高氯酸非水滴定法测定酱油中氨基酸态氮含量可行性研究

Feasibility Study on the Determination of Amino Acid Nitrogen Content in Soy Sauce by Perchloric Acid Non-aqueous Titration Method

旨在研究高氯酸非水溶液滴定法测定酱油中氨基酸态氮含量的可行性。考察了烘干与加入乙酸酐去除酱油中水分的方法,最终选择在酱油溶解过程中加入乙酸酐,初步建立了高氯酸非水滴定测定酱油中氨基酸态氮方法并考察了该方法的重复性与回收率。结果表明,平行测定样品6次获得的重复性相对标准偏差RSD=0.16%,低标、中标、高标的加标回收率为94.87%~97.92%,RSD为0.62%~1.01%(n=3)。将所建立的方法用于测定6种酱油样品中氨基酸态氮含量,结果与国家标准中酸度计法进行比较,无显著性差异(P>0.05)。相比于酸度计法,该方法具有分析速度快、无甲醛、易于操作等优点,对于酱油样品中氨基酸态氮的测定具有指导意义。

The purpose of this paper is to study the feasibility of determining amino acid nitrogen content in soy sauce by perchloric acid non-aqueous titration method.The methods of drying and adding acetic anhydride to remove the moisture in soy sauce are investigated.Finally,acetic anhydride is added in the dissolution process of soy sauce.A perchloric acid non-aqueous titration method for the determination of amino acid nitrogen in soy sauce is established and its repeatability and recovery rate are investigated.The results show that the relative standard deviation(RSD)of repeatability obtained for 6 parallel tests is 0.16%,and the recovery rates of low standard,middle standard and high standard are 94.87%~97.92%,with RSDs of 0.62%~1.01%(n=3).The established method is applied to determine the amino acid nitrogen content in 6 kinds of soy sauce samples,and there's no significant difference(P>0.05)compared with that by pH meter titration method in national standard.Compared with pH meter titration method,this method has the advantages of high detection speed,without formaldehyde and easy control,and it could provide reference for the determination of amino acid nitrogen in soy sauce samples.