Yeast extract, water-soluble, R.

(SRIP, 1963, p. 215).

Yellow stock standard TS.

Procedure. To 9.5 mL of cobalt colour TS, add 1.9 mL of copper colour TS, 10.7 mL of dichromate colour TS, 4.0 mL of iron colour TS, dilute to 100.0 mL with sulfuric acid (~10 g/l) TS, and mix.