Abstract: A universal standard chemical reagent for quantitative visual and spectrometric analysis of compounds having reactive functional groups, including mixtures and homologs of said compounds, said reagent comprising a compound of the general formula Q-B-f, wherein: Q stands for an organic moiety which can be measured quantitatively, visually by color, spectroscopically, or fluorometrically; B represents a non-reactive organic bridging unit linking the moiety Q to a reactive functional group f, said bridging unit being of sufficient length or size to prevent any possible interaction of Q that might alter its spectroscopic properties even upon derivatization; and f is a reactive group which can react with a compound to form covalently bonded derivatives.