Chromatographic analysis response function

It has also proven advantageous to use a combination of individual responses in order to optimize as many parameters as possible (39-43). The two performance goals for a separation of bisphenols by MEKC were good resolution among five peaks and short total analysis time (42). Thus, a chromatographic response function (CRF) was employed that was a product of two types of desirability functions, as used by Divjak et al. (30-33, 44). Resolution (R) between two adjacent peaks in an electropherogram was calculated using... 

As indicated in the previous sections, the antioxidant content in plastic material is often determined by chromatographic methods. Another widely used technique for polymer characterization is thermal analysis with differential scanning calorimetry (DSC). When the oxygen induction time (OIT) for a sample containing a phenoHc antioxidant is measured, a significant oxidative exothermic response is obtained in the DSC when all the phenolic antioxidant in a sample is consumed. The OIT is thus directly related to the antioxidant content in the material and to the stabihzing function, i.e. the antioxidant efficiency in the sample, if the consumption of phenolic antioxidants obeys zero-order kinetics at the temperature used [44]. Table 1 shows the amount of the antioxidant Irganox 1081 in polyethylene (PE) determined by HPLC and extraction by microwave assisted extraction (MAE),... 

The radioactivity detector has an obvious application in metabolic studies. Unfortunately it is necessary when using this detector to trade resolution and speed for sensitivity. The response of the radioactivity detector is a function of the total amount of radioactivity in the detector cell, which means that the detector cell should be as large as possible. On the other hand a large cell volume will cause dispersion of the chromatographic peaks, and a compromise must therefore be found. The response is also a function of the residence time of the solute in the cell, calling for slow pumping velocity of the mobile phase, thus giving increased time of analysis. 

It is also possible to perform GLC on the trimethyl-silyl ethers of the sterols. In that case, the residue is gently heated with a mixture of dimethylformamide, hexamethylsilazane and trimethylchlorosilane to prepare the trimethylsilyl ethers. The gas chromatographic method described provides a qualitative analysis of sterols in oils and fats. However, it can be employed for quantitative analysis within certain limitations (a) the response of each sterol is a function of the type of detector used (b) an accurate quantitative interpretation of the chromatogram... 

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