Determination of chlorcholine chloride residues in strawberries

Abstract

The chlorcholine chloride residue in strawberries has been determined by a chemical method that consists in extraction, preliminary purification of the quaternary ammonium compounds by cation-exchange resion chromatography, further purification by adsorption with an alumina column and absorptivity measurement of a dipicrylamine-chlorcholine chloride complex at 415 nm.

Average recoveries of chlorcholine chloride are about 80 per cent., with average control values of 0·05 p.p.m.

The field experiments carried out give results on the level of the chlorcholine chloride residues in strawberries treated for the control of runnering activity. A large decrease in residue is recorded with increasing time between application and harvest.

To determine the residue in perishable and high moisture content material, fresh fruits were lyophilised. This process does not interfere with the extraction of chlorcholine chloride.