Comparison of Thermodynamic Data Obtained by Knudsen Vaporization Magnetic and Quadrupole Mass Spectrometric Techniques

Author(s):  
Gary A. Murray ◽  
Robert J. Kematick ◽  
Clifford E. Myers ◽  
margaret A. Frisch
1999 ◽  
Vol 18 (3) ◽  
pp. 99-109 ◽  
Author(s):  
Yongxin Tang ◽  
Zhenhui Han ◽  
Qizong Qin

Pulsed laser ablation of TiO2 at 355 nm and 532 nm has been investigated using an angleand time-resolved quadrupole mass spectrometric technique. The major ablated species include O (m/e = 16), O2 (m/e = 32), Ti (m/e = 48), TiO (m/e = 64) and TiO2 (m/e = 80). The time-of-flight (TOF) spectra of ablated species are measured for the ionic and neutral ablated species, and they can be fitted by a Maxwell – Boltzmann (M – B) distribution with a center-of-mass velocity. The measured angular distributions of the ionic species (O+ and Ti+) and the neutral species (O and Ti) can be fitted with cos⁡nθ and a cos⁡θ + (1−a)cos⁡nθ, respectively. In addition, a continuous wave oxygen molecular beam is introduced into the ablated plume, and the enhancement of the signal intensities of TiO is observed. It implies that the ablated Ti atoms/ions species can react with ambient oxygen molecules in the gas phase. In the meanwhile, the physicochemical mechanism of pulsed laser ablation of TiO2 is discussed.


2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Josefina Pérez-Arantegui ◽  
Francisco Laborda

Abstract Inorganic mass spectrometry has been used as a well-known analytical technique to determine elemental/isotopic composition of very diverse materials, based on the different mass-to-charge ratios of the ions produced in a specific source. In this case, two mass spectrometric techniques are explained and their analytical properties discussed: inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionisation mass spectrometry (TIMS), since they are the most used in art and archaeological material studies. Both techniques combine advantageous analytical properties, like low detection limits, low interferences and high precision. The use of laser ablation as sample introduction system in ICP-MS allows to avoid sample preparation and to perform good spatial-resolution analysis. The development of new instruments, improving the mass separation and the detection of the ions, specially multicollection detectors, results in high-precision isotopic analysis. A summary of the important applications of these mass spectrometric techniques to the analysis of art and archaeological materials is also highlighted.


2014 ◽  
Vol 116 (2) ◽  
pp. 1027-1031 ◽  
Author(s):  
M. R. R. Prasad ◽  
K. Sudhakarbabu ◽  
B. Sreedhar ◽  
D. Keerthi Devi

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