What Is Chromatography? The Role Of Chromatography In The Purification of Bioproducts
Updated: Oct 27, 2020
Using Chromatography To Create Bio-based Products
At Activatec, we specialise in the purification of bio-based products and the upscaling of processes to commercialise and valorise by-products.
Before we can begin to purify materials and maximise product output, we must first analyse the compounds that we will use to later develop our bioproducts.
What Is Chromatography and Why Is It Useful?
In short, chromatography is a technique that separates different molecules or compounds within a mixture, allowing us to study the individual components therein. A technique with a vast range of applications, chromatography has been used outside of the industrial biotechnology sector to look for pollution in a body of water and analyse blood from crime scenes or during drug tests. Chromatography has also been used in medicine, to evaluate alcohol content, and has even played a part in the creation of vaccines.
Accommodating this wide range of uses, there are several distinct types of chromatography. At Activatec, we use both Gas Chromatography (GC) and High-Performance Liquid Chromatography (HPLC) at an analytical level before increasing the scale of purification via other methods, including electrodialysis, ultrafiltration, nanofiltration, solvent extraction and several other types of chromatography.
How Does Chromatography Work?
At the most basic level, both GC and HPLC separate compounds within a mixture, allowing us to identify and analyse the target molecules (known as 'analytes') in question. The mixture to be analysed is dissolved in a 'mobile phase' before being passed over a 'stationary phase' (sometimes called the immobilised or solid phase).
Molecules that interact strongly with the stationary phase pass through that phase slowly, while molecules that interact weakly with the stationary phase move through it quickly. Therefore, molecules are separated based on the strength of their reaction with the stationary phase.
Simply put, as different compounds travel at different speeds through the stationary phase, they emerge from the process at different times, and are therefore separated.
While GC and HPLC both involve this shared general principle, there are some differences between the two processes.
Our equipment for conducting (left: GC, right: HPLC) chromatography at our lab in BioCity.
We have a wide range of columns, and the one we use depends on the analyte of interest
In GC, mixtures are heated past the boiling point of their least volatile component. This mixture is then passed across the stationary phase (a long column containing a liquid or polymer) using a continuous flow of gas.
During HPLC, molecules are dissolved in a liquid mobile phase before being passed through the solid stationary phase.
In both types of chromatography, molecules emerge from out the column at different rates depending on how strongly they interact with the stationary phase.
The Advantages and Disadvantages of GC and HPLC
GC is fast and efficient when separating very complex mixtures, while HPLC is more versatile. Ultimately, the type of Chromatography used depends on the sample mixture and desired analyte in question.
GC is used for the separation of volatile compounds, while HPLC is used for non-volatile compounds. GC is therefore effective when studying oils, fatty acids, toxins and a number of drug samples, while HPLC is used to investigate polymers, lipids and proteins.
After we use the relevant chromatography method to separate and analyse our analytes, we use processes to purify these molecules at a large scale so that they can be used as ingredients for the creation of bio-based products and materials. Through the upscaling of processes, we ensure the commercial viability of our high-value bioproducts, helping to promote a sustainable circular bioeconomy.
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