A modified electrode (Purpald®/GC) was prepared by electrochemical deposition of 4-Amino-5-hydrazino-1,2,4-triazole-3-thiol (Purpald®) on the glassy carbon electrode surface to determine sunset yellow (SY). The sensor was characterized by Fourier transform infrared spectroscopy, scanning electron microscope with energy dispersive X-ray spectrometer attached, and electrochemical techniques. Optimum experimental conditions were determined for the determination of SY. To obtain better analytical performance on the Purpald®/GC sensor, the response surface methodology experimental design was used. The square wave voltammetry technique’s parameters were optimized to obtain the highest anodic peak current of SY. The working range was obtained as three linear concentration ranges were 4.97 nM-1.18 µM, 1.18 µM-15.16 µM, and 15.16 µM-0.153 mM. The LOD value was found as 1.15 nM with the optimum parameters combination. Using the proposed sensor, SY concentration was determined with satisfactory results in instant powder drink and orange-flavored carbonated drink samples.