PLS and PARAFAC applied to determination of noscapine in biological fluids by excitation-emission matrix fluorescence

Abstract

A method for the direct determination of noscapine, an opium alkaloid, in biological fluids such as urine and human plasma has been developed using excitation-emission matrix fluorescence measurements and chemometrics techniques based on partial least squares (PLS) and parallel factor (PARAFAC) analysis. A two-factor PARAFAC trilinear model without restrictions was used in the data analysis. The excitation wavelength range was from 285 to 315 nm and the emission was recorded from 325 to 500 nm. The calibration graph was constructed using sixteen standard solutions in the concentration range from 0.50 to 21.00 mg/ml for noscapine. The capabilities of the method for the analysis were evaluated by determining noscapine in synthetic and real samples with satisfactory results. In addition, a PLS model was built at one excitation wavelength and used to determine noscapine in a series of synthetic and real samples. The accuracy of the proposed methods, evaluated through the root mean square error of prediction (RMSEP) for noscapine by PARAFAC and PLS models was 0.2375 and 0.4901, respectively. The best model was obtained using PARAFAC analysis. This result shows that molecular fluorescence spectroscopy can be used for the development of robust analytical methods for the direct determination of noscapine on a complex background such as urine and human plasma.