PARAFAC Decomposition of Three‐Way Kinetic‐Spectrophotometric Spectral Matrices Based on Phosphomolymbdenum Blue Complex Chemistry for Nitrite Determination in Water and Meat Samples

Abstract

A three‐way analytical methodology experimentally based on kinetic‐spectrophotometric and parallel factor analysis (PARAFAC) chemometrics analysis was assessed for the quantification of nitrite in water and meat samples. This method is based on the reduction of phosphomolybdic acid to phosphomolymbdenum blue complex by sodium sulfide. The obtained phosphomolymbdenum blue complex is oxidized by the addition of nitrite and this causes a reduction in intensity of the blue color. Three‐way data matrices were generated by acquisition of ultraviolet‐visible (UV‐Vis) spectra (600–900 nm) as a function of the time and of different relative concentration of the nitrite (0.10–2.10 µg mL⁻¹). The PARAFAC trilinear model, without restrictions, was used in the data analysis. A full decomposition of the data matrices was obtained (spectra, concentration, and time profile). It was shown that kinetic methods coupled to three‐way chemometrics analytical methods can be used for the development of robust sensors for the analysis of nitrite in water and meat samples. The accuracy of the method, evaluated through the root mean square error of prediction (RMSEP), was 0.0515 and 0.1181 for nitrite by PARAFAC and partise least squares (PLS) models respectively. The results with the PARAFAC model are better than those of the PLS model, according to results, it being possible to recover the spectra and kinetic profiles, as well as the initial concentration of nitrite with good accuracy.

Keywords:

• Nitrite
• PARAFAC
• PLS
• kinetic‐spectrophotometric
• determination