MICROBORE HPLC DETERMINATION OF POLYETHER ANTIBIOTICS USING POSTCOLUMN DERIVATIZATION WITH BENZALDEHYDE REAGENTS

Monensin, narasin, and salinomycin have been separated by HPLC on micr obore column packed with octadecyl-bonded silica gel and detected via postcolumn color reaction with derivative of benzaldehyde in packed-be d reactor. Various benzaldehyde reagents have been tested in batch and 4-dimethylaminobenzaldehyde (DMABA) and vanillin selected as most pro mising ones. Requirements and characteristics of postcolumn reaction w ith the two reagents have been investigated and optimized and DMABA ha s been shown as superior over currently used vanillin reagent. The app licability of postcolumn derivatization with DMABA has been demonstrat ed by monensin assay in premixes and feeds.