HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY DETERMINATION FOLLOWING MICROWAVE-ASSISTED EXTRACTION OF 3-NITRO-4-HYDROXYPHENYLARSONIC ACID FROM SWINE LIVER, KIDNEY, AND MUSCLE

A simple and rapid analytical method is described for the determinatio n of 3-nitro-4-hydroxyphenylarsonic acid (roxarsone, 3-nitro) in tissu es. It involves extraction of 3-nitro from swine tissues by microwave- assisted process (MAP(TM)) followed by high performance liquid chromat ography using a PRP-1 column. The compound is detected in visible regi on at 410 nm after post-column reaction with 0.15 N sodium hydroxide. The detection limit is estimated to be 0.25 mu g g(-1) for 3-nitro, eq uivalent to about 0.2 mu g g(-1) of arsenic. Official tolerances for a rsenic in liver and muscle are set at 2.0 mu g g(-1) and 0.5 mu g g(-1 ), respectively. The method was employed to detect 3-nitro residues in incurred tissue samples from pigs fed 150 mg kg(-1) of 3-nitro for a 28-d period.