Polydopamine-Coated Magnetic Molecularly Imprinted Polymers as a Dispersive SPE Adsorbent for Selective Recognition and Enrichment of Basic Orange 2 in Food Matrices with High-Performance Liquid Chromatography Analysis.

Abstract

Background: Basic orange 2, as an industial dye, exhibits severe effects to human health and has been forbidden to use as food additives in many countries. The practical use of common pretreatment process for basic orange 2 in food might be limited owing to time consuming, high consumption of solvents and weak selectivity. Therefore, the aim of this study was to validate a pre-treatment technology for basic orange 2 based on simplicity, being rapid, good selectivity, high sensitivity and inexpensiveness to ensure the tongue safety for people.

Objectives: To develop a strategy for the extraction and enrichment of basic orange 2 in food matrices by the specific magnetic molecularly imprinted polymers prior to the determination by HPLC.

Methods: The polymers with basic orange 2 as the template were deposited on the surface of ferroferric oxide nanoparticles (Fe3O4@PDA MIPs) through the self-assembly of dopamine in the weak alkaline solution. The Fe3O4@PDA MIPs as a disperse SPE sorbent were used for extracting and detecting basic orange 2 using HPLC. Parameters influencing extracting efficiencies were optimized, including the mass of MIPs, pH value, time for ultrasonication, elution solvent and volume.

Results: Under optimal experimental conditions, the detection linearity of basic orange 2 was in the range of 0.04-1.0 μg/mL with correlation coefficient of 0.9991 and the limit of detection (LOD) of 5.8 ng/mL. The recoveries from spiked samples were 73.3%-90% with RSD 3.1%-8.1% in food samples. Notably, the magnetic MIPs showed an excellent reusability during 3 times extraction procedures.

Conclusion: The Fe3O4@PDA MIPs prepared have great potential for purification and enrichment of basic orange 2 prior to its determination by HPLC in dried beancurd stick, yellow fish, chili powder, drinks and wine.

Highlights: The magnetic MIPs developed show good adsorption performance for basic orange 2 with a very low detection, and excellent reusability. The assay was applied to detect basic orange 2 in food samples successfully.