[Determination of carmine in carbonated beverages using 3-D fluorescence spectra coupled with second-order...

Three-dimensional fluorescence spectra combined with second-order calibration algorithm based on alternate a weighted residual (ANWE) was applied to the direct concentration determination of carmine in carbonated beverages. Firstly, 3-D fluorescence spectra of carmine and sunset yellow mixed solutions with different concentrations were obtained by employing spectrometer, and analyzed by using ANWE, the correlation coefficient between calibration concentration and the actual concentration was 0.9917, and the average recovery was 100.92%±2.71%. The results show that the ANWE algorithm is reliable. Then, the commercial carbonated soft drinks in 8, 9, 12 and 13 times diluted concentration were detected by using ANWE algorithm, the correlation coefficient between relative concentration and the actual concentration were 0.9930, 0.9930, 0.9932 and 0.7932, respectively, and the contents of carmine in beverage were 38.88, 37.71, 37.68 and 39.65 μg · mL(-1), respectively. The average concentration was (38.48±0.96) μg · mL(-1). Finally, the standard addition method was applied to estimate the prediction accuracy between calibration concentration and the actual concentration was 0.9935, and the average recovery was 102.99%±2.15%. The results can provide a new idea for the rapid content determination of food pigments in commercial beverages.