Inductively coupled plasma mass spectrometry spectral interferences

In inductively coupled plasma-mass spectrometry, isobaric interference occurs between species with the same mass and charge. Interference can be eliminated if the mass spectral resolution is sufficiently great or by dissociating an interfering polyatomic species with a collision cell. When laser ablation is used to sample a solid, matrix-matched standards are often necessary for quantitative analysis. 

At present, inductively coupled plasma mass spectrometry provides a unique, powerful alternative for the determination of rare earths in natural samples [638,639]. Nevertheless, its application to the determination of rare earths at ultratrace concentration level in seawater is limited, because highly saline samples can cause both spectral interferences and matrix effects [640]. Therefore, a separation of the matrix components and preconcentration of the analytes are prerequisites. To achieve this goal, many preconcentration techniques have been used, including coprecipitation with... 

Inductively coupled plasma mass spectrometry has been used for the analysis of uranium. However, the technique suffers from spectral interferences and it has relatively poor detection limits. 

Mass Resolution Required to Resolve Common Spectral Interferences Encountered in Inductively Coupled Plasma Mass Spectrometry... 

MASS RESOLUTION REQUIRED TO RESOLVE COMMON SPECTRAL INTERFERENCES ENCOUNTERED IN INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY... 

The table below lists some common spectral interferences that are encountered in inductively coupled plasma mass spectrometry (ICP-MS), as well as the resolution that is necessary to analyze them.1 The resolution is presented as a dimensionless ratio. As an example, the relative molecular mass (RMM) of the polyatomic ion 15N160+would be 15.000108 + 15.994915 = 30.995023. This would interfere with 31P at a mass of 30.973762. The required resolution would be RMM/8RMM, or 30.973762/0.021261 = 1457. One should bear in mind that as resolution increases, the sensitivity decreases with subsequent effects on the price of the instrument. Note that small differences exist in the published exact masses of isotopes, but for the calculation of the required resolution, these differences are trivial. Moreover, recent instrumentation has provided rapid, high-resolution mass spectra with an uncertainty of less than 0.01%. 

Marshall, J., and Franks, J. (1990) Multielement analysis and reduction of spectral interferences using electrothermal vaporization inductively coupled plasma-mass spectrometry. Atomic Spectroscopy 11, 177-186. 

Inductively Coupled Plasma-Mass Spectrometry ICP-MS has been accepted as a powerful technique for elemental and isotopic analysis [21D25]. It is characterized by a linear dynamic range of Eve to six orders of magnitude, rapid multielemental analysis, comparative freedom from spectral interferences, and LoDs in the range of 10D100 pg mL-1 for most elements. This makes it ideal for the multielemental analysis of food samples on a routine basis. 

I. Rodushkin, T. Ruth, D. Klockare, Non-spectral interferences caused by a saline water matrix in Q and high resolution inductively coupled plasma mass spectrometry, J. Anal. Atom. Spectrom., 13 (1998), 159-166. 

Tittes W., Jakubowski N., Stuewer D., Toelg G. and Broekaert J. A. C. (1994) Reduction of some selected spectral interferences in inductively coupled plasma mass spectrometry, J Anal At Spectrom 9 1015—1020. 

Concentration of the elements Mn, Fe, Cr, Ni, Co, As, Cd, Pb, Zn and Cu in water and plant samples were measured by inductively coupled plasma mass spectrometry (ICP-MS) (ELAN 5000, Perkin-Elmer). The instrument was calibrated by external standards of multi-element solutions for a range of 1-10 p-g/kg for water samples and 0.5-20 (xg/kg for plant material. Digested plant samples were diluted accordingly. Matrix effects and spectral interference were compensated by addition of internal standards ( Rh and Th). 

With respect to the analyte, it must be taken into account that the matrix is soluble and stable in the digestion method selected. The concentration of the analyte in the sample should also be considered, since lesser the concentration greater is the need to obtain low quantification limits. The limits of detection and elemental interferences of the matrix can depend on the matrix-analyte-acid combination. The analysis technique should take extreme care to avoid interferences in the final detection. Thus, when inductively coupled plasma mass spectrometry is employed, the use of H2SO4 and HCl can cause important spectral interferences that can completely annul the results. 

Apart from the nuclides selected for quantification purposes, very often some additional ion signals are monitored for diagnostic or correction purposes. Similarly to conventional pneumatic nebuhzation inductively coupled plasma mass spectrometry (PN-ICPMS), these include nuclides used as internal standards or signals used for mathematical correction of spectral interferences. As a result of the particular nature of ETV-ICPMS, it is advisable to also select some other diagnostic signals, aiding in the process of method development or improving quality control once the method is developed. 

Begerow,/., and Dunemann, L. (1996). Mass spectral interferences in the determination of trace levels of precious metals in human blood using quadrupole magnetic sector field and inductively coupled plasma mass spectrometry./. Aim/. At. Spectrom. 11(4), 303. 

Goossens, J., Moens, L., and Dams, R. (1994). A mathematical correction method for spectral interferences on selenium in inductively coupled plasma mass spectrometry. Talanta 41(2), 187. 

Kuss, H.-M., and MuUer, M. (1995). Spectral interference of polyatomic ions of Cr, Fe, Mn, Mo, Ni, and W in steel using inductively coupled plasma mass spectrometry. Arch. Eisen-huettenwes. 66(12), 516. 

Van derVelde-Koerts,T, and De Boer,J. L. M. (1994). Minimization of spectral interferences in inductively coupled plasma mass spectrometry by simplex optimization and nitrogen addition to the aerosol carrier for multi-element environmental analysis.. Anal. At. Spectrom. 9(10), 1093. 

Van Veen, E. H., Bosch, S., and De Loos-Vohebregt, M.T. C. (1994). Spectral interpretation and interference correction in inductively coupled plasma mass spectrometry. Spectrochim. Ada. Part B 49(12/714), 1347. 

Vanhaecke, E, Dams, R., and Vandecasteele, C. (1993). Zone model as an explanation for signal behaviour and non-spectral interferences in inductively coupled plasma mass spectrometry./zl a/. Ai. Spectrom. 8(3), 433-438. 

Bjorn, E. and Freeh, W. (2001) Non-spectral interference effects in inductively coupled plasma mass spectrometry using direct injection high efficiency and microconcentric nebulization. J. Anal. At. Spectrom., 16, 4-11. 

Mason, P. R. D. and Kraan, W. J. (2002) Attenuation of spectral interferences during laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) using an rf only collision and reaction. J. Anal At. Spectrom., 17(8), 858-67. 

Milgram, K. E. Abatement of spectral interferences in elemental mass spectrometry design and construction of inductively coupled plasma ion sources for Fourier Transform ion cyclotron resonance instrumentation, Ph. D. Thesis, University of Florida, 1997, Diss. Abstr. Int., B 1998, 59(2), 639. 

Inductively coupled plasma (ICP) ionization has currently assumed a more prominent role in the field of elemental and isotopic analysis [1,2,14]. It is apphcable to solid-state as well as to solution-phase samples. A plasma is defined as a form of matter that contains a significant concentration of ions and electrons. The heart of this technique is a plasma torch, first developed as an efficient source for optical emission spectroscopy (OES) [15,16]. Multielement analysis with OES has, however, some serious shortcomings, such as complicated spectra, spectral interferences, high background levels, and inadequate detection of some rare-earth and heavy elements. The high ionization efficiency (>90%) of ICP for most elements is an attractive feature for its coupling to mass spectrometry. 

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