在线衍生–高效液相色谱法测定食品中的甲醛次硫酸氢钠

Determination of sodium formaldehyde sulfoxylate in food by HPLC combined with online derivatization

建立在线衍生–高效液相色谱法测定食品中的甲醛次硫酸氢钠。食品中的甲醛次硫酸氢钠用碘酸钾溶液氧化后释放出甲醛并被水提取,以2,4-二硝基苯肼(DNPH)的乙腈–乙酸溶液为衍生液,在线衍生2 min,衍生物在Agilent C_(18)色谱柱上分离,以乙腈–水(65∶35)溶液为流动相进行洗脱,用二极管阵列检测器测定,检测波长为350 nm。试验结果表明,在0.1～5.0 mg/L范围内,甲醛的质量浓度与色谱峰面积呈良好的线性关系(r^2=0.999),方法检出限为0.4 mg/kg,样品的加标回收率为89.84%～97.46%,测定结果的相对标准偏差为0.25%～0.43%(n=6)。该方法操作简单快捷,分离效果好,适用于食品中甲醛次硫酸氢钠的日常分析测试。

The method for determining sodium formaldehyde sulfoxylate in food by HPLC combined with online derivatization was established.Formaldehyde released from the oxidation of formaldehyde sodium bisulfite with KIO3 solution was extracted by water,which was extracted by acetonitrile and reacted efficiently with 2,4-dinitrophenylhydrazine in acetonitrile–acetic acid solution for 2 min.The formaldehyde derivative was separated on an Agilent C18 chromatographic column with acetonitrile–water(65∶35)as the mobile phase for elution,and then detected by DAD at the wavelength of 350 nm.Tests results showed that the mass concentration of formaldehyde had a good linear relationship with the chromatograph peak area in the range of 0.1–5.0 mg/L with the correlation coefficient(r2)of 0.999,and the detection limit was 0.4 mg/kg.The recovery rates obtained by standard addition method were 89.84%–97.46%,and the relative standard deviations were 0.25%–0.43%(n=6).The method is simple with fast operation,good separation effect,it is suitable for daily analysis and testing of sodium formaldehyde bisulfate in foods.