Response Factor In HPLC Analysis
The High Performance Liquid Chromatography (HPLC) is a very important technique employed in analytic chemistry and is used to separate a mixture component, identify and quantify each of the components found in the mixture. The ratio between the concentration of a compound being analysed to the response of the detector to that compound is what is commonly referred as the response factor. This is because each component is known to interact quite differently with the adsorbent material hence resulting to a varied flow rates of these components hence facilitating the separation of the said components of a mixture. This technique has hence found immense use in medical units as well as in manufacturing plants for various uses.
The response factor is obtained by dividing the concentration by the peak area. For instance when a solution containing three substances is being handled, it is simpler to separate these components by immersing it in an adsorbent material and then injecting it into the HPLC. It is expected that the chromatogram used tends to show a response from a detector as a peak of the different components. In analysis methodology and Gas Chromatography, these variations are actually the cause of the different variations experienced. While response factors are very important in the use of Gas Chromatography (GC) during quantitative analysis, there is need to seek a method aimed at eliminating any arising variability in response factor. A simple way to achieve this is by using the relative response factors as well as an internal standard in calibrating this GC.
This response factor in a HPLC is also used in pharmaceutical production. In pharmaceutical ingredients, it is expected that impurities are produced and their analysis is vital so as to obtain the impurity standard. This is only achieved upon obtaining the response factor and proceeding to employ the Relative Response Factor (RRF). The RRF is used as an alternative method in the determination of the amount of impurities found in the pharmaceutical products.This is obtained by the look of the peak area of each component. RRF is obtained by dividing the RF of the impurity by the Response Factor of the Active Pharmaceutical Ingredient (API). Therefore the accurate response factor is clearly obtained by the quantitative analysis of the impurity standard and the API. During this process, it is also very important to calculate the slop of the area concentration and standard of impurity so as to accurately determine the RRF.
The RF of various substances actually differ hence the need to differently figure them out and this determination should be based on the individual substance. Different detectors should also not be used because they will show a different response to the same compound. That is why it is important to use a particular detector in calculation of a particular component so as to enable accurate standards. The RF in HPLC analysis has had a great impact in the making of pharmaceutical drugs because different drug components and impurities get to be adequately separated.
