气相色谱-质谱法测定废酸油渣中的16种多环芳烃

建立了废酸油渣中16种多环芳烃超声萃取、Florisil萃取柱净化、气相色谱-质谱测定的方法。笔者对提取方式、提取剂类型和体积、提取时间和次数、净化方式等进行研究,采用无水硫酸钠分散,二氯甲烷作为提取剂超声40 min,提取液经纯水清洗、离心后取适量有机相经过3 g Florisil萃取柱净化,采用气相色谱-质谱选择离子模式(SIM),加入内标进行定量分析。结果表明:二氯甲烷提取效率比正己烷好,丙酮可能引起酸性样品中多环芳烃的降解,丙酮超声萃取时加入无水硫酸钠能在一定程度上防止目标物降解,但萃取效率不可控制,宜采用二氯甲烷作为萃取剂。分散提取能有效减少提取时间,超声清洗仪超声40 min提取效率为86.2%～104%。3g Florisil萃取柱净化比1 g Florisil萃取柱净化和GPC净化效果略好。方法检出限为0.4～1.3 mg/kg,6次空白加标的相对标准偏差为2.3%～15.3%,6个实际样品测定结果的相对标准偏差为1.2%～27.3%,基体加标回收率为51.3%～126%,连续校准稳定。该方法适用于废酸油渣样品中16种多环芳烃的检测,比直接溶解有效,比加速溶剂萃取、索氏提取、微波萃取和超声探头萃取简单、快捷,能有效减少设备污染和腐蚀,净化方法有效,测定结果准确可靠,是实现大批量样品检测的可行方法。

Determination of 16 PAHs in Waste Acid Oil Residue by Gas Chromatography Mass Spectrometry

A method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in waste acid oil residue with ultrasonic extraction, Florisil column purification, and gas chromotogarphy-mass spectrometry (GC-MS) is introduced. In this paper, the effect of extraction methods, extractants, extractant volume, extraction time, the number of extractions, and purification methods were studied. Using anhydrous sodium sulfate for dispersion, samples were ultrasonically extracted with methylene chloride for 40 min. The extract was cleaned with pure water and centrifuged. Certain amount of organic phase of extract was purified with 3 g Florisil column, and then analyzed quantitatively with internal standard by select ion mode (SIM) of GCMS. The results showed that the extraction efficiency of dichloromethane was better than that of n-hexane. Acetone was not suitable as extractant since it may cause the PAHs degradation in acid samples. Adding anhydrous sodium sulfate in ultrasonic extraction of acetone could prevent the degradation of the target to some extent, but the extraction efficiency could not be controlled, so dichloromethane should be used as extractant. The extraction time can be effectively reduced by disperse extraction, and the extraction efficiency of ultrasonic cleaning instrument for 40 min was 86.2%-104%. Purification effect of 3 g Florisil column was slightly better than that of 1 g Florisil column and GPC. The detection limit was 0.4-1.3 mg/kg, and the relative standard deviations of 6 blank tests and 6 actual samples were 2.3%-15.3% and 1.2%-27.3%, respectively. The recovery rate of matrix standards was 51.3%-126%, and the continuous calibration was relatively stable. This method is suitable for the determination of 16 Polycyclic aromatic hydrocarbon in waste acid oil residue samples. It is more effective than direct dissolution, simpler and faster than accelerated solvent extraction, soxhlet extraction microwave extraction and ultrasonic probe extraction, and can effectively reduce equipment pollution and corrosion, the purification method is effective, the result of determination is accurate and reliable, and it is an economical and feasible method for the detection of large quantities of samples.