Roxarsone and transformation products in chicken manure: Determination by capillary electrophoresis-inductively coupled plasma-mass spectrometry

Abstract The determination of the animal feed additive roxarsone (3‐nitro‐4‐hydroxyphenylarsonic acid) and six of its possible transformation products (arsenite, arsenate, monomethylarsonate, dimethylarsinate, 3‐amino‐4‐hydroxyphenylarsonic acid, and 4‐hydroxyphenylarsonic acid) in chicken manure was investigated using capillary electrophoresis‐inductively coupled plasma‐mass spectrometry (CE‐ICP‐MS). Initial method development was conducted using ultraviolet (UV) detection for ruggedness and time efficiency. Separation of these seven arsenic species was effected using a 20 m M phosphate buffer at pH 5.7. The CE‐ICP‐MS limits of detection in terms of As for each of the species was in the low µg·L −1 range, corresponding to absolute detection limits in the range 20–70 fg As (based on a 23 nL injection). Overall, the method developed in this study provides high selectivity and low limits of detection (1–3 µg·L −1 or low‐ppb, based on As), uses small sample volume (low nL), and produces minimal wastes.