用顶空固相微萃取法提取样品中5种邻苯二甲酸酯类化合物(PAEs),用气相色谱法测定其含量。移取水栽培法培育辣椒的营养液10 mL,置于顶空瓶中,进行固相微萃取到达要求的时间后,将萃取头迅速插入色谱仪进样口进行解吸。选用65 μm PDMS/DVB纤维头作为微萃取头,并在下述条件下进行固相微萃取:① 萃取时间及温度:50 min,80 ℃;② 样品体积:10 mL;③ 搅拌速率:1 000 r·min-1;④ 样品溶液的离子强度:氯化钠加入量达18%;⑤ 溶液的酸度:近中性,样品溶液的原始酸度(pH 6.5~7.2)正符合此要求;⑥ 解吸温度和时间:250 ℃,10 min。结果表明:5种PAEs的线性范围均在0.2~10 mg·L-1之间,检出限(3S/N)均小于0.12 mg·L-1。方法的回收率在83.4%~105%之间,测定值的相对标准偏差(n=5)均小于9%。

GC with head-space SPME was applied to the determination of 5 phthalates in exudation from root of hot pepper. Ten mL of the sample, i.e., the nutritious liquor in which hot pepper seedlings were cultivated hydroponically, were transferred into the head space flask, and SPME was carried out with 65 μm PDMS/DVB fibre head as microextractor and under the following conditions: ① time and temperature of extraction: 50 min, 80 ℃; ② rate of agitation: 1 000 r·min-1; ③ ionic strength of sample solution: content of NaCl amounted to 18%; ④ acidity of sample solution: nearly neutral; the initial acidity of the sample (pH 6.5-7.2) conformed with this requirement; ⑤ temperature and time of desorption: 250 ℃, 10 min. At the end of SPME, the microextractor was inserted quickly into the sample inlet of chromatograph, and desorbed. As shown by the results, linearity ranges of the 5 phthalates were found to be same between 0.2 and 10 mg·L-1, with detection limits (3S/N) all less than 0.12 mg·L-1. Values of recovery of the method were found between 83.4% and 105% and values of RSD′s (n=5) were all less than 9%.