Determination of arsenic by ICP-MS after retention on thoria nanoparticles

Abstract

A procedure for arsenic determination by ICP-MS in environmental and biological samples was developed using thoria nanoparticles for arsenic retention. Both inorganic arsenic species, As^(III) and As^(V), show similar behaviour regarding this thoria nanosorbent. The experimental data related to the amount of arsenic retained per gram of nanoparticles were theoretically modelled using mechanistic and empiric equations. The best kinetic theoretical relationship allowed us to obtain a feasible quantification of the retention process before reaching steady-state. In addition, calculation of the overall retention constant was also possible at steady-state. The maximum effective retention capacity for arsenic was about 30 mg As per g nanomaterial. The detection limit of the developed procedure was 0.07 μg As L⁻¹ and the relative standard deviation 2.9%. The accuracy of the developed procedure was assayed by the determination of arsenic in two certified reference materials.