Vanadium pentoxide R

V₂O₅.

Description. A yellow-brown to rust-brown powder.

Solubility. Slightly soluble in water; soluble in concentrated acids and alkalis; practically insoluble in ethanol (~750 g/L) TS.

Vanadium/sulfuric acid TS.

Procedure. Dissolve 0.20 g of vanadium pentoxide R in 4 mL of sulfuric acid (~1760 g/L) TS and dilute carefully with water to 100 mL.

Vanillin (10 g/L) TS

A solution of vanillin R containing about 10 g of C₈H₈O₃ per litre.

Vanillin R

C₈H₈O₃ (SRIP, 1963, p. 214).

Vanillin/hydrochloric acid TS

Procedure. Dissolve 1.0 g of vanillin R in sufficient hydrochloric acid (~250 g/L) TS to produce 100 mL.

Note: Vanillin/hydrochloric acid TS must be freshly prepared.

Vanillin/sulfuric acid TS1

Procedure. Dissolve 5 g of vanillin R in 100 mL of sulfuric acid (~1760 g/L) TS.

Note : Vanillin/sulfuric acid TS1 should be freshly prepared.

Vanillin/sulfuric acid TS2

Procedure. Dissolve 1 g of vanillin R in sufficient ethanol (~750 g/L) TS to produce 100 mL. Carefully add, drop by drop, 2 mL of sulfuric acid (~1760 g/L) TS.

Note : Vanillin/sulfuric acid TS2 must be used within 48 hours.