Massah Raïssa Tagueu, Zambou Jiokeng Sherman Lesly, Liang Jun, Njanja Evangeline, Ma Ntep Tobie Matemb, Spiess Alex, Rademacher Lars, Janiak Christoph, Tonle Ignas Kenfack
Electrochemistry and Chemistry of Materials, Department of Chemistry, University of Dschang, P.O. Box 67, 00237 Dschang, Cameroon.
Institut für Anorganische Chemie, Heinrich-Heine-Universität Düsseldorf, D-40204 Düsseldorf, Germany.
ACS Omega. 2022 Jun 1;7(23):19420-19427. doi: 10.1021/acsomega.2c01106. eCollection 2022 Jun 14.
The aminated metal-organic framework HN-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 HN-MIL-101(Cr)-modified CPE [HN-MIL-101(Cr)-CPE] was then characterized by cyclic voltammetry (CV) using [Fe(CN)] and [Ru(NH)] ions as the redox probes, showing good accumulation of [Fe(CN)] 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 HN-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), 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 HN-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.
胺化金属有机框架HN-MIL-101(Cr)被用作碳糊电极（CPE）修饰剂，用于测定软饮料中的柠檬黄（Tz）。该氨基材料通过电化学阻抗谱进行表征，与用未官能化的MIL-101(Cr)材料修饰的电极（1.1 kΩ）相比，显示出显著更快的电子转移，电荷转移电阻更低（0.13 kΩ）。然后，以[Fe(CN)]和[Ru(NH)]离子作为氧化还原探针，通过循环伏安法（CV）对HN-MIL-101(Cr)修饰的CPE [HN-MIL-101(Cr)-CPE]进行表征，结果表明[Fe(CN)]离子在电极表面有良好的富集。在 Britton Robinson缓冲溶液中对Tz进行CV扫描，结果显示该体系为不可逆体系，相对于Ag/AgCl/KCl的氧化峰位于 +0.998 V。利用CV和差分脉冲伏安法，随后开发了一种在水介质中定量测定Tz的电化学方法。对影响富集和检测步骤的几个参数进行了优化。使用2 mg的HN-MIL-101(Cr)材料，在Britton Robinson缓冲溶液（pH 2）中富集180 s后，实现了对Tz的最佳检测。在最佳条件下，该传感器在0.004 - 0.1 μM的浓度范围内呈现线性响应，检测灵敏度良好（35.4 μA μM），Tz的检测限为1.77 nM（S/N = 3）。HN-MIL-101(Cr)-CPE还具有令人满意的重复性、稳定性和抗干扰性能。该传感器应用于市售果汁，所得结果与紫外可见分光光度法给出的结果大致相似。
