REVIEW OF RECENT SAMPLE PREPARATION METHODS FOR THE ANALYSIS OF AZO DYES IN FOODS AND DRINKS: A COMPARISON OF SOLID-PHASE EXTRACTION AND QuEChERS

Abstract

Azo dyes, characterized by the presence of the azo functional group (-N=N-), are among the most widely used synthetic colourants in the food and beverage industry because of their low cost, chemical stability, and vibrant coloration. However, a number of studies notably have linked dyes such as Sudan I–IV, Tartrazine, and Sunset Yellow to genotoxicity, carcinogenesis, and allergic reactions, raising serious public health concerns. Therefore, it is essential to develop trustworthy analytical techniques for identifying and measuring azo dyes in intricate food matrices. This study compares Solid-Phase Extraction (SPE) and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe), two commonly used sample preparation methods in food analysis. The methods were evaluated based on analytical efficiency, recovery performance, solvent use, and operational cost. Literature data indicate that SPE yields recoveries of 80–95%, while QuEChERS achieves 85–120%, with reduced solvent usage and time. Although conventional SPE can be labour-intensive, modified forms such as dispersive SPE (d-SPE) have improved extraction speed and reproducibility. Both methods face limitations from matrix effects in high-fat or protein-rich foods. Future trends include green analytical modifications, such as bio-sorbent-based SPE and miniaturized QuEChERS formats, to enhance environmental sustainability. Consequently, because of its exceptional effectiveness, ease of use, and environmental advantages, QuEChERS is suggested for further study and regular analytical applications in food safety and quality control.