柱前衍生-高效液相色谱法测定婴幼儿谷类辅食中的甲醛

Determination of formaldehyde in infant cereal-based supplementary food by high performance liquid chromatography with pre-column derivatization

目的建立柱前衍生-高效液相色谱法测定婴幼儿谷类辅食中甲醛含量的分析方法。方法样品中的甲醛经柠檬酸钠缓冲溶液和含有2,4-二硝基苯肼的乙腈混合体系衍生提取,生成的甲醛-2,4-二硝基苯腙经色谱柱Agilent Poroshell 120 EC-C18(4.6 mm×150 mm, 2.7μm)以乙腈-水(70:30, V:V)等度洗脱分离,柱温30℃,流速为0.5 mL/min,检测波长为355 nm,外标法定量分析。结果甲醛在0.025~2.00 mg/L质量浓度范围内线性关系良好且相关系数(r2)大于0.995,方法检出限和定量限分别为0.03 mg/kg和0.10 mg/kg,在3个加标水平(1.00、5.00和10.0 mg/kg)的平均加标回收率为86.8%~89.0%,相对标准偏差为0.7%~2.1%。结论该方法操作简便,灵敏度高,重现性好,适用于婴幼儿谷类辅食中甲醛含量的测定。

Objective To establish a method for determination of formaldehyde in infant cereal-based supplementary food by high performance liquid chromatography with pre-column derivatization. Methods Formaldehyde in the samples was extracted with sodium citrate buffer solution and acetonitrile mixture containing 2,4-dinitrophenylhydrazone, and the resulting formaldehyde-2,4-dinitrophenylhydrazone was eluted with acetonitrile-water(70:30, V:V) on a chromatographic column(4.6 mm×150 mm, 2.7 μm). The column temperature was 30 ℃, the flow rate was 0.5 mL/min, the detection wavelength was 355 nm, and the quantitative analysis was performed by external standard method. Results The detection limit and quantitative limit were 0.03 mg/kg and 0.10 mg/kg, respectively. The average standard recoveries were 86.8%-89.0% at the 3 standard levels(1.00, 5.00, and 10.0 mg/kg), and the relative standard deviations were 0.7%-2.1%. Conclusion The established method is simple, sensitive and reproducible, which is suitable for determination of formaldehyde in infant cereal-based supplementary food.