Kinetic Spectrophotometric Determination of Sulfite Using a Full Curve (PLS) and a Fixed Time Method

Abstract

The univariate and multivariate calibration method was applied for the determination of sulfite based on the addition reaction of sulfite with new fuchsin at pH = 7.5 and 25°C. The decrease in absorbance of new fuchsin at 540 nm over a fixed time is proportional to the concentration of sulfite over the range of 0.15–2.0 µg mL⁻¹. The detection limit and RSD% are 0.08 µg mL⁻¹ and 1.1% respectively. The experimental calibration matrix for PLS calibration method was designed with 20 samples. The cross-validation method was used for selection of the optimal number of factors. The RMSEP was 0.0043 at optimum value of factors. The effects of various cations and anions on sulfite determination were investigated.

Keywords:

• Partial least squares
• New fuchsin
• Noncatalytic
• Sulfite
• Determination