Ultra Performance Liquid Chromatography

Do You Need “UPLC” In Your Laboratory? ACCTA, Inc. takes a critical look at the numbers, not the marketing!

Ultra Performance Liquid Chromatography

Introduction

“UPLC” is one of the biggest chromatography marketing successes in many years.  Despite the fact that it is more than five years old, many laboratories are still confused about the technology, and whether they should consider it for their laboratory.  This article will look at some typical operating issues and compare three different configurations for an HPLC analysis – standard HPLC, high speed HPLC, and UPLC.

What is UPLC?

The term UPLC, meaning “UltraPerformance Liquid Chromatography,” was introduced by Waters Corporation when they introduced their Acquity LC system.  The biggest change was the use of sub-2 um particles, which were operated at higher flows and pressures than a conventional system.  This concept resulted in significantly shorter analysis times.

What are my HPLC options?

When developing an HPLC method, you now have three operating choices, based on your column selection – “standard” HPLC, “high speed” HPLC, and “UPLC.”  (Note: this is an arbitrary description of your options, but it makes our comparison easier).  The differences are the particle diameter for the column packing, and operating conditions.  Table 1 provides a comparison of typical conditions.  Of course there are many more options, but for this discussion we will only consider these.

Figure 1 shows a typical chromatogram for a standard column.  This sample has five components and the separation is complete in six minutes.  Maybe your separation looks something like this.

Figure 1. Typical chromatogram of a five component mixture using a “standard” HPLC column: 4.6 X 150 mm C18, 5 um particles, 1.5 mL/min. flow rate.

High Speed HPLC

High speed HPLC has been around for many years.  It really just uses smaller particles, in shorter columns, and at faster flow rates.  The same sample, when analyzed on a high speed column, produces the chromatogram in Figure 2.  The analysis is complete in just under three minutes.

Figure 2. Typical chromatogram using a high speed column: 4.6 X 100 mm C18, 3.5 um particles, 2.14 mL/min. flow rate.

UPLC

If we move to a typical UPLC column, we can generate the chromatogram in Figure 3.  The retention time is now just under 0.9 minutes.

Figure 3. Typical chromatogram using a UPLC column: 4.6 X 50 mm, 1.8 um particles, 4.17 mL/min. flow rate.

Comparing the Numbers

We can now calculate some practical parameters based on these “typical” results.

So, do I need to buy a UPLC system?

It depends!  If you have a large number of samples to analyze on each instrument (much more than 100 per shift), then UPLC may make some sense.  Assuming that you can get about six hours of operation during an eight hour shift (one hour each for startup and shutdown), this translates to almost 350 samples for a UPLC system.  However, if you only have a maximum of about 100 samples per instrument, you could complete those in just over six hours, using the high speed column.  The standard column will analyze less than 60 samples over the same time period. 

The other consideration is capital equipment cost.  The high speed columns can be used on a “good” HPLC system; no new equipment is needed.  UPLC columns require an optimized system.  While some standard HPLC units can be upgraded to some extent, to get the most from your column you probably should buy a new system.

Don’t get caught up in the marketing hype.  Look at your needs, do some calculations like we show here, and then make an educated decision.  At ACCTA, Inc. we understand these technologies and the assumptions behind them.  Maybe you just need to optimize your existing method, or transfer it to a high speed column.  Maybe you need to make a change to the fastest technology.  Either way, we can help you make the best decision for your laboratory.