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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 establish a method for the analysis of caffeine in cold medicines by using hollow fiber liquid-phase microextraction (HF-LPME) as a pretreatment technique combined with gas chromatography (GC). Methods Appropriate amounts of carefully ground samples were dissolved in 100 ml of deionized water under ultrasonic and magnetic stirring. Accurel Q3 / 2 polypropylene hollow fiber impregnated with toluene was used as a protective device. The sample was extracted with chloroform as extraction solvent. Caffeine in the solution is extracted and enriched, and the extract is directly subjected to GC for chromatographic analysis. Results The experimental conditions were as follows: p H≈7, extraction time 10 min, salinity (NaCl as inorganic salt) 30%, extraction temperature 25 ℃, stirring rate 600 r / min, extraction solvent 3μl After extraction, 2μl extractant was taken for chromatographic analysis. The limit of detection (LOD) was 0.3 mg / L, the limit of quantification (LOQ) was 1 mg / L, the spiked recoveries were 91% -108% and the relative standard deviations (RSDs) were 4.7% -7.3% = 5), the linear range of 1 mg / L ~ 100 mg / L, the correlation coefficient of 0.998. Conclusion The cost of the party, fast and accurate, can be used for the analysis of caffeine in cold medicines.