Atomic mass spectrometry interferences

Isobaric Interferences. Isobaric species are two elements that have isotopes of csscnually the same mass. For atomic mass spectrometry with a quadrupole mass spectrometer, isobaric species arc isotopes that differ in mass by less than one unit. With higher-resolution instruments, smaller differences can be tolerated. 

There are three primary instrumental approaches to eliminating or reducing interferences in atomic mass spectrometry (1) use of high mass resolution ICP-MS (HR-ICP-MS) (2) use of a collision cell to break apart polyatomic interferences (3) use of gas phase chemical reactions in a reaction cell to eliminate polyatomic interferences. The approach of changing the instrument operating conditions to form a cool or cold plasma has been discussed. 

See also Atomic Absorption Spectrometry Principles and Instrumentation Interferences and Background Correction. Atomic Mass Spectrometry Inductively Coupled Plasma Laser Microprobe. Liquid Chromatography Column Technology. 

See also Atomic Absorption Spectrometry Interferences and Background Correction. Laser-Based Techniques. Liquid Chromatography Principles Instrumentation. Mass Spectrometry Overview. Pesticides. Phosphorus. Sulfur. 

See also Atomic Absorption Spectrometry Interferences and Background Correction. Atomic Emission Spectrometry Principles and Instrumentation Interferences and Background Correction Flame Photometry Inductively Coupled Plasma Microwave-Induced Plasma. Atomic Mass Spectrometry Inductively Coupled Plasma Laser Microprobe. Countercurrent Chromatography Solvent Extraction with a Helical Column. Derivatization of Analytes. Elemental Speciation Overview Practicalities and Instrumentation. Extraction Solvent Extraction Principles Solvent Extraction Multistage Countercurrent Distribution Microwave-Assisted Solvent Extraction Pressurized Fluid Extraction Solid-Phase Extraction Solid-Phase Microextraction. Gas Chromatography Ovenriew. Isotope Dilution Analysis. Liquid Chromatography Ovenriew. 

Spectra such as that in Figure Il-I5b led early workers in the field of ICPMS to have hopes of an interference-free method. Unfortunately, this hope was not realized in further studies, and serious interference problems are sometimes encountered in atomic mass spectrometry just as in optical atomic spectroscopy. 

What types of interferences are encountered in atomic mass spectrometry ... 

Mass spectrometry is the only universal multielement method which allows the determination of all elements and their isotopes in both solids and liquids. Detection limits for virtually all elements are low. Mass spectrometry can be more easily applied than other spectroscopic techniques as an absolute method, because the analyte atoms produce the analytical signal themselves, and their amount is not deduced from emitted or absorbed radiation the spectra are simple compared to the line-rich spectra often found in optical emission spectrometry. The resolving power of conventional mass spectrometers is sufficient to separate all isotope signals, although expensive instruments and skill are required to eliminate interferences from molecules and polyatomic cluster ions. 

Mechanistic insight into this process was obtained by administration of labeled trideca- or undeca-3,6,9-trienoic acid instead of the natural C12 precursor (Figure 2). In this case, the artificial 2H metabolites can be analyzed by mass spectrometry without interference from the plants own 1H metabolites, since a homo- or norectocarpene is formed. The sequence of the oxidative decarboxylation/cyclization reaction proceeds without loss of 2H atoms from the double bonds but with loss of a single 2H atom from certain methylene groups of the precursor acids (Figure 3). If C(l) and a 2H atom from C(5) of the labeled precursor is lost, finavarrene is the product of the reaction channel. If the methylene group... 

Discuss in detail the origins and effects of interferences in ICP atomic emission and ICP mass spectrometry, and describe how they may be minimized or eliminated in practice. Explain why some of these interferences are common to both methods. Illustrate your answer with suitable examples where appropriate. 

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