微波辅助萃取-气相色谱测定土壤中多氯联苯

建立了微波辅助萃取-气相色谱-微电子捕获检测土壤样品中6种多氯联苯(pcb28, pcb52, pcb101, pcb138, pcb153和pcb180)的方法. 确定了以V(20 mL丙酮):V(正己烷)＝1:1混合溶剂作萃取剂, 萃取温度110 ℃, 仪器功率800 W, 微波萃取5 min的样品前处理条件, 并用柱温程序优化了GC-μECD分析条件. 方法的检出限为0.027～0.087 ng/g; 相对标准偏差为3.4%～7.6% (n=6); 加标平均回收率79.8%～91.1%. 可用于土壤环境中多氯联苯的监测分析.     

全自动固相微萃取-气相色谱联用测定土壤中的多氯联苯

建立了简单可靠的自动固相微萃取-气相色谱联用测定土壤中的六种指示性多氯联苯(PCBs).同时研究了主要环境因素对方法萃取效率的影响.结果表明对六种分析物来说,用100μm的PDMS萃取头,在100℃的条件下萃取40 min能够得到较好的萃取效果.该方法简便、快捷、成本低,线性良好,检测限低至0.1～0.2 ng·g1,...     

微波皂化萃取气相色谱法测定生物样品中的多氯联苯

１引言 多氯联苯（ＰＣＢｓ）的性质稳定、毒性大,贻贝等海洋生物能摄取和富集海水中的ＰＣＢｓ,因此研究其中ＰＣＢｓ的测定具有重要意义。生物样品中 ＰＣＢｓ的测定一般要进行预分离处理,索氏萃取分离 ＰＣＢｓ耗时至少８ｈ,加碱皂化生物组织再以液－液萃取提取ＰＣＢｓ需要在沸水浴中回流１～２ｈ,微波直接革取能有效地分离环境样品中的ＰＣＢｓ。本文利用微波皂化萃取（ＭＡＳＥ）气相色谱法（ＧＣ）测定生物样品中的多氯联苯,实验以未受ＰＣＢｓ污染的淡水鱼为空白,用正交试验系统优化了微波功率、微波加热时间、皂化及萃取溶…     

生物样品中多氯联苯的微波皂化萃取气相色谱法测定

以KOH－甲醇－正己烷为皂化萃取溶剂,利用微波皂化萃取－气相色谱法测定了生物样品中的多氯联苯（PCBs）,实现了在皂化的同时对待测物的萃取。方法的检出限为质量分数6.25×10     

加速溶剂萃取-固相萃取-气相色谱串联质谱测定土壤中的乙草胺

提出一种准确、高效测定土壤中乙草胺的分析方法。优化方法后,土壤样品经过预处理,加速溶剂萃取(ASE),固相萃取柱(SPE)净化,样液经气相色谱串联质谱仪(GC-MS/MS)测定,用空白样品基质液配标,浓度在0.005~0.2μg/mL范围内,线性相关系数达0.9998。对空白土壤样品进行0.5,5,20μg/kg 3个水平加标(n=6),平均回收率为89.3%~102.1%,RSD范围为2.9%~4.1%。此方法可用于实际样品测定。     

超声-微波协同萃取分离、气相色谱-质谱联用测定土壤中多环芳烃

建立了常温常压条件下超声-微波协同萃取分离、气相色谱-质谱法（GC-MS）测定土壤样品中微量多环芳烃的方法,结果表明：在土壤含水量和无机盐质量分数分别为10％和6％时,以正已烷-二氯甲烷（1＋1）混合溶液40mL作萃取溶剂,采用100W微波辐射功率（超声振动功率固定为50W）萃取9min,模拟土壤样品中多环芳烃平均回收率可达86．9％,其相对标准偏差为3．6％;通过与索氏抽提、高压密闭微波和开放式微波、直接超声波和间接超声波等萃取方法相比,证明此方法具有样品容量大、萃取时间短、萃取效率高、重现性好等优点。     

微波辅助-微固相在线萃取/气相色谱质谱联用法对污泥中19种多氯联苯的测定

建立了微波辅助-微固相在线萃取/气相色谱-质谱联用(GC-MS)测定污泥中19种多氯联苯(PCBs)含量的分析方法。对微波辅助-微固相在线萃取条件进行优化,得出最优萃取条件为:萃取温度60℃,萃取时间25 min,解吸溶剂为乙酸乙酯,解吸剂用量150μL,解吸时间25 min。在优化条件下,方法的检出限为0.2~2.5 ng/g,相对标准偏差(RSD)小于14%,回收率为81.4%~102.1%。与传统的微波萃取、微固相萃取、超声萃取等方法相比,该方法集萃取、净化和浓缩于一体,极大地缩短了分析时间,适合于复杂环境样品体系中痕量PCBs的分析检测。     

墓头回CO2超临界萃取物的气相色谱-质谱分析

莫头回别名箭头风、臭罐子等,系败酱科败酱属植物异叶败酱patrinia heterophylla Bge或糙叶败酱patrinia scabra Bge。根及全草入药用,能治伤寒、温疟、妇女崩中,赤白带下,跌打损伤等疾病[1],对艾氏癌细胞有抑制及伤害作用[2]。目前对其化学成分的研究已有报道[3,4],对其挥发油     

超声波萃取-分散固相萃取净化-气相色谱电子捕获法测定土壤或底泥中的多氯联苯

采用超声波萃取、分散固相萃取净化结合气相色谱电子捕获检测法,建立了快速测定环境土壤或底泥中7种指示性多氯联苯(Polychlorinated biphenyls,PCBs)的方法.根据提取液的颜色,灵活选择是否增加浓H2SO4净化步骤,并对分散固相萃取净化过程中吸附剂的种类和用量进行了优化.当提取液颜色基本无色透明时,仅选用150 mgⅣ-丙基乙二胺(Primary secondary amire,PSA)吸附剂进行分散固相萃取净化(即一步净化),否则提取液先经过浓H2SO4净化,再采用100 mg PSA吸附剂进行分散固相萃取净化(即两步净化).整个分散固相萃取净化过程不超过5min,前处理时间显著缩短.结果表明,在1.25 ～ 100 μg/L浓度范围内,7种PCBs峰面积与浓度呈线性相关,相关系数为0.9990 ～0.9999,检出限为0.02 ～0.03 μg/kg,样品经两步净化和一步净化时,7种PCBs不同浓度加标水平回收率分别为72％ ～ 107％和88％ ～ 115％,相对标准偏差分别为3.5％ ～5.8％和3.7％～6.9％(n=5),已成功应用于舟山朱家尖某菜地土壤样品和岱衢洋海域底泥样品检测,且检测结果与国家标准方法保持一致.本方法简单快速,高效,基体干扰小,灵敏度、准确度、精密度均满足土壤或底泥中PCBs的定量分析要求.     

Monitoring of Polychlorinated Biphenyls in Surface Water Using Liquid Extraction,GC/MS,and GC/ECD

Abstract

A rapid and reliable analytical method, at trace level concentration was developed and validated for monitoring polychlorinated biphenyls (PCBs) in Jordanian surface water. The method combines the advantage of liquid extraction together with gas chromatography‐mass spectrometry (GC/MS) and gas chromatography‐electron capture detector (GC/ECD). The performance of the method was evaluated by analyzing certified reference material (CRM) of the analytes and applied on real water samples collected from different sites in Jordan. A mixture of 60∶40 dichloromethan‐petroleum ether was chosen as a convenient binary solvent for liquid–liquid extraction. The GC conditions for GC/MS were optimized using He as a carrier gas, temperature programming, and chlorpropham as an internal standard (IS).

The conditions for GC/ECD were performed using N₂ gas and a temperature program from 160 to 280°C with different increasing rates. The method of GC/MS in the selective ion mode (SIM) gave linear relationships for all PCBs tested between 0.60–6.0 µg/l with R ²=0.9934 (n=7×18). Recoveries from spiked water samples ranged between 87.6 and 91.4%. The mean accuracy and precision obtained were 4.9% and 2.16%, respectively. The mean of detection limit was 0.14±0.04 µg/l. In GC/ECD, linear relationships for all PCBs examined over the range of 0.3–2.4 µg/l was verified as characterized by a linear regression equation and correlation coefficient, R ²=0.9915 (n=12). The average precision and accuracy were 4.86% and 5.21%, respectively. Analyses results clarified that none of the examined Jordanian water samples contained any of the searched for PCBs within the detection limit achieved.     

Determination of selected polychlorinated biphenyls in soil by miniaturised ultrasonic solvent extraction and gas chromatography-mass-selective detection

Miniaturised ultrasonic solvent extraction procedure was developed for the determination of selected polychlorinated biphenyls (PCBs) in soil samples by gas chromatography-mass-selective detection by using 2³ factorial experimental design. Recoveries of PCBs from fortified soil samples are over 90% for three different fortification levels between 40 and 120 μg kg⁻¹, and relative standard deviations of the recoveries are below 7%. The limits of detection (LODs) ranged from 0.003 to 0.006 μg kg⁻¹. The performance of the proposed method was compared to traditional shake flask extraction method on the spiked real soil sample and extraction methods showed comparable efficiencies. Proposed miniaturised ultrasonic solvent extraction offers several advantages, i.e., reducing sample requirement for measurement of target compound, less solvent consumption and reducing the costs associated with solvent purchase and waste disposal.     

Determination of selected polychlorinated biphenyls in soil and earthworm (Eisenia fetida) using a QuEChERS‐based method and gas chromatography with tandem MS

Soil and earthworms are important objects in soil pollution assessment and environmental behavior and toxicity study for polychlorinated biphenyls. Accelerated solvent extraction and solid‐phase extraction are generally required for the extraction and clean‐up of polychlorinated biphenyls in soil and earthworm, which are tedious and time‐consuming. In this work, a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography and triple quadrupole mass spectrometry was developed for the determination of 20 selected polychlorinated biphenyl congeners in soil and earthworm. Different extraction times, solvents, and clean‐up adsorbents were compared and optimized. The average recoveries from spiked soils ranged between 70 and 120% with satisfactory relative standard deviations for all the polychlorinated biphenyls. In earthworm, the recoveries of polychlorinated biphenyls 180, 183, and 189 were relatively low (< 70% in some spiking levels) compared to that of the other polychlorinated biphenyls. The limits of quantification were in the range of 0.01–0.05 ng/g. The method was successfully applied to the analysis of 66 agricultural soils. To our knowledge, a combined method based on QuEChERS for the determination of polychlorinated biphenyls in soil and earthworms has not been published before. The procedure proved to be simple, sensitive, efficient, and environmentally friendly.     

Evaluation of Soxhlet extraction, accelerated solvent extraction and microwave-assisted extraction for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers in soil and fish samples

Three commonly applied extraction techniques for persistent organic chemicals, Soxhlet extraction (SE), accelerated solvent extraction (ASE) and microwave-assisted extraction (MAE), were applied on soil and fish samples in order to evaluate their performances. For both PCBs and PBDEs, the two more recent developed techniques (ASE and MAE) were in general capable of producing comparable extraction results as the classical SE, and even higher extraction recoveries were obtained for some PCB congeners with large octanol-water partitioning coefficients (K_ow). This relatively uniform extraction results from ASE and MAE indicated that elevated temperature and pressure are favorable to the efficient extraction of PCBs from the solid matrices. For PBDEs, difference between the results from MAE and ASE (or SE) suggests that the MAE extraction condition needs to be carefully optimized according to the characteristics of the matrix and analyte to avoid degradation of higher brominated BDE congeners and improve the extraction yields.     

Ultrasound‐assisted magnetic SPE based on Fe3O4‐grafted graphene for the determination of polychlorinated biphenyls in water samples

An ultrasound‐assisted magnetic SPE procedure with an Fe₃O₄‐grafted graphene nanocomposite as the magnetic adsorbent has been developed to determine seven polychlorinated biphenyls (PCBs; PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) simultaneously in 200 mL environmental water samples, in combination with GC–MS/MS. Several factors related to magnetic SPE efficiencies, such as the superparamagnetic intensity and amount of adsorbent, extraction time, sample pH, and desorption conditions were investigated. With the assistance of ultrasound, the extraction achieved the maximum within only 20 s, attributed to the powerful adsorptive ability of the magnetic adsorbent toward the PCBs. Under the optimized conditions, an excellent linearity was observed in the range of 0.1–100 ng/L for PCB28, 0.2–100 ng/L for PCB52, and 0.5–100 ng/L for the other five PCBs with the correlation coefficients ranging from 0.9988 to 0.9996. The mean recoveries at spiked levels of 5.0 and 10.0 ng/L were 84.9–108.5%, the coefficients of variations were <6.5%. With convenient magnetic separation, the synthesized magnetic adsorbent could be recycled more than ten times. The proposed method was demonstrated to be feasible, simple, rapid, and easy to operate for the trace analysis of the PCBs in environmental water samples.     

Determination of polychlorinated biphenyls in sediment by on-line narrow-bore column liquid chromatography/capillary gas chromatography

Narrow-bore column liquid chromatography coupled on-line with capillary gas chromatography (LC/GC) is used for the determination of polychlorinated biphenyls (PCBs) in sediment via a heart-cutting technique. This method is compared with a method in which two off-line column clean-up steps are used with subsequent analysis by capillary gas chromatography. For the LC/GC analysis the recovery of PCBs was 90–100%. For two sediment samples from the river Meuse the LC/GC and the other, more laborious method showed good agreement.     

Pressurized liquid extraction in determination of polychlorinated biphenyls and organochlorine pesticides in fish samples

Pressurized liquid extraction (PLE) is a relatively new technique applicable for the extraction of persistent organic pollutants from various matrices. The main advantages of this method are short time and low consumption of extraction solvent. The effects of various operational parameters (i.e. temperature of extraction, number of static cycles and extraction solvent mixtures) on the PLE efficiency were investigated in this study. Fish muscle tissue containing 3.2% (w/w) lipids and native polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and other related compounds was used for testing. Purification of crude extracts was carried out by gel permeation chromatography employing Bio-Beads S-X3. Identification and quantitation of target indicator PCBs and OCPs was performed by high-resolution gas chromatography (HRGC) with two parallel electron-capture detectors (ECDs). Results obtained by the optimized PLE procedure were compared with conventional Soxhlet extraction (the same extraction solvent mixtures hexane–dichloromethane (1:1 v/v) and hexane–acetone (4:1 v/v) were used). The recoveries obtained by PLE operated at 90–120 °C were either comparable to “classic” Soxhlet extraction (for higher-chlorinated PCB congeners and DDT group) or even better (for lower chlorinated analytes). The highest recoveries were obtained for three static 5 min extraction cycles.     

Development of a solid-phase extraction method for the determination of polychlorinated biphenyls in water

Polychlorinated biphenyls (PCBs) in water were extracted with a rebuilt extraction unit using 47 mm C18 solid-phase extraction (SPE) disks. Three types of disks (SPEC, ENVI and Empore) were investigated for the extraction of seven PCBs from 11 reagent water spiked at two concentration levels (20 and 1000 ng/l). The Empore disks produced the best analyte recoveries (91-107% with R.S.D. of 1-8%) at the low concentration level and displayed no leaking tendency. Empore disks were therefore considered superior to ENVI and SPEC disks for the conditions outlined in this work. The obtained extracts were dried and purified in an additional clean-up step using custom-made columns containing Florisil and Na2SO4. For water containing large amounts of organic matter, a pre-filtration was included. Final analysis was carried out on a dual-column GC-electron-capture detection system with on-column injection. The optimised extraction method, including clean-up, was less time-consuming and used less hazardous organic solvents than conventional liquid-liquid extraction (LLE) methods. Recoveries were 92-102% with R.S.D. of 3-8%.     

微波辅助萃取-GC/MS联用分析竹子中氨基酸

建立了微波辅助萃取-GC/MS联用测定竹子中谷氨酸、天冬氨酸和苯丙氨酸等10种氨基酸的分析方法, 优化了微波辅助萃取条件, 方法的线性范围在0.100～100 μg/mL之间, 检出限在0.0098～0.36 μg/mL之间, RSD为4.1%～9.7%, 回收率在84.3%～118%之间. 分析了4种不同产地、竹龄竹子的竹叶、竹枝和竹沥中氨基酸含量. 结果表明, 不同竹种、产地及竹龄的竹子中氨基酸总量有较大差异;相同竹种其竹沥中氨基酸含量显著高于竹叶及竹枝中氨基酸含量.