Analytical approach for the simultaneous determination of quinolones in edible animal products. Modeling pH-modulated fluorescence excitation-emission matrices four-way arrays

This paper describes a novel procedure for the simultaneous determination of four quinolones pipemidic acid, enoxacin, marbofloxacin and enrofloxacin in different edible animal tissues. It is based on third-order data excitation-emission fluorescence matrices modulated by pH gradient, generated in situ through the hydrolysis of glucono delta-lactone. To overcome the strongly overlapped spectra within the analytes, and also with the highly complex tissue matrix, we have used the multivariate calibration procedure unfolded partial least-squares coupled to residual trilinearization (U-PLS/RTL). The method has been validated by application to bovine kidney, chicken and porcine meat samples, fortified at concentration levels between 70 and 600 mu g kg(-1) corresponding to values near the maximum residue level (MRL) regulated by the European Community. Good recoveries were obtained for all analytes, with values between 80% and 113%, depending on the quinolone and the matrix.