A dual-functional Cu-BTC/COOH-MWCNTs ratiometric electrochemical sensing device for the detection of sunset yellow and tartrazine

A ratiometric electrochemical sensor for sunset yellow (SY) and tartrazine (TZ) was constructed by modifying a glassy carbon electrode with a composite of carboxylated multiwalled carbon nanotubes (COOH-MWCNTs) and a redox-active metal–organic frameworks (Cu-BTC MOFs). Cu-BTC served as an internal reference probe with a constant oxidation peak current. The sensor exhibited excellent linearity in the concentration range of 2–200 μM under optimized conditions. The detection limits for SY and TZ were found to be 0.73 μM and 0.78 μM, respectively. When the sensor was used to determine SY and TZ in two carbonated beverages, the resules were good and did not significantly differ from those obtained by UV–Vis spectrophotometry.