Partial least squares method for simultaneous spectrophotometric determination of uracil and 5-fluorouracil in spiked biological samples



A quantitative spectroscopic method using multivariate data models based upon ultraviolet spectroscopy, is proposed for the simultaneous analysis of binary mixtures of uracil (UR) and 5-fluorouracil (5-FU). By multivariate calibration methods, such as partial least squares (PLS), it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. In this study, the calibration model is based on absorption spectra in the 220–314 nm range for 25 different mixtures of UR and 5-FU. PLS was used for the construction of the calibration sets containing UR and 5-FU in the concentration range of 1.12-28.02 and 1.30-38.76 (in μg mL-1), respectively. Prediction error sum of squares (PRESS) was 0.5172 and 3.8191 and the root mean standard error of prediction (RMSEP) was 0.2936 and 0.7978 for UR and 5-FU, respectively. This procedure allows the simultaneous determination of UR and 5-FU in synthetic and spiked real samples.