QUANTITATIVE-ANALYSIS OF L-TRYPTOPHAN IN FERMENTATION BROTHS

Quantitative thin-layer chromatography of L-tryptophan has been perfor med on Sorbfil TLC plates with 2-propanol -25% aqueous ammonia as mobi le phase. Detection was performed by postchromatographic derivatizatio n with solutions of 4-dimethylaminobenzaldehyde, using either spraying or dipping, Quantitation was performed by either videodensitometry or scanning densitometry. Results obtained by videodensitometry or scann ing densitometry after derivatization by spraying or dipping were comp ared. Coefficients of variation <5% were achieved by using dipping in combination with videodensitometry. TLC results obtained using this co mbination were compared with those obtained by use of an amino acid an alyzer and showed good correlation (r = 0.992), confirming that videod ensitometry can be used for the analysis of L-tryptophan.