DETERMINATION OF LYSINOALANINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

This work suggests an HPLC method for qualitative and quantitative det ermination of N-epsilon(2-amino-2-carboxyethyl)-L-lysine (LAL). LAL wa s released from total hydrolysates of various proteins of animal origi n and derivatized with dansyl chloride, The performance of two differe nt columns, Spherisorb 3S TG and mu-Bondapack C-18, was compared; bett er resolution and quantitative response were obtained with the former. The mobile phase was a mixture of 0.01 M phosphate buffer (pH 7) and acetonitrile. Linear response and quantitative repeatability were test ed for both detectors used (UV-Vis set at 254 nm; fluorimetric set at lambda(ex(max))= 360 nm and lambda(em(max))= 525 nm). For LAL standard the minimum detectable amount was 0.05 ng, whereas for LAL in actual samples the amount was 0.5 ng (40 mu g/g of analyzed proteins). Good a nalytical repeatability was obtained, resulting in CV% of 4.7 and 3.8 for UV and fluorimetric detectors, respectively. LAL recovery was dete rmined using both detectors; the values obtained were 94 % (fluorimetr ic) and 92 % (UV). Greater noise levels were observed with the fluorim etric detector and its higher sensitivity could not, therefore, be ful ly utilized, The highest amounts of LAL were found in the casein (2816 mu g/g) and cooked albumin (615 mu g/g) samples.