| Abstract: | Single noble metal permanent modifiers such as, Rh, Ir, and Ru, as well as mixed tungsten plus noble metal (W–Rh, W–Ru, W–Ir) permanent modifiers thermally deposited on the integrated platform of a transversally heated graphite atomizer (TGA) were employed for the determination of antimony in sludge, soil, sediment, coal, ash and water samples by electrothermal atomic absorption spectrometry (ETAAS).Microwave digests of solid samples and water samples were directly introduced into different pre-treated platforms of graphite tubes. The performance of the modifiers for accurate antimony determination in real samples depended strongly on the type of permanent modifier chosen. The single noble metal (Rh, Ir and Ru) permanent modifiers were suitable for analyte determinations in simpler matrices, such as waters (recoveries of certified values 95–105%), but the analyte recoveries of certified values in sludge, soil, sediment, coal, and ash samples were always lower than 90%. On the other hand, for the determination of antimony, using W–Rh, W–Ru, and W–Ir permanent modifiers presented recoveries of certified values within 95–105% for all the samples.Long-term stability curves obtained for the determination of antimony in environmental samples with different permanent modifiers (Rh, Ir, Ru, W–Rh, W–Ir, W–Ru) showed that the improvement in tube lifetime depends on the tungsten deposit onto the platform. The tungsten plus noble metal permanent modifier presents a tube lifetime of at least 40% longer compared to a single permanent modifier. |
