离心管微生物法优化食品中的烟酸检测

Optimization of niacin detection in food by microbiological method cultured in centrifuge tube

目的简化GB 5009.89—2016微生物法检测食品中烟酸的步骤和操作,提高可操作性。方法在国标微生物法的基础上,将试管改进为一次性离心管,将移液管改进为微量移液器,优化校准曲线,再通过分析校准曲线线性、定量限、精密度和加标回收率验证方法的适用性。结果离心管微生物法根除了试管残留的培养基和试样等造成的污染,节省准备时间,配制测定系列管的时间缩短为国标法的56.8%;培养体积优化为2 mL,称量精密度得到提高;将烟酸拟合曲线确定为对数曲线方便样品含量的计算,相关系数r2达到0.997。离心管法的定量限是0.17 mg/100 g,加标回收率是93.52%~107.95%,相对标准偏差为4.60%(n=7)。实测16种不同类型的样品,烟酸含量在0.913~5.539mg/100g之间。结论离心管微生物法改善了微生物法的培养体系、缩短了检测周期、操作简便,适合检测使用。

Objective To simplify the steps and operation of microbiological method GB 5009.89—2016 for detecting niacin in food and improving the maneuverability. Methods Based on the national microbiological method, the test tube was improved to a disposable centrifuge tube, and the pipette was improved to a micropipette, and the calibration curve was optimized. The applicability of the method was verified by analyzing the linearity of the calibration curve, limit of quantification, precision and recovery of this method. Results The microbiological method of centrifuge tube eradicated the pollution caused by the residual culture medium and samples in test tubes, and the method saved the preparation time. The time for preparing determination series tubes was shortened to 56.8% of that in the national standard method. The culture volume was optimized to be 2 mL, and the weighing precision was improved. The fitting curve of niacinwas determined as the logarithmic curve to facilitate the calculation of the sample content, and the correlation coefficient r2 reached 0.997. The limit of quantitation for the centrifuge tube method was 0.17 mg/100 g, and the recoveries were 93.52%–107.95% with a relative standard deviation of 4.60%(n=7). The content of niacin in 16 different types of samples was measured to be within the range of 0.913– 5.539 mg/100 g. Conclusion Microbiological method of centrifugal tube improves the culture system of microbiological method which shortens the detection period. The method is easy to operate and suitable for detection.