There are various methodologies when it comes to analyzing amino acids. HPLC is, however, the most common one, but there are others as well, which are being used to offer very good results. Here is a brief look into some of them:
Pre-label method
This method of amino acid analysis features the derivitization of the components of the amino acid prior to insertion, so that the reaction products are separated before the detection. Some of the benefits of this method include, but are not limited to the following:
- It makes it possible to increase the sensitivity by using expensive reagents known to result into lower background levels.
- It features low rate of reagent consumption
- The unreacted agents, if detected, will not have any effects in the separation column.
There are also a few disadvantages attributed to this method of amino acid analysis. For instance, the sample matrix will have effects on the efficiency of the reaction products, as well as the reactants. This may sometimes make the amino acids unstable, and may lead to errors during the quantization of the results.
Detection type methods
This method uses ultra violet rays, and it involves the absorption of the carboxyl group in the 200 and 210nm range. In most cases, certain types of amino acids are difficult to analyze as is, unless there is sufficient sensitivity and selectivity. At the end, detection type methods normally end up in the use of derivitization methods, which have always been resorted to in the past.
Post column reaction detection method
This method features the use of derivitization reagent delivery, and the amino acid separation method. The steps get to react with the amino acids before the products are allowed to access the detector. The method can be automated to offer very good performance, and quantitative reproducibility. Again, since the sample components will be separated before the reaction takes place, the efficiency is very good, and is less prone to sample matrix. As a result, the method is applicable to a wide range of uses.
