Slurry sampling electrothermal atomic absorption spectrometric determination of sodium and iron impurities in optical crystals of rubidium titanyl phosphate

A simple and rapid slurry sampling electrothermal atomic absorption spectrometric (ETAAS) method was developed for the determination of traces of sodium and iron in single crystals of rubidium titanyl phosphate (RTP). The finely ground crystal material was dispersed in 5 mL of 2% (v/v) HNO3, containing 0.005% (v/v) Triton-X-100. The fast furnace ETAAS analysis was performed using a pyrolytic platform coated with titanium carbide. No matrix interference was registered for either of the analytes in slurries containing 4 to 10 mg mL(-1) of RTP, which permitted simple calibration against aqueous solutions. The precision was about 2% RSD. The results for sodium and iron content in RTP were in good agreement with those obtained by flame AAS after sample digestion.