Chromatography Techniques Overview

The process of removing strongly interacting molecules from the chromatography column by changing the buffer composition.

A technique in chromatography where the mobile phase composition remains constant during the separation process.

A technique in chromatography where the mobile phase composition changes gradually during the separation process.

The step where the chromatography column is cleaned and prepared for reuse.

The final washing step in chromatography to remove any remaining compounds that are not specifically bound to the resin.

A measure of how well a chromatography system can separate two components. It is calculated as the difference in retention times of the two peaks divided by the average width of the peaks.

A measure of the efficiency of a chromatography system. It is defined as the number of theoretical plates in the column. A higher number of theoretical plates indicates a more efficient system.

The height of a theoretical plate, calculated as the column length divided by the number of theoretical plates. It helps to understand factors like mobile phase flow rate and particle size that affect peak broadening.

A type of diffusion that occurs when the mobile phase moves through the column at different speeds, resulting in band broadening. This effect is more significant in packed columns.

A type of diffusion that occurs when the solute molecules move between the stationary phase and the mobile phase, resulting in band broadening. This effect is more significant in slow mobile phases.

A type of diffusion that occurs when the solute molecules move within the stationary phase, resulting in band broadening. This effect is more significant in slow stationary phases.

A type of diffusion that occurs when the molecules in a band diffuse in the direction of the flow of the mobile phase. This effect is more significant in long columns.

A type of gas chromatography column that is flexible and typically wound into coils. They are strong due to their polyimide coating, which also makes them less reactive than traditional glass columns.

A method used in gas chromatography to improve separation of compounds with a wide boiling range. The column temperature is gradually increased during the analysis, allowing components to elute at different temperatures.

A type of detector used in gas chromatography that responds to all compounds except the carrier gas. They are sensitive to any compound that enters the detector.

A type of detector used in gas chromatography that responds to a specific group of compounds with similar physical or chemical properties. They are designed to identify compounds with shared characteristics.

A type of detector used in gas chromatography that responds to a single specific compound. These detectors are highly selective and are ideal for identifying a particular analyte.

A type of detector that produces a signal proportional to the concentration of the analyte in the detector. The signal is influenced by the amount of analyte present.

A type of detector that produces a signal related to the rate at which the analyte enters the detector. The signal is affected by the flow rate of the analyte.

This detector is commonly used in gas chromatography and measures the ion current produced when organic molecules in the sample are burned in a flame. The ions and electrons generated conduct electricity, producing a detectable signal.

A detector that measures the amount of ions and electrons produced when a sample is burned in a flame. The signal is proportional to the mass of the analyte, regardless of flow rate changes.

The FID is highly sensitive and can detect even small amounts of organic compounds. It has a wide range of linearity and a low noise level, making it a reliable detector. However, the sample is destroyed during the analysis.

A technique used to separate and analyze components of a mixture by passing them through a heated column containing a stationary phase.

The gas used to carry the vaporized sample through the column in GC. It must be unreactive with the sample and the stationary phase.

The component of the GC system where the sample is vaporized and injected onto the column.

The material inside the column that interacts with the components of the sample, causing them to separate at different rates.

One of the two main types of columns in GC, containing a finely divided solid support material coated with the stationary phase. They are typically shorter and wider.

A type of capillary column where the stationary phase is directly coated onto the inner wall of the column.

A type of capillary column where a thin layer of support material is present on the inner wall, onto which the stationary phase is adsorbed.

A type of capillary column made from fused silica, a type of glass, which is often used for its high performance and stability.

A powerful analytical technique using high pressure and small resin particles for separating various molecules, including organics, nucleic acids, peptides, and proteins.

HPLC is capable of detecting incredibly low concentrations, down to parts per trillion, with small sample requirements (microliters).

HPLC utilizes various detectors, including UV-absorbance, evaporative light scattering (ELSD), and mass spectrometry (MS), to identify and quantify the separated components.

The combination of HPLC and mass spectrometry, often abbreviated as LC-MS, provides a powerful analytical tool for determining the mass-to-charge ratios of separated molecules.

HPLC, like other chromatography techniques, can separate molecules based on size, hydrophobicity, or charge using different modes such as size exclusion, hydrophobic interaction, and ion exchange chromatography.

HPLC is not suitable for affinity chromatography, which relies on specific interactions between a molecule and its binding partner.

A critical step in HPLC protocols, where a compatible buffer is run through the column to prepare the stationary phase for separation.

The process of introducing the sample into the HPLC column, either manually or using a pump, following the equilibration step.

After sample loading, weakly interacting molecules are removed by washing the column with several column volumes of wash buffer, ensuring a clean separation.

The process of removing unwanted molecules from the stationary phase using a specific buffer, ensuring a cleaner separation.