Interferences atomic ions

High-mass resolution is needed to separate mass interferences of molecular and atom ions. Because of the mass defect of the binding energy of the nucleus, atomic ions have a slightly smaller mass than the corresponding molecular ions. To observe this typical mass resolutions between 5000 and 10000 are necessary. 

There are two themes in this work (1) that all soil is complex and (2) that all soil contains water. The complexity of soil cannot be overemphasized. It contains inorganic and organic atoms, ions, and molecules in the solid, liquid, and gaseous phases. All these phases are both in quasi equilibrium with each other and are constantly changing. This means that the analysis of soil is subject to complex interferences that are not commonly encountered in standard analytical problems. The overlap of emission or absorption bands in spectroscopic analysis is but one example of the types of interferences likely to be encountered. 

An overview of commercial ICP mass spectrometers from different companies (quadrupole based ICP-MS with and without collision/reaction cell, double-focusing sector field instrumentation with single and multiple ion collectors, time-of-flight (ToF), ICP-ion trap-MS and non-commercial ICP-Fourier transform ion cyclotron resonance (FTICR) mass spectrometers is given in Figure 5.2. By using ion traps and FTICR mass spectrometers in ICP-MS isobaric interferences of atomic ions... 

To avoid interferences of isobaric atomic ions of different elements and polyatomic ions at the same nominal mass, off line separation of matrix elements or analyte separation can be applied and/or enrichment and hyphenated techniques such as HPLC- or CE-ICP-MS. Analytical procedures have been developed in the author s laboratory for the determination of spallation nuclides in an irradiated tantalum target using HPLC and CE coupled on line to ICP-MS after dissolution and separation of the tantalum matrix.12,17 The mass spectra of rare earth elements (REEs)... 

Moens et al.124 demonstrated that ion-molecule reactions in a dynamic reaction cell (DRC) of ICP-QMS allow the 87Rb+/87Sr+ isobaric interference to be eliminated. A special ion-molecular reaction in a collision cell was studied in order to avoid this isobaric interference of atomic ions... 

Spectral interferences from ion-atom recombination, spectral line overlaps, molecular band emission, or stray light can occur that may alter the net signal intensity. These can be avoided by selecting alternate analytical wavelengths and making background corrections. 

Other gas-phase ion chemical reactions were explored by using oxygen introduced into the octopole collision cell product ions were injected into and analyzed by the quadrupole ion trap [55]. Reaction of oxygen with Y+, Zr+, and Xe+ was found to proceed rapidly, forming YO+, ZrO+, and Xe neutrals, effectively eliminating interferences by the atomic ions. These ions are particularly difficult... 

While the sensitivity enhancement is highly beneficial, care is needed with the technique to avoid interferences.2 Ions which complex mercury, such as sulfide3 and halides, may interfere with the rate of reduction to Hg. Interference may also be encountered from any volatile organic compounds in the sample which happen to absorb at the wavelength used (253.6 nm). Invariably a water trap is built into the apparatus to avoid problems caused by condensation in the atom cell.2... 

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