Application of Polypyrrole (Ppy) nanofibers in Solid Phase Extraction of samples before the determination of vitamin B families in infant powder

Abstract

In this study, a kind of core/sheath Polystyrene/Polypyrrole (PS/PPy) electrospun nanofibers was prepared and used as the solid phase extraction (SPE) adsorbent. Primary extraction of target analytes, three kinds of vitamin B (VB2, riboflavin; VB9, folic acid; VB12, cobalamin), was carried out by loading samples onto the column along with appointed boric acid compound reagent, and then the column should also be rinsed with the same reagent solution before elution. The boric acid compound was applied as complexing reagent to retain as much of three analytes as possible on the column based on the multi interaction between three vitamins and the boronate affinity reagent, thus improving hydrophobicity of targets and adsorption efficiency through loading and rinsing steps. Analytical parameters include linearity r²> 0.99; limit of detection (LOD) ranged from 0.05 to 0.093μg/ml; Intraday and Interday precision of the method, 0.59%-12.1% and 0.64%-14.5%, respectively; the spiked extraction recoveries ranged from 84.9% to 111.7% in the infant powder samples. A Ppy nanofibers SPE column coupled with HPLC-UV was established for assay of elements in infant powder. The levels of three vitamin Bs in three brands of real milk powder samples were determined and the results were compared with the prescription. Results showed that the analysis method in the paper were reliable to be used in the determination of vitamin B families in infant powder.