Differential scanning calorimetry as a tool to detect antibiotic residues in ultra high temperature whole milk

Abstract

Detection of penicillin G, ampicillin and tetracycline in ultra high temperature whole milk was studied by differential scanning calorimetry (DSC). Thermal parameters including the heat of fusion, the evaporation temperature, the heat of evaporation and the melting temperature obtained from DSC analysis were used to characterise thermal behaviour of antibiotic free milk samples and milk samples fortified with Penicillin G, Ampicillin and Tetracycline. DSC curves of these antibiotics at selected concentrations (0, 2, 4, 8 ppb for Penicillin G and Ampicillin; 0, 100, 250, 500 ppb for Tetracycline) show big endothermic peaks in the temperature range of -30 °C and 200 °C. It was concluded that the antibiotic concentration had a significant effect on the thermal parameters at a 95% confidence level. The differences between the melting temperatures and the peak areas in heat flow curves provided a basis for detection of antibiotic residues in UHT whole milk.