Graphite furnace atomic absorption spectrophotometric determination of 4-hydroxy-3-nitrobenzenearsonic acid, other organic arsenicals, and inorganic arsenic in finished animal feed.
4-Hydroxy-3-nitrobenzenearsonic acid (roxarsone) is administered in animal feed as a growth stimulant over a concentration range of 25-50 ppm. The drug is extracted from 5 g feed with 200 mL aqueous 1.0% ammonium carbonate solution and 5 min of mechanical shaking. Undissolved feed particles are allowed to settle and 1.0 mL aliquot of extract is diluted with 9.0 mL 15% methanol solution. This solution is subjected to sample atomization by a graphite furnace and arsenic detection by atomic absorption spectrophotometry (AAS). Roxarsone recovery from nonmedicated commercial feed fortified at 25 ppm was 103.6% with a relative standard deviation (RSD) of 4.0%. Recovery for 50 ppm fortification was 104.5% (RSD 4.3%). Roxarsone assay results by furnace AAS were compared with results by the current AOAC spectrophotometric method and the AOAC total arsenic method. Results by the 3 methods compare well. The procedure was also used to determine other organic arsenicals and inorganic arsenic in laboratory-fortified feed samples; these recoveries were essentially theoretical.
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001151:Arsenic / Q000032:analysis*; D001152:Arsenicals / Q000032:analysis*; D006108:Graphite; D011200:Poultry; D012406:Roxarsone / Q000032:analysis*; D013054:Spectrophotometry, Atomic / Q000295:instrumentation; D013552:Swine
D001152:Arsenicals; D006108:Graphite; D012406:Roxarsone; D001151:Arsenic