Simultaneous determination of sunset yellow and tartrazine in real samples on an...

A composite electrode was fabricated for simultaneous determination of sunset yellow (SY) and tartrazine (Tz) in foods and syrup. It is based on n-butylamine intercalation into graphite and then dropped on a poly (4-aminophenol)/glassy carbon electrode (GCE). The electrode surface morphologies, chemistry, and electrical properties were identified by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RS), and electrochemical impedance spectroscopy (EIS). The new composite electrode significantly increased the electrochemical response of SY and Tz relative to a bare GCE. The peak current of SY and Tz increased linearly depending on their concentrations from 0.006 μmol L^-1 to 1.0 μmol L^-1 (r = 0.994) and over two linear ranges from 0.06 to 1.50 μmol L^-1 (r = 0.9955) and from 2.0 to 10.0 μmol L^-1 (r = 0.9902), respectively. The limits of detection of SY and Tz were 2.60 nmol L^-1 and 0.025 μmol L^-1, respectively (S/N = 3). SY and Tz contents in real samples were determined in syrup, juice powder, and candy. Spiked recovery for samples was from 96.4% to 106.8%. The relative standard deviations were lower than 5.0%.