Search for New Metal Ion Additives for Improved Cadmium Vapor Generation

Metals Analysis and Remediation
Oral Presentation

Prepared by Z. Arslan1, A. Celik2
1 - US GEOLOGICAL SURVEY, Denver Federal Center Building 20, MS 973, DENVER, CC, 80225, United States
2 - Jackson State University, Deparment of Chemistry, Physics & Atmospheric Sciences, Jackson, MS, 39217, United States


Contact Information: zarslan@usgs.gov; 303-236-1856


ABSTRACT

Though cadmium (Cd) forms volatile vapor under controlled-reaction conditions, Cd vapor generation (VG) has not been a preferred method for Cd determinations due to poor VG efficiency that varies highly with chemical conditions and sample matrix. Recent publications indicate that adding tri-valent transition metals into reaction medium greatly improve Cd vapor generation affording an attractive approach for ultra-trace Cd determinations. In this work, the performances of three trivalent cations, aluminum, Al(III), scandium, Sc(III) and yttrium, Y(III) were investigated on generation of volatile Cd species for determination of Cd by ICP-MS. Chemical vapor generation was carried out on-line and potassium cyanide (KCN) was utilized as a masking agent to alleviate the interferences of transition metals and hydride forming elements. Volatile Cd species were generated in 4% (v/v) HCl in the presence of 1% (m/v) KCN. Optimum concentrations of Al(III), Sc(III) and Y(III) were 0.1, 0.06 and 0.08 mol L-1, respectively. Al(III) was more effective than Sc(III) and Y(III). An improvement up to 10-fold in vapor generation was achieved. The method was successfully applied to determination of Cd by VG-ICP-MS in several certified reference materials, including seawater (CASS-4), estuarine water (SLEW-3), bone ash (SRM 1400) and domestic sludge (SRM 2781).