Doong R, Chang S, Sun Y
Department of Atomic Science, National Tsing Hua University, Hsinchu, Taiwan.
J Chromatogr Sci. 2000 Dec;38(12):528-34. doi: 10.1093/chromsci/38.12.528.
The feasibility of direct-immersion (DI) solid-phase microextraction (SPME) and headspace (HS) SPME for the determination of high-ring polycyclic aromatic hydrocarbons (PAHs) (4- to 6-ring PAHs) in water and soil samples is studied. Three SPME fibers--100- and 30-microm polydimethylsiloxane (PDMS) and 85-microm polyacrylate (PA) fibers-are compared for the effective extraction of PAHs. Parameters affecting the sorption of PAHs into the fiber such as sampling time, sampling volume, and temperature are also evaluated. The extracted amounts of high-ring PAHs decrease with the decreasing of film thickness, and the 100-microm PDMS has the highest extraction efficiency than 85-microm PA and 30-microm PDMS fibers. Also, the extraction efficiency decreases with the increasing molecular weights of PAHs. Of the 10 high-ring PAHs, only fluoranthene and pyrene can reach equilibrium within 120 min at 25 degrees C for DI-SPME in a water sample. Increasing the temperature to 60 degrees C can increase the sensitivity of PAHs and shorten the equilibrium time. A 0.7- to 25-fold increase in peak area is obtained for DI-SPME when the working temperature is increased to 60 degrees C. For HS-SPME, the extraction efficiency of PAHs decrease when the headspace volume of the sampling system increases. All high-ring PAHs can be detected in a water sample by increasing the temperature to 80 degrees C. However, only 4- and 5-ring PAHs can be quantitated in a CRM soil sample when HS-SPME is used. The addition of a surfactant with high hydrophilic property can effectively enhance the sensitivity of high-ring PAHs. HS-SPME as well as DI-SPME with 100-microm PDMS or 85-microm PA fibers are shown to be suitable methods for analyzing high-ring PAHs in a water sample; however, this technique can only apply in a soil sample for PAHs having up to 5 rings.
研究了直接浸入（DI）固相微萃取（SPME）和顶空（HS）SPME用于测定水和土壤样品中高环多环芳烃（PAHs）（4至6环PAHs）的可行性。比较了三种SPME纤维——100微米和30微米的聚二甲基硅氧烷（PDMS）纤维以及85微米的聚丙烯酸酯（PA）纤维——对PAHs的有效萃取效果。还评估了影响PAHs吸附到纤维上的参数，如采样时间、采样体积和温度。高环PAHs的萃取量随膜厚度的减小而降低，100微米的PDMS纤维比85微米的PA纤维和30微米的PDMS纤维具有最高的萃取效率。此外，萃取效率随PAHs分子量的增加而降低。在10种高环PAHs中，对于水样中的DI-SPME，仅荧蒽和芘在25℃下120分钟内可达到平衡。将温度升至60℃可提高PAHs的灵敏度并缩短平衡时间。当工作温度升至60℃时，DI-SPME的峰面积增加0.7至2.5倍。对于HS-SPME，当采样系统的顶空体积增加时，PAHs的萃取效率降低。通过将温度升至80℃，水样中所有高环PAHs均可被检测到。然而，当使用HS-SPME时，在有证土壤样品中仅可对4环和5环PAHs进行定量。添加具有高亲水性的表面活性剂可有效提高高环PAHs的灵敏度。HS-SPME以及使用100微米PDMS或85微米PA纤维的DI-SPME被证明是分析水样中高环PAHs的合适方法；然而，该技术仅适用于分析土壤样品中最多5环的PAHs。
