Determination of the Isotope Ratio for Metal Samples Using a Laser Ablation/Ionization Time-of-flight Mass Spectrometry

Abstract

The laser ablation/ionization time-of-flight mass spectrometry is applied to the isotopic analysis of solid samples using a home-made instrument. The technique is convenient for solid sample analysis due to the onestep process of vaporization and ionization of the samples. The analyzed samples were lead, cadmium, molybdenum, and ytterbium. To optimize the analytical conditions of the technique, several parameters, such as laser energy, laser wavelength, size of the laser beam on the samples surface, and high voltages applied on the ion source electrodes were varied. Low energy of laser light was necessary to obtain the optimal mass resolution of spectra. The 532 nm light generated mass spectra with the higher signal-to-noise ratio compared with the 355 nm light. The best mass resolution obtained in the present study is ~1,500 for the ytterbium.

Isotopic and elemental analysis by electrostatic energy analyzer laser ablated time-of-flight mass spectrometer

“…For this purpose, one needs to adjust the potentials on the field assembly electrodes (acceleration and extraction region). Electric field adjustment in extraction and accelerating region [1] is called the K factor. This technique is very efficient and provides good results, but the drawback of this method is to adjust the K factor for different samples and laser energies.…”

“…Laser absorption spectroscopy, glow discharge mass spectroscopy, secondary ion mass spectrometry, laser ablation inductively coupled plasma mass spectrometry, thermal ionization mass spectrometry, and time of flight mass spectrometry (TOF-MS), etc. All these techniques are well established and have advantages and disadvantages over each other [1]. Recently laser-induced breakdown spectroscopy (LIBS) * Author to whom any correspondence should be addressed.…”

“…Many authors used the LIBS combined with the TOF-MS and produced very promising results [6][7][8][9]. When the laser ablation is adapted with TOF-MS, the integrated system has many advantages such as: (1) all mass spectra can be obtained by using a single laser pulse. (2) Tunable lasers (wavelengths) are not necessary as required by resonance ionization mass spectrometry [10,11].…”