High irradiance laser ionization orthogonal time-of-flight mass spectrometry: A versatile tool for solid analysis

This article reviews the development of and applications for high irradiance laser ionization orthogonal time‐of‐flight mass spectrometry (LI‐O‐TOFMS). LI‐O‐TOFMS has solved the bottleneck problems in traditional high irradiance laser ionization mass spectrometry, which allows the instrument to acquire explicit spectra with high resolution. A buffer‐gas‐assisted ion source effectively reduces the kinetic energy of the ions and suppresses the multiply charged ion interference. The pulse train data acquisition technique was applied to reduce the spectrum interference from multiply charged ions and polyatomic ions according to the temporal profiles of different ion packets in the repelling region. Relatively high laser irradiance (≥1010 W/cm2) is preferable for achieving uniform relative sensitivities for different elements in the samples of different matrices. LI‐O‐TOFMS has been used in the standardless, semiquantitative analysis of solids, which is proved to be a fast and convenient technique for solid sample analysis. By increasing the laser irradiance and reducing the buffer gas pressure, the determination of nonmetallic elements in solids can also be achieved without losing spectral explicity. Recent applications, such as elemental analysis of a single egg cell and acquiring elemental, fragmental, and molecular information of chemicals, were given to demonstrate the potential of the new technique. All of these results reveal that LI‐O‐TOFMS is an advanced tool in the elemental analysis of solids in terms of modern mass spectrometry. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:1256–1268, 2011