Polyatomic ions formation

In contrast, the LA-ICP-MS (in comparison to laser ionization mass spectrometry (LIMS) where the ion source operates under high vacuum conditions) at present, in spite of the disadvantage of a higher polyatomic ion formation rate, uses an argon plasma ionization at normal pressure - a promising inorganic mass spectrometric technique for trace, isotope and surface analysis which will... 

Figure 6.8 Interference problem in SIMS polyatomic ion formation by sputtering of borophosphosilicate glass using an 02+ primary ion beam. (R. C. Wilson, F. A. Stevie and C. W. Magee, Secondary Ion Mass Spectrometry (1989). Reproduced by permission of John Wiley Sons, Inc.)...

Study of Cluster and Polyatomic Ion Formation by Mass Spectrometry... 

Investigations of cluster formation serve to explain the evaporation and atomization of sample material and ion formation processes. A further aim of cluster research is to find out under what conditions cluster or polyatomic ion formation can be influenced in order to avoid disturbing interferences and decrease the detection limits of elements. On the other hand, polyatomic ions have also been used as analyte ions for analysis, e.g. the application of MCs+ and MCs2+ dimeric and trimeric ions as analyte11 or of cluster primary ion beams (e.g., of bismuth and gold primary clusters)15 16 by the bombardment and sputtering of a solid surface in SIMS.17-21 Especially in SIMS, a multitude of cluster ions with high ion formation rates are observed.18 22 23... 

Polyatomic ion formation of REEs in different plasmas measured by LIMS, SSMS and... 

The capability to obtain accurate isotope ratio results at very low concentrations as presented here is dependent on the system used. MS-ICP-MS is a more sensitive instrumentation than is a Q-ICP-MS.The use of a desol-vating introduction system permits greater sensitivity than does use of a standard double-pass, cyclonic, or conical spray chamber, even if Peltier cooled. The use of desolvation also permits lower polyatomic ion formation as demonstrated by very low uranium oxides during optimization. Thus, instrumental setups that differ from those utilized here will have to be evaluated for limitations of their capabilities. The results obtained using SPE, a desolvating introduction system with nitrogen addition, and an MS-ICP-MS instrument will differ dramatically from those obtained at the same concentration using dilution only with a Q-ICP-MS and a standard introduction system. One should not expect to use QC samples spiked with only 20 ng/L total uranium with the latter system. 

Polyatomic ion formation. The most notable example with the present technique is the appearance of lines at most multiples of twelve due to carbon. 

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