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目的建立全自动凯式定氮仪-超高效液相色谱法测定啤酒中甲醛残留量的检测技术。方法采用全自动凯式定氮仪代替传统水蒸汽蒸馏法提取啤酒中的甲醛,经2,4-二硝基苯肼衍生后,生成苯腙类化合物。超高效液相色谱分离,外标法定量。色谱条件为:流动相:乙腈-水(60∶40,V/V)溶液;紫外检测器波长:355 nm。结果通过实验证明,浓度为0μg/ml~10μg/ml时,标准曲线线性关系良好,线性相关系数r为0.999 5。精密度、准确度符合检测要求。相对标准偏差(RSD)为0.6%~2.5%,加标回收率为87.6%~95.7%。结论本方法采取全自动凯式定氮法代替传统蒸馏法,并利用超高效液相色谱仪作为最终检测方法,可检测啤酒中微量的甲醛,具有灵敏度高、选择性好、精密度和准确度好等优点,而且更简便、更快捷,适合对大批量啤酒进行分析检测。
Objective To establish an automatic Kjeldahl apparatus for the determination of formaldehyde in beer by ultra performance liquid chromatography. Methods An automatic Kjeldahl apparatus was used to replace the traditional steam distillation method to extract the formaldehyde in beer. After derivatized with 2,4-dinitrophenylhydrazine, phenylhydrazone compounds were generated. Ultra Performance Liquid Chromatography, external standard method. Chromatographic conditions: mobile phase: acetonitrile-water (60:40, V / V) solution; UV detector wavelength: 355 nm. The results showed that the calibration curve showed a good linearity at a concentration of 0μg / ml ~ 10μg / ml with a linear correlation coefficient of 0.999 5. Precision, accuracy in line with testing requirements. The relative standard deviations (RSDs) ranged from 0.6% to 2.5%, and the spiked recoveries ranged from 87.6% to 95.7%. Conclusion This method takes the automatic Kjeldahl method instead of the traditional distillation method and uses ultra performance liquid chromatography as the final detection method to detect the trace amount of formaldehyde in the beer with high sensitivity, good selectivity, precision and accuracy Good, etc., but also more simple, faster, suitable for large quantities of beer for analysis and testing.