What is the Difference Between HPLC and GC?

High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) are both separation techniques used in various applications, but they have some key differences:

1. Mobile phase: HPLC uses a liquid (solvent) as the mobile phase, while GC uses a gas as the mobile phase.
2. Columns: HPLC columns are shorter and wider, while GC columns are longer and thinner.
3. Temperature: GC requires a higher temperature (around 150°C) to ensure samples are volatile, which makes the analysis faster compared to HPLC.
4. Detection methods: HPLC detection methods are non-destructive, typically using ultraviolet-visible (UV/Vis) spectroscopic detectors or refractive index detectors (RID). In contrast, GC detection methods are more destructive, such as flame ionization detectors (FID).
5. Applications: HPLC is commonly used for inorganic ions, food substances, polymers, and pharmaceuticals. GC is typically used for measuring oils, organic compounds, air samples, toxins, and drugs.
6. Cost: HPLC solvents are more expensive than the gases used in GC, and HPLC requires a pressure pump to push the mobile phase through the column. As a result, GC is generally considered more cost-effective.

In summary, the main differences between HPLC and GC lie in the mobile phase, column characteristics, temperature requirements, detection methods, applications, and cost. Both techniques are versatile and have a wide range of applications, but the choice between them depends on the specific requirements of the analysis.

Comparative Table: HPLC vs GC

Here is a table comparing the differences between High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC):

HPLC uses a liquid solvent as the mobile phase and is suitable for analyzing soluble compounds that can be either volatile or non-volatile, such as amino acids, drugs, and carbohydrates. GC, on the other hand, uses a gaseous mobile phase and is designed for analyzing volatile compounds that are usually gas at room temperature. The separation in HPLC is based on the polarity of molecules, while in GC, separation occurs based on the respective volatility of each compound in the sample.