Sample nebulization for minimization of transition metal interferences with selenium hydride generation ICP-AES

A new hydride generation approach was devised with the aim of minimization of transition element interferences. A Meinhard nebulizer was modified by insertion of a capillary tube into the sample introduction channel. The acidic sample, introduced through the inserted capillary, and the tetrahydroborate solution through the normal sample introduction channel of the nebulizer were mixed just prior to nebulization. Gas-liquid phase separation took place in a conventional Scott double-pass spray chamber with the aid of the nebulization gas. Due to the extremely short reaction time and fast gas-liquid separation, 50 g l(-1) Ni2+, 25 g l(-1) Co2+ and 20 mg l(-1) Cu2+ could be tolerated in a selenium sample solution without interference. The precision of 10 replicate measurements at 500 mu g l(-1) Se was less than 2% and a detection limit of 2 mu g l(-1) (3 sigma(b)) was achieved using inductively coupled plasma atomic emission spectrometry. The system was successfully applied to the determination of selenium in NIST certified reference material nickel oxide using a standard calibration curve. This hydride generation system was also interfaced to an electrically heated quartz atomizer and a graphite furnace (with in situ collection) for atomic absorption spectrometric measurements. (C) 1999 Elsevier Science B.V. All rights reserved.