Interactions between natural organic matter and organic pollutants as revealed by NMR spectroscopy

Abstract

Natural organic matter (NOM) plays a critical role in regulating the transport and the fate of organic contaminants in the environment. NMR spectroscopy is a powerful technique for the investigation of the sorption and binding mechanisms between NOM and pollutants, as well as their mutual chemical transformations. Despite NMR relatively low sensibility but due to its wide versatility to investigating samples in the liquid, gel, and solid phases, NMR application to environmental NOM-pollutants relations enables the achievement of specific and complementary molecular information. This report is a brief outline of the potentialities of the different NMR techniques and pulse sequences to elucidate the interactions between NOM and organic pollutants, with and without their labeling with nuclei that enhance NMR sensitivity.

Statement on the FERA guidance proposal: ‘Guidance on how aged sorption studies for pesticides should be conducted, analysed and used in regulatory assessments’ (FERA, 2012)

“…In general, pesticides or metabolites supporting free reactive chemical groups, such as aniline or phenol, have a tendency to give a larger proportion of NERs (Helling, 1975;Katan and Liechtenstein, 1977;Bollag et al, 1980;Talebi and Walker, 1993). The degradation of pesticides presenting metabolites with hydroxyl or amine groups leads to an increase in the formation of NERs because of an increased affinity to the amphiphilic humic molecules (Bollag et al, 1980;Mazzei and Piccolo, 2015).…”

HRMAS NMR spectroscopy applications in agriculture

“…Following the pulse interaction between the applied electromagnetic radiation and the dipolar moments of the nuclei subjected to the static field, the resonance energy is relaxed producing a free induction decay that contains detailed information about the structure, dynamics, reaction state, and chemical environment of the target molecular material [1,2]. The combination of phase-and length-modulated pulses specific of the selected NMR pulse sequences enables a controlled manipulation of nuclear spins that ultimately provides structural and dynamical information and reveals through-bonding or through-space correlations among nuclei, in either mono-or multidimensional systems [3].…”

Water-mediated NOE: a promising tool for interrogating interfacial clay–xenobiotic interactions

“…1 [14,20,[25][26][27][28]. For a complete review of NMR techniques and applications to understand interactions in environmental samples, readers should refer to an excellent review by Mazzei and Piccolo [28].…”

“…1 [14,20,[25][26][27][28]. For a complete review of NMR techniques and applications to understand interactions in environmental samples, readers should refer to an excellent review by Mazzei and Piccolo [28]. In environmental research, NMR is becoming an important tool used to highlight specific interactions between different constituents in soils [21,[29][30][31][32].…”

“…Recently, a novel NMR technology was introduced, termed as comprehensive multiphase (CMP) NMR [38]. This approach combines hardware from solution, gel, and solid-state NMR into a single probe and permits environmental samples to be investigated in situ, in their fully hydrated state, and in all phases, allowing for all phases to be simultaneously investigated [28,[35][36][37][38]. A number of NMR techniques can be used to investigate interactions between organic soil constituents [31,36,39].…”