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目的建立超声辅助离子液体分散液液微萃取样品前处理技术,结合高效液相色谱测定蜂蜜中咖啡因的方法。方法样品采用分散固相萃取吸附剂N-丙基乙二胺(PSA)、C18、石墨炭黑粉(GCB)净化后,用离子液体[Omim][PF6]做萃取剂,甲醇做分散剂,通过超声、离心、对目标物进行富集,用高效液相色谱-紫外检测器分析测定,同时对分散固相萃取吸附剂的选择及影响分散液液微萃取的因素进行了优化。结果在最优条件下,咖啡因的富集倍数达到120倍,检出限为0.2μg/L,线性范围为1μg/L~500μg/L,线性相关系数为0.999 6,平均加标回收率为84.1%~108.5%,相对标准偏差(RSD)为2.4%~3.7%。结论方法具有简便快速、准确灵敏、萃取效率高、有机溶剂消耗少等特点。建立的方法能成功用于蜂蜜中咖啡因的测定。
OBJECTIVE To establish a method for the pre-treatment of ultrasound-assisted ionic liquid dispersion liquid-liquid microextraction and determination of caffeine in honey by high performance liquid chromatography. Methods The samples were purified with dispersed solid-phase extraction adsorbents N-propyl ethylenediamine (PSA), C18 and graphite carbon black powder (GCB), and the ionic liquid [Omim] [PF6] The objects were enriched by ultrasonication and centrifugation, and analyzed by high performance liquid chromatography-ultraviolet detector. The selection of dispersive solid-phase extraction adsorbents and the factors influencing dispersion liquid-liquid microextraction were also optimized. Results Under optimal conditions, the enrichment factor of caffeine reached 120-fold, the detection limit was 0.2μg / L, the linear range was 1μg / L ~ 500μg / L, the linear correlation coefficient was 0.999 6, the average recovery was 84.1% ~ 108.5%, and the relative standard deviation (RSD) was 2.4% ~ 3.7%. Conclusion The method is simple and rapid, accurate and sensitive, high extraction efficiency, less consumption of organic solvents and so on. The established method can be successfully used for the determination of caffeine in honey.