Doubly charged analyte ion

In early work it was recognized that the seledion of the sampling zone in the plasma and the aerosol carrier gas flow may strongly influence the occurrence of cluster ions and doubly charged analyte ions [502, 503]. This is clearly demonstrated by the results for lanthanum, where even doubly and triply charged ions may be expected in the argon plasma. This necessitates specific optimization of the power and especially of the carrier-gas flow, which influence both temperature and residence times of the sampled substance in the plasma. This is documented e.g. for the intensities of the signal for the ArO+ and the Cu+ ions in Fig. 113 [504]. 

Depending on the analyte and on the energy of the primary electrons, doubly charged and even triply charged ions may be observed... 

The conditions of the FAB process also promote unwanted reactions between analyte and matrix. Even though such processes are not relevant in the majority of FAB measurements, one should be aware of them Besides addition or condensation reactions with matrix fragment ions, [81,82] reduction [83-86] and dehalo-genation [87,88] of the analyte represent the more prominent side-reactions in FAB. Electron transfer to cause the reduction of otherwise doubly charged ions have also been observed. [47]... 

However, the most common interferences are the spectral interferences, also called isobaric interferences. They are due to overlapping peaks which can mask the analyte of interest and can give erroneous results. Such interferences may occur from ions of other elements within the sample matrix, elemental combination, oxide formation, doubly charged ions, and so on. 

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