Sensitive determination of erythrosine and other red food colorants using capillary electrophoresis with laser-induced fluorescence detection

Capillary electrophoresis with laser-induced fluorescence detection (CE–LIF) was applied to separation and sensitive determination of red food colorants. Diode pumped frequency-doubled Nd:YAG laser (532 nm) was used as an excitation source in a laboratory-built CE–LIF system. For highly fluorescent erythrosine B (E127), an extrapolated limit of detection (LOD) of 0.4 ng mL−1 (S/N = 3) was achieved. Extrapolated LODs of other tested red additives, such as carmoisine, E122 (0.5 μg mL−1); amaranth, E123 (0.2 μg mL−1); ponceau 4R, E124 (0.3 μg mL−1) and red 2G, E128 (0.3 μg mL−1) were about one-order lower compared to results obtained with CE with absorbance detection in UV/vis (CE–UV/vis). The main advantages of using CE–LIF for analysis of food samples are high selectivity and minimization of matrix effect. To our knowledge, this is the first use of CE–LIF for determination of red food colorants.