Thin-layer chromatographic method of screening the anthocyanes containing alimentary products and precautions taken at the method development step

The purpose of this study was to develop a novel and cost-effective thin-layer chromatographic method (TLC) using cellulose powder as stationary phase for authentication of the selected fruit-based alimentary products and targeting anthocyanes as the authenticity markers. Our method outperformed the HPTLC method earlier developed by another research team using silica gel as stationary phase. It was demonstrated that due to a limited chemical stability of anthocyanes, employing them as authenticity markers is burdened with a non-negligible uncertainty risk. Hydrolytic split of the glycosides into the aglycone and carbohydrate moieties can lead to a confusing multiplication of chromatographic bands and therefore it is advisable to use for the authentication purposes a limited set of well selected and stable enough anthocyane markers. Cyanin chloride, keracyanin chloride, pelargonidin chloride and delphinidin chloride were selected as the external standards and for the development of the calibration curves. The TLC-obtained LOD and LOQ values were 0.025 and 0.075 μg spot−1 for cyanin, 0.055 and 0.166 μg spot−1 for keracyanin, 0.047 and 0.140 μg spot−1 for pelargonidin, and 0.171 and 0.513 μg spot−1 for delphinidin, respectively. The analogous HPTLC-obtained LOD and LOQ values were 0.107 and 0.321 μg spot−1 for cyanin, 0.189 and 0.566 μg spot−1 for keracyanin, and 0.161 and 0.484 μg spot−1 for pelargonidin, respectively. Delphinidin was not detectable with use of the HPTLC method. Consequently, quantification of anthocyanes in the alimentary products carried out with use of TLC allowed identification of more target compounds and in a higher number of alimentary products than it was possible with use of HPTLC, apparently due to the LOD levels by one magnitude order lower for TLC than HPTLC.