Nanomolar detection of organic pollutant -tartrazine in food samples using zinc-metal organic framework/carbon nano fiber - composite modified screen-printed electrode

In this study, we achieved a significant breakthrough by applying a binder-free Zn-MOF@CNF composite as a modifier on a screen-printed electrode (SPE) to achieve highly sensitive and selective detection of tartrazine (TRZ). This composite, with its unique rod-like structure for Zn-MOF and a curl thread-like morphology for carbon nanofibers (CNF), demonstrated a remarkable threefold increase in the sensing current of TRZ at a lower anodic oxidation potential (0.92 V) compared to the bare SPE. The Zn-MOF@CNF/SPE also exhibited a reduced charge transfer resistance of 61.9 Ω, elevated electrochemical active surface area of 0.416 cm2, and high heterogeneous electron transfer rate constant (k0) of 9.77×10−5 cm s−1. Furthermore, it displayed a broad linear range from 0.2 μM to 1000 μM with a remarkable sensitivity of 0.136 µAµM−1cm−2 and an impressive detection limit of 54 nM. Ultimately, the developed Zn-MOF@CNF/SPE sensor demonstrated excellent selectivity amidst various structurally similar overlapping species, outstanding repeatability, reproducibility, and stability in TRZ detection. The practical applicability of Zn-MOF@CNF/SPE was validated through 97 – 100.9 % recovery results in food samples such as jelly, ice cream, soft drinks, and candies. •The Zn-MOF@CNF composite was synthesized using the sonochemical method.•The fabricated Zn-MOF@CNF/SPE probe has a high sensitivity towards TRZ detection.•The Zn-MOF@CNF/SPE sensor possessed a wide linear range with a low detection limit.•The proposed sensor has excellent recovery results for detecting TRZ in food samples.