Determination of halquinol (chloroquinolin-8-ols) in pre-mixes and medicated feeding stuffs

Abstract

An absorptiometric method for determining halquinol in a pre-mix by extracting with chloroform, adding iron(III) chloride and measuring the absorbance of the green chelate solution at 685 nm is recommended for routine use. Low results were found in the determination of medicinal amounts of halquinol in aged compound feeds; the reason for this was not established. With the knowledge of these limitations, the UV spectrophotometric method of Cowen and Heyes, with a slightly modified extraction procedure, is recommended for freshly medicated feeds. The gas-liquid chromatographic method used by Cowen and Heyes to determine specifically the mono- and dichloro components of halquinol in pig feed was found to require further research before its general acceptability for routine use for feeds containing halquinol could be recommended.