- centrifuge for 2 minutes

- decant and discard supernatant

precipitate in centrifuge tube

(Groups B, C, and D)

- wash with 10 drops cold dH2O

- centrifuge for 2 minutes

- decant and discard supernatant

supernatant in centrifuge tube

precipitate in centrifuge tube

- heat in boiling H2O bath for 3 minutes

- centrifuge for 2 minutes

- decant supernatant in separate centrifuge tube

supernatant in centrifuge tube

precipitate in centrifuge tube

- swirl

- add few drops 6M HNO3 until white ppt forms

white ppt

yellow ppt