内标法和外标法在测定己酸菌发酵液己酸含量中的应用

Application of ISTD and ESTD in the Determination of Caproic Acid Content in Caproic Acid Bacteria Fermenting Liquid

采用气相色谱内标法和外标法测定己酸菌发酵液的己酸含量,并进行比较分析。结果表明,内、外标法的定量方法在线性范围内呈线性关系,可决系数R2>0.99,且具有良好的精密度和稳定性,RSD<5%。两种方法均满足己酸发酵液中己酸检测的要求,但内标法的R2、精密度和稳定性方面均优于外标法,外标法在样品处理和进样中操作要求更高。将内、外标法应用于己酸菌发酵液中己酸含量的检测,经F检验和t检验,两种方法测得结果并无显著性差异。

In this study, gas phase chromatography internal standard method（ISTD） and external standard method（ESTD） were used respectively for the determination of caproic acid content in caproic acid bacteria fermenting liquid. The results showed that both methods displayed good linearity（R^2〉0.99） within the concentration range, and good precision and stability（RSD〈5 %）. However, R^2, the precision and the stability of ISTD were better than that of ESTD, and ESTD had higher requirements in sample treatment and sampling operation. The results of ISTD and ESTD were examined via F-test and t-test, and there was no significant difference between ISTD and ESTD.