Development of a second-order standard addition fluorescence method for the direct determination of riboflavin in human urine samples without previous clean up and separation steps

Abstract

A new strategy for the determination of riboflavin (RF, or vitamin B2) in human urine samples has been developed, combining excitation-emission fluorescence matrix (EEFM) data in standard addition mode and second-order chemometric analysis. The method is simple, fast and eco-friendly because it complies with the green analytical chemistry principles, avoiding the need of previous clean up and separation steps that consume high amounts of organic solvents. Successful results were obtained by different chemometric algorithms, namely parallel factor analysis (PARAFAC), unfolded partial least-squares/residual bilinearization (U-PLS/RBL) and multidimensional partial least-squares/residual bilinearization (N-PLS/RBL), all in the modified standard addition. These algorithms allowed us to achieve selectivity in a system, which requires standard addition and shows a significant background spectral overlapping with the studied vitamin. The quality of the proposed strategy was evidenced on the basis of the analytical recoveries from urine samples spiked with RF. The detection limits achieved in urine samples are encouraging compared to those obtained using chromatographic approaches. The relative prediction errors were lower than 5.6%.