silica wash
2.At the condintion of pH=4.0～6.5, the selenium was fixed on finely divided silica gel as the complex with ammonium pyrrolidinedithiocarbamate (APDC) and the silica gel was collected on a membrane filter by filtration under suction, then wash down by 0.1mol/L hydrochloric acid from membrane filter paper and the suspension was directly subjected to the determination by Hydride Generation Atomic Absorption Spectrometry.
