Sensitive Electrochemical Sensor Based On an Aminated MIL-101(Cr) MOF for the Detection of Tartrazine

Raïssa Tagueu Massah; Sherman Lesly Zambou Jiokeng; Jun Liang; Evangeline Njanja; Tobie Matemb Ma Ntep; Alex Spiess; Lars Rademacher; Christoph Janiak; Ignas Kenfack Tonle

doi:10.1021/acsomega.2c01106

Sensitive Electrochemical Sensor Based On an Aminated MIL-101(Cr) MOF for the Detection of Tartrazine

ACS Omega. 2022 Jun 1;7(23):19420-19427. doi: 10.1021/acsomega.2c01106. eCollection 2022 Jun 14.

Authors

Raïssa Tagueu Massah¹, Sherman Lesly Zambou Jiokeng¹, Jun Liang^{2

3}, Evangeline Njanja¹, Tobie Matemb Ma Ntep², Alex Spiess², Lars Rademacher², Christoph Janiak², Ignas Kenfack Tonle¹

Affiliations

¹ Electrochemistry and Chemistry of Materials, Department of Chemistry, University of Dschang, P.O. Box 67, 00237 Dschang, Cameroon.
² Institut für Anorganische Chemie, Heinrich-Heine-Universität Düsseldorf, D-40204 Düsseldorf, Germany.
³ Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Blvd, Nanshan District, 518055 Shenzhen, China.

Abstract

The aminated metal-organic framework H₂N-MIL-101(Cr) was used as the carbon paste electrode (CPE) modifier for the determination of tartrazine (Tz) in soft drinks. The amino material was characterized by electrochemical impedance spectroscopy and showed significantly faster electron transfer with lower charge-transfer resistance (0.13 kΩ) compared to the electrode modified with the unfunctionalized MIL-101(Cr) material (1.1 kΩ). The H₂N-MIL-101(Cr)-modified CPE [H₂N-MIL-101(Cr)-CPE] was then characterized by cyclic voltammetry (CV) using [Fe(CN)₆]^3- and [Ru(NH₃)₆]³⁺ ions as the redox probes, showing good accumulation of [Fe(CN)₆]^3- ions on the electrode surface. A CV scan of Tz in Britton Robinson buffer solution revealed an irreversible system with an oxidation peak at +0.998 V versus Ag/AgCl/KCl. Using CV and differential pulse voltammetry, an electrochemical method for quantifying Tz in aqueous medium was then developed. Several parameters that affect the accumulation and detection steps were optimized. Optimal detection of Tz was achieved after 180 s of accumulation in Britton Robinson buffer solution (pH 2) using 2 mg of H₂N-MIL-101(Cr) material. Under optimal conditions, the sensor exhibited a linear response in the concentration range of 0.004-0.1 μM and good detection sensitivity (35.4 μA μM^-1), and the detection limit for Tz was found to be 1.77 nM (S/N = 3). Satisfactory repeatability, stability, and anti-interference performance were also achieved on H₂N-MIL-101(Cr)-CPE. The sensor was applied to commercial juices, and the results obtained were approximately similar to those given by UV-vis spectrophotometry.