DETERMINATION OF UNSULPHONATED QUINOLINE YELLOW IN SOFT DRINKS BY SOLID-PHASE SPECTROPHOTOMETRY

A spectrophotometric method for determination of quinoline yellow spir it soluble (QYSS) in the presence of sulphonated quinoline yellow wate r soluble (QYWS) in soft drinks at trace levels is reported. The metho d is based on the fixation of QYSS on C-18 silica gel, followed by mea surement of its absorbance at lambda = 418 nm in the solid phase after being packed in a 1-mm cell. The applicable concentration range was 1 .5-15.0 ng/ml, the detection limit 0.4 ng/ml and the relative standard deviation 5.2%. The method was applied satisfactorily to the determin ation of this compound in samples of commercial soft drinks.