An Investigation of Efficient Detection of Ultra-Low Concentration of Penicillins in Milk Using AuNPs/PSi Hybrid Structure

In this work, porous silicon (PSi) sample was employed to increase the SERS efficiency for rapid detection of penicillins in spiked milk by developing Au nanoparticles (AuNPs)/PSi hybrid structure. SERS was used to study penicillin G and ampicillin residue in milk. The results show that the AuNPs/PSi hybrid structure is very able to detect penicillins residue in milk with an excellent linear relationship and a correlation coefficient (R-2 = 1) in the range of 1 x 10(-7) mol/L to 1 x 10(-9) mol/L. The highest enhancement factors of penicillin G (2.8 x 10(8)) and of ampicillin (1.2 x 10(8)) with an excellent relative standard deviation (RSD) of 2.69 and 0.93, respectively, are obtained at the ultra-low concentration of 1 x 10(-9) mol/L. The detection limit of penicillin G and ampicillin is 1 x 10(-9) mol/L (equal to 0.33 mu g/kg and 0.35 mu g/kg, respectively) which is very lower than the maximum residue limit (MRL) of penicillins in milk (4 mu g/kg) established by the European Union.