Facile Synthesis of Glutathione-Copper Nanoparticles for 3-Monochloropropanediol Colorimetric Detection

3-Monochloropropanediol (MCPD) is a carcinogen compound commonly found in refined cooking oil, including palm oil. The high risk of human intoxication increases the importance of 3-MCPD detection. This study proposes the optimum chemical reduction synthesis condition of colloidal copper nanoparticles functioned by L-glutathione (GSH-Cu NPs) as an alternative accessible 3-MCPD detector used in the colorimetric method. The volume of copper source, capping agent, and reducing agent were optimized to find the optimum synthesis formula. 3.6 mL of 3 mM CuCl2, 25 μL of 20 mM L-glutathione (GSH), and 150 μL hydrazine hydrate were found to be the best combination to form GSH-Cu NPs; the combination made the sharpest UV-Vis absorption peak. Fourier Transform Infrared (FTIR) spectrometry measurement confirmed the reaction and encapsulation of Cu NPs with GSH. Transmission Electron Microscopy (TEM) and Particle Size Analyzer (PSA) observations revealed the quasi-spherical morphology of the nanoparticles, with an average size of 51.3 nm. The sample withstood 1:1 dilution with deionized water and maintained its dispersion and distribution after 10 days. The fabricated GSH-Cu NPs were able to detect 3-MCPD until 50 ppm. This study aimed to provide insight into the synthesis of copper nanoparticles as non-precious metals for the application of 3-MCPD colorimetric detection.