Development of a Fast Chromatographic Method for the Detection of Organoarsenic Antimicrobials

New protocols were developed for the routine analysis of the organoarsenic drugs roxarsone (4-hydroxy-3-nitrophenylarsonic acid), p-arsanilic acid, and acetarsone (N-acetyl-4-hydroxy-m-arsanilic acid) based on ion-pairing high performance liquid chromatography (IP-HPLC) with rapid-resolution technology and diode array detection. The drugs under study have been used for veterinary applications as antimicrobial agents and growth promoters for poultry. The high water-solubility exhibited by these drugs represents a serious environmental problem since poultry litter is mainly used as fertilizer. Once applied to crops, these agents can leach into bodies of water and readily be absorbed by plants. The use of these drugs at high concentration levels by poultry farms have been targeted by the FDA due to QA/QC deficiencies related to feed preparations. The developed procedure is linear with a correlation coefficient (R2) ≥ 0.9990 and p-values < 0.05; reproducible in area and tR (%RSD < 1.0 %); and demonstrated a limit-of-quantitation (LOQ) ≤ 0.03 ppm (for roxarsone and p-arsanilic acid) and ≤ 0.24 ppm (for acetarsone). This method provides a simple, reliable and cost effective alternative for the routine analysis of organoarsenic compounds present in water due to their rapid elution times (< 1.5 minutes). The samples did not require complex preparation techniques prior to the analysis. The robustness was demonstrated by application of the method to complex matrixes such as poultry litter leachates. The application of this method for the analysis of real samples for QA/QC processes and remediation studies is discussed.