Identification of Synthetic Colorants Using HPLC-DAD and Chemometrics

A team of researchers from the State Laboratory of Chemo/Biosensing and Chemometrics in China has developed a novel high performance liquid chromatography-diode array detection (HPLC-DAD) method for the identification of six synthetic colours in five beverages.¹   Synthetic colours are a very popular type of food colourings because they are brighter, more uniform, and have a wider range of hues. They are also less expensive than colours derived from nature.   A chemometrics-assisted strategy was utilized to solve interfering patterns from different chromatographic columns and sample matrices for the rapid simultaneous determination of synthetic colorants in five kinds of beverages. The experiment was performed using two types of LC columns under the same elution conditions. Although analytes using different columns have different co-elution patterns that appear more seriously in complex backgrounds, all colorants were properly resolved by alternating a trilinear decomposition (ATLD) method, and accurate chromatographic elution profiles and spectral profiles as well as relative concentrations were obtained. The results were verified by those obtained using traditional HPLC-UV, with the results of both consistent with one other.   The team concluded that the proposed chemometrics-assisted HPLC-DAD method is accurate, economical, and universal, and can potentially be applied to solve varying interfering patterns from different chromatographic columns and sample matrices for the analysis of complex food samples.   Reference   1. Xiao-Li Yin et al., Journal of Chromatography A1435, 75–84 (2016).