Optimum Chromatographic Condition for 2,6-di-t-Butyl-4-pyrazinylaminophenol on RP-HPLC: Metal Influence on Its Elution Profile

Abstract

The optimization of chromatographic conditions for the determination of 2,6-di-t-butyl-U-pyrazinyl-aminophenol(DBAP) on reversed-phase HPLC with an aqueous-organic mobile phase were investigated. Undesirable peak shape, of which the quinone form(QF) was produced by the decomposition of DBAP in a stainless steel column, was observed on both of RPC packings containing small and large amounts of metal impurities. Although this conversion reaction was suppressed by washing the ODS gels with a 1 mM EDTA solution, the decomposition of DBAP in the column was still taking place. Concluding that the contamination of metal impurities on the column packing occurs continueously. The use of inert columns such as peek (polyether-ether-ketone), glass-lining columns but except a titan column, packed a high purity RPC packing material which was washed with the EDTA solution prior to use, led to the quantitative result of DBAP in the inert chromatographic system.