What is the difference between gas chromatography and hplc

Inadvertently, HPLC analyzes samples that are only liquid in nature. Instrumentation: Both these methods use chromatography columns, but there is differentiation in their sizes. The gas chromatography uses columns which are long and thick usually 10 to 30 meters in length as compared to the chromatography column which is shorter and thin basically being 5 to 25 cm in length. Detection: After chromatography is done on the analyte, the composition of the eluent has to be done. This calls for detection methods that are stringent to get the perfect sample type and volume.

Each analytical technique has its own method of sample detection. For gas chromatography, two types of detectors are the most widely used i. In the case of High Performance Liquid Chromatography system, the only method use is via an Ultraviolet Spectrometric detector which uses the principle of absorption and transmittance to detect the different types of samples In spectrophotometry, a sample is placed between a source of light and a photometric reader.

Since gas chromatography utilizes temperature, they must use thermal conducting detectors to measure the heat-related movement inside. HPLC machines track absorption and transmittance, so they use ultraviolet spectrometric detectors.

These UV sensors understand how a molecule responds to certain light levels and track it on a graph. Over the last 25 years, GenTech Scientific has built a reputation as a trusted partner in equipping research labs with warrantied analytical instrumentation, servicing that equipment, buying and refurbishing instruments, and providing scientists, universities, and corporations with technology and customer service they need to move their research further.

Hit enter to search or ESC to close. Close Search. The Types of Chromatography The science of chromatography is not monolithic; there are several types that chemists use. The Main Components of Chromatography Machines Chromatography machines require similar parts to carry out their work.

Chromatographical Method Chromatography machines use specialized parts for the kind of sample they process, but the core dynamics are often the same. The Movement Method Gas chromatography-mass spectroscopy machines vaporize samples and carry them through the column with an inert gas. The Measurement Tools Since gas chromatography utilizes temperature, they must use thermal conducting detectors to measure the heat-related movement inside.

GenTech Scientific. Recent Comments. Categories Buy Refurbished! Buy Refurbished! GenTech Scientific November 9, Therefore, the particles with stronger interactions separate from the particles that show weaker interactions. GC is gas chromatography. Also, it is a column chromatographic technique. The technique is useful to separate components in mixtures that easily vaporize without decomposition.

The two major uses of this technique are to determine the purity of a sample and to separate the components in a mixture. In some cases, it also helps to identify the components. In this method, the mobile phase is a carrier gas moving phase while the stationary phase is a liquid moving or a polymer material on an inert solid support. Usually, the carrier gas is an inert gas such as helium or nitrogen.

So, detection can limit your options depending on which detector is available to you, and whether your sample has the necessary characteristics for its detection. GC detectors vary in selectivity and sensitivity 2. The first is selective to hydrocarbons, whereas the second is universal. The refractive index detector RID is also commonly used because it has universal detection capabilities.

These analytical systems combine the features of the chromatograph with that of a mass spectrometric MS detector. So, one part separates components and the other provides mass analysis for each of those components — giving you additional information for compound identification.

If money is an issue , you may want to consider that a tank of gas is generally cheaper than solvents. In addition, because liquids are more viscous than gas, HPLC relies on pressure pumps to force the mobile phase through the column. GC on the other hand is not very complex. Simply think of it as a large, sophisticated oven that requires a lower degree of maintenance.

The table below summarizes the differences described above and lists typical sample types for both chromatography techniques.

Always keep in mind that both HPLC and GC are invaluable advancements in analytical instrumentation and indispensable in many scientific fields. But they are also susceptible to issues and limitations. Common problems are related to selectivity, sensitivity, and resolution. And these are affected by the nature of the sample.