  We present a detailed abundance analysis of high-resolution ultraviolet
echelle spectra of five subdwarf B stars obtained with HST-STIS The goal of our
observations was to test the hypothesis that pulsations in sdBs are correlated
to the surface abundances of iron-group elements. We study two pulsators and
three non-pulsators and determined abundances for 25 elements including the
iron group and even heavier elements such as tin and lead using LTE spectrum
synthesis techniques. We find strong enrichments of heavy elements up to 2.9dex
with respect to solar which are probably caused by atomic diffusion processes.
No clear-cut correlation between pulsations and metal abundances becomes
apparent. Abundances for lead isotopes are derived from very high resolution
spectra using an UV line of triply ionised lead. As Pb terminates the s-process
sequence Pb isotopic abundance ratios yield important constraints. It is very
difficult to measure them in hot stars. For the first time we were able to
measure them in two subluminous B stars and conclude that the 207Pb/208Pb is
solar.
