Integration and NMR peak area measurement

Initiation step, 149, 153-154, 221, 246 Initiators of free-radical reactions, 220-221, 245-246, 415 16 Insulin, 1070, 1073-1074, 1080 Integration and NMR peak area measurement, 497... 

The overall blending stability of SMA in the material bulk and the surface grafting stability on material surfaces were examined by leaching tests and evaluated respectively with proton nuclear magnetic resonance spectroscopy [ H-NMR] and quantitative ATR-FT-IR. Firstly, SMA-MSPEO and SPEO with equivalent amounts of PEG components were respectively blended into PEU matrix materials. The initial quantity of PEG was measured and recorded by integrating the PEG-specific I-NMR peak areas at S = 3.52 ppm (- O - CH2 - CH2 - 0 -). The integral values were normalized... 

The area of each fjeak gives the relative number of protons and is produced directly on the spectrum (Fig. 29.6). On CW—NMR spectrometers the height of the peak area integration line must be measured using a ruler, whereas on FT-NMR machines the area is calculated and displayed as a number. You must remember that ... 

Areas under nmr signals are measured by an electronic integrator, and are usually given on the spectrum chart in the form of a stepped curve heights of steps are proportional to peak areas. Nmr chart paper is cross-hatched, and we can conveniently estimate step heights by simply counting squares. We arrive at a set of numbers that are in the same ratio as the numbers of different kinds of protons. We convert this set of numbers into a set of smallest whole numbers just as we did in calculating empirical formulas (Sec. 2.27). The number of protons... 

In the NMR method, a deuterated chloroform solution of the polymer containing trimethylsilane internal standard is run on the proton NMR spectrometer. Integration of peak areas at delta 8 and 1-4 delta, respectively, gives a measure of signal strengths from aliphatic protons (methacrylate units) and aromatic protons (styrene). These areas can be used as a basis for calculating the methacrylate and styrene emit contents of the polymer. 

As you are no doubt aware, integrals are one of the key parameters in the interpretation of proton spectra and are pivotal in quantification. They measure the area under a peak and this is directly proportional to the number of protons (in the case of proton NMR) in that environment. Most software will automatically try to identify the peaks in your spectrum and integrate them for you. If you need to do it yourself, then it is a fairly trivial matter of defining the start and end point of the integrals of interest. The only complication is that you may need to tweak the slope and bias of the integral. This should be unnecessary if you have got the phase and baseline of your spectrum correct. If you find that you need to adjust slope and bias, we suggest that you go back and try to sort out baseline and phase a bit better. 

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