An automated methodology for non-targeted compositional analysis of small molecules in high complexity environmental matrices using coupled ultra-performance liquid chromatography Orbitrap mass spectrometry

Abstract

The life-critical matrices of air and water are among the most complex chemical mixtures that are ever encountered. Ultra-high resolution mass spectrometers, such as the Orbitrap, provide unprecedented analytical capabilities to probe the molecular composition of such matrices, but the extraction of non-targeted chemical information is impractical to perform via manual data processing. Automated non-targeted tools rapidly extract the chemical information of all detected compounds within a sample dataset. However, these methods have not been exploited in the environmental sciences. Here, we provide an automated and (for the first time) rigorously tested methodology for the non-targeted compositional analysis of environmental matrices using coupled liquid chromatography-mass spectrometric data. First, the robustness and reproducibility was tested using authentic standards, evaluating performance as a function of concentration, ionization potential and sample complexity. The method was then used for the compositional analysis of particulate matter and surface waters collected from world-wide locations. The method detected >9,600 compounds in the individual environmental samples, arising from critical pollutant sources, including carcinogenic industrial chemicals, pesticides, pharmaceuticals, among others. This methodology offers considerable advances in the environmental sciences, providing a more complete assessment of sample compositions, whilst significantly increasing throughput.