title: Comprehensive multiphase NMR spectroscopy: basic experimental approaches to differentiate phases in heterogeneous samples.
abstract: Heterogeneous samples, such as soils, sediments, plants, tissues, foods and organisms, often contain liquid-, gel- and solid-like phases and it is the synergism between these phases that determine their environmental and biological properties. Studying each phase separately can perturb the sample, removing important structural information such as chemical interactions at the gel-solid interface, kinetics across boundaries and conformation in the natural state. In order to overcome these limitations a Comprehensive Multiphase-Nuclear Magnetic Resonance (CMP-NMR) probe has been developed, and is introduced here, that permits all bonds in all phases to be studied and differentiated in whole unaltered natural samples. The CMP-NMR probe is built with high power circuitry, Magic Angle Spinning (MAS), is fitted with a lock channel, pulse field gradients, and is fully susceptibility matched. Consequently, this novel NMR probe has to cover all HR-MAS aspects without compromising power handling to permit the full range of solution-, gel- and solid-state experiments available today. Using this technology, both structures and interactions can be studied independently in each phase as well as transfer/interactions between phases within a heterogeneous sample. This paper outlines some basic experimental approaches using a model heterogeneous multiphase sample containing liquid-, gel- and solid-like components in water, yielding separate (1)H and (13)C spectra for the different phases. In addition, (19)F performance is also addressed. To illustrate the capability of (19)F NMR soil samples, containing two different contaminants, are used, demonstrating a preliminary, but real-world application of this technology. This novel NMR approach possesses a great potential for the in situ study of natural samples in their native state.
authors.affiliation: Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, ON, Canada M1C 1A4.
authors.forename: Denis
authors.initials: D
authors.lastname: Courtier-Murias
authors.forename: Hashim
authors.initials: H
authors.lastname: Farooq
authors.forename: Hussain
authors.initials: H
authors.lastname: Masoom
authors.forename: Adolfo
authors.initials: A
authors.lastname: Botana
authors.forename: Ronald
authors.initials: R
authors.lastname: Soong
authors.forename: James G
authors.initials: JG
authors.lastname: Longstaffe
authors.forename: Myrna J
authors.initials: MJ
authors.lastname: Simpson
authors.forename: Werner E
authors.initials: WE
authors.lastname: Maas
authors.forename: Michael
authors.initials: M
authors.lastname: Fey
authors.forename: Brian
authors.initials: B
authors.lastname: Andrew
authors.forename: Jochem
authors.initials: J
authors.lastname: Struppe
authors.forename: Howard
authors.initials: H
authors.lastname: Hutchins
authors.forename: Sridevi
authors.initials: S
authors.lastname: Krishnamurthy
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kumar
authors.forename: Martine
authors.initials: M
authors.lastname: Monette
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Stronks
authors.forename: Alan
authors.initials: A
authors.lastname: Hume
authors.forename: André J
authors.initials: AJ
authors.lastname: Simpson
mesh_terms: D045424:Complex Mixtures / Q000032:analysis* / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods*; D044367:Phase Transition; D013048:Specimen Handling / Q000295:instrumentation* / Q000379:methods*
chemical_list: D045424:Complex Mixtures