通过优化背景电解液酸度及背景电解液中硼砂、羧甲基-β-环糊精(CM-β-CD)、二甲基-β-环糊精(DM-β-CD)的浓度,利用多环芳烃(PAHs)与CM-β-CD以及PAHs与DM-β-CD亲和力的差异,提出了提示方法.参考GB/T 28189-2011进行样品前处理,将样品剪成0.5 cm×0.2 cm的细条,分取1 g,加入50 mL环己烷,密封后于50 ℃超声提取1 h.冷却至室温,过滤,滤液用附激光诱导荧光检测器的高效毛细管电泳仪分析,背景电解液为含30 mmol·L-1 CM-β-CD、20 mmol·L-1 DM-β-CD和40 mmol·L-1硼砂的混合溶液(pH 5.0),荧光检测波长为325 nm.结果显示:16种PAHs的质量浓度在0.01~0.5 mg·L-1内与峰面积呈线性关系,检出限为0.002~0.040 mg·L-1;按照标准加入法进行回收试验,结果为91.4%~104%,测定值的相对标准偏差(n=5)为0.40%~6.3%.方法用于3种纺织品以及5种食品塑料包装的分析,8种样品均不同程度地检出了 PAHs.
By optimizing the acidity of background electrolyte and the concentrations of borax,carboxymethyl groups-β-cyclodextrin(CM-β-CD)as well as dimethyl-β-cyclodextrin(DM-β-CD)for background electrolyte,the title method was proposed utilizing differences of the affinity between polycyclic aromatic hydrocarbons(PAHs)and CM-β-CD as well as PAHs and DM-β-CD.Refer to GB/T 28189-2011 for sample pretreatment,the sample was cut into the thin strip with 0.5 cm× 0.2 cm.An aliquot(1 g)of the sample was taken,and 50 mL of cyclohexane was added.The mixture was sealed,and extracted by ultrasound at 50 ℃ for 1 h.After cooling to room temperature and filtering,the filtrate was analyzed by high performance capillary electrophoresis instrument with laser induced fluorescence detector at fluorescence detection wavelength of 325 nm,and the mixed solution containing 30 mmol·L-1 CM-β-CD,20 mmol·L-1 DM-β-CD and 40 mmol·L-1 borax was used as the background electrolyte(pH 5.0).It was shown that mass concentrations of 16 PAHs showed linear relationships with peak areas in the range of 0.01-0.5 mg·L-1,with detection limits in the range of 0.002-0.040 mg·L-1.Test for recovery was conducted using the standard addition method,giving results in the range of 91.4%-104%,and RSDs(n=5)of the determined values ranged from 0.40%to 6.3%.The proposed method was applied to the analysis of 3 textiles and 5 plastic food packages,and PAHs were detected to varying degrees in 8 samples.