The origins of high-performance liquid chromatography (HPLC) date back to the invention of chromatography in the early 20th century, then to partition and paper chromatography in the 1940s, and finally to the introduction of liquid chromatography in the early 1960s. Shortly thereafter, the need for better resolution and high-speed analyses of non-volatile samples led to the development of HPLC.
In HPLC, a pump pushes the mobile phase with the sample through the column. This is similar to classical LC, in which the mobile phase and analyte are driven through the column by gravity alone. HPLC separation media are typically very dense, which creates a high back pressure, usually measured in the hundreds to thousands of psi. This allows for higher resolution and faster separation on columns of shorter length when compared to open column chromatography.
HPLC is, for many scientists, an essential piece of apparatus for the separation, identification, purification and quantification of various compounds. Users of HPLC work in a variety of fields including biomedical research, and the cosmetics, energy, and food industries. UHPLC is gaining rapid acceptance for its performance, speed of analysis and low consumption of eluent.
Types of HPLC systems respondents are using.
Many LC systems incorporate a detector that analyzes different fractions. As a researcher, your detector needs to be matched to identify your compounds of interest. UV/Vis, a common detector, comes in a few different types, including diode array. Other popular detectors include ultraviolet, fluorescence, mass spectroscopy (MS) and refractive index (RI).
|Mass spectroscopy (MS)||12%|
|Refractive index (RI)||11%|
|Light scattering (LS)||6%|
Separations based on polarity utilize reverse-phase chromatography (most popular) and normal phase. The reverse-phase columns separate analytes based on their hydrophobicity, with the more hydrophobic compounds being retained longer on the column. Separations based on charge utilize ion exchange chromatography. Recently, many companies have introduced hydrophilic interaction chromatography (HILIC) columns for analysis of polar analytes.
|Ultra high-performance (UHPLC)||8%|
|Hydrophilic interaction (HILIC)||7%|
|Size exclusion (SEC)||7%|
|Gel permeation (GPC)||4%|
|Gel filtration (GFC)||2%|
Manufacturers typically offer HPLC components as a system; however, there can be a mixing of the system components from various vendors. Today, 95 percent or more of HPLC systems from major manufacturers ship with autosamplers, a testament to the improved reliability and reproducibility of autosampler hardware and controls. No wonder it’s the most commonly used HPLC component among survey respondents.
Average annual budget for supplies, accessories, maintenance, repairs, etc.
|$0 to $5,000||20%|
|$5,000 to $10,000||22%|
|$10,000 to $15,000||17%|
The need for speed and quality of data among researchers has led to faster, more efficient HPLC separations. Some purchasers prefer an integrated chromatography system in which all components are supplied in a single unit. Other purchasers prefer a modular system, in which individual components are purchased separately.
More researchers are identifying operating and acquisition cost, service, support and training as key factors in their decision-making process. Vendors recommend, when looking for a new HPLC instrument, to look a little into the future (about six to 12 months ahead) to figure out exactly what you need. For a smaller lab with lower throughput, cheaper machines working at low pressure may suffice, depending on the application. All vendors offer a range of different machines, and there are instruments that fall somewhere between HPLC and UHPLC that are sometimes 20 percent cheaper.
|Top ten factors/features|
|Quality of data||100%|
|Service, support, training||100%|
|Availability of supplies/accessories||99%|
|Precision and accurate flow rates||99%|
|Ease of use||99%|
Completed Surveys: 233