Determination of amino acids using o-phthalaldehyde-2-mercaptoethanol derivatization - Effect of reaction conditions

This paper presents a systematic approach to determine the optimal reaction conditions, with respect to accuracy and sensitivity, of the quantitative determination of primary amino acids in a single run, using o-phthalaldehyde-2-mercaptoethanol derivatization. To this end an experiment was designed in which the effects of reaction time, concentration of 2-mercaptoethanol and type of solvent were determined simultaneously. The response of all parameters tested was found to be interrelated: the effect of a change in one reaction condition also depended on the other reaction conditions. The reaction conditions determined in this research resulted in an accuracy better than 0.25 mu M, an average reproducibility of 0.6% and an average sensitivity of 136 fmol.