Copper metal organic framework based electrochemical sensor for dimethyl phthalate in bottled water samples

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Science

Background:

• Dimethyl phthalate (DMP) is a common plasticizer found in consumer products and environmental samples.
• Accurate and sensitive detection methods for DMP are essential for environmental monitoring and human health risk assessment.
• Existing detection methods may lack sensitivity or require complex sample preparation.

Purpose of the Study:

• To develop a novel electrochemical sensor for the sensitive detection of dimethyl phthalate (DMP).
• To utilize an electrochemically transformed copper benzene tricarboxylate (Cu-BTC) metal-organic framework (MOF) integrated with graphene oxide (GO) for enhanced sensing performance.
• To validate the sensor's performance in real-world samples like bottled water.

Main Methods:

• Electrochemical activation of Cu-BTC MOF on a glassy carbon electrode (GCE) in the presence of GO to form Cu(OH)₂@Cu-BTC-rGO.
• Physiochemical characterization of the composite material.
• Electrochemical analysis using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) for DMP detection.
• Ex-situ spectroscopic analyses (NMR, UV-Vis, EPR) to elucidate the detection mechanism.
• Validation of results using High-Performance Liquid Chromatography (HPLC).

Main Results:

• The developed Cu(OH)₂@Cu-BTC-rGO composite exhibited excellent sensing performance for DMP.
• The sensor demonstrated a wide linear detection range from 1 µM to 500 µM with a low detection limit of 0.17 µM.
• The detection mechanism was confirmed to be cation-π interaction between Cu¹⁺/Cu²⁺ ions and the benzene ring of DMP.
• The sensor's performance in PET bottled water was analyzed, showing good applicability.
• Electrochemical results were consistent with conventional HPLC analysis, validating the sensor's accuracy.

Conclusions:

• The electrochemically activated Cu-BTC-rGO composite provides a highly sensitive and reliable platform for DMP detection.
• The developed sensor surpasses the EPA's recommended threshold for DMP, indicating its potential for environmental safety monitoring.
• This method offers a promising alternative to conventional techniques for quantifying DMP in real-world samples.