Microwave Digestion - Graphite Furnace Atomic Absorption Spectrometry Determination of Trace Arsenic in the Nano-Titanium Dioxide

Abstract

The analysis method that the microwave digestion - graphite furnace atomic absorption spectrometry (GF-AAS) determination of trace impurity element arsenic in the nanotitanium dioxide has been built. It uses a mixture digestion reagent which is composed of a certain concentration and the proportion of hydrofluoric acid and nitric acid in the experiments, and then combined with high pressure microwave heating technology so as to quickly and completely digest the nanotitanium dioxide sample into solution. The composition and ratio and amount of the mixed digestion reagent, and the best microwave heating control program are all optimized in this paper, which not only solved the problem of the digestion of titanium dioxide and the loss of the analyte arsenic that is likely to be volatile in the high temperature digestion process, but also ensure that high content of titanium matrix in the low acidity solution is still existing in a stable complex ion form to avoid hydrolysis by complexation of the fluoride ion. Therefore, it can greatly reduce the detection affection of acidity and avoid the erosion of GF-AAS graphite tube. In order to eliminate the influence of the thermal stable titanium dioxide matrix on the determination of volatile trace element arsenic, the type of graphite tube, graphite furnace atomization procedures and atomic absorption spectrometer detection parameters all have been optimized through the matrix effect testing. The detection limit is 0.000 001% and the recovery rate is in the range of 93.0% to 106.0%. Otherwise, RSD is less than 9.36%, which is consistent with ICP-MS detection method.