在线固相萃取-高效液相色谱法测定水体中的多环芳烃

摘要

A method was developed for the determination of polycyclic aromatic hydrocarbons ( PAHs ) in water by HPLC coupled with online solid phase extraction ( online SPE ) . After filtered, 1 mL of a water sample was injected directly, and then trapped on the SPE column ( Acclaim PAⅡ, 50 mm × 4. 6 mm, 3 μm) for extraction and purification; finally, the trapped analytes were transferred to the analytical column (Hypersil Green PAH, 150 mm × 3 mm, 3 μm) for the separation using valve-switching technique. The mobile phase used for online SPE was water/acetonitrile at different flow rate ( 0 . 4 and 0 . 6 mL/min ) in gradient elution mode;and that used for the separation was water/acetonitrile at 0. 8 mL/min flow rate. UV wavelength was set at 254 nm for the determination of naphthalene and acenaphthylene with no/very weak fluorescent response;fluorescence detection using programmed wavelength switching in three parallel channels was used for the other PAHs. The whole analysis process including online SPE and separation was completed within 32 min. The relative standard deviation ( RSD) of 20 PAHs were all less than 0. 16% for retention time, and less than 1. 3% for peak area (n=7). The peak area had a good linearity with the sample concentration in three orders of magnitude with correlation coefficients of above 0 . 9910 . The recoveries for 0 . 05 μg/L of each analyte in tap water were in the range of 57%-140%, and for 5 . 0 μg/L of each analyte were in the range of 85%-116%. The limits of detection of the method were less than 0 . 05 μg/L ( S/N=3 ) for most PAHs.%建立了在线固相萃取-液相色谱测定水体残留的多环芳烃的方法,用于测定自来水中的20种多环芳烃( PAHs)。直接进样1 mL经过过滤的水体样品,其中的被测组分富集在SPE柱( Acclaim PA II,50 mm×4.6 mm,3μm)上,在线完成净化和萃取富集；再通过阀切换将它们转移至分析流路,在Hypersil Green PAH色谱柱(150 mm ×3 mm,3μm)上分离检测。在线固相萃取流路以水和乙腈为流动相,0.4和0.6 mL/min流速梯度富集/萃取和洗脱；分析流路亦以水和乙腈为流动相,0.8 mL/min流速梯度洗脱,采用紫外254 nm检测无荧光效应的苊烯和弱荧光效应的萘,其它的多环芳烃化合物则于不同的荧光检测通道里,在其对应的最大激发/发射波长下灵敏测定。整个分析流程32 min即可完成。20种PAHs的保留时间的相对标准偏差均小于0.2％,色谱峰面积的相对标准偏差均小于1.3％(n=7)；在3个浓度数量级范围内峰面积与进样质量浓度的线性相关系数均大于0.9910,0.05μg/L的自来水加标样品的回收率为57％~140％,5μg/L的自来水加标样品的回收率为85％~116％；多数有荧光响应的PAHs的方法检出限均小于0.02μg/L (S/N=3)。