Let me give you the technical difference between HPLC & UPLC.
UPLC, first of all, is a registered trademark of Waters Corporation. Other companies call their version of UPLC something like UHPLC or STM or something other than UPLC.
What is Ultra Performance Liquid Chromatography (UPLC)?
UPLC is HPLC using particles that are less than 2 microns, commonly 1.7-1.8 micron particles.
So, now let me give you my definition of UPLC. It’s the same as HPLC. I don’t want to discount the work Waters did in producing the high-pressure pumps, but the reality is it’s an HPLC. Let’s look at it from a chronological perspective. I started doing this in 1980, and we were using 10-micron particles. And then we realized the smaller, the better. We went to 5 microns. We knew that smaller was the goal based on every equation that we had, so we went from 5 microns to 3.5 microns. And then, one day, we went to 1.8 microns, and then that was somehow labeled a new technique, UPLC/UHPLC.
Are There Advantages using an UHPLC System?
So, whichever way you want to argue it, I will say UPLC/UHPLC is the most advanced version of HPLC. It uses the smallest particles, which give us the highest efficiency and the best resolutions. The best resolution per unit time is always going to be on a UHPLC system. The beauty of UHPLC is the fact that now we have high-pressure pumps. So, we have the ability to go above the traditional 5 or 6,000 psi. Now we could go to 9,000, 12,000, even up to 20,000 psi. These advanced pumps allow us to use UHPLC.
That’s the difference between HPLC and UPLC. Most all applications out there should work using either technique, but you’re going to get better separations on UPLC/UHPLC .
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