱼、对虾和大黄鱼为样品基质,在3个不同的添加水平下,5种硝基咪唑类和6种苯二氮卓类药物的平均回收率为73.2%~110.6%,相对标准偏差(RSD)小于15%。本研究建立的方法具有简单、快速、灵敏度高和成本低等优势,可用于水产品中5种硝基咪唑类和6种苯二氮卓类药物的快速检测。该方法的建立为我国水产品质量安全相关监管部门同时监控水产品中硝基咪唑类和苯二氮卓类药物残留提供了技术支持。     

混合型固相萃取-高效液相色谱-串联质谱法测定稻米中3种谷维素北大核心CSCD

建立了利用高效液相色谱-串联质谱结合混合型阴离子交换固相萃取柱测定稻米中3种谷维素(环木菠萝烯醇阿魏酸酯(CA-FA)、24-亚甲基环木菠萝烯醇阿魏酸酯(24MCA-FA)和菜油甾醇阿魏酸酯(Camp-FA))含量的分析方法。实验通过优化3种谷维素的多反应监测(MRM)质谱参数,比较了在不同流动相中的分离度以及响应强度,同时考察了不同提取条件、净化条件对3种谷维素提取率和净化效果的影响,再结合外标法定量,实现了对稻米中3种谷维素的定量分析。实验结果表明,采用5 mmol/L乙酸铵水溶液为流动相A,甲醇∶乙腈=1∶1(v/v)为流动相B,梯度洗脱,3种谷维素在Agilent Eclipse XDB-C8色谱柱(150 mm×2.1 mm,3.5μm)上基本分离且响应强度和峰形最佳;提取条件经正交实验优化后可得:料液比为1∶20(g/mL)、提取溶剂为甲醇、浸泡时间为12 h、超声温度为40℃以及超声时间为20 min时,3种谷维素提取率最高;对混合型阴离子交换固相萃取柱的上样溶剂以及洗脱溶剂优化后,样品基质效应为1.6%~10.8%。在各优化条件下,3种谷维素在各自的线性范围内线性良好,相关系数(r2)均≥0.9983,检出限(LOD)为0.5~1.0μg/L,定量限(LOQ)为2.0~3.5μg/L。在稻米样品本底浓度2、5和10倍的加标水平下3种谷维素的平均回收率为86.1%~110.6%,相对标准偏差(RSD)为0.9%~3.2%。该方法可快速准确测定稻米中3种谷维素的含量,为后续稻米中谷维素类化合物测定及鉴定奠定基础。     

Preparation of flower-like molybdenum disulfide for solid-phase extraction of N-nitrosoamines in environmental water samples

In this paper, a flower-like molybdenum disulfide material was prepared by hydrothermal method and was first used as adsorbents in the solid-phase extraction process for enriching N-nitrosoamines. Molybdenum disulfide exhibited three-dimensional petal-like microspheres with about 500 nm in diameter. The relevant analyte extraction and elution parameters (sample volumes, solution pH, washing solvents, elution solvents, and elution volumes) were optimized to improve the solid-phase extraction efficiency. The solid-phase extraction process coupled with high-performance liquid chromatography-tandem mass spectrometry for determining N-nitrosoamines in environmental water samples was established. The limits of detection were in the range of 0.01–0.05 ng/mL. The satisfactory recoveries (68.9–106.1%) were obtained at three different spiked concentrations (2, 5, and 8 ng/mL) in water samples, and the relative standard deviations were between 1.96 and 8.38%. This proposed method not only showed high sensitivity and good reusability but also provided a new adsorbent for enriching trace N-nitrosoamines in environmental water samples.     

Extraction of parabens by melamine sponge with determination by high-performance liquid chromatography

In the present study, we propose a novel method for the extraction of parabens in personal care products. A new, simple adsorptive material was obtained by combining metal-organic frameworks and melamine sponges using the adhesive property of polyvinylidene fluoride. This new material, metal-organic frameworks/melamine sponges, was found to be particularly suitable for solid-phase extraction. The structural characteristics of metal-organic frameworks/melamine sponges were first analyzed by scanning electron microscopy. Subsequently, solid-phase extraction was performed on sample solutions, and the extracted substances were then analyzed by high-performance liquid chromatography. Following optimization of important experimental conditions, excellent recovery rates were obtained. Our novel method was then applied to the extraction of four parabens (methylparahydroxybenzoates, ethylparahydroxybenzoates, propylparahydroxybenzoates, and butylparahydroxybenzoates) from real samples. The results yielded limits of detection of 0.26–0.41 ng/mL. The inter- and intra-day recoveries were 104.0–109.7% and 91.2–98.1%, respectively (relative standard deviation, <13.8%).     

热激活延迟荧光材料的光物理行为及性能预测

热激活延迟荧光(Thermally activated delayed fluorescence, TADF)材料由于三线态激子可通过反系间窜越(Reverse intersystem crossing, RISC)转换为单线态激子,在有机发光二极管(Organic light-emitting diodes, OLEDs)中理论上可达到100%的激子利用率而被广泛关注。但实验上开发设计高性能TADF材料较为复杂且研究周期较长,理论研究可以从本质上建立材料结构-性能的关系,预测材料的性质并提供一定的分子设计策略。本文围绕高性能TADF材料的开发,从发光原理出发,系统阐述了分子的设计策略及光物理参数如材料单-三线态能级差(Single-triplet energy gap, ΔE_ST)、系间/反系间窜越速率、吸收/发射光谱、辐射/非辐射速率等的计算原理、计算方法和研究进展。最后我们探讨了TADF材料理论研究面临的机遇和挑战,通过对TADF材料的理论研究综述和研究前景的展望,期待吸引更多的研究工作者,推动该领域的发展和突破。     

Current Advances in Aptamer-based Biomolecular Recognition and Biological Process Regulation

The interaction between biomolecules with their target ligands plays a great role in regulating biological functions. Aptamers are short oligonucleotide sequences that can specifically recognize target biomolecules via structural complementarity and thus regulate related biological functions. In the past ten years, aptamers have made great progress in target biomolecule recognition, becoming a powerful tool to regulate biological functions. At present, there are many reviews on aptamers applied in biomolecular recognition, but few reviews pay attention to aptamer-based regulation of biological functions. Here, we summarize the approaches to enhancing aptamer affinity and the advancements of aptamers in regulating enzymatic activity, cellular immunity and cellular behaviors. Furthermore, this review discusses the challenges and future perspectives of aptamers in target recognition and biological functions regulation, aiming to provide some promising ideas for future regulation of biomolecular functions in a complex biological environment.