A method based on alkaline hydrolysis coupled with high-performance liquid chromatography (HPLC) was developed for the determination of tryptophan in infant formula and infant formula for special medical purposes with α-methyl tryptophan as the internal standard. The sample was hydrolyzed by alkali solution and separated by C18 column. Then it was detected by a fluorescence detector. The internal standard method could correct the loss of tryptophan during hydrolysis, reduce the difference between substrates and improve the accuracy of quantitative results. The recovery was in the range of 92.5%-97.4%, and the relative standard deviation (RSD) was less than 3.11%. Furthermore, the relative standard deviation between laboratories was less than 6.7%. The method was simple, accurate and reproducible and could be applied for the accurate qualitative and quantitative determination of tryptophan in infant formula and infant formula for special medical purposes.
BIE Mei
,
SUN Lizhen
,
WANG Jun
,
XUE Xia
,
LIU Yanming
. Determination of tryptophan in infant formula by HPLC internal standard method[J]. Food and Fermentation Industries, 2021
, 47(17)
: 272
-276
.
DOI: 10.13995/j.cnki.11-1802/ts.026962
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