Chromatographic developments for the analysis of toxic organic chemicals in the environment and food samples

As awareness grows about compounds harmful to human health, the need for sensitive detection methods at low concentration levels becomes increasingly critical. Chromatography is a powerful analytical technique that enables the separation of complex mixtures, allowing for the simultaneous analysis of multiple analytes—even at trace levels. This dissertation applies chromatography in two distinct contexts: (1) Investigating the sorption of polycyclic aromatic sulfur heterocycles (PASHs) onto nylon microplastics; and (2) Detecting illegal dyes in various food matrices. Microplastics have emerged as significant vectors for transporting pollutants into aquatic ecosystems. Due to their hydrophobic nature, many organic pollutants readily sorb onto microplastics in these environments. Among these pollutants, PASHs are particularly concerning due to their carcinogenic and mutagenic properties. These compounds have been detected in environmental water sources at concentrations as low as 40–60 pg/mL. This study demonstrates that solid-phase extraction (SPE) followed by high-performance liquid chromatography with fluorescence detection (HPLC-FLD) can effectively detect PASHs at these low concentrations. The sorption behavior of three selected PASHs onto nylon microplastic pellets was examined, revealing that all three compounds sorbed onto the pellets and followed pseudo-second-order kinetics. Like PASHs, synthetic dyes pose health risks to consumers, including children. The U.S. Food and Drug Administration (FDA) regulates approved color additives under the Federal Food, Drug, and Cosmetic Act. However, illegal dyes—often more harmful than their legal counterparts—are still found in food products. Due to the diversity of dye structures and food matrices, different dye classes often require distinct separation and detection strategies, complicating the analysis and extending processing times. In this work, we developed a method using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) to simultaneously analyze four dye classes. A single extraction method was applied across various food samples to determine the presence of any targeted illegal dyes.