Comprehensive Non-Targeted Analysis of Contaminated Groundwater of a Former Ammunition Destruction Site using 1H-NMR and HPLC-SPE-NMR/TOF-MS

Abstract

The aim of the present study was to explore the capabilities of the combination of 1H NMR (proton nuclear magnetic resonance) mixture analysis and HPLC-SPE-NMR/TOF-MS (high-performance liquid chromatography coupled to solid-phase extraction and nuclear magnetic resonance and time-of-flight mass spectrometry) for the characterization of xenobiotic contaminants in groundwater samples. As an example, solid-phase extracts of two groundwater samples taken from a former ammunition destruction site in Switzerland were investigated. 1H NMR spectra of postcolumn SPE enriched compounds, together with accurate mass measurements, allowed the structural elucidation of unknowns. This untargeted approach allowed us to identify expected residues of explosives such as 2,4,6-trinitrotoluene (2,4,6-TNT), Hexogen (RDX) and Octogen (HMX), degradation products of TNT (1,3,5-trinitrobenzene (1,3,5-TNB), 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT), 3,5-dinitrophenol (3,5-DNP), 3,5-dinitroaniline (3,5-DNA), 2,6-dinitroanthranite, and 2-Hydroxy-4,6-dinitrobenzonitrile), benzoic acid, Bisphenol A (a known endocrine disruptor compound), and some toxicologically relevant additives for propelling charges: Centralite I (1,3-diethyl-1,3-diphenylurea), DPU (N,N-diphenylurethane), N,N-diphenylcarbamate (Acardite II), and N-methyl-N-phenylurethane. To our knowledge, this is the first report of the presence of these additives in environmental samples. Extraction recoveries for Centralite I and DPU have been determined. Contaminants identified by our techniques were quantified based on HPLC-UV (HPLC-ultraviolet detection) and 1H NMR mixture analysis. The concentrations of the contaminants ranged between 0.1 and 48 microg/L assuming 100% recovery for the SPE step.

Determination of Band Structure Parameters and the Quasi‐Particle Gap of CdSe Quantum Dots by Cyclic Voltammetry

“…Rapid detection and screening of RDX explosives in the environment represent a significant challenge because current analytical techniques involve lengthy laboratory preparations and the use of expensive instrumentation (e.g. EPA Method 8330) 45, 46. Moreover, groundwater can contain organic impurities which can interfere with the detection and identification of explosives such as RDX, since the EPA method relies on HPLC with analyte detection via retention time only, which is potentially susceptible to false positives.…”

A new analytical approach for the comprehensive characterization of polar xenobiotic organic compounds downgradient of old municipal solid waste (MSW) landfills

“…Therefore, in many cases, the unknown XOCs must be isolated by HPLC fractionation and enriched off-line or on-line [24] to allow the use of 2D NMR methods which are the most efficient tools for the structural elucidation.…”

Contaminants in water: non-target UHPLC/MS analysis

“…As a fast evaluation tool for possible candidates, HRMS is ideal when it is subsequently combined with a powerful structure elucidation technique like nuclear magnetic resonance (NMR) (Godejohann et al 2009), although this requires sufficiently high concentrations and often the isolation of the unknown compound.…”