液相色谱-质谱法同时测定塑料制品中的双酚A和四溴双酚A

建立了高效液相色谱-质谱同时测定塑料制品中的双酚A(BPA)和四溴双酚A(TBBP-A)的方法。采用超声波萃取技术萃取样品。系统地考察了前处理条件、色谱条件和质谱参数。实验表明,在50 ℃条件下,加入20 mL二氯甲烷对塑料样品中的BPA和TBBP-A超声提取60 min可获得较好的提取效果。以甲醇和水为流动相,采用液相色谱-质谱联用分离和检测BPA和TBBP-A。该方法的线性范围为0.1～2.0 mg/L; BPA和TBBP-A检出限分别为0.01 mg/kg和0.02 mg/kg;回收率为85.4%～97.6%。该方法分离时间短,操作简便,实用性强,灵敏度高,适用于塑料制品中双酚A和四溴双酚A的残留分析。     

分子印迹固相萃取检测罐装食品中双酚A

以双酚A为模板分子,3-氨基丙基乙氧基硅烷为功能单体,通过溶胶-凝胶反应合成双酚A分子印迹纳米硅胶微球。以印迹微球为固相萃取吸附剂,优化固相萃取条件,确定二氯甲烷为上样溶剂。固相萃取选择性实验表明,在双酚A及其结构类似物四溴双酚A、双酚C、壬基酚的混合物溶液中,印迹萃取柱对双酚A具有良好的选择性能,回收率达到90.7%。浓度为2.5和5μmol/L的加标罐装食品样品,经印迹萃取柱预处理,液相色谱检测得到回收率72%～84%,相对标准偏差2.9%～4.4%。     

超声辅助-分散液相微萃取/高效液相色谱法测定沉积物中双酚A及其衍生物

建立了超声辅助-分散液相微萃取/高效液相色谱测定沉积物中双酚A,四溴双酚A,四溴双酚A双烯丙基醚,四溴双酚A双(2,3-二溴丙基)醚的方法。对萃取剂与分散剂的种类与用量、超声时间、盐效应及p H等萃取条件进行了优化。在优化的条件下,此方法的线性范围为0.1~100 mg/L,线性相关系数(r)为0.9996~0.9999。样品平均回收率为83%~91%,相对标准偏差为1.8%~4.9%。检出限(S/N=3)为0.01~0.15μg/L。方法可用于实际水库沉积物中双酚A及其衍生物的测定。     

微波辅助萃取-衍生气相色谱-电子捕获检测器法测定电子电气产品中的四溴双酚A

以N,O-双(三甲基硅烷基)三氟乙酰胺(BSTFA)作衍生化试剂,采用微波辅助萃取-衍生气相色谱-电子捕获检测器法(GC-ECD)测定电子电气产品中的四溴双酚A。使用V(甲苯)∶V(甲醇)=10∶1微波辅助萃取电子电气样品,用正己烷沉淀萃取液中的高聚物,净化后,将萃取液进行衍生化反应,采用ECD检测器进行定量测定。对衍生化时间、衍生化温度、衍生化试剂用量、沉淀试剂用量等前处理条件进行了优化,并进行了线性、回收率、精密度等试验。结果表明,方法线性范围为0.005~5 mg/L,相关系数为0.9985,方法的检测下限为0.02 mg/kg。采用样品加标的方式进行四溴双酚A的精密度及回收率实验,回收率在81.7%~110%之间,相对标准偏差RSD(n=7)小于7.2%。所建方法能很好的应用于电子电气产品中四溴双酚A的检测。     

凝胶渗透色谱-固相萃取结合色谱-质谱法测定乳制品中18种溴系阻燃剂

采用索氏提取、凝胶渗透色谱和固相萃取技术作为前处理方法,建立乳制品中6种新型溴系阻燃剂、8种多溴联苯醚、四溴双酚A和α、β、γ-六溴环十二烷异构体共18种溴系阻燃剂的同时提取与净化方法,并结合气相色谱-负化学源质谱法(GC-NCI/MS)和高效液相色谱-电喷雾电离-串联质谱法(HPLC-ESI-MS/MS)进行检测。奶样经冷冻干燥后以正己烷-丙酮(1：1, V/V)索氏提取,采用凝胶渗透色谱结合酸化硅胶柱净化,随后以LC-Si固相萃取柱分离气相和液相待测物。以GC-NCI/MS测定6种新型溴系阻燃剂和8种多溴联苯醚,以HPLC-MS/MS检测四溴双酚A和六溴环十二烷异构体,内标法定量。结果表明,以空白牛奶样品为加标基质,多数待测物平均回收率为80.1%~114.7%,方法具有良好的精密度(多数待测物相对标准偏差( RSD)在0.87%~14.9%)和灵敏度(检出限在0.2~119.2 pg/g之间),可满足乳制品中多种溴系阻燃剂同时提取、净化和检测需求。     

分散液液微萃取-柱前衍生-高效液相色谱法测定水样中双酚A

建立了分散液液微萃取-柱前衍生-高效液相色谱法测定水样中双酚A的分析方法.通过交互正交试验和混合型优化实验设计对影响因素(萃取剂体积、分散剂类型及其体积、水样体积、pH值及离子强度)进行了优化.优化后的分散液液微萃取条件为:60 μL萃取剂,0.4 mL分散剂(甲醇),pH 4.0;优化后的柱前衍生化条件:0.1 mL 2.0 g/L衍生剂(对硝基苯甲酰氯)、衍生化时间30 min;方法的线性范围:0.002～0.2 mg/L(r=0.9997),检出限0.007 μg/L(S/N=3);不同浓度双酚A的萃取率为59.0%～63.0%,相对标准偏差(RSD)2.5%～9.2%(n=5);水样中双酚A的加标率为86.5%～107.1%,RSD为4.0%～11.9%(n=5),其它雌激素(雌酮、雌二醇、雌三醇和17α-乙炔基雌二醇)对双酚A的测定无干扰.本方法可以对水环境中的痕量BPA进行检测,具有操作简便、快速等优点.     

微波辅助萃取新鲜芦荟叶中芦荟甙的研究

应用密闭微波萃取装置对芦荟中的有效成分芦荟甙进行了微波萃取研究,并利用透射电子显微镜对微波萃取机理进行了初步探讨.讨论了不同萃取剂、溶剂浓度、萃取时间和微波功率等对提取率的影响.在萃取剂为乙醇-水体系,溶剂(乙醇)体积分数为70%、萃取时间为4min及微波功率为340W的条件下,萃取效果最佳.与索氏提取及超声波萃取法相比,本法具有萃取速度快、提取率高及溶剂用量少等特点.     

磁固相萃取-高效液相色谱法测定环境水样中双酚A

采用磁固相萃取-高效液相色谱法测定环境水样中双酚A的含量。优化的试验条件如下:1 50mL水样中加入20mg磁性微球进行萃取;2水样的pH为3.0;3萃取时间为15min;4解析溶剂为甲醇(80+20)溶液;5解析时间为10 min。采用C18色谱柱为分离柱,以甲醇-水(85+15)混合液为流动相,在检测波长224nm处进行测定。双酚A的质量浓度在5.0~500μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)为1.0μg·L-1。方法应用于环境水样的分析,加标回收率在81.4%~109%之间,测定值的相对标准偏差(n=6)在5.7%~8.6%之间。     

单分散磁性亚微米粒子固相萃取-液相色谱-串联质谱法测定牛奶中的双酚A

采用溶剂热还原法制备的单分散性Fe3O4磁性亚微米粒子(Fe3O4-magnetic submicron particles)进行固相萃取(SPE),结合高效液相色谱-串联质谱(HPLC-MS/MS)测定了牛奶中的双酚A(BPA)。对溶液的pH、磁性粒子用量、洗脱溶剂和体积等影响因素进行了优化,得到的最优萃取条件为: 溶液的pH 6,磁性粒子用量3.5 mg,用0.4 mL甲醇洗脱。以Agilent XDB C18柱为分析柱,流动相为乙腈-0.25 mmol/L氨水（80:20, v/v）溶液,在负离子模式下进行MS/MS测定。双酚A在1～100 μg/L范围内线性关系良好(r=0.9993);在3个添加水平下,回收率为85.3%～96.1%,相对标准偏差小于10%;通过不断稀释加标浓度确定方法的检出限(信噪比为3)为1.0 μg/L。该方法简单、准确,能用于牛奶中双酚A的快速测定。     

超声辅助萃取/气相色谱-质谱测定沉积物中的对苯二酚

建立了超声波辅助萃取,乙酸酐衍生化后用气相色谱-质谱(GC - MS)法测定沉积物中对苯二酚的分析方法.对超声辅助萃取影响因素如萃取溶剂、超声功率、萃取次数和萃取时间进行了优化.在优化条件下,对苯二酚的回收率为85%～92%,相对标准偏差(RSD)为3.0% ～7.2%,线性范围为0.05～10 mg/L,检出限为12...     

对氨基酚络合萃取机理的探讨

对氨基酚络合萃取机理的探讨;对氨基酚; 络合萃取; 萃取机理; 萃取反应热     

Focused microwave aqueous extraction of chlorophenols from solid matrices and their analysis by chromatographic techniques

Open-vessel focused microwave (FMW) extraction with a purely aqueous carbonate solution was used for the extraction of chlorophenols from various solid matrices. After SPE on C18-bonded silica, the analytes were determined as such by LC-UV or, as their acetyl derivatives, by GC-ECD. The FMW aqueous extraction is efficient and rapid and no organic solvents are used. PCP was detected in several solid samples, with recoveries of 101-115% (RSD, 2-4%) relative to Soxhlet extraction. Similar recoveries were obtained for the other chlorophenols for spiked samples.     

超声辅助液液萃取法提取烟用香精成分的研究

采用超声辅助液液萃取法(ULLE)提取某品牌烟用香精成分,GC-MS对其进行分析,研究了不同萃取剂、萃取时间和萃取温度对分析结果的影响,初步确定了最佳条件为:以二氯甲烷为萃取剂,饱和NaCl溶液作水相,室温下超声萃取5 min.又分别与同时蒸馏萃取法(SDE)和传统的液液萃取法(LLE)作以比较,对ULLE法和SDE法鉴定出的化学成分、重现性和定量值进行了对比.结果表明:超声辅助液液萃取具有操作简便、快速、节能、萃取效率高、重现性好等特点,适合于烟用香精成分的提取.     

杂粮中总黄酮的提取及含量测定的实验设计

通过学生分组，采用溶剂提取法，超声提取法和微波提取法等提取方法，测定了小米、糜子、青稞、荞麦和高梁等杂粮中黄酮含量，结果表明5种杂粮中，青稞中总黄酮的含量最高。该综合实验能够锻炼大学生运用所学实验技术解决实际问题的能力，适合作为高年级本科综合实验项目开设。     

中草药化学成分提取新技术

介绍五种提取新技术棗微波萃取技术、超临界二氧化碳萃取技术、超声波提取技术、半仿生提取技术和酶法的原理和特点,以及这些新技术近年来在中草药化学成分提取工艺中的研究应用现状,并展望了它们的应用前景。     

Improved extraction and clean-up of imidazolinone herbicides from soil solutions using different solid-phase sorbents

Extraction and quantification of herbicide residues from soil are important in understanding the behaviour of persistent herbicides. This research investigated extraction and clean-up methods for imidazolinone herbicides from soil and soil amended with organic material. A series of solvent mixes, pH conditions and sorbents was tested. Across three imidazolinone herbicides: imazapyr, imazethapyr and imazaquin, 0.5 M NaOH extraction gave greater than 90% recovery from soil samples; however, 0.5 M NaOH:MeOH (80:20) resulted in higher recovery for imazaquin, but not for the other two herbicides. Of the sorbents tested, the use of chromatographic mode sequencing using C₁₈ and SCX sorbents provided consistent high (>85%) recovery of all three herbicides from soil and separation of the herbicides from other soil components by high performance liquid chromatography (HPLC). These two methods will allow high recovery of these imidazolinone herbicides from soil and have the ability to detect these herbicides without interference from other soil components.     

Supercritical fluid extraction

Supercritical fluid extraction (SFE) provides for the first time a viable option to conventional and widely used Soxhlet extraction. The ability to change the solvating power of a single supercritical fluid by changing its density is an exceedingly attractive feature. An environmentally safe alternative such as supercritical carbon dioxide to organochlorine solvents which are widely used today in many government and industrial analytical laboratories for sample preparation is desirable. SFE may also constitute a viable alternative to other popular sample preparation techniques such as liquid-liquid extraction, solid phase extraction and purge/trap. Much research, however, must be done in order to understand, optimize and apply this technology. For example, (a) automation of extraction, (b) matrix effects, (c) new fluids/modifiers/additives, (d) trapping efficiency, (e) recovery of extracted analytes, and (f) extraction kinetics are some areas which need a greater understanding. This review is concerned with many of these topics as they relate to trace organic analysis wherein SFE is the primary sample preparation technique.     

Comparison of alternative and conventional extraction techniques for the determination of zearalenone in corn

Naturally contaminated corn samples of different origin were extracted using two conventional techniques (blending and shaking) and three alternative approaches (ultrasonic extraction, accelerated solvent extraction, and microwave-assisted extraction). Use of the same extraction mixture for all trials enabled the efficiency of the various extraction techniques to be compared. Extracts were filtered and directly analyzed by LC–ESI–MS, without further clean-up. The yield from the alternative extraction techniques showed efficiency to be higher than for conventional techniques. In particular, microwave-assisted extraction was slightly superior to other techniques.     

A Unified Sample Preparation System for Extraction of Various Analyte/Matrix Combinations

A supercritical fluid extraction/enhanced solvent extraction system (SFE/ESE) was used to remove polar and non-polar analytes from various matrices. Extraction of environmental pollutants from soil, additives from low density polyethylene, sulfa drugs from animal tissue, and drug from tablet was performed using both SFE and ESE. Results showed that a single instrumental system can be used to perform both ESE with organic solvents and SFE with carbon dioxide-based fluids. Each method has its own unique advantages and applications. The ability to carry out both solvent extraction and supercritical fluid extraction with one system has obvious economical advantages.     

Effect of Ultrasound-Assisted,Microwave-Assisted and Ultrasound-Microwave-Assisted Extraction on Pectin Extraction from Industrial Tomato Waste

This work aimed to study the effect of ultrasound-assisted (UAE), microwave-assisted (MAE), and ultrasound-microwave-assisted (UMAE) methods for pectin extraction from industrial tomato waste. The overall performance index from the fuzzy analytical method with three criteria, pectin yield, galacturonic acid, and lycopene content, was applied to evaluate the best extraction conditions by using the weight of 75, 20, and 5, respectively. The UAE conditions was performed at a temperature of 80 °C for 20 min with the variations in the extraction pH and the solid liquid (SL) ratio. The best UAE conditions with high pectin yield, and high total carboxyl group, as well as a lycopene content, was the pH of 1.5 and the SL ratio of 1:30. The MAE conditions was performed with variations in the microwave powers and times. The results showed that the best MAE conditions were 300 W for 10 min, which gave high pectin yield with high galacturonic acid and lycopene content. Various conditions of UMAE at the best conditions of MAE and UAE were performed and exhibited that the UAE had more positively affected the pectin yield. However, the FTIR spectra of obtained pectins from different extraction techniques showed a similar pectin structure.