SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF FOLIC ACID, PYRIDOXINE, RIBOFLAVIN, AND THIAMINE BY PARTIAL LEAST-SQUARES REGRESSION

ABSTRACT

A new method for the simultaneous spectrophotometric determination of folic acid, pyridoxine, riboflavin and thiamine based on total absorbance measurements and their processing by partial least square regression is proposed. The concentration ranges used to construct the calibration matrix were 1.02–14.3 µg mL⁻¹, 1.01–16.2 µg mL⁻¹, 1.02– 10.2 µg mL⁻¹ and 6.00–20.0 µg mL⁻¹ for folic acid, pyridoxine, riboflavin and thiamine, respectively. Estimated limits of detection were: folic acid 0.08 µg mL⁻¹, pyridoxine 0.45 µg mL⁻¹, riboflavin 0.09 µg mL⁻¹ and thiamine 0.17 µg mL⁻¹. The proposed methodology was checked by applying it to the analysis of a set of laboratory-made samples. It was shown that is possible to resolve complex mixtures of compounds even when they have strongly overlapped signals. The analytical results obtained were good in all cases.

Keywords:

• Numerical methods
• Partial least-square
• Spectrophotometry
• Determination
• Vitamins

ACKNOWLEDGMENTS

We wish to acknowledge the financial support from the Ministerio de Educación y Cultura (DGICyT), research project No. PB98-0439.