Chromatograms resolution

Testing the Chromatogram Resolution Procedure. Known Distribution Chromatograms. Several chromatograms of known distribution were prepared by selectively blending some of the PS fractions (Table II). These chromatograms were used to test the resolution procedure. 

Resolution a measure of the separation of two adjacent peaks (A and B), in the chromatogram. Resolution may be assessed by the valley between the peaks hy or by peak width Wb in quantitative analyses a baseline separation should be obtained. The separation of overlapping peaks may be measured as follows ... 

The general elution problem in chromatography. Improving the resolution of the overlapping bands in chromatogram (a) results in a longer analysis time for chromatogram (b). 

Using the partial chromatogram shown here, determine the resolution between the two solute bands. 

The chromatogram in Problem 4 was obtained on a 2-m column with a column dead time of 50 s. How long a column is needed to achieve a resolution of 1.5 What height of a theoretical plate is needed to achieve a resolution of 1.5 without increasing the length of the column ... 

A single peak from an ordinary gas chromatogram (a) is revealed as two closely separated peaks by resolution enhancement (b). 

Gel filtration is very suitable for the purity check of protein preparations, especially if these have been purified by adsorptive techniques. It can be expected that high-resolution gel filtration columns will easily separate dimeric forms from monomeric forms to reveal heterogeneities of the preparations. However, a size difference of less than 20% will not result in total resolution of the peaks (although the chromatogram may be used for a qualitative judgment of the... 

Figure 6.5 shows a chromatogram of Epikote 1004 using the KE-600 series and SYSTEM-24H (a newly developed GPC system used with the KF-600 series for full utilization of the efficiency of the downsized columns). Compared with conventional-sized columns such as the KF-800 series, the time of analysis is shortened to one-half and the chromatographie resolution is improved. 

FIGURE 11.4 Comparison of chromatograms obtained on conventional (A) and solvent-efficient Styragel columns (B). In each case the column bank was a bank of Styragel HR 0.5, HR I, HR 2, and HR 3 columns at 3S°C with THF as the solvent. The sample is a mixture of polystyrene standards. With proper care and optimized instrumentation, good resolution can be obtained with solvent-efficient Styragel columns. (Courtesy of Waters Corp.)... 

Figure 16.15 shows the resulting chromatograms for the three glucan fractions obtained by previous preparative separation on Sephacryl S-200/S-1000 (Fig. 16.14). From the normalized fraction chromatograms, the elution profile of the initial mixture has been reconstructed by mixing 50% fraction 1, 40% fraction 2, and 10% fraction 3. Compared to the chromatogram of the preparative Sephacryl S-200/S-1000 system, separation with the TSK/ Superose system yields improved resolution in the low dp (high V, ) domain.

Comparison of the separation efficiency between two columns in the same mobile phase or one column in two mobile phases is based on the extent of resolution of the peaks of the PEO standards in the respective chromatograms of the PEO A, B, and C group. Due to the limitation of space, only the TSK PEO A chromatograms for the four columns in water and water/methanol are... 

The above theoretical analysis of the total number of resolvable components in a complex mixture has shown that in LC, relative to the maximum peak content or peak capacity for closely spaced peaks, a random chromatogram will never contain more than about 37% of its potential peaks and furthermore that only 18% of such components will emerge as single-component peaks having a minimum specified resolution with respect to the neighbouring peaks. 

Figure 10.3 Gas cliromatograms of a cold-pressed lemon oil obtained (a) with an SE-52 column in the stand-by position and (b) with the same column showing the five heart-cuts (c) shows the GC-GC chiral chromatogram of the ti ansfeired components. The asterisks in (b) indicate electric spikes coming from the valve switcliing. The conditions were as follows SE-52 pre-column, 30 m, 0.32 mm i.d., 0.40 - 0.45 p.m film tliickness cairier gas He, 90 KPa (stand-by position) and 170 KPa (cut position) oven temperature, 45 °C (6 min)-240 °C at 2 °C/min diethyl-tert-butyl-/3-cyclodextrin column, 25 m X 0.25 mm i.d., 0.25 p.m film thickness cairier gas He, 110 KPa (stand-by position) and 5 KPa (cut position) oven temperature, 45 °C (6 min), rising to 90 °C (10 min) at 2 °C/min, and then to 230 °C at 2 °C/min. Reprinted from Journal of High Resolution Chromatography, 22, L. Mondello et al, Multidimensional capillary GC-GC for the analysis of real complex samples. Part IV. Enantiomeric distribution of monoterpene hydrocarbons and monoterpene alcohols of lemon oils , pp. 350-356, 1999, with permission from Wiley-VCH.

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