同位素稀释高分辨气相色谱-高分辨质谱法检测烟道气中的低氯代二恶英

建立了同位素稀释高分辨气相色谱-高分辨质谱检测烟道气中痕量低氯代二恶英的分析方法。采用索氏提取富集烟道气样品中的目标物,提取液经过复合硅胶柱和碱性氧化铝柱净化后,进行高分辨气相色谱-高分辨质谱检测。采用DB-5MS毛细管色谱柱（30 m×0.25 mm×0.25 μm）分离,以保留时间和同位素特征离子丰度比定性,以与同位素的峰面积比值定量。实验结果表明,方法的回收率为66.6%~112.5%,相对标准偏差（RSD）的范围为19.9%~40.5%（n=5）,方法的检出限（LOD）为0.027~0.485 μg/L。应用该方法检测了3个焚烧炉烟道气样品,回收率在85.7%~137.0%范围内,样品中目标物含量分布在11.4~9183 pg/Nm³之间。结果表明该方法适合用于烟道气中痕量低氯代二恶英的检测。     

神经递质类相关物质的毛细管电泳分离及实际尿液的检测应用

建立了单胺类神经递质（5-羟色胺、多巴胺和肾上腺素）、神经递质类代谢产物（高香草酸、5-羟吲哚乙酸和香草扁桃酸）及神经递质类前体（精氨酸和酪氨酸）混合物的毛细管电泳（CE）分离方法. 利用标准试剂混合样考察了缓冲体系的组成、pH值及添加剂对分离的影响,并探讨了尿液中基体成分如肌酸酐、尿酸和乙酰乙酸对分离的干扰. 在Na₂B₄O₇-NaOH缓冲体系（pH=9.90）及紫外（UV）检测（波长200 nm）条件下对8种神经递质类相关物质的分析获得了良好的定量线性关系,检出限（LOD）为0.04~0.60 μmol/L,迁移时间和峰面积的相对标准偏差（RSD,n=5）范围分别为0.09% ~0.48%和0.47% ~3.34%. 利用该方法对实际尿液中的精氨酸和香草扁桃酸进行了定性和定量分析,其定量结果分别为（95.8±3.8）和（44.6±3.5） μmol/L,加标回收率为96.65%~104.5%.     

基质固相分散萃取和固相萃取-高效液相色谱-三重四极杆-复合线性离子阱质谱同时测定奶制品中6种雌激素

采用了基质固相分散萃取（MSPD）和固相萃取（SPE）技术分别对奶制品（奶粉和牛奶）中6种雌激素进行提取和净化。结果显示,MSPD适用于固体奶粉的处理,而SPE则适用于液体牛奶的处理。基于优化结果,利用高效液相色谱-三重四极杆-复合线性离子阱质谱（HPLC-Q-TRAP-MS）建立了在不同奶制品中同时测定6种雌激素含量的方法。方法学考察结果显示,建立的分析方法符合含量测定要求,在0.1~200 mg/L（雌三醇为0.1~20 mg/L）范围内线性关系良好（相关系数（R²）>0.99）;检出限（LOD,S/N=3）和定量限（LOQ,S/N=10）分别为0.01~0.05 mg/L和0.05~0.10 mg/L。在添加水平分别为1.0、5.0和10 mg/kg时,固态奶粉经MSPD处理后,6种雌激素的平均回收率为71.8%~106.0%（RSD为1.6%~9.2%,n=3）;液态牛奶经SPE处理后,6种雌激素的平均回收率为70.3%~108.4%（RSD为2.0%~11.0%,n=3）。该方法灵敏度和重复性高,适于分析复杂基质中雌激素的痕量残留。     

柱前衍生-超高效液相色谱-串联质谱法同时检测茶叶中草甘膦和草铵膦的残留量

采用超高效液相色谱-串联质谱建立了茶叶中草甘膦和草铵膦残留同时快速测定的方法。茶样经超纯水、二氯甲烷提取和C₁₈固相萃取柱净化后,在硼酸盐缓冲液中与9-芴甲氧羰酰氯(FMOC-Cl)进行衍生反应,衍生后产物在C₁₈色谱柱上进行超高效液相色谱分离;质谱检测采用电喷雾正离子化模式和多反应监测模式。结果表明,在0.003125~0.1 mg/L范围内,草甘膦和草铵膦均有良好的线性关系(r> 0.990),检出限(LOD)均为0.03 mg/kg;在添加浓度为0.375、1.5和4.5 mg/kg时,草甘膦的平均回收率为87.37%~99.11%,相对标准偏差(RSD)(n=6)为0.68%~1.35%;草铵膦的平均回收率为81.44%~86.17%,RSD(n=6)为1.01%~2.33%。该方法样品前处理简单,分析时间短,回收率和精密度等均符合农药多残留检测技术的要求,适用于茶叶中草甘膦和草铵膦残留的同时检测。     

石化废水中低碳有机酸的毛细管电泳分析

建立了毛细管电泳测定石化废水中低碳有机酸的方法。以25%(体积分数)甲醇-0.5 mmol/L十六烷基三甲基溴化铵-10 mmol/L邻苯二甲酸氢钾(pH 6.0))为缓冲溶液,-30 k V为分离电压,200 nm为间接检测波长,甲酸、乙酸、丙酸、丁酸、乙醇酸、乳酸、苹果酸、草酸、丙二酸、酒石酸、马来酸、丁二酸等12种有机酸达到基线分离。在试验浓度范围内,有机酸浓度与峰面积呈良好的线性关系(r在0.9981~0.9996之间)。方法回收率为91.2%~114.1%。迁移时间和峰面积的精密度(RSD)分别为0.10%~0.28%和1.6%~2.6%之间。采用电动进样模式,12种有机酸检出限低至3.2~5.6μg/L。方法已应用于石化废水中低碳有机酸的检测。     

迁移时间归一化法改善毛细管电泳表征中药大黄的重现性

探讨了迁移时间归一化法改善中药毛细管电泳分析迁移时间重现性的原理,并将其应用于实际样品的分析。迁移时间归一化法认为,在相同的操作电压、缓冲液组成和温度条件下,多次电泳实验中迁移时间产生差别的主要原因是多次电泳实验中电渗流产生了差异。迁移时间归一化法就是通过选择电泳谱图中的一个或两个峰作为标记峰,将各次电泳实验的迁移时间都归一到第一次电泳实验中的迁移时间。比较多次电泳实验中迁移时间(t)的相对标准偏差(RSD)、经单峰归一化处理的迁移时间(t′)的RSD、经双峰归一化处理的迁移时间(t″)的RSD、迁移时间比(t/tistd,istd代表所选择的标记物)的RSD,发现RSD(t″)相似文献   

射干的毛细管电泳指纹图谱研究

采用毛细管区带电泳法,以80 mmol/L硼酸-15 mmol/L硼砂缓冲液(用氢氧化钾溶液调pH 9.7)为背景电解质,运行电压12.1 kV,检测波长228 nm,重力进样10 s(高度7 cm),建立了射干药材的毛细管电泳指纹图谱(CEFP)。标定CE指纹峰为21个,方法的精密度和重现性较好,相对迁移时间的相对标准偏差(RSD)不大于3.5%, 相对峰面积的RSD约为5.0%,10个产地样品的CEFP与标准CEFP的相似度为0.913～0.993。同时,对指纹图谱中各指纹峰确立的方法和各组分含量情况     

加速溶剂萃取-超高效液相色谱-串联质谱法测定茶叶中拟除虫菊酯类农药残留

建立了加速溶剂萃取（ASE）-超高效液相色谱（UPLC）-串联质谱法（MS/MS）测定茶叶中拟除虫菊酯类农药残留的方法。ASE萃取温度为80 ℃，萃取压力为10.34 MPa，以正己烷-丙酮（2∶1，v/v）为溶剂静态萃取5 min，循环一次。萃取液浓缩后经GCB/NH₂-Florisil柱净化，UPLC分离，MS/MS正离子扫描（ESI⁺）、多反应离子监测（MRM）模式进行分析，外标法定量。线性回归分析表明：10种拟除虫菊酯的浓度与其峰面积的线性关系显著，相关系数（r）均不小于0.9995，检出限（LOD）在0.5~5.0 μg/kg之间，定量限（LOQ）在1.6~16.6 μg/kg之间；在定量限、0.4 mg/kg以及最高残留限量（MRL，无MRL的加入1 mg/kg）3个水平进行添加回收试验（n=7），回收率为68.7%~103.8%，RSD为0.8%~13.2%。该方法前处理简单，耗时短，灵敏度和准确度高，可满足茶叶中痕量拟除虫菊酯类农药残留测定的要求。     

毛细管电泳结合压力辅助电动进样测定水样中4种酚类雌激素

在毛细管电泳的胶束电动色谱（MEKC）模式下,采用压力辅助电动进样（PAEKI）的进样方式在线富集4种酚类雌激素（PEs）。对影响PAEKI的进样电压、进样时间等进行考察,并与传统的压力进样比较。结果表明,在最优的PAEKI条件下（-9 kV,0.3 psi（约2.1 kPa）,0.4 min）,4种PEs在7 min内基线分离,线性关系良好,相关系数（r）大于0.9936,己烷雌酚和双烯雌酚的线性范围为0.05~5 mg/L、双酚A和己烯雌酚的线性范围为0.1~10 mg/L;检出限（S/N=3）为0.0071~0.017 mg/L,富集倍数为11~15。使用该MEKC-PAEKI法对自来水和湖水水样进行测定,得到定量限（S/N=10）分别为0.029~0.064 mg/L和0.033~0.079 mg/L;加标回收率为75.6%~110.1%,相对标准偏差（n=5）为4.6%~11.8%。PAEKI不需要使用其他试剂,只需对电泳仪的参数进行适当调整即可实现对分析物的在线富集,简单、快速、自动化程度高。     

食品中柠檬黄铝色淀和日落黄铝色淀的毛细管区带电泳分析

发展了一种新的采用毛细管区带电泳分析柠檬黄铝色淀和日落黄铝色淀的方法。通过前处理步骤成功实现了铝色淀中铝基质与色素的分离。利用石英毛细管柱（48.50 cm（有效长度40.00 cm）×50 μm）,分别针对柠檬黄铝色淀和日落黄铝色淀进行了电泳条件的优化,并得到最优分离结果。所建立的定量分析方法的检出限对于柠檬黄铝色淀和日落黄铝色淀分别达0.26 mg/L和0.27 mg/L,线性范围分别为0.53~1.3×10²mg/L和0.54~1.4×10²mg/L,两种被分析物的测定重复性（RSD,n=6）分别为4.3%和5.7%,日间重复性（RSD,n=6）分别为5.6%和6.0%。经过更深入研究后,该方法可以发展为食品中相应色淀的检测方法。     

基于场放大进样和石墨烯量子点双重富集毛细管电泳分离检测三聚氰胺和双氰胺

通过热解法制备了硫掺杂的石墨烯量子点(S-GQDs),同石墨烯量子点(GQDs)相比,S原子的引入有效改善了GQDs的表面状态和化学特性、增强其对正电荷的捕获能力,使其更易与阳离子相互作用.以S-GQDs为载体,结合电堆积富集技术,发展了一种基于场放大进样(FASI)和S-GQDs放大的双重富集毛细管电泳(CE)分离检...     

Large volume sample stacking of cationic tetracycline antibiotics toward 10 ppb level analysis by capillary electrophoresis with UV detection

This paper aimed to build up a sensitive CE method for the analysis of tetracyclines (TCs) antibiotics (including tetracycline, chlorotetracycline, oxytetracycline, and doxycycline) with conventional UV detection. Here, the large volume sample stacking was applied to achieve in capillary preconcentration of the targets. To achieve large volume sample stacking, the essential step was a large volume of sample (around 83.3% of total capillary length from inlet to detection window) hydrodynamically loaded. Then, the reserved voltage was added in order to push the sample matrix out of the capillary. Due to different pH between sample solution (pH 4.6) and BGE (pH 11.0), the cationic TCs would turn into negatively charged while the sample matrix was removing from the capillary. Finally, the anionic TCs were stacked at the inlet for the subsequent separation. Although the loss of sample existed during their charge transformation, the LODs could be improved around 40 times than that obtained by normal hydrodynamic injection CE method. Here, the LODs were in the range of 8.1–14.5 μg/L, around 10 ppb that close to the level by electrochemiluminescence or laser‐induced fluorescence detection of TCs by CE. The precision was characterized by RSDs of migration times and peak areas, which were in the range of 0.19–0.24% and 0.97–2.54%, respectively. The recoveries of the developed method were in the range of 95–112% by spiking TCs in the tap water. The proposed inline preconcentration CE method could be a simple, speed, and sensitive method for the quantitative analysis of TCs.     

Analysis of tetracycline residues in bovine milk by CE-MS with field-amplified sample stacking

A rapid, sensitive, and robust CE-MS method has been developed for the determination of tetracycline, oxytetracycline, and chlortetracycline in milk. Field-amplified sample stacking with electromigration injection (FASS-EMI) was used for the online concentration of tetracyclines. The conditions of separation, MS detection, and stacking were systematically optimized. The optimum buffer composition was 35 mM Tris, 1.1% formic acid, 5% methanol, and 15% ACN. By using the online concentration method of field-enhanced sample stacking (FESI)-EMI stacking, the sensitivity was increased six- to seven-fold. The RSDs (n=6) of the relative migration time of tetracyclines were 1.1-1.4% for intraday and 2.4-2.9% for interday. The RSDs (n=6) of the relative peak area of tetracyclines were 3.2-4.6% for intraday and 4.7-6.1% for interday. The LODs (S/N=3) were 7.14 ng/mL for tetracycline, 11.4 ng/mL for oxytetracycline, and 14.9 ng/mL for chlortetracycline. The method has been successfully used to analyze tetracyclines residues in bovine milk.     

Analysis of acrylamide in food products by in-line preconcentration capillary zone electrophoresis

Two in-line preconcentration capillary zone electrophoresis (CZE) methods (field amplified sample injection (FASI) and stacking with sample matrix removal (LVSS)) have been evaluated for the analysis of acrylamide (AA) in foodstuffs. To allow the determination of AA by CZE, it was derivatized using 2-mercaptobenzoic acid. For FASI, the optimum conditions were water at pH > or = 10 adjusted with NH3 as sample solvent, 35 s hydrodynamic injection (0.5 psi) of a water plug, 35 s of electrokinetic injection (-10 kV) of the sample, and 6s hydrodynamic injection (0.5 psi) of another water plug to prevent AA removal by EOF. In stacking with sample matrix removal, the reversal time was found to be around 3.3 min. A 40 mM phosphate buffer (pH 8.5) was used as carrier electrolyte for CZE separation in both cases. For both FASI and LVSS methods, linear calibration curves over the range studied (10-1000 microg L(-1) and 25-1000 microg L(-1), respectively), limit of detection (LOD) on standards (1 microg L(-1) for FASI and 7 microg L(-1) for LVSS), limit of detection on samples (3 ng g(-1) for FASI and 20 ng g(-1) for LVSS) and both run-to-run (up to 14% for concentration and 0.8% for time values) and day-to-day precisions (up to 16% and 5% for concentration and time values, respectively) were established. Due to the lower detection limits obtained with the FASI-CZE this method was applied to the analysis of AA in different foodstuffs such as biscuits, cereals, crisp bread, snacks and coffee, and the results were compared with those obtained by LC-MS/MS.     

In-capillary non-covalent labeling and determination of tomato systemin with quantum dots in capillary electrophoresis with laser-induced fluorescence detection

Quantum dots (QDs), with their superior size-dependent fluorescence properties, have been employed as non-covalent fluorescent labels for the determination of tomato systemin (TomSys) by capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection. The optimum conditions of in-capillary labeling and CE separation were investigated in detail, and complete separation of QDs-labeled TomSys from free QDs labels was achieved. Satisfactory results were obtained in terms of linearity (R(2)=0.998), sensitivity (limit of detection, 66 fmol) and repeatability (run-to-run RSDs of migration time and peak area, 0.9 and 4.6%, respectively; day-to-day RSDs of migration time and peak area, 3.1 and 11.9%, respectively). The established CE-LIF method was later applied in the detection of TomSys spiked in the sample of tomato leaves, which showed the applicability of the proposed method in the analysis of the target plant peptide hormone in the complex matrix.     

Different strategies for the preconcentration and separation of parabens by capillary electrophoresis

Several strategies, namely, large volume sample stacking (LVSS), field‐amplified sample injection (FASI), sweeping, and in‐line SPE‐CE, were investigated for the simultaneous separation and preconcentration of a group of parabens. A BGE consisting of 20 mM sodium dihydrogenphosphate (pH 2.28) and 150 mM SDS with 15% ACN was used for the separation and preconcentration of the compounds by sweeping, and a BGE consisting of 30 mM sodium borate (pH 9.5) was used for the separation and preconcentration of the compounds by LVSS, FASI, and in‐line SPE‐CE. Several factors affecting the preconcentration process were investigated in order to obtain the maximum enhancement of sensitivity. The LODs obtained for parabens were in the range of 18–27, 3–4, 2, and 0.01–0.02 ng/mL, and the sensitivity evaluated in terms of LODs was improved up to 29‐, 77‐, 120‐, and 18 400‐fold for sweeping, LVSS, FASI, and in‐line SPE‐CE, respectively. These preconcentration techniques showed potential as good strategies for focusing parabens. The four methods were validated with standard samples to show the potential of these techniques for future applications in real samples, such as biological and environmental samples.     

Determination of chloroacetic acids in water by capillary zone electrophoresis with field-amplified sample injection

A simple and sensitive method has been developed for the determination of chloroacetic acids and acetic acid in water using capillary zone electrophoresis under modified electroosmotic flow with indirect UV detection. Potassium hydrogen phthalate at pH 5.40 was used as background electrolyte (BGE), and hexadecyltrimethylammonium bromide was used as electroosmotic flow modifier. Field-amplified sample injection (FASI) method was used to enhance the sensitivity. Results showed that the limit of detection for these analytes was enhanced more than 15-fold and the repeatabilities were good with relative standard deviations (RSDs %) of migration time and corrected peak areas being below 0.33%, 4.45% (intra-day) and 0.87%, 9.67% (inter-day), respectively. An off-line liquid–liquid extraction (LLE) process with methyl tert-butyl ether was carried out to detect these compounds in water samples. The dissociation constants of acetic acid and monochloroacetic acid (MCA) were determined with two methods and the results obtained were consistent with the reference values.     

肌肽类生物活性肽的毛细管电泳在线富集技术

建立了毛细管区带电泳(CZE)在线富集3种肌肽类活性肽(肌肽、鹅肌肽和高肌肽)的两种简便有效的方法。一种是大体积进样反向压力排除基体富集（LVSRP）技术,即通过流体动力学进样,在不改变电源极性的条件下,利用反向压力排除样品基体,电堆积富集后进行CZE分离;另一种是大体积进样电渗流排除基体富集（LVSEP）技术,即通过流体动力学进样,于运行缓冲液中加入溴化十六烷基三甲基铵(CTAB)动态修饰毛细管表面,通过电渗流排除样品基体,改变电源极性后进行CZE分离。与常规CZE相比,LVSRP技术和LVSEP技术使检测灵敏度提高了40~60倍。对影响两种富集过程的一些因素进行了研究,在最优富集条件下考察本方法的线性范围为0.080~5.0 μmol/L。对3种生物活性肽的检测限(S/N=3)分别为LVSRP 41~58 nmol/L,LVSEP 35~43 nmol/L。     

Development and comparison of HPLC and MEKC methods for the analysis of cyclic sulfur mustard degradation products

In this study, novel, fast, and simple methods based on RP‐HPLC and MEKC with DAD are developed and validated for the qualitative and quantitative determination of five cyclic sulfur mustard (HD) degradation products (1,4‐thioxane, 1,3‐dithiolane, 1,4‐dithiane, 1,2,5‐trithiepane, and 1,4,5‐oxadithiepane) in water samples. The HPLC method employs a C18 column and an isocratic water‐ACN (55:45, v/v) mobile phase. This method enables separation of all five cyclic compounds within 8 min. With the CE method, the baseline separation of five compounds was achieved in less than 11 min by applying a simple BGE composed of a 10 mM borate buffer and 90 mM SDS (pH 9.15). Both methods showed good linear correlation (R ² > 0.9904). The detection limits were in the range of 0.08–0.1 μM for the HPLC method and 10–20 μM for MEKC. The precision tests resulted in RSDs for migration times and peak areas less than 0.9 and 5.5%, respectively, for the HPLC method, and less than 1.1 and 7.7% for the MEKC method, respectively. The developed methods were successfully applied to the analysis of five cyclic HD degradation products in water samples. With the HPLC method, the LODs were lowered using the SPE for sample purification and concentration.     

基于细菌纤维素的毛细管电泳法同时测定果蔬中3种苯并咪唑类杀菌剂

建立了高效毛细管电泳同时测定果蔬中3种常见的苯并咪唑类杀菌剂(甲基硫菌灵、多菌灵和苯菌灵)的分析方法。以细菌纤维素(BC)为电泳缓冲液添加剂来提高毛细管电泳的分离能力。系统考察了检测波长、缓冲液离子强度、缓冲液pH、分离电压及BC添加量对3种苯并咪唑类杀菌剂分离效果的影响。最终的优化条件:H3BO3/Na2B4O7缓冲液(4 mmol/L,pH 9.0);BC添加质量分数0.3%;运行电压15 kV;分离柱温25℃;检测波长275 nm。3种苯并咪唑类杀菌剂在8 min之内可实现基线分离及准确定量。结果显示:3种苯并咪唑类杀菌剂在各自线性范围内线性关系良好,相关系数(r2)≥0.997;检出限为5.0~10.0μg/L;保留时间及峰面积的日间相对标准偏差(n=5)分别为0.82%~1.0%和2.4%~2.9%。该法用于葡萄、番茄及黄瓜中3种苯并咪唑类杀菌剂的测定,加标回收率为93.5%~103.0%,RSD≤8.0%。该法可作为果蔬中甲基硫菌灵、多菌灵和苯菌灵同时检测的有效手段。