基于聚氨酯海绵的顶空液膜微萃取方法结合气相色谱-质谱联用技术分析环境水中挥发性多环芳烃

Analysis of Volatile Polycyclic Aromatic Hydrocarbons in Environmental Water Using Headspace Microextraction Based on a Polyurethane Sponge-Supported Liquid Film Combined with Gas Chromatography-Mass Spectrometry

  • 摘要: 本研究开发了一种基于聚氨酯海绵的新型顶空液膜微萃取方法及装置,结合气相色谱-质谱技术用于环境水中萘、苊烯、苊、芴、菲、蒽等6种多环芳烃(PAHs)的快速、高灵敏分析,并考察了萃取溶剂种类及用量、抽吸次数、萃取温度、搅拌速度、洗脱剂体积对6种PAHs富集效果的影响。结果表明,以40 µL四氯化碳作为萃取剂,加载于底部直径和高均为4 mm的聚氨酯海绵微型圆柱内,在65 ℃、1 000 r/min萃取条件下动态抽吸150次,随后采用30 µL四氯化碳洗脱并结合物理挤压回收溶剂的萃取效果较佳。方法学验证结果表明,在低、中、高3个加标水平(0.1、0.5、1 μg/L)下,6种PAHs的相对回收率为94.7%~113.2%,日内、日间精密度分别为1.0%~8.1%和4.2%~9.5%;在0.01~5 μg/L浓度范围内的线性关系良好(R2≥0.997);以3倍和10倍信噪比确定的检出限和定量限分别为3~30 ng/L和10~100 ng/L。该方法操作便捷、装置简单、成本低、富集效果好、检测灵敏度高,在微量挥发物分析与检测领域具有较好的开发和应用价值。

     

    Abstract: A method of combining headspace microextraction technique based on a polyurethane sponge-supported liquid film with gas chromatography-mass spectrometry (GC-MS) was developed for convenient and sensitive analysis of six polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. The microextraction device consists of three parts, namely injector, polyurethane sponge, and headspace bottle. Firstly, the commercially available polyurethane sponge was specially tailored to be fitted into miniature cylinders that were compatible with the internal cavity of the 2.5 mL syringe needle. Then the extraction solvents were loaded to form a microextraction liquid film on the surface and inside of the sponge. After sealed with syringe barrel, the syringe needle was inserted into the septum of headspace bottle for headspace microextraction. The dynamic suction, heating assistance, and magnetic stirring were adopted to accelerate the volatilization process and transferring of the analytes in gas-liquid interface. Given the excellent elasticity of polyurethane sponge, the extraction solution could be successfully recovered through solvent elution and physical extrusion. The influence of the types and amounts of extraction solvents, suction time, heating (extraction) temperatures, stirring speeds, and eluent volumes on the enrichment efficiency of the monitored PAHs were systematically investigated. The results indicated that the satisfactory extraction efficiency could be achieved by using 40 µL of carbon tetrachloride as an extractant, which were loaded into a polyurethane sponge microcylinder with a bottom diameter and height of 4 mm, and followed by 150 cycles dynamic suction under extraction conditions of 65 ℃ and 1 000 r/min. Subsequently, physical extrusion was adopted to collect the extraction solution after elution with 30 µL of carbon tetrachloride. The validation results demonstrated that the proposed method achieves good relative recoveries of PAHs ranging from 94.7% to 113.2% at three spiked levels of 0.1, 0.5, and 1 μg/L. The intra- and inter-day precisions are in the range of 1.0%-8.1% and 4.2%-9.5%, respectively. Good linearities are observed for all monitored PAHs with the regression coefficients (R2) greater than 0.997 in the concentration range of 0.01-5 μg/L. The limits of detection (LODs) and quantification (LOQs) are in the range of 3-30 ng/L and 10-100 ng/L, respectively. This method is easy to operate, and has the advantages of low cost, high sensitivity as well as fast speed, having highly potential in the field of trace volatile analysis in environmental samples.

     

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