Enhanced electrochemical performance of Sr doped ZnO for tartrazine detection in sports drink

Abstract

Tartrazine (Tz) is a widely used synthetic food colorant that has raised health concerns due to its potential adverse effects. Developing sensitive and reliable methods for Tz detection in food products is crucial for ensuring consumer safety. In this study, Sr-doped ZnO nanoparticles with varying doping levels (0–7 mol%) were synthesized by mechanical milling and applied as an electrochemical sensor for detecting Tz in sports drinks. The ZnO-Sr modified carbon paste electrode (CPE), with an optimal Sr doping level of 5 mol%, exhibited the best sensing performance under optimized conditions of pH 7.0 and an accumulation time of 180 s. The sensor demonstrated a linear range from 1 to 1000 μM, a detection limit of 0.3 μM, and a sensitivity of 0.38 μA/μM for Tz identification. This performance surpasses that of many previously reported electrochemical Tz sensors. The ZnO-Sr modified CPE showed good reproducibility (RSD 3.2%), long-term stability (91.2% current retention after one month), and high selectivity against common interferents. The sensor’s practical applicability was validated by determining Tz in commercial sports drink samples, with results in good agreement with a standard UV-Vis spectrophotometric method (relative errors < 5%). Recovery tests (97.2–103.5%) further confirmed the accuracy and reliability of the proposed sensor. This work presents a simple, sensitive, and reliable approach for monitoring Tz levels in food products, addressing important food safety and human health concerns.

Keywords
Food colorant sensing; Strontium doping; Electrochemical detection; Carbon paste electrode; Selectivity