腺嘌呤柱前衍生化-HPLC-FLD法测定3-氯-1,2-丙二醇的方法优化

Optimization of the method for determination of 3-chloro-1,2-propanediol by adenine pre-column derivatization-HPLC-FLD

3-氯-1,2-丙二醇(3-MCPD)经高碘酸钠溶液氧化裂解、腺嘌呤衍生化后的产物——1,N6-亚乙烯基腺嘌呤(ε-Ade)为强荧光物质,通过对其荧光光谱与重要影响因素进行研究与优化,结合测定体系背景干扰的抑制,对高效液相色谱-荧光法(HPLC-FLD)测定3-MCPD水溶液的条件进行了优化。得到优化条件为:使用耐碱性反相C18色谱柱进行测定,流动相中甲醇体积分数为20%,水相为pH 9.0的碳酸钠-碳酸氢钠缓冲液。食用油中3-MCPD的测定需以0.01 g/mL的NaCl溶液作为萃取水相,氧化裂解3-MCPD的高碘酸钠可采用等量的亚硫酸钠还原、1.1倍量的醋酸铅沉淀予以去除,从而抑制空白峰的干扰,将该方法应用于多种食用植物油样品的测定,结果表明:该方法准确度高、重现性好(RSD在0.32%~4.63%之间);样品谱图显示基质干扰很小,方法选择性高。

The 3-chloro-1,2-propanediol(3-MCPD) was oxidatively cleaved with sodium periodate solution and then derivatized with adenine to produce a strong fluorescent substance of 1, N6-vinylidene adenine(ε-Ade). According to the study of the product’s fluorescence spectrum and the optimization of important influencing factors, the determination conditions of 3-MCPD by high performance liquid chromatography-fluorescence detection(HPLC-FLD) method was optimized after the suppression of the background interference of the measurement system. The optimal conditions were obtained as follows: an alkaline-resistant reverse-phase C18 column used for determination, the volume fraction of methanol in the mobile phase 20%, and sodium carbonate-sodium bicarbonate buffer solution of pH 9.0 used as the aqueous phase. For the determination of 3-MCPD in edible oil, 0.01 g/mL NaCl solution should be used as the extraction aqueous phase, and the sodium periodate used for oxidative cracking of 3-MCPD was reduced by the same amount of sodium sulfite and finally removed by the precipitation with 1.1 times its amount of lead acetate so as to suppress the interference of the blank peak. The method was applied in the determination of a variety of edible vegetable oil samples, and the results showed that the method was highly accurate and reproducible(RSD was between 0.32% and 4.63%). The edible oil samples’ chromatography showed that the matrix interference was very low and the selectivity of the method was wonderful.