Peak Separation height

In our early evaluations, three parameters were utilized for the resolving power of the columns (3,4,7). These were the valley-to-peak height ratio, v, the peak separation parameter, P, and the parameter mentioned earlier, Djcr. The valley-to-peak height ratio is defined as... 

The peak-shaped response of differential-pulse measurements results in unproved resolution between two species with similar redox potentials, hi various situations, peaks separated by 50 mV may be measured. Such quantitation depends not only upon the corresponding peak potentials but also on the widths of the peak. The width of the peak (at half-height) is related to the electron stoichiometry ... 

Attempts to do this indicated that differences on the order of 30% of the peak separation shown in Figure 16 were probably due to such effects. At other sampling points, better and worse results were observed likely because the tail heights of distributions were being sampled. 

As shown in Figure 31c, when Ei = E, one obtains a single catho-anodic peak-system, the peak height of which is twice that of a one-electron process and the peak-to-peak separation (A p) is equal to 42 mV. 

An external standard method is used when the standard is analyzed on a separate chromatogram from the sample. Quantitation is based on a comparison of the peak area/height (HPLC or GC) of the sample to that of the reference standard for the analyte of interest. The external standard method is more appropriate for samples with a single target analyte and narrow concentration range, where there is a simple sampling procedure, and for the analysis of hydrocarbon fractions. The calculation requires an accurate extract final volume and constant injection size. The peak area of an analyte is compared with that from a standard or standard curve and corrected for volume ... 

In addition, even if manual measurements are employed, a separation of 6a is far more than necessary for accurate quantitative analysis. In fact, accurate quantitative results can be obtained with a separation of only 4a and it will be shown later that if peak heights are employed for quantitative measurement, then even less resolution may be tolerated. Duplicate measurements of peak area or peak height on peaks separated by 4a should not differ by more than 2%. If the chromatographic data is acquired and processed by a computer, then with modern software, even a separation of 4a could be more than necessary. Poor resolution can often be accommodated by deconvoluting the peak and measuring the peak heights or areas of the deconvoluted peaks. 

Two solutes will be resolved if their peaks are moved apart in the column and maintained sufficiently narrow to permit them to be eluted as discrete peaks. Resolution is usually defined as the ratio of the distance between the peaks to the peak width at the points of inflection. It is generally accepted that a separation of 4a is adequate for accurate quantitative analysis, particularly when employing peak heights measurements. It is, therefore, necessary to derive an expression for the peak width in order to equate to the peak separation. 

Resolution. A variation on calculating the required column height is to calculate the resolution or degree of separation of two components. Resolution is the ratio of peak separation to average peak width ... 

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