National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)
“ Heat on 400 °C hotplate until dense fumes of perchloric acid appear. Remove watchglass and rinse into the beaker with distilled water. Place the beakers on the 400 °C hotplate and allow to go to dryness. Cool each beaker and dissolve the residues in 5 mL 5% HCl. Transfer the solution quantitatively to a 100-mL volumetric flask containing 2 mL of 50 mg/mL Cs solution and 2 mL of 50 mg/mL La solution. NOTE: Dilute to a smaller volume (e.g., 10 mL) with proportionally less Cs and La if required for sensitivity of analysis for other metals in the sample. ”
