IntroductionVery recently, the number of elements that may potentially be converted into volatile species by hydride generation technique has been enlarged. In the light of the latest publications,1–8some transition and noble metals are capable of forming volatile species in the reaction performed by NaBH4in the acidic medium. So far, transition metals such as Co,5,6Cd,9,10Cu,1–3,5,6Cr,5Fe,5Mn,6Ni,4-6Zn,3,6Ti6and Tl,2along with the following noble metals: Ag,2,3,6,8Au,2,3,6,7Ir,6Pd,2,6,7Pt6,7and Rh2,6have been found to form volatile compounds under the conditions of the hydride generation reaction. No information on Os and Ru volatile species generation in the reaction with sodium tetrahydroborate has been reported so far accordingly to our knowledge. The majority of novel species of the transition and noble metals have been generated at relatively low concentrations of HCl or HNO3.1,3-7According to the former research works, it was concluded that these species are very unstable.1,3,4It was also observed that experimental parameters, especially the sample acidity and the type of acid, affect significantly the efficiency of the volatile species generation and response of the metals.In the present contribution, the reaction of Ir, Os, Rh and Ru ions with NaBH4in the acid medium was studied. Experimental conditions influencing generation of Os, Rh and Ru volatile species, among them the type of acid and its concentration in the sample, sample flow rate and flow rate of the reductant, were examined. The efficiency of the noble metal volatile species generation reaction was evaluated. An investigation on analytical performance,i.e.detection limits and linearity ranges of Rh and Ru analytical lines, was also performed.