beta-Hydroxynaphthoic acid synthesis monitoring by capillary zone electrophoresis and high-performance liquid chromatography - Determination of polynaphthyl derivatives

Unidentified peaks were observed during the purity control of beta-hydroxyn aphthoic acid industrial samples using capillary zone electrophoresis (CZE) and HPLC methods. The origin of such peaks was supposed to be (1) a conseq uence of interaction between separated compounds and berate species, which might cause peak splitting, or (2) other side-products formed during the sy nthesis, such as polynaphthyl derivatives of beta-hydroxynaphthoic acid and /or others. Both hypotheses were studied using CZE, HPLC, and TLC methods. The synthesis of 2,2'-dihydroxy-1,1'-binaphthyl-3,3'-dicarboxylic acid was done. The purified compound was use as standard to identify the unknown imp urities in beta-hydroxynaphthoic acid samples. To control the quality of th e standard, NMR, HPLC and CZE were applied. It has been proved that the uni dentified impurities were other sub-products from the synthesis and the for mation of 2,2'-dihydroxy-1,1'-binaphthyl-3,3'-dicarboxylic acid was verifie d. (C) 1999 Elsevier Science B.V. All rights reserved.