微乳电动毛细管色谱法分离检测酱油中的氯丙醇

建立了微乳电动毛细管色谱分离3种氯丙醇的方法。以十二烷基硫酸钠(SDS)作为表面活性剂,系统考察了pH值、缓冲溶液类型和浓度、SDS浓度、助表面活性剂浓度、油相浓度、温度和运行电压对3-氯-1,2-丙二醇(3-MCPD),1,3-二氯-2-丙醇(1,3-DCP),2,3-二氯-1-丙醇(2,3-DCP)分离的影响。结果表明,最佳微乳缓冲液为1%(V/V)正庚烷,100 mmol/L SDS,10%(V/V)正丁醇和8 mmol/L磷酸二氢钠-硼砂溶液(pH 8.50),检测波长为192 nm,温度20℃,分离电压为15 kV。3种氯丙醇的线性范围为2.0×10-6～3.2×10-5 mol/L,相关系数大于0.996,检出限(S/N=3)为0.95～1.9μmol/L。酱油样品经乙醚液液萃取,萃取平均回收率为93.2%～103.0%,相对标准偏差小于6.5%。本方法应用于实际样品和加标后样品中三氯丙醇的检测,结果满意。

Separation and Analysis of Chloropropanol in Soy Sauces Using Microemulsion Electrokinetic Capillary Chromatography

A microemulsion electrokinetic capillary chromatographic(MEEKC) method for the simultaneous separation of three chloropropanols,3-chloro-1,2-propanediol(3-MCPD),1,3-dichloro-2-propanol(1,3-DCP) and 2,3-dichloro-1-propanol(2,3-DCP),has been developed.Using sodium dodecylsulfate(SDS) as surfactant,a systematic study of the influence of buffer pH,type and concentration of buffer solution,SDS concentration,co-surfactant concentration and oil concentration,temperature and operating voltage have been carried out.The results showed that the optimum conditions were as follows: the detection wavelength: 192 nm,temperature: 20 ℃,separation voltage: 15 kV,running buffer: 1%(V/V) heptane,100 mmol/L SDS,10%(V/V) 1-butanol,and 8 mmol/L sodium dihydrogen phosphate-borax buffer solution(pH 8.50).The calibration curve showed a good linearity over the concentration of three chloropropanols in the range of 2.0×10-6-3.2×10-5 mol/L with a correlation coefficient more than 0.996.The detection limit(S/N=3) ranged from 0.95 to 1.9 μmol/L.Prior to electrophoresis,the soy sauce was extracted by ethe.The extraction average recoveries were 93.2%-103% with RSDs less than 6.5%(n=6).The method was applied to the determination of three chlorine propanols in real samples and spiked samples with satisfactory results.