Microchim. Acta 141, 87–91 (2003) DOI 10.1007/s00604-002-0931-7 Original Paper Determination of Antimony in Waters by Electrothermal Atomic Absorption Spectrometry with Preconcentration on a Tantalum Wire Md. Nurul Amin 1 , Satoshi Kaneco 1 , Ken Nomura 1 , Tohru Suzuki 2 , and Kiyohisa Ohta 1 1 Department of Chemistry for Materials, Faculty of Engineering, Mie University, Tsu, Mie 514-8507, Japan 2 Environmental Preservation Center, Mie University, Tsu, Mie 514-8507, Japan Received March 20, 2002; accepted June 26, 2002; published online November 28, 2002 # Springer-Verlag 2002 Abstract. A preconcentration method for antimony in waters involving adsorption on a tantalum wire, fol- lowed by electrothermal atomic absorption spectrome- try with a tungsten tube atomizer is described. The best pH for the adsorption of antimony was 2. The optimal immersing time was 120 s. Under the optimal condi- tions, the detection limit for antimony by the tantalum wire preconcentration method was 50 pg=mL (3S=N) and the relative standard deviation was 9.4%. The effects of large amounts of concomitants on the pre- concentration of antimony were evaluated. Even though 10 3 –10 4 fold excess of matrix elements existed in water, the antimony response was not significantly affected by the matrix elements. The method with preconcentration on a tantalum wire was applied to the determination of antimony in waters and proved to be sensitive, simple, and convenient. This adsorption method can be utilized in in-situ sampling of ultra-trace antimony in environ- mental samples (water). Furthermore, after sampling it is easy to carry and store the tantalum wire without contamination for a long time. The technique developed was shown to be useful for the determination of Sb in waste waters at the 1–5 mg=L level. Key words: Electrothermal atomic absorption spectrometry; metal atomizer; antimony; waters; preconcentration on tantalum wire. Antimony is a hazardous substance, and significant quantities of Sb are used by several industries. The United States Environmental Protection Agency (USEPA) [1] and the Council of the European Com- munities [2] now consider Sb to be a priority pollutant. According to the USEPA drinking waters standards, the maximum contaminant level (MCL) allowed is at 6 mg=L [3]. The European Union (EU) established a maximum admissible concentration of antimony in drinking water of 5 mg=L [4]. Therefore, highly-sensi- tive methods for the determination of traces of anti- mony in waters need to be established. Preconcentration has frequently been applied in the determination of ultra trace analytes in complex matrix samples by instrumental analysis. Adsorption, chromatography, coprecipitation, electrolytic deposi- tion, evaporation, extraction, flotation, freezing, ion exchange, etc. are well known as preconcentration methods in analytical chemistry [5, 6]. Most of them are complicated and time-consuming. Among these methods, however, the adsorption method is simple and convenient [6]. So far, activated carbon, porous polymers, polyurethane foam, silica gel, glass beads and tungsten wire were used for collecting trace elements and have been reported as adsorbents [6–10]. In 1973, a preconcentration method [7] was reported in which heavy metals such as Cd and Pb were con- centrated by adsorption onto a tungsten wire loop, which had been immersed for a fixed time in aqueous sample solutions. The wire loop was subsequently used as an electrically heated atomizer for atomic