Differences between HPLC and UPLC

Liquid chromatography is a technique that is utilized to separate any sample into its individual components. In this case, the chromatographic procedure involves a liquid as the moving phase. HPLC and UPLC stand for High Performance Liquid Chromatography and Ultra Performance Liquid Chromatography respectively.

It is understandable to find these terminologies quite daunting, but at its core HPLC and UPLC are both used to separate the various components of compounds found in mixtures, using high pressures to push solvents through columns. However, the similarities between the two end there and the differences between HPLC and UPLC begin.

UPLC operates at considerably high pressures of 15,000 psi (psi, in this case, stands for Pounds per square inch and is a unit of pressure), while HPLC operates at relatively lower pressures of 500-6000 psi.

The key difference between HPLC and UPLC here is that UPLC has a clear advantage of HPLC, thanks to its higher pressure. This allows for shorter run times, lower solvent consumption and greater analyte separation and detection by the detector. In case you were wondering, The use of the term 'analyte' refers to any substance whose chemical constituents are being identified and measured.

The differences between HPLC and UPLC do not end here, as it is important to gain a deeper understanding of both terms before moving further. High Performance Liquid Chromatography system is the most widely used technique for the quantification, identification and separation of the various components of a mixture. High Performance Liquid Chromatography system is particularly used in the pharmaceutical industry for the analysis of drug products, pesticides and a number of other substances. So if you intend to head into that industry, you would be wise to familiarize yourself with these terms and understand them to the best of your ability.

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Column particle sizes of less than 2um can be used for UPLC, as opposed to the 5um particle size that is typical of HPLC. Furthermore, perhaps one of the most appealing differences between HPLC and UPLC is that UPLC allows for very fast analysis. While HPLC may take anywhere between 15-20 minutes to deliver separations, UPLC can deliver separations in 3-10 minutes. UPLC has the capability to outperform HPLC at every turn.

Related: Steps for HPLC Method Validation

In actuality, Ultra Performance Liquid Chromatography system is a trademarked technology, however, it is still used as a general term to describe this technique. The pump pressure plays a vital role in making UPLC such an exciting technology. While the HPLC has a pump pressure of 40 MPa (Mega Pascal), the UPLC has a pump pressure of 100 MPa. This massive increase of pump pressure is of immense importance to the rapid functioning of UPLC.

In conclusion, the differences between HPLC system and UPLC system clearly illustrate how the latter is superior to the former in every way. However, despite the clear superiority of UPLC, HPLC is the more widely used technique currently being used in the industry. This may change in the future, but it is difficult to ascertain at this point in time. Hopefully, this article proves helpful to you and allows you to gain an understanding of both techniques, in regards to their similarities and key differences.