Peak height measurement

The peak width (w) is the distance between each side of a peak measured at 0.6065 of the peak height. The peak width measured at this height is equivalent to two standard deviations (2o) of the Gaussian curve and, thus, has significance when... 

The peak measured for a plate number determination contains additional information about the packing quality of a column. The same peak may also be used to quantify information about the shape as well. The peak width on both sides of the perpendicular through the peak maximum is measured at a height of 10% of the maximum height (see Fig. 14.2). The quotient of the back by the front part of the peak is defined as the asymmetry factor (AF) ... 

It is seen that there is not a great difference between the use of peak heights or peak areas for quantitative analysis, except possibly for very early peaks, where the results seem to indicate that peak height measurements might be more precise. However, it again must be emphasized that the measurements made by Scott and Reese were overall precision measurements that will include all variations in the chromatographic system. The difference between the two methods of measurement may well be significant, but the absolute values for precision will not, by any means, be solely dependent on the method of peak measurement. 

Therefore, the total height (peak to peak) of the capacitor current waveform (measured to the center of the ramp) is still 1A, which is also the case for the switch waveform from which it is derived. 

B. Use of Peak Intensity (Peak Height) for Measuring the Degree... 

Plotting the peak potentials as a function of the logarithm of the scan rate allows one to determine the transfer coefficient from the slope of the resulting straight fine in the total irreversibility region. Another possibility for determining a is to measure the half-height peak widths ... 

Once a DISP mechanism has been recognized, the procedures for determining the rate constant of the follow-up reaction and the standard potential of the A/B couple from peak current and/or peak potential measurements are along the same lines as the procedures described above for the ECE mechanism. A distinction between the ECE and DISP mechanisms cannot be made when the pure kinetic conditions are achieved since the peak height, peak width, and variations of the peak potential with the scan rate and rate constant are the same, and so is its independence vis-a-vis the concentration of substrate. The only difference is then the absolute location of the peak, which cannot be checked, however, unless the standard potential of the A/B couple and the follow-up rate constant are known a priori. 

For external standardization, replicate standards of known concentration of the pure substance are injected and the height of the resulting peaks measured. The sample is then injected and the peak height compared with those of the standards to calculate the concentration of the test. In using this technique, replicate injections of both the standards and the test must be made. 

To get a measure of the transfer, the ratio of the acceptor to donor peak heights was measured for several particles at each of several acceptor concentrations. Figure 8.26 shows the experimental results for the two donor-acceptor pairs, C1/R6G and 9AA/R6G. The data were corrected for a small... 

The chromatogram of the sample for which A /A V) — 9/14 (heights of the peaks measured from the original chromatogram), leads to... 

Bromate near its detection limit gave the following chromatographic peak heights and standard deviations. The blank is 0 because chromatographic peak height is measured from the baseline adjacent to the peak. For each concentration, estimate the detection limit. Find the mean detection limit. 

Figure 5.1 shows a portion of a chromatogram. Three parameters are illustrated, the peak width, W, the noise, N, and the peak height, S. Peak height is measured in any convenient units from the base of the peak to its maximum. The width of the peak (in seconds) is defined in various ways (a) the peak width at half the height (illustrated), (b) the base of the triangle which most closely matches the shape of the peak, (c) a multiple of the variance, or second moment, of the peak shape, (d) the ratio (in consistent units) 2A/S where A is the area of the peak. The first method is used here because it is the easiest to measure. 

CALCULATION OF RESULTS. Peak heights are measured in millimeters and the following equation is used to calculate the amount of cholesterol in the unknown ... 

First, peak heights are measured at five points in the NMR spectra (Figure 2). All NMR spectra of fulvic acids described in this study were determined as the sodium salt in D20 at pH 8 (21). Peak heights were used rather than peak areas to minimize overlapping spectral contributions from various proton structures. From structural-model considerations, peak 1 appears to be a combination of methylene and methine protons in aliphatic alicyclic rings and branched methyl groups located beta to carbonyl groups of a carboxylic acid, ester, or ketone. The structural model rules out meth-... 

Peak heights were measured at points noted in Figure 2. 

Method C makes use of a so called dispersion analyzer, which is a particular form of stylus type surface roughness meter. The principle is that the worse the dispersion the rougher the surface. A dispersion index is obtained from the number of peaks/cm and average height of peaks measured, plus material constants obtained by method B. The object appears to be to use the analyzer as a convenient routine control method after the compound has been evaluated by the more tedious method B. 

A. Peak Height Peak height is measured from the baseline to the peak apex, as shown in Figure 7.7. When the baseline is unstable, a baseline must be interpolated from the start of the peak to its end. Peak heights should not be used for distorted peaks or shoulders. 

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