kollisjonsgass

Kollisjonsgass, often translated as collision gas or reaction gas, is a concept used in mass spectrometry. It refers to a gas that is deliberately introduced into a mass spectrometer to induce fragmentation of ions. When sample molecules are ionized in the mass spectrometer, they often exist as intact molecular ions. To gain structural information about these molecules, they are typically subjected to fragmentation.

Collision gas plays a crucial role in a technique called Collision-Induced Dissociation (CID), also known as Collision-Activated Dissociation (CAD). In CID, the ions are accelerated and collide with molecules of the collision gas. These collisions are energetic enough to transfer kinetic energy to the ions, causing them to break apart into smaller fragment ions. The mass-to-charge ratios of these fragment ions are then analyzed, providing a unique fingerprint that can be used to identify the original molecule or elucidate its structure.

Commonly used collision gases include helium (He), argon (Ar), and nitrogen (N2). These gases are chosen because they are relatively inert, easily handled, and have a suitable mass to effectively transfer energy to the analyte ions without significant chemical reaction. The pressure of the collision gas and the energy of the ion collisions are important parameters that can be adjusted to control the extent and type of fragmentation observed. This control is vital for optimizing the analysis for specific applications in fields like proteomics, metabolomics, and environmental analysis.