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FLUOROMETRIC DETERMINATION OF CYSTEINE IN BEER BY HIGH‐PERFORMANCE LIQUID CHROMATOGRAPHY WITH PRECOLUMN DERIVATISATION
Author(s) -
Matsui S.,
Kitabatake K.,
Meguro H. Takahashi and H.
Publication year - 1984
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1984.tb04227.x
Subject(s) - chemistry , high performance liquid chromatography , chromatography , reagent , gradient elution , elution , maleimide , fluorescence , organic chemistry , physics , quantum mechanics
A high‐performance liquid chromatographic procedure (HPLC) is described for the fluorometric determination of cysteine (CySH) in beer. Reduced CySH in beer is reacted with a fluorescent reagent, N ‐(9‐acridinyl) maleimide (NAM), at pH 8·8 for 15 h to form a stable fluorescent derivative. The resulting reaction mixture is analysed by reversed‐phase gradient elution HPLC. Under the optimised conditions for chromatography, ca 0·1 mg of CySH per litre of beer can be determined. Total CySH is determined by electrolytic reduction at a Hg pool electrode prior to the HPLC analysis. The levels of reduced and total CySH in 28 brands of commercial lager beers ranged from 0·2 to 0·9 mg/litre, and from 2·1 to 13·5 mg/litre, respectively.