ISO 6636-1:1986

Fruits, vegetables and derived products — Determination of zinc content — Part 1: Polarographic method

The method consists in ashing of a test portion in a muffle furnace at 525+25 C, treating the ash obtained with hydrochloric acid, neutralizing with ammonia solution and determing of the value using an ammonia/ammonium chloride electrolyte. Copper, tin, lead and cadmium do not interfere.