Low-resolution NMR

V.M. Litvinov and P.A.M. Steeman, EPDM-Carbon black interactions and the reinforcement mechanisms, as studied by low resolution NMR, Macromolecules, 32(25), 8476-8490, 1999. 

Low Resolution Nuclear Magnetic Resonance (LR-NMR) systems are routinely used for food quality assurance in laboratory settings [25]. NMR based techniques are standardized and approved by the American Oil Chemist s Society (AOCS) (AOCSd 16b-93, AOCS AK 4-95), the International Union of Pure and Applied Chemistry (IUPAC) (solid fat content, IUPAC Norm 2.150) and the International Standards Organization (ISO) (oil seeds, ISO Dis/10565, ISO CD 10632). In addition to these standardized tests, low resolution NMR is used to measure moisture content, oil content and the state (solid or liquid) of fats in food. Table 4.7.1 summarizes common food products that are analyzed by low-resolution NMR for component concentration. 

Fig. 4.7.5 Si mulated proton signal decay from a low resolution NMR measurement ofthe solid/liquid ratio from an oil with 20% solid and 80% liquid (%-w/w).

In food chemistry, the water distribution and its interaction with polymeric structures plays a fundamental role as it determines important food quality parameters. low resolution NMR proved to be an... 

TD-NMR sampling is decidedly more difficult than HR-NMR because on-line applications of low-resolution NMR have tended to focus on solid materials such as tablets, polymers, toothpaste, cellulose, foodstuffs. 

R. Garner and P. Mayo, Online prediction of mechanical properties in PP using a low resolution NMR, available www.progression-systems.eom/pdfs/PP0905.pdf accessed 19 November 2009. 

A lot depends upon the development of the many potential application fields. Though, from the chemical point of view, FFC is still a low-resolution NMR technique, it has already proved itself as an excellent research-tool in many application areas such as the study of contrast agents (134-141), dynamics of prosteins (142-153), polymers (154-162) and liquid crystals (163-168), dynamics of water in rocks and cements (169-176), etc. 

A1.3 Application of Low-Resolution NMR for Simultaneous Moisture and Oil Determination in Food (Oilseeds)... 

Basic principles of low-resolution NMR with an emphasis on the minispec for oil and moisture determinations. 

Solid Fat Content (SFC) by Low Resolution NMR (wide-line or pulse)... 

Low resolution NMR spectrometer has been applied to determination of oil and moisture in oilseeds [79], water content in food [80], and "unfrozen" water content during freezing[81,82]. 

Quality control and analysis in the agro-food industry by the low resolution NMR was reviewed by D. N. Rutledge [83], in which NMR method is described as faster, more precise, simpler and cheaper technique than those traditionally used. For on-line monitoring of wine fermentation, EtOH and sugar alcohol beverage and fermenting musts were determined to a precision of 0.005-0.1% for EtOH and 4 8g/L for sugar by low resolution NMR [84]. 

The pulsed field gradient NMR technique can be readily used for the determination of the water droplet size distribution in W/O emulsions or the oil droplet size distributions in O/W emulsions. Important advantages are the non-invasive nature, the ease of sample preparation, and the feet that pulsed field gradient NMR measures the droplet size distribution of the bulk in contrast with microscopic methods which estimate the size distribution of the surface. Both the proposed matrix method and the iterative curve fitting procedure can be successfully applied in a factory environment. The method can be implemented on a high as well as on a low resolution NMR spectrometer. 

Milgrom LR, King KR, Lee J, Pinkus AS, 2001. On the investigation of homeopathic potencies using low resolution NMR T2 relaxation times An experimental and critical survey of the work of... 

The most comprehensive information on the phase structure and molecular mobility in polymer materials can be gained with high-resolution NMR techniques [17, 18, 30, 31, 34]. Low-resolution NMR techniques may offer some advantages in the following cases ... 

Workers in the United States have been slow to make the switch from dilatometry to pNMR (Shukla, 1995). However, the AOCS has published two standard methods for determining SFC by, respectively, pNMR and low-resolution NMR (AOCS Official Methods Cd 16-81 and Cd 16b 93, Firestone, 1998). 

We are left with a paradox. To get an acceptable signal, we need to have as many nuclei as possible in the sample region (remember the minute difference between spin state populations ). But we must restrict our sample to the smallest possible volume in the interest of precision and resolution. The eventual compromise results in a sample cavity of 0.05 cm3 for instruments that accommodate narrow-bore (5-mm-o.d.) tubes to -1.0 cm3 for instruments using wide-bore (10-20-mm-o.d.) tubes. [However, for medical use, some low-resolution NMR instruments have been constructed that accommodate entire human bodies (See Chapter 16)] Typically, H and l3C spectra require ca. 5 and 15 mg of sample, respectively. 

The first thing you should do is check out the low resolution NMR spectrum of etha-... 

The IR spectra of all four crystal modifications were reported by Cady and Smith (1962) and by Holston (1962). The latter did point out some distinguishing features among the polymorphs, but Cady and Smith noted that problems with sample preparation and conversions among forms indicated that the optical properties described by McCrone (1950a) were the basis for the best rapid qualitative and even rough quantitative analysis. Raman spectroscopy, which requires less potentially destructive sample preparation, has been used to distinguish the polymorphs (Goetz and Brill 1979). The low resolution NMR spectra of the four crystal modifications were reported by Landers et al. (1985). The nuclear quadrupole resonance spectrum... 

A low resolution NMR spectrum22 of vinblastine sulfate is reproduced in Figure 3 NMR has played an important part in the structure determinations of the Vinca alkaloids. Several review articles29 3°>3 - summarize the use of NMR in the structure elucidation of VLB. 

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