Quantitative nuclear magnetic

A single measurement of a calibration sample can give the concentration of the test solution by a simple ratio. This is often done in techniques where a calibration internal standard can be measured simultaneously (within one spectrum or chromatogram) with the analyte and the system is sufficiently well behaved for the proportionality to be maintained. Examples are in quantitative nuclear magnetic resonance with an internal proton standard added to the test solution, or in isotope dilution mass spectrometry where an isotope standard gives the reference signal. For instrument responses As and /sample for internal standard and sample, respectively, and if the concentration of the internal standard is Cjs, then... 

Al-Deen, T Saed, Hibbert, D B, Hook, J, and Wells, R (2002), Quantitative nuclear magnetic resonance spectrometry II. Purity of phosphorus-based agrochemicals glyphosate (N-(phosphonomethyl)-glycine) and profenofos (0-(4-bromo-2-chlorophenyl) O-ethyl S-propyl phosphorothioate) measured by 1H and 31P QNMR spectrometry. Analytica Chimica Acta, 474 (1-2), 125-35. 

The process of review is continual. I have encouraged the rejection (suitably documented and justified) of insignificant components at any stage. In the spreadsheet example of quantitative nuclear magnetic resonance above,... 

Fig. 9 Composition of organic compounds for a quantitative nuclear magnetic resonance comparison experiment...

Liu SY, Hu CQ, A comparative uncertainty study of the calibration of macrolide antibiotic reference standards using quantitative nuclear magnetic resonance and mass balance methods. Anal. Chim. Acta 2007 602(1) 114-121. 

Another universal response detector that has been used to perform standard-free metabolite-level determination is quantitative nuclear magnetic resonance (NMR) spectroscopy. The concept of quantitation using NMR was established in the 1980s (Mackenzie, 1984). Malz and Jancke (2005) validated the use of... 

The great advantage of the bottom-up approach to measurement uncertainty, even if precision data are to be used extensively, is that the analyst is made to consider the experiment in detail and he or she must understand the analysis and components of vmcertainty. This may provide a useful insight into possible improvements that could be made to lower the combined uncertainty. Influence factors that are estimated to contribute less than, say, 20% to the measurement uncertainty can really be ignored when finding aspects for improvement. The contributions to measurement uncertainty can be displayed on a Pareto chart, which shows the individual components and cumulative effect. An example for a quantitative nuclear magnetic resonance (NMR) study is shown in Figure 4. 

D.C. Apperley, R.K. Harris, T. Larsson, T. Malmstrom, Quantitative nuclear magnetic resonance analysis of solid fotmoterol fumarate and its dihydrate, J. Pharm. Sci. 92 (12) (2003) 2487-2494. 

R594 X.-b. Yu, W.-b. Shen and B.-r. Xiang, Advances in Application of Quantitative Nuclear Magnetic Resonance Technique in Pharmaceutical Field , Yaoxue Jinzhan, 2010, 34, 17. 

R659 N. Sugimoto, How to Determine the Absolute Purities of Target Organic Compounds. Development of Quantitative Nuclear Magnetic Resonance (qNMR) , Nippon Yakurigaku Zasshi, 2011, 137, 232. 

Purity of reference substances determined by quantitative nuclear magnetic resonance (NMR) [21]. 

T. Huang, W. Zhang, C. Quan and H.-m. Li, Review on Quantitative Nuclear Magnetic Resonance, Huaxue Shiji, 2012, 34, 327. 

Instmmental methods of analysis provide information about the specific composition and purity of the amines. QuaUtative information about the identity of the product (functional groups present) and quantitative analysis (amount of various components such as nitrile, amide, acid, and deterruination of unsaturation) can be obtained by infrared analysis. Gas chromatography (gc), with a Hquid phase of either Apiezon grease or Carbowax, and high performance Hquid chromatography (hplc), using siHca columns and solvent systems such as isooctane, methyl tert-huty ether, tetrahydrofuran, and methanol, are used for quantitative analysis of fatty amine mixtures. Nuclear magnetic resonance spectroscopy (nmr), both proton ( H) and carbon-13 ( C), which can be used for quaHtative and quantitative analysis, is an important method used to analyze fatty amines (8,81). 

As with other diffraction techniques (X-ray and electron), neutron diffraction is a nondestructive technique that can be used to determine the positions of atoms in crystalline materials. Other uses are phase identification and quantitation, residual stress measurements, and average particle-size estimations for crystalline materials. Since neutrons possess a magnetic moment, neutron diffraction is sensitive to the ordering of magnetically active atoms. It differs from many site-specific analyses, such as nuclear magnetic resonance, vibrational, and X-ray absorption spectroscopies, in that neutron diffraction provides detailed structural information averaged over thousands of A. It will be seen that the major differences between neutron diffraction and other diffiaction techniques, namely the extraordinarily... 

Some preliminary laboratory work is in order, if the information is not otherwise known. First, we ask what the time scale of the reaction is surely our approach will be different if the reaction reaches completion in 10 ms, 10 s, 10 min, or 10 h. Then, one must consider what quantitative analytical techniques can be used to monitor it progress. Sometimes individual samples, either withdrawn aliquots or individual ampoules, are taken. More often a nondestructive analysis is performed, the progress of the reaction being monitored continuously or intermittently by a technique such as ultraviolet-visible spectrophotometry or nuclear magnetic resonance. The fact that both reactants and products might contribute to the instrument reading will not prove to be a problem, as explained in the next chapter. 

In this review recent theoretical developments which enable quantitative measures of molecular orientation in polymers to be obtained from infra-red and Raman spectroscopy and nuclear magnetic resonance have been discussed in some detail. Although this is clearly a subject of some complexity, it has been possible to show that the systematic application of these techniques to polyethylene terephthalate and polytetramethylene terephthalate can provide unique information of considerable value. This information can be used on the one hand to gain an understanding of the mechanisms of deformation, and on the other to provide a structural understanding of physical properties, especially mechanical properties. 

Nuclear magnetic resonance (NMR) spectrometry has seldom been used as a quantitative analytical method but can have some practical importance in the characterization of surfactants [296-298]. 13C-NMR spectrometry has been used for the qualitative and also quantitative analysis of dodecyl, tetradecyl, and cetyl sulfates [299]. H- and, 3C-NMR spectra of sodium dodecyl sulfate are given by Mazumdar [300]. 

Many techniques for the analysis of anthocyanins have been used for almost a century and are still of importance, along with considerable advances in technologies such as mass spectroscopy (MS) and nuclear magnetic resonance (NMR). This section summarizes the analytical procedures for quantitative and qualitative analyses of anthocyanins, including classical and modem techniques. 

Perhaps the most revolutionary development has been the application of on-line mass spectroscopic detection for compositional analysis. Polymer composition can be inferred from column retention time or from viscometric and other indirect detection methods, but mass spectroscopy has reduced much of the ambiguity associated with that process. Quantitation of end groups and of co-polymer composition can now be accomplished directly through mass spectroscopy. Mass spectroscopy is particularly well suited as an on-line GPC technique, since common GPC solvents interfere with other on-line detectors, including UV-VIS absorbance, nuclear magnetic resonance and infrared spectroscopic detectors. By contrast, common GPC solvents are readily adaptable to mass spectroscopic interfaces. No detection technique offers a combination of universality of analyte detection, specificity of information, and ease of use comparable to that of mass spectroscopy. 

R.J. Lehnert, P.J. Hendra, N. Everall and N.J. Clayden, Comparative quantitative study on the crystallinity of poly(tetrafluoroethylene) including Raman, infra-red and F nuclear magnetic resonance spectroscopy, Polymer, 38(7) (1997) 1521-1535. 

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