Iron, manganese, copper and titanium in welding fume dust on filters for internal and external quality assurance

Summary Filters charged with welding fume dust were developed and produced for internal and external quality assurance to evaluate and improve the performance of analytical methods used for monitoring iron, manganese, copper and titanium in the working environment. The filters were simultaneously loaded, using a Sputnic air sampling unit containing 100 cellulose nitrate filters. The welding fume dust was collected in industrial working conditions where Metal Inert Gas welding in construction steel was being carried out. The metal concentrations on the filters were close to the metal concentrations from environmental and industrial exposure. The homogeneity of the filter materials was evaluated to document the suitability of the air sampler in producing quality control materials. The filters were homogeneous within 5.0–12.7% according to amount of metal. The welding fume dust loaded on the filters was (0.2021±0.0093 mg/filter) and the amounts of metals loaded on the filters were (34.6±6.4 g/filter, 16.0±0.8 g/filter, 2.4±0.1 g/filter) for iron, manganese and titanium, respectively. Normalizing the amount of metal according to the welding fume dust improved the homogeneity. The most satisfactory results were obtained for manganese and titanium, for which within batch variation was below 6.3%. The Sputnic air sampler was shown to be suitable in preparing quality control materials, although a few improvements are needed for future experiments, such as the method of charging the dust and rules for outlier exclusion.