Determination of danofloxacin in milk combining second-order calibration and standard addition method using excitation–emission fluorescence data

For this paper we propound a new procedure for fast detection and determination of danofloxacin (DANO) in commercial bovine milks. For this aim, a spectrofluorimetric method coupled with chemometric (PARAFAC) tools has been optimized. This method provides valuable information about the total amount of DANO in the selected sample in a short analysis time. After a cleanup step, consisting in protein precipitation in acidic medium, excitation–emission fluorimetric scans (EMMs) were recorded and a standard addition calibration method, using second order multivariate procedures, was applied. The analytical method has been validated according to the European Community directive related to the decision limit (CCα) and detection capability (CCβ). The obtained values, 7.3 and 12 ng mL−1, respectively calculated are well below the MRL for DANO in milk (30 ng mL−1). This procedure has been applied to different commercial milks in order to accomplish the strength of this methodology by PARAFAC standard addition. Recoveries around 100% were observed for all the samples. The high sensitivity of the fluorimetric technique and the fast cleanup step make this method an easy and fast way for quality and antibiotic residues surveys in commercial milks.