Hi Duri,

It all depends on the instrument requirements; collision gas is required to be of high purity/quality and that makes it expensive. Please define "regular LC-MS"

Thank you.

Hediye.

Hi Duri,

There are many different types of MS systems so there is no definition of regular LC-MS and conditions for each type of system will differ as well as the type of acquisition method used.

It gets a bit more complicated when looking at the different systems available and the various modes you can run. Generally, colision gases will pass through a collision cell but fragmentation of ions won't have enough energy to significantly impact the ions passing through the cell until more energy is given to the gas.

As the collision energy is increased then each molecule in the gas has more energy to transfer. When an ion passes through the energised gas and on colliding with the gas fragments the ions passing through.

I think you should review any literature and look at the system they have used, type of acquisition and the nature of the analysis they are performing.

Mass spectrometry is a powerful technique but there are a lot of very different areas within the field. With experience you will be able to understand more of the literature.

I hope this helps.

The collision energy (CID) used to further fragment an ion is optional during analysis (for LC-MS and of course part of MS-MS).

e.g In Orbitrap CID More collision voltage is mean to effectively fragment the molecule.” it can be observed an increase of the activation energies of both fragmentation processes as the molecular weight increases.

MS is a technology that identify substances by their molecular mass. To do so, the substance is first ionized and then fragmented into small fragments by collision with an inert gas. The mass detector at the last chamber of the MS will detect the mass of each fragment that arrives at the detector.

This is an introduction to MS, from which we understand that for sure we need collision to happen in every MS (tandem or single).

I am not aware of an MS that detects only molecular ions (parent ions) and identify substances accordingly. Many substances share a similar Molecular mass which makes it not differentiable in the MS without another criterion for identification, which is why fragmentation is used to make unique fragments for the purpose of identification of different substances in one sample.

Who said there is no collision in single quad MS??