High-resolution mass spectrometry (HRMS) has emerged as a powerful analytical tool in for investigating fate and transport of organic contaminants in complex mixtures.  Recent advances in instrumentation have allowed for new approaches in trace organic analysis, including non-target contaminant screening, transformation product identification, retrospective sample analysis, and increased certainty in the identification and quantitation of legacy and emerging contaminants.  The high mass accuracy and exceptional tolerance for sample complexity inherent to HRMS instruments allows measurement of ultra trace (ppq-ppt) levels of polar organic pollutants by incorporating high performance liquid chromatography (HPLC) and electrospray ionization (ESI). However, HPLC-ESI-MS analysis of complex environmental samples such as wastewater often suffers from matrix-related signal suppression and poor chromatographic resolution of target analytes from background contaminants. To address these limitations while maximizing the performance of the LTQ-Orbitrap HRMS/MS instrumentation, we have developed a comprehensive two-dimensional liquid chromatography (2D-LC) method for the HRMS analyses of emerging contaminants in highly complex environmental samples. This method was optimized and implemented for the analysis of both target (e.g xenoestrogens, surfactants, pesticides, herbicides, and fungicides) and non-target anthropogenic contaminants in wastewater and surface water. We have used two distinct configurations for these analyses.  First, we have explored the coupling of hydrophilic interaction (HILIC) in the first dimension with rapid reversed-phase UHPLC in the second dimension in order to achieve highly orthogonal separations of nonionic surfactants such as alkylphenol and alcohol ethoxylates.  Second, we coupled high performance size exclusion chromatography (SEC) to reversed-phase UHPLC for enhanced matrix removal in analysis of emerging contaminants in surface water.  Our results indicate that the chromatographic resolution achieved by 2D-LC coupled with the high performance capabilities of the Orbitrap HRMS (R>100,000, mass error <2ppm) provides a new, unique, and powerful tool for the monitoring of target and non-target analytes in highly complex samples.

Comprehensive 2D liquid chromatography coupled with high-resolution mass spectrometry: Application to analysis of polar organic contaminants in the aquatic environment

248th National Meeting (2014)

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