中空纤维液相微萃取-气相色谱法检测感冒药中的咖啡因

Determination of caffeine in cold medicine using hollow fiber liquid-phase microextraction combined with gas chromatography

目的以中空纤维液相微萃取(HF-LPME)为前处理技术,结合气相色谱(GC)建立感冒药中咖啡因的分析方法。方法取适量经仔细研磨的样品在超声和磁力搅拌下溶解于100 ml去离子水,再用浸渍过甲苯的Accurel Q3/2聚丙烯中空纤维作为保护装置,以三氯甲烷为萃取溶剂,对样品溶液中的咖啡因进行萃取和富集,萃取物直接上GC进行色谱分析。结果实验优化的样品萃取条件:p H≈7,萃取时间为10 min,盐度(以NaCl为无机盐)为30%,萃取温度为25℃,搅拌速率为600 r/min,萃取溶剂为3μl,萃取后取2μl萃取剂进行色谱分析。本方法检出限(LOD)为0.3 mg/L,定量限(LOQ)为1 mg/L,加标回收率为91%~108%,相对标准偏差(RSD)为4.7%~7.3%(n=5),线性范围为1 mg/L^100 mg/L,相关系数为0.998。结论本方成本低廉、快速、准确,可用于对感冒药品中咖啡因的分析测定。

Objective To develop an efficient method for the determination of caffeine in cold medicine by combining hollow fiber-based liquid-phase microextraction（ HF-LPME） with gas chromatography spectrometry（ GC）. Methods The crushed sample was first dissolved into 100 ml deionized water under ultrasonic and stirring conditions. The analyte caffeine was then extracted from the as-prepared sample solution by hollow fiber-protected liquid-phase microextraction using chloroform and Accurel Q3/2 polypropylene as organic solvent and fiber,respectively. The caffeine of solution samples was conducted for extraction and enrichment,and the extractant was directly conducted for the GC chromatographic analysis. Results The extraction conditions were optimized,and the optimum conditions were obtained as follows： p H value was near 7,extraction time was10 min,salinity was 30%,temperature was 25 ℃,stirring speed was 600 r/min. After extraction,2 μl organic solvent was introduced to GC for analysis. Under the optimized conditions,the limit of detection and quantification were 0. 3 mg/L and 1 mg/L,respectively. The recovery of standard addition was within 91%-108%,with precision of 4. 7%-7. 3%（ n = 5）. The linear range was 1 mg/L-100 mg/L,with relevant coefficient（ r） = 0. 998. Conclusion The method has advantages of low cost,quickness,good accuracy and can be applied for the determination of caffeine in cold medicine.