The effect of six reaction media on the determination of bismuth at trace levels in environmental samples by hydride generation and inductively coupled plasma-atomic emission spectrometry

An investigation was carried out to explore the effect of hydrochloric, tar taric, citric, oxalic, acetic and sulfosalicylic acids on the hydride gener ation of Bi at trace levels in a continuous flow system in conjunction with inductively coupled plasma atomic emission spectrometric detection. The op erating conditions (chemical and physical parameters) and the concentration s of the acids studied were evaluated for the efficient generation of BiH3 (bismuthine). Kinetic information about the decomposition process of BiH3 w as also obtained. Analytical figures of merit including detection limits, p recision and linear dynamic ranges are given for the six acids employed. Th e detection limits for Bi ranged between 0.3 and 0.7 mu g l(-1) depending o n the acid used to generate BiH3. Compared with conventional continuous neb ulization, the present coupling gives a sensitivity increase of approximate ly two orders of magnitude. The interfering effect of transition metals (Cd , Co, Cu, Cr, Fe, Mn, Ni, Zn), other hydride-forming elements (As, Ge, Pb, Sb, Se, Sn, Te) and Hg on the Bi signal using the different acids studied w as evaluated. Tartaric acid is the most suitable reaction medium, in terms of efficiency in the hydride generation process and in the control of inter ferences. The proposed method was applied to the determination of Bi in cer tified reference materials (fresh water, silicate) and real environmental s amples (iron ore and coal fly ash).