Determination of residual arsenic compounds in chicken muscle by ultra-performance liquid chromatography coupled with ultraviolet detection after pre-column derivatization with toluene-3,4-dithiol

A simple and sensitive derivatization method using toluene-3,4-dithiol as a derivatization reagent for the simultaneous analysis of seven arsenic compounds (roxarsone, nitarsone, p-arsanilic acid, o-arsanilic acid, phenylarsonic acid, phenylarsine oxide, and mono-methylarsonic acid) in chicken muscle was developed and validated by ultra-performance liquid chromatography coupled with ultraviolet detection (UPLC-UV). The structure of the derivatized arsenic compounds was confirmed by liquid chromatography-ion trap mass spectrometry or gas chromatography-mass spectrometry. Optimization of the derivatization reaction conditions was carried out by investigating the influence of reagent concentration, buffer or additive acids, temperature, and time. The optimized conditions were a derivatization reagent concentration of 20 mg/mL with 0.05 mol/L HCl as an additive acid at 60 °C for 15 min. In this study, baseline separation of arsenic compounds could be achieved within 13 min, except for phenylarsonic acid and phenylarsine oxide whose derivatized products are equal. The developed method was successfully validated and applied to 12 chicken muscle samples from Korean districts and other countries.