Comparison of Liquid Chromatographic Method to AOAC Microbiological Method for Determination of L-Tryptophan in Tablets and Capsules

Autor:	Henry S Kim, Gerald Angyal
Rok vydání:	1993
Předmět:	Pharmacology Chromatography Chemistry Tryptophan Environmental Chemistry Chromatography liquid Hard Capsule Microbiological Techniques Agronomy and Crop Science Dosage form Food Science Analytical Chemistry Precolumn derivatization
Zdroj:	Journal of AOAC INTERNATIONAL. 76:414-417
ISSN:	1944-7922 1060-3271
DOI:	10.1093/jaoac/76.2.414
Popis:	A reversed-phase liquid chromatographic (LC) method coupled with precolumn derivatization of L-tryptophan with phenylisothiocyanate was compared to the AOAC microbiological method for determining L-tryptophan in tablets and capsules. For the microbiological method, the concentrations of L-tryptophan were 4-8% lower in autoclaved test samples (hot method) than in test samples that were not autoclaved (cold method). When L-tryptophan values obtained by the LC method were compared to those obtained by the cold microbiological method, no significant differences were observed (P > 0.05). The mean relative standard deviations were 2.9% for the LC method and 1.6% for the cold microbiological method. The mean recoveries of standard L-tryptophan added before analysis were 99% for the LC method and 101 % for the cold microbiological method. These results demonstrate that both methods are reliable for determining free L-tryptophan contained in tablets and capsules. However, the LC method has the advantages of using a smaller test portion and having a shorter analysis time.
Databáze:	OpenAIRE
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