Publications by authors named "Ronald V Emmons"

Matrix effects can significantly impede the accuracy, sensitivity, and reliability of separation techniques presenting a formidable challenge to the analytical process. It is crucial to address matrix effects to achieve accurate and precise measurements in complex matrices. The multifaceted nature of matrix effects which can be influenced by factors such as target analyte, sample preparation protocol, composition, and choice of instrument necessitates a pragmatic approach when analyzing complex matrices.

View Article and Find Full Text PDF

Per- and polyfluoroalkyl substances (PFAS), an emerging class of toxic anthropogenic chemicals persistent in the environment, are currently regulated at the low part-per-trillion level worldwide in drinking water. Quantification and screening of these compounds currently rely primarily on liquid chromatography hyphenated to mass spectrometry (LC-MS). The growing need for quicker and more robust analysis in routine monitoring has been, in many ways, spearheaded by the advent of direct ambient mass spectrometry (AMS) technologies.

View Article and Find Full Text PDF

Effective quantitative analysis of BMAA (β-N-methylamino-L-alanine) and its isomers without the need for derivatization has always been an analytical challenge due to their poor retention and separation on various liquid chromatography stationary phases. Previous studies that utilized conventional hydrophilic interaction chromatography (HILIC) demonstrate false negatives compared to reverse-phase workflows with derivatization. This work evaluates the chromatographic behavior of BMAA and its isomers, in their underivatized forms, on selected stationary phases, in particular fluorophenyl-based columns, to attain effective retention and separation.

View Article and Find Full Text PDF

Produced water (PW), a waste byproduct of oil and gas extraction, is a complex mixture containing numerous organic solubles and elemental species; these constituents range from polycyclic aromatic hydrocarbons to naturally occurring radioactive materials. Identification of these compounds is critical in developing reuse and disposal protocols to minimize environmental contamination and health risks. In this study, versatile extraction methodologies were investigated for the untargeted analysis of PW.

View Article and Find Full Text PDF

Per- and polyfluoroalkyl substances (PFAS) are toxic and bioaccumulative compounds that are persistent in the environment due to their water and heat resistant properties. These compounds have been demonstrated to be ubiquitous in the environment, being found in water, soil, air and various biological matrices. The determination of PFAS at ultra-trace levels is thus critical to assess the extent of contamination in a particular matrix.

View Article and Find Full Text PDF

The rapid and quantitative analysis of anthropogenic contaminants in environmental matrices is crucial for regulatory testing and to elucidate the environmental fate of these pollutants. Direct ambient mass spectrometry (AMS) methodologies greatly increase sample throughput, can be adapted for onsite analysis and are often regarded as semi-quantitative by most developed protocols. One of the limitations of AMS, especially for on site analysis applications, is the irreproducibility of the measurements related to the occurrence of transient microenvironments (TME) and variable background interferences.

View Article and Find Full Text PDF

The continued rise in the extraction of unconventional oil and gas across the globe poses many questions about how to manage these relatively new waste-streams. Produced water, the primary waste by-product, contains a diverse number of anthropogenic additives together with the numerous hydrocarbons extracted from the well. Due to potential environmental hazards, it is critical to characterize the chemical composition of this type of waste before proper disposal or remediation/reuse.

View Article and Find Full Text PDF