The Scientists and the analytical chemist were looking for a reliable and accurate method the measure the various parameters of gas and liquids. What the chromatography came is as a boom to them. The meaning of his Greek word is ‘to write colour'. The first product using this technology-y was to measure gas –the gas chromatograph which was introduced in 1900 in Russia.
But the question remained unsolved for measuring liquid until the advent of HPLC (high-performance liquid chromatography). What this consists of • A mobile phase is a liquid and
• A stationary phase which is packed into a stainless steel column at high pressure.
The basic components of an HPLC system are the following:
• Sample preparation and injection
• Flow through cell
• Computer for interpretation and analysis.
HPLC works on the principle of differential speed of different molecules to pass through a liquid chromatography column. The pace will vary depending on the affinity of the molecule with the mobile phase (liquid or gas) and the stationary phase (solid or liquid). The later ones take longer to pass through.
The 1952 Nobel Prize in Chemistry was for two scientists for their contribution in chromatography. The evolution of Chromatography was in the order of paper chromatography, gas chromatography, and HPLC (high-performance liquid chromatography). Since then HPLC has proven to be the optimal set up for analysis of samples in the laboratory. Now a days even portable versions of HPLC are available offering ultimate online analysis.
The chemicals in the mixture that spend most of their time in the mobile phase as it travels down the column leave the column, are eluted, at earlier time intervals than chemicals in the mixture that spend most of their time in the stationary phase; so are eluted at later time intervals off the column.
HPLC is broadly divided into two different sub-classes based on the polarity of the mobile and stationary phases. The size of the particles is preferred to be smaller for better accuracy. If the volume of samples to be substantial, it is advisable to break them into smaller portions to facilitate analysis. Also, this reduces the requirement of longer columns. Mostly, the surface area needs to be big enough. However, very fine particles may be lost as traces.
There are different HPLC methods available depending on the applications i.e.) • Ion exchange,
• Size exclusion,
• Normal phase,
The sample preparation is critical in HPLC as it works on the principle of the separation of the material according to their molecular weight and polarity. When a mixture of compounds is passed through the HPLC column, it gets separated into its components before it exits from the column.the advent of computer and internet gave the HPLC further boost.
There are number of manufacturers for HPLC in the market, while choosing you should opt for the best manufacturers like Selon who has all the expertise, expertise and commitment.