Instrumentation Three instruments are available for mass spectrometric analyses. Samples are prepared for analysis by mixing the analyte with a chemical matrix, usually a small MW weak organic acid. The matrix absorbs pulsed laser energy and transmits it to the analyte, desorbing it from the target. The ablated ions are accelerated into a field-free drift tube.
Lighter ions have a higher velocity than heavier ones, and therefore reach the detector faster.
It is used primarily to quickly screen samples for which an accurate mass is not necessary, and as a teaching instrument The third instrument is a Bruker Esquire-LC ion trap mass spectrometer, which uses three electrodes to trap ions in a potential energy well. Common solvents include water, methanol, ethanol, isopropanol and acetonitrile. The ion trap is an ion storage and mass analysis device consisting of two end caps and a ring electrode. The end caps have small perforations that allow ions to enter and leave the trap. Mass spectra are obtained by ramping the electrode voltages to selectively eject ions from the trap, with unit resolution up to ca.