Sampling and determination of metal hydrides by solid phase microextraction thermal desorption inductively coupled plasma mass spectrometry

Direct coupling of solid phase microextraction (SPME) with inductively coup led plasma mass spectrometry (ICP-MS) was used for the non-selective determ ination of arsenic, selenium, antimony and tin species amenable to hydride generation. A thermal desorption interface consisting of a heated glass-lin ed splitless type GC injector was placed directly at the base of the torch to minimize the length of the transfer-line. The effects of time and concen trations of sodium borohydride and hydrochloric acid on the extraction effi ciency were optimized. Polydimethylsiloxane (PDMS) and polydimethylsiloxane /Carboxen (PDMS/Carboxen) SPME coatings were compared for the headspace ext raction of the hydrides. PDMS/Carboxen showed better extraction capacity an d enhanced selectivity for tin hydrides. SPME provided good sensitivity and an approximately 3.5 decade linear response range. Detection limits for As , Se, Sn and Sb using a PDMS/Carboxen fiber were 70, 5300, 8 and 310 pg mL( -1), respectively. Method validation using NRCC SLRS-4 (Riverine Water) and CASS-4 (Nearshore Seawater) reference materials showed good agreement betw een certified and measured values for total arsenic.