Detecting tartrate additives in foods: Evaluating the use of capillary electrophoresis

In order for legislation relating to the levels of additives permitted in food to be enforced, practical methodology is needed for their extraction and analysis. This study demonstrates the suitability of capillary electrophoresis to successfully separate and detect tartrate moieties at appropriate levels in spiked sample matrices; cocoa, jam, lemonade, sugar syrup, Madeira cake and digestive biscuit, in less than 12 min. It was discovered that the best method, in terms of its ability to detect a range of tartrate-containing species, at different concentrations, used a neutral polyacrylamide-coated capillary and a high ionic strength buffer. These conditions allow the generation of a reversed electroosmotic flow (EOF), in which the negatively charged tartrate moieties migrate in a counter-current direction, towards the anode. This method gave a linear calibration, was reproducible and had a limit of detection of 10 μg ml−1. Spiking and extraction procedures are also detailed.