High mass resolution time‐of‐flight secondary ion mass spectrometry. Application to peak assignments

Niehuis, E.; Velzen, P. N. T. Van; Lub, Johan; Heller, Thomas; Benninghoven, A.

doi:10.1002/sia.740140307

Cited by 65 publications

(26 citation statements)

References 11 publications

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“…Brinkhuis and van Ooij gained, this approach became ambiguous above m/z ¾ 70. Niehuis et al 6 proved this and illustrated the benefits of the first high mass resolution ToF-SIMS instrument by making direct assignments for a number of low mass m/z < 70 positive ion fragments of PMMA both before and after oxygen plasma treatment. These results served to underline further the likely complexity of the spectrum, especially in the high mass region.…”

Section: Introductionmentioning

confidence: 92%

Positive secondary ion mass spectrum of poly(methyl methacrylate): a high mass resolution ToF-SIMS study

Briggs

Fletcher

Gonçalves

2000

Surf. Interface Anal.

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The positive SIMS spectrum of poly(methyl methacrylate) (PMMA) has been obtained with a mass resolution in excess of 8000 and all the components assigned up to m/z 200 based on accurate mass measurements. Aspects of the interpretation of the spectrum, previously based on quadrupole SIMS data from a number of acrylic polymers, need to be revised significantly. In particular, the spectrum is dominated by oxygen‐containing fragments derived from oligomeric units rather than hydrocarbon fragments derived from the polymer backbone. To aid further the understanding of the fragmentation of acrylic polymers, a less‐detailed study of poly(methyl acrylate) has also been carried out. Copyright © 2000 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 92%

Positive secondary ion mass spectrum of poly(methyl methacrylate): a high mass resolution ToF-SIMS study

Briggs

Fletcher

Gonçalves

2000

Surf. Interface Anal.

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“…Niehuis et al [4] used a single stage reflection time-of-flight analyzer to illustrate the benefits of improved mass resolution and to study the mass scale accuracy using a trimethyl silylated silicon oxide surface. They found an average value for W of 20 ppm for 26 negative ions with masses between 60 and 149 u.…”

mentioning

confidence: 99%

“…They showed that, with a mass calibration using the 3 peaks for CH 3 ϩ , C 2 H 3 ϩ , and C 3 H 5 ϩ , an average W of 10.4 ppm was achieved for 7 further peaks in the mass range 104 to 577 u for poly(ethylene terephthalate). By adding the 3 calibration peaks for C 4 Mass accuracy, ⌬M, of the protonated Irgafos molecular ion for instruments with reasonable quality data from 32 instruments in an interlaboratory study [1]. The error bars show the standard deviations of the five repeat measurements in each laboratory.…”

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confidence: 99%

TOF-SIMS: Accurate mass scale calibration

Green

Gilmore

Seah

2006

J. Am. Soc. Mass Spectrom.

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A study is presented of the factors affecting the calibration of the mass scale in time-of-flight secondary ion mass spectrometry (TOF-SIMS). At the present time, TOF-SIMS analysts using local calibration procedures achieve a rather poor relative mass accuracy of only 150 ppm for large molecules (647 u) whereas for smaller fragments of Ͻ200 u this figure only improves to 60 ppm. The instrumental stability is 1 ppm and better than 10 ppm is necessary for unique identification of species. The above experimental uncertainty can lead to unnecessary confusion where peaks are wrongly identified or peaks are ambiguously assigned. Here we study, in detail, the instrumental parameters of a popular single stage reflection TOF-SIMS instrument with ion trajectory calculations using SIMION. The effect of the ion kinetic energy, emission angle, and other instrumental operating parameters on the measured peak position are determined. This shows clearly why molecular and atomic ions have different relative peak positions and the need for an aperture to restrict ions at large emission angles. These data provide the basis for a coherent procedure for optimizing the settings for accurate mass calibration and rules by which calibrations for inorganics and organics may be incorporated. This leads to a new generic set of ions for mass calibration that improves the mass accuracy in our interlaboratory study by a factor of 5. A calibration protocol is developed, which gives a relative mass accuracy of better than 10 ppm for masses up to 140 u. The effects of extrapolation beyond the calibration range are discussed and a recommended procedure is given to ensure that accurate mass is achieved within a selectable uncertainty for large molecules. Additionally, we can alternatively operate our instrument in a regime with good energy discrimination (i.e., poor energy compensation) to study the fragmented energies of molecules. This leads to data that support previous concepts developed in G-SIMS. tatic SIMS (SSIMS) is a powerful technique for the analysis of organic and molecular surfaces. Over the last decade, instrumentation has improved significantly so that modern instruments now have very high reliability. Together with reference procedures and methods, the intensity repeatability has improved by over a factor of 10. In a recent VAMAS interlaboratory study [1] conducted by NPL, over 84% of instruments exhibited excellent intensity repeatabilities of better than 1.9%. It was also demonstrated that the comparability of relative ion intensities between different instrument designs can be Ͻ4% by incorporation of the concept of the relative instrument spectral response (RISR) function [1].A significant issue for many analysts is establishing an accurate calibration of the mass scale for time-of-flight (TOF) instruments. In a recent ISO [2] survey of needs for standardization in static SIMS, analysts ranked a procedure for mass calibration as the top priority. Typically, this needs to be conducted for each spectrum since small variations in t...

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“…While SIMS provides analytical information on elements and small organic molecules, MALDI allows identification of large biomolecules such as proteins. In the so-called static SIMS mode [32], analytical information is obtained from the first monolayer only. Static SIMS is therefore known as a real surface analytical technique.…”

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confidence: 99%

Scanning microprobe matrix-assisted laser desorption ionization (SMALDI) mass spectrometry: Instrumentation for sub-micrometer resolved LDI and MALDI surface analysis

Spengler

Hubert

2002

J. Am. Soc. Mass Spectrom.

269

256

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A new instrument and method is described for laterally resolved mass spectrometric surface analysis. Fields of application are in both the life sciences and the material sciences. The instrument provides for imaging of the distribution of selected sample components from natural and artificial surfaces. Samples are either analyzed by laser desorption ionization (LDI) time-of-flight mass spectrometry or, after preparation with a suitable matrix, by matrixassisted laser desorption ionization (MALDI) mass spectrometry. Areas of 100 ϫ 100 m are scanned with minimal increments of 0.25 m, and between 10,000 and 160,000 mass spectra are acquired per image within 3 to 50 min (scan rate up to 50 pixels per s). The effective lateral resolution is in the range of 0.6 to 1.5 m depending on sample properties, preparation methods and laser wavelength. Optical investigation of the same sample area by UV confocal scanning laser microscopy was found to be very attractive in combination with scanning MALDI mass analysis because pixel-identical images can be created with both techniques providing for a strong increase in analytical information. This article describes the method and instrumentation, including first applicational examples in elemental analysis, imaging of pine tree roots, and investigation of MALDI sample morphology in biomolecular analysis. (J Am Soc Mass Spectrom 2002, 13, 735-748)

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High mass resolution time‐of‐flight secondary ion mass spectrometry. Application to peak assignments

Cited by 65 publications

References 11 publications

Positive secondary ion mass spectrum of poly(methyl methacrylate): a high mass resolution ToF-SIMS study

Positive secondary ion mass spectrum of poly(methyl methacrylate): a high mass resolution ToF-SIMS study

TOF-SIMS: Accurate mass scale calibration

Scanning microprobe matrix-assisted laser desorption ionization (SMALDI) mass spectrometry: Instrumentation for sub-micrometer resolved LDI and MALDI surface analysis

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