Direct current GDMS has been applied to conducting and non-conducting nuclear samples, namely, different types of nuclear fuels, cladding materials and nuclear-waste glasses. For the non-conducting oxide-based nuclear samples the relative sensitivity factors (RSFs), applied for quantitative analysis, are affected by the oxygen content in the matrix. For these samples the effect of ‘getter metals,’ such as tantalum and titanium as binder material, has been investigated and the results compared with those obtained using silver as the host matrix. Moreover, when tantalum was used as a secondary cathode, it was found to behave as a getter of oxygen. For the quantitative analysis of nuclear-waste glasses the use of matrix specific RSFs was necessary. Comparisons with RSFs obtained from other workers are made. Metallic alloys were analysed using several analytical techniques. The GDMS results obtained applying RSFs from the major metallic element uranium were in agreement with those from independent techniques, such as titration, thermal ionization MS and ICP-MS.