顶空固相微萃取-气相色谱法测定生活饮用水中痕量1,4-二氧六环

建立了生活饮用水中痕量1,4-二氧六环的顶空固相微萃取(HS/SPME)-气相色谱测定方法。考察并优化了萃取头、萃取温度、萃取时间、pH值、样品量、色谱条件等参数。结果表明:提取效率较好的方法是3 mL水样中加入3 mL 600 g/L氢氧化钠溶液,用85 μm Carboxen-PDMS萃取头萃取,用键合碱改性的大口径、厚液膜PTA-5毛细管色谱柱测定。1,4-二氧六环在0.50~50.0 μg/L范围内线性关系良好,相关系数为0.9995;方法检出限(以S/N>3计)为0.14 μg/L;相对标准偏差为2.1%~4.5% (n=6);对实际样品中进行线性范围内的高、中、低3个加标水平的测定,回收率为95.5%~107%,相对标准偏差为1.1%~5.3% (n=6)。建立的方法简便、准确、重现性好、灵敏度高,适合生活饮用水中痕量1,4-二氧六环的常规监测。     

膜萃取-气相色谱/微分离子迁移谱检测水中的1,4-二恶烷

利用膜萃取-气相色谱/微分离子迁移谱（ME-GC/DMS）对水中的1,4-二恶烷污染物进行了检测。考察了射频电压、采样流速、膜渗透时间、Trap预富集时间等参数对检测二恶烷的影响规律。结果显示：在优化条件下,二恶烷的定量线性范围为2.0~20.0 μg/L,检出限为0.67 μg/L。实验证明,二恶烷与5种氯代烃的混合物在ME-GC/DMS的二维分离谱图中得到特异性响应,增加了识别的准确性。该研究为发展现场实时监测地下水中污染物的方法提供了重要参考。     

Quantification of 4-hydroxy-2,5-dimethyl-3-furanone in fruit samples using solid phase microextraction coupled with gas chromatography-mass spectrometry

Furaneol is an important aroma compound. It is very difficult to extract furaneol from food matrices and separate it on a gas chromatography column due to its high polarity and instability. A new quantitative method was developed to quantify furaneol in aqueous samples by the use of derivatization/solid phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS). The derivatization was carried out by reacting pentafluorobenzyl bromide with furaneol in basic solutions at elevated temperatures. The derivative was stable and less polar so that SPME-GC/MS could be applied for extraction, separation and detection. The automated analytical method had a limit of detection (LOD) of 0.5 ng mL(-1), a limit of quantification (LOQ) of 2 ng mL(-1), a repeatability of 9.5%, and a linear range from 2 to 500 ng mL(-1). The method was applied to analyze fruit samples. And it was found that the concentrations of furaneol in tomato ranged from 95 to 173 μg kg(-1), in strawberries ranged from 1663 to 4852 μg kg(-1). The results were verified with a LC procedure. To facilitate analytical method development, some physico-chemical parameters for furaneol were determined in this work. Its solubility in water was determined as 0.315 g mL(-1) (25°C). Its LogD in water and LogP in 0.1 M phosphate buffer were -0.133 and 0.95 (20 °C), respectively. Its pKa was 8.56 (20 °C).     

顶空采样-毛细管气相色谱法分析格列美脲原料药中的溶剂残留

建立了顶空采样-毛细管气相色谱检测格列美脲原料药中溶剂残留的分析方法。对产自国内8个生产厂家的格列美脲样品中有机溶剂的残留状况进行了系统评价,结合药品生产工艺信息,确定了丙酮、乙酸乙酯、甲醇、异丙醇、乙醇、氯仿、甲苯、1,4-二氧六环、吡啶、氯苯、乙醚、二氯甲烷、正己烷和苯等14种有机溶剂为残留检测对象。根据被测组分在色谱柱上的保留性质将其分为两类,以实现基线分离。用Supelco-Wax极性色谱柱,以乙腈为内标物,分离检测了丙酮、乙酸乙酯、甲醇、异丙醇、乙醇、氯仿、甲苯、1,4-二氧六环、吡啶和氯苯的残留量;用Supelco OVI-G43弱极性色谱柱,以丁酮为内标,分离检测了乙醚、二氯甲烷、正己烷和苯的残留量。14种残留组分在各自的浓度范围内呈良好的线性关系(r=0.99167～0.99997,n=8),最低检出限范围为0.2～13.5 μg/g;14种残留组分检测的日间重复性(以相对标准偏差(RSD)计)为0.6%～9.2%(n=3),3种加标浓度的平均添加回收率为86.3%～104.1%(RSD为0.2%～5.3%,n=16)。实验结果表明,该方法简单、灵敏、可靠,适用于格列美脲中残留溶剂的分析确证。     

Determination of methyl-substituted phenols in water by gas chromatography with preliminary iodination

A procedure is developed for determining phenol; 2-, 3-, and 4-methylphenols, and 2,4- and 2,6-dimethylphenols in aqueous media, which consists in the synthesis of iodine derivatives, their extraction with toluene, and determination by gas chromatography with electron-capture detection. The optimal conditions for the iodination of phenols in water are found; also the extraction and gas chromatography behavior of methylphenols and their iododerivatives are investigated. To make the identification of iododerivatives of methylphenols more reliable, they are subjected to acylation with acetic anhydride in the extract. The analytical range of phenols in water is 0.01–10 μg/L, the relative standard deviation is 2–6%, and the duration of analysis is up to 40 min.     

Multi-residue determination of organophosphorus and organochlorine pesticides in environmental samples using solid-phase extraction with cigarette filter followed by gas chromatography-mass spectrometry

A solid‐phase extraction (SPE) method was developed to extract 14 pesticides simultaneously from environment samples using cigarette filter as the sorbent before gas chromatography‐mass spectrometry (GC‐MS) analysis. Parameters influencing the extraction efficiency, such as the sample loading flow rate, eluent and elution volume, were optimized. The optimum sample loading rate was 3 mL/min, and the retained compounds were eluted with 6 mL of eluent at 1 mL/min under vacuum. Good linearity was obtained for all the 14 pesticides (r²>0.99) from 0.1 to 20 μg/L for water and from 2 to 400 μg/kg for soil samples. The detection limits (signal‐to‐noise=3) of the proposed method ranged from 0.01 to 0.20 μg/L for water samples and from 0.42 to 6.95 μg/kg for soil samples. The developed method was successfully applied for determination of the analytes in real environmental samples, and the mean recoveries ranged from 76.4 to 103.7% for water samples and from 79.9 to 105.3% for soil samples with the precisions (relative standard deviation) between 2.0 and 13.6%.     

Determination of polycyclic aromatic hydrocarbons in water by gas chromatography/mass spectrometry with accelerated sample preparation

A novel simplified sample preparation method for quantitative analysis of polycyclic aromatic hydrocarbons (PAH) in water samples by gas chromatography/mass spectrometry (GC/MS) was proposed. The method requires just 1 mL of water and 1 mL of dichloromethane. The detection limits of PAH with the use of high resolution GC/MS are about 1 μg/Λ, while the limits of quantification—10 μg/L. These limits correspond to those for the standard 8270 method of the United States Environmental Protection Agency.     

Headspace gas chromatographic determination of 1,4-dioxane with adsorption preconcentration on silica modified with λ-carrageenan

Organosilica materials containing λ-carrageenan on their surface are synthesized. The conditions for the immobilization of the polysaccharide, such as phase contact time and pH and concentration of solutions, are optimized. It is shown that the chemisorption of the polysaccharide passes through ion exchange multipoint immobilization, which provides a high hydrolytic stability of the prepared organosilica. The rate of washing of λ-carrageenan to the solution does not exceed 0.5%. The physical and chemical characteristics of the new material are studied. In particular, it is shown that the material is completely stable up to 200°C and reversibly desorbs water at 120°C; it well adsorbs 1,4-dioxane from the gas phase and desorbs it under heating to 70°C. This ensures the use of the prepared carrageenan-containing material as an adsorbent for a solid-phase cartridge designed for the adsorption preconcentration of 1,4-dioxane in its headspace gas chromatographic determination in samples of nonionic surfactants. The developed procedure ensures the determination of 1,4-dioxane by gas chromatography with a flame ionization detector in the concentration range 0.012–3.750 mg/L with a limit of detection of 0.0014 mg/L. Preconcentration lowers the limit of detection in the determination of 1,4-dioxane by 50 times.     

气相色谱法同时测定溶剂型胶黏剂中的9种有害物质

建立了利用毛细管柱气相色谱同时测定溶剂型胶黏剂中苯、 甲苯、 对（间）二甲苯、 邻二甲苯、 二氯甲烷、1,2-二氯乙烷、1,1,2-三氯乙烷、三氯乙烯、甲苯二异氰酸酯（TDI）的方法,并对样品中有害物质的分离提取和色谱条件进行了研究.实验结果表明,方法化合物浓度在10~300 μg/mL时,线性相关系数不低于0.999 1,样品加标回收率在91.2%~104.1%之间,相对标准偏差均小于5%,检出限为0.1~3.0 μg/mL.方法不仅回收率高、重现性好,而且简便、快速.     

Fast determination of octinoxate and oxybenzone uv filters in swimming pool waters by gas chromatography/mass spectrometry after solid‐phase microextraction

A fast gas chromatography/mass spectrometry method was developed and validated for the analysis of the potential endocrine disrupters octinoxate and oxybenzone in swimming pool water samples based on the solvent‐free solid‐phase microextraction technique. The low‐pressure gas chromatography/mass spectrometry method used for the fast identification of UV filter substances was compared to a conventional method in terms of sensitivity and speed. The fast method proposed resulted in 2 min runs, leading to an eightfold decrease in the total analysis time and a sevenfold improvement in detection limits. The main parameters affecting the solid‐phase microextraction process were also studied in detail and the optimized conditions were as follows: fiber coating, polyacrylate; extraction mode, direct immersion; extraction temperature, 25°C; sample volume, 5 mL; extraction time 45 min; pH 6.5. Under the optimized conditions, a linear response was obtained in the concentration range of 0.5–25 μg/L with correlation coefficients in the range 0.990–0.999. The limits of detection were 0.17–0.29 μg/L, and the recoveries were 80–83%. Combined method uncertainty was assessed and found to be less than 7% for both analytes for concentrations equal to or higher than 5 μg/L. Pool water samples were analyzed to demonstrate the applicability of the proposed method. Neither octinoxate nor oxybenzone were detected in the swimming pool water samples at concentrations above the respective limits of detection.     

Trace-level determination of 1,4-dioxane in water by isotopic dilution GC and GC-MS

The volatile and polar solvent 1,4-dioxane has recently been reported as a contaminant of ground and surface waters, establishing the need to determine this substance in drinking water. This investigation established that 1,4-dioxane can be determined in water by various techniques including direct aqueous injection (DAI) gas chromatography (GC) and purge and trap GC-mass spectrometry (MS). Purge and trap GC-MS is limited by 1,4-dioxane's poor purge efficiency, resulting in detection limits up to 100 times greater than the efficiently purged volatile organic compounds. To attain the sensitivity required for drinking water monitoring, a method based on continuous liquid-liquid extraction with dichloromethane was developed. Isotope dilution was more accurate and reproducible than quantification with external standards, and the improvement in precision led to a lower method detection limit, 0.2 microgram L-1, using a quadrupole ion trap instrument in the electron ionization mode. Isotope dilution accuracy approached 100% in ppb determinations. Isotopic dilution quantification was also possible using a non-selective GC detector owing to the high efficiency of capillary GC columns that resolve the deuterium-labeled solvent from the natural isotopes.     

Combination of dispersive solid‐phase extraction and salting‐out homogeneous liquid–liquid extraction for the determination of organophosphorus pesticides in cereal grains

A new analytical method for the determination of organophosphorus pesticides in cereal samples was developed by combining dispersive SPE (d‐SPE) and salting‐out homogeneous liquid–liquid extraction (SHLLE). The pesticides were first extracted from cereal grains with acetonitrile, followed by d‐SPE cleanup. A 2 mL aliquot of the extract was then added to a centrifuge tube containing 9.2 mL water and 3.3 g NaCl for SHLLE. Analysis of the extract was carried out by gas chromatography coupled with flame photometric detection. The d‐SPE procedure effectively provides the necessary cleanup of the extract while SHLLE is used as an efficient concentration technique. Experimental parameters influencing the extraction efficiency including amounts of added water and salt were investigated. Recovery studies were carried out at three fortification levels, yielding recoveries in the range of 57.7–98.1% with the RSD from 3.7 to 10.9%. The reported limits of determination obtained from this study were 1 μg/kg, which is better than the conventional methods. In the analysis of 40 wheat and corn samples taken from Beijing suburbs, only two wheat samples have chlorpyrifos residue over the limits of determination.     

Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry

A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid‐phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C₁₈ cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected‐ion monitoring mode. Good linear relationships were obtained in the range of 0.1–50 μg/L for chlorpyrifos, and 0.05–50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54–86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.     

Determination of 1,4-dioxane impurity levels in Triton X-100 raw material by gas chromatography with mass spectrometric detection

Triton X-100 (octoxynol 9) is a commercially available surfactant used as a solvent detergent in numerous pharmaceutical applications including virus inactivation. A byproduct formed during its synthesis is 1,4-dioxane, the cyclic dimer of ethylene oxide and a possible carcinogen to humans. The United States Pharmacopoeia (USP) contains a labor-intensive 1,4-dioxane test for Triton X-100. The method couples vacuum distillation to extract the 1,4-dioxane from the Triton X-100 matrix followed by gas chromatography (GC) using a packed column with flame-ionization detection. In order to provide a more automated and specific test methodology, a headspace GC-mass spectrometry (MS) method has been developed for this application. Analyte quantitation is accomplished by the method of standard additions. The automated sample preparation, coupled with the specificity inherent in high-efficiency capillary column separations together with single-ion MS detection, results in an assay that is more efficient, accurate, and precise than the USP procedure. Performance characteristics of the headspace GC-MS method are contrasted with those characteristics of the USP methodology.     

气相色谱法快速同时测定室内装饰装修材料胶黏剂中的苯、甲苯、二甲苯的含量

建立了快速、同时测定室内装饰装修材料胶黏剂中苯、甲苯、二甲苯含量的气相色谱检测法.样品用乙酸乙酯溶解处理后,用改性的聚乙二醇(FFAP)毛细管色谱柱分离,氢火焰离子化检测器检测,外标法定量.胶粘剂中苯、甲苯、二甲苯的浓度分别在8.58～171.40μg/mL、9.04～180.62μg/mL、8.80～175.92μg...     

The extraction and analysis of 1,4-dioxane from water using solid-phase microextraction coupled with gas chromatography and gas chromatography-mass spectrometry

In this study, two methods are developed for the extraction of 1,4-dioxane (dioxane) from water using 80-microm carboxen-polydimethylsiloxane solid-phase microextraction fibers followed by either gas chromatography (GC)-flame ionization detection (FID) or GC-mass spectrometry (MS). With GC-FID, the lower limit of detection (LOD) for 1,4-dioxane is 2.5 microg/L (ppb) with a linear range of 5 to 10,000 microg/L, obtained by immersing the fiber in the sample for 20 min with agitation. Using GC-MS, the lower limit of quantitation is 0.5 microg/L, and the LOD is 0.25 microg/L. The upper linear range limit is 100 microg/L. Samples are extracted in 20 min using either heated headspace with agitation or direct immersion with agitation.     

Use of buffering and other means to improve results of problematic pesticides in a fast and easy method for residue analysis of fruits and vegetables

A modification that entails the use of buffering during extraction was made to further improve results for certain problematic pesticides (e.g., folpet, dichlofluanid, chlorothalonil, and pymetrozine) in a simple, fast, and inexpensive method for the determination of pesticides in produce. The method, known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods, now involves the extraction of the sample with acetonitrile (MeCN) containing 1% acetic acid (HAc) and simultaneous liquid-liquid partitioning formed by adding anhydrous MgSO4 plus sodium acetate (NaAc). The extraction method is carried out by shaking a centrifuge tube which contains 1 mL of 1% HAc in MeCN plus 0.4 g anhydrous MgSO4 and 0.1 g anhydrous NaAc per g sample. The tube is then centrifuged, and a portion of the extract is transferred to a tube containing 50 mg primary secondary amine sorbent plus 150 mg anhydrous MgSO4/mL of extract. After a mixing and centrifugation step, the extract is transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry. Independent of the original sample pH, the use of buffering during the extraction yields pH <4 in the MeCN extract and >5 in the water phase, which increases recoveries of both acid- and base-sensitive pesticides. The method was evaluated for 32 diverse pesticides in different matrixes, and typical percent recoveries were 95 +/- 10, even for some problematic pesticides. Optional solvent exchange to toluene prior to GC/MS analysis was also evaluated, showing equally good results with the benefit of lower detection limits, but at the cost of more time, material, labor, and expense.     

气相色谱法测定活泥鳅中硫丹及其硫酸盐残留

建立了检测活泥鳅中α-硫丹、β-硫丹及硫丹硫酸盐残留量的气相色谱法.泥鳅样品经过正己烷-丙酮混合液提取后,转溶至乙腈中,冷冻去脂,再经中性氧化铝小柱净化处理,用丙酮-正己烷(体积比1:2)洗脱,洗脱液用气相色谱-电子捕获检测器检测,外标法定量.标准曲线的线性范围为10～100 ng/mL,相关系数不小于0.998,硫丹定量限为3.3 μg/kg,检出限为1.0 μg/kg.进行4.0,8.0和10.0 μg/kg 3个浓度水平的加标回收试验,回收率为91.3％～105.4％.该方法分析成本低,测定结果准确,能满足常规检测及食品安全监控的需要.     

Solidification of floating organic droplet microextraction for determination of seven insecticides in fruit juice,vegetables and agricultural runoff using gas chromatography with flame ionization and mass spectrometry detection

Liquid microextraction employing solidification of the floating organic droplet, with vortexing and heating to optimize extraction efficiency, was developed for the determination of seven insecticides in fruit juice, vegetables, and agricultural runoff water. The extracts were analyzed by gas chromatography with both flame ionization and mass spectrometry detection for the determination of chlorpyrifos, prothiofos, profenofos, ethion, λ‐cyhalothrin, permethrin, and cypermethrin, respectively. Using 20 μL of 1‐undecanol in 10 mL of aqueous solution containing 1% w/v sodium chloride provided preconcentration factor of 500. The enrichment factor of the analytes was in the range of 355 to 509 with extraction recovery >71%. The linearity ranges were 4–200 μg/kg for gas chromatography with flame ionization detection and 1–100 μg/kg for gas chromatography with mass spectrometry, with limits of detection ranging from 0.04 to 1.2 μg/kg, which are lower than the international maximum residue limits for vegetables and fruit juice. Intra‐day and inter‐day precisions are less than 5.4 and 7.0% relative standard deviation, respectively. The method was successfully applied to the determination of the seven insecticides in samples of vegetables, fruit juice and agricultural runoff, with recoveries ranging from 61.7 to 120.8%. The extraction method is simple, efficient and environmentally friendly.     

分散液液微萃取-气相色谱/质谱法测定水中多环芳烃

用分散液液微萃取-气相色谱/质谱法测定水样中的16种多环芳烃(PAHs)。通过实验确定最佳萃取条件为:20μL四氯化碳作萃取剂,1.0 mL乙腈作分散剂,超声萃取1 min。在优化条件下,多环芳烃的富集倍数达到216～511,方法在0.05～50μg/L范围内呈良好的线性关系,相关系数(R2)在0.9873～0.9983之间,检出限为0.0020～0.14μg/L。相对标准偏差(RSD)在3.82%～12.45%(n=6)之间。该方法成功用于实际水样中痕量多环芳烃的测定。