A screen-printed electrode modified with tungsten disulfide nanosheets for nanomolar detection of the arsenic drug roxarsone

A sensitive electrochemical (voltammetric; DPV) sensor has been developed for the determination of coccidiostat drug (roxarsone) based on the use ofan SPCE (screen-printed carbon electrode) modified with tungsten disulfide nanosheets (WS2 NSs). The electrochemical detection of roxarsone on the WS2-modified SPCE was examined by electrochemical strategies. XPS, XRD, Raman, SEM, TEM, EDS and EIS were used tocharacterize the nanosheets. The effects of scan rate, pHvalues (phosphate buffer) and bufferconcentration were optimized. A selective roxarsone sensor was developed that works bestat -0.64 V (vs. Ag/AgCl)and performs much better than the bare SPCE. Features include (a) a wider linear range (0.05 to 490 M), (b) ananomolar detection limit (0.03 M) and (c)high sensitivity (29 AM(-1)cm(-2)). Themodified SPCEs have been successfully applied to thedetermination of roxarsone in spiked meat sampleswhere they gavehigh accuracy and good recoveries.