The report describes the advances in instrumentation and the research activities of the Analytical Mass Spectrometry Section during the period July 1968 to June 1969.Chemical and mass spectrometric procedures are described for the determinations of the absolute isotopic abundance ratios of natural rubidium, boron in a natural boric acid and a 10B enriched boric acid, and of uranium in six SRMs.Procedures are also described for the determination of trace amounts of copper and lead in steel, and silver, copper, boron and uranium in glass by isotope dilution mass spectrometry.(Author).