Fabrication of gold nano-particles embedded in the Langmuir Blodgett film of Poly (methyl methacrylate) for rapid screening of melamine adulterant in milk powder

The current work elaborates the development of a rapid and sensitive method for trace detection of melamine precisely in powdered milk using Surface Enhanced Raman Scattering (SERS). The main focus of the work is to develop a reproducible SERS active substrate to detect trace level melamine contamination in milk products. Langmuir-Blodgett (LB) thin film of Poly (methyl methacrylate) (PMMA) with impregnated gold nanoparticles (AuNPs) has been used as a potent SERS active substrate. The LB film of PMMA and AuNPs embedded PMMA were meticulously characterized in our contemporary work. The efficacy of the as prepared substrate as a SERS sensing platform was studied up to trace concentrations using Raman probe molecules. Moreover, the reproducibility and homogeneity of the substrate was also verified using Raman mapping studies. The as prepared substrate was further engaged for melamine detection in powdered milk at trace concentrations. The sensor practically exhibits its noteworthy proficiency in detecting melamine adulteration in milk with limit of detection ∼220 ppb. The as prepared substrate emerges as a promising device for underscoring its significance in ensuring human health and food safety.