RHA™ anti-Tartrazine monoclonal antibody, clone TAR

A simple, fast and efficient on-line pre-concentration method (large-volume sample stacking) by capillary electrophoresis was proposed for determination of azo dyes residues (allura red [AR], sunset yellow [SY] and tartrazine [TAR]) in water samples. Pre-concentration variables involved in the system were optimised using of a Box-Bhenken design. Under the optimal conditions: injection time 150.0 s, pre-concentration time 120.0 s and reverse potential -8.0 kV, the proposed methodology improved the analytical sensibility achieving limits of detection of 21.0-41.4 mu g L-1 with enrichment factors of 82.1-210.8 fold. The large-volume sample stacking-capillary electrophoresis method was validated and applied to determine azo dyes residues in 20 water samples (bottled, spring and tap water). Two samples were positive for sunset yellow and tartrazine with a concentration of 25.3 and 30.2 mu g L-1 and % RSD less than 10.0% in all cases.

This work demonstrates the fabrication of a carbon paste electrode containing NiO/CNTs modified with 1-methyl-3-butylimidazolium bromide as the binder (CPE/1-M-3BIBr/NiO/CNTs), and its applications related to the highly sensitive detection of carmoisine. The CPE/1-M-3BIBr/NiO/CNTs system was successfully utilized for the nanomolar determination of carmoisine at pH = 7.0. The CPE/1-M-3BIBr/NiO/CNTs successfully resolved the oxidation signals of carmoisine and tartrazine with a peak separation of 450 mV. This is the first time that an application of an electrochemical sensor for the simultaneous determination of carmoisine and tartrazine, two important azo dyes, has been reported. In addition, wide dynamic linear concentration ranges (70-650 mu M for carmoisine and 0.1-750 mu M for tartrazine), low detection limits (20 nM for carmoisine and 0.06 mu M tartrazine) and excellent reproducibility were reported. The CPE/1-M-3BIBr/NiO/CNTs were successfully used for the analysis of carmoisine and tartrazine in dried fruit and soft drink samples.