An introduction to the time-of-flight technique

Håkansson, P.

doi:10.1590/s0103-97331999000300004

Cited by 17 publications

(4 citation statements)

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“…As one of the effective methods to narrow the initial kinetic energy distribution, delayed extraction was first put forward by Wiley and McLaren in 1955, and was applied on MALDI by Brown and Vestal [4]. The principle of delayed extraction is: after the ionization, two ions with same mass number have different initial speeds and positions, without any electric field, they will do uniform rectilinear motion (assuming it is vacuum inside the instrument).…”

Section: Determination Of Key Parametersmentioning

confidence: 99%

A linear matrix assisted laser desorption ionization time-of-flight mass spectrometer used in pathogenic microorganism detection

Wang¹,

Wang²,

Xu³

et al. 2013

2013 6th International Conference on Biomedical Engineering and Informatics

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In order to achieve high throughput of microbial detection, this time of flight mass spectrometer (TOF-MS) is designed. A whole linear matrix assisted laser time-of-flight mass spectrometer (MALDI-TOF-MS) consists of six parts: vacuum system, sample inputting system, high voltage power supply system, laser system, detection system, mass analyzer system. In this paper, the functions, including devices, control process and the resulting effects of each part are introduced respectively. And aiming at the most influencing factor which means the focusing electrodes group of mass analyzer, simulations and analysis are done to optimize its structure parameters. Compared with other instruments, this MALDI-TOF-MS has faster analysis speed, smaller volume, lower cost and suitable for clinical testing. Finally the completed equipment is used for the detection of standard samples with mass number 1531 Daltons, the spectrogram shows this analysis system's resolution is about 2500 FWHM.

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Section: Determination Of Key Parametersmentioning

confidence: 99%

A linear matrix assisted laser desorption ionization time-of-flight mass spectrometer used in pathogenic microorganism detection

Wang¹,

Wang²,

Xu³

et al. 2013

2013 6th International Conference on Biomedical Engineering and Informatics

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“…The solution can be: (1) the use of high flux (10 26 photons per second) femtosecond lasers to initiate the multiphoton absorption within femtosecond pulse duration to efficiently ionize with considerable less fragmentation of parent molecules; 19 (2) the use of hybrid instruments like the quadrupole-TOF, an MS/ MS 21 technique employed to obtain structure information about molecules. A quadrupole here would be used to select a certain mass of a parent ion whose formula is that of the original matrix introduced into the graphite furnace.…”

Section: At 266 Nmmentioning

confidence: 99%

Identification of molecules in graphite furnace by laser ionization time-of-flight mass spectrometry: sulfur and chlorine containing compounds

Raseleka

Human

2004

J. Anal. At. Spectrom.

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“…Embora o primeiro espectrômetro de massas do tipo tempo de voo (TOF) tenha sido descrito pela primeira vez na literatura no final da década de 1940, levou mais de cinquenta anos para adaptá-lo para uso em um sistema ICP-MS (Håkansson, 1999).…”

Section: Analisador De Massas Do Tipo Tempo De Voounclassified

Correção de interferências isobáricas em análises de elementos terras raras em apatita e feldspato alcalino por LA-ICP-MS

Sousa¹

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The residence of REE in minerals has been widely studied with the use of in situ analysis techniques such as mass spectrometry with plasma inductively coupled with laser ablation (LA-ICP-MS) because it allows the quantification of these elements in levels within the range of mg L-1 or even µg L-1 in addition to a high resolution spatial analysis of REE in minerals with microscopic dimensions. Although the analytical results are fully satisfactory for the vast majority of matrices, important spectral interferences are known for some minerals, which can deteriorate or even make the results unfeasible. In particular, medium and heavy RRE, normally present at lower levels than light REE, can suffer significant interferences from Ba oxides and light REE, requiring corrections. In this work, a systematic study was made on the interferences of light oxides of Ba and REE, observed on the medium and heavy REE, in samples of alkaline feldspar and apatite from Pedra Branca Syenite and in the analyzes by LA-ICP-MS. For the calibration of interferences, spot sizes between 15 e 80 µm were used for ablation of the NIST K-378 standard containing high concentration of Ba to analysis of feldspar and synthetic monoelementary standards of La, Ce and Nd in the analysis of apatite. A study was also carried out using aqueous solutions, generating a hybrid between the LA system and the conventional one for solutions in order to avoid the synthesis of patterns, once it is not so trivial. In feldspar analyzes, Ba oxides interfere with Sm, Eu and Gd. In order to generate 1 mg L-1 of the interference, the Ba/Sm, Ba/Eu and Ba/Gd ratio must be 1,400,000, 38,500 e 1,075,000, respectively. In the two groups of samples studied, the Eu correction resulted in values between ~ 10% and ~ 90% lower than those measured. The Sm and Gd corrections, although minor, are recommended, but may be ineffective in some samples, whose actual levels are below the method's quantification limit. For apatite, the oxides of La, Ce and Nd interfere in Gd, Tb, Dy, Ho and Er. For the formation of 1 mg L-1 of Gd, the ratio La/Gd and Ce/Gd must be 250000 and 1800, respectively. For Tb, the Ce/Tb ratio is 15000 mg L-1 and Nd/Tb is 3000 mg L-1. In Dy and Ho elements, the interference caused by La, Ce and Nd was practically null. For Er, the ratio in concentration of Nd/Er is 7400. The interference calibration via synthetic standard for both feldspar and apatite is more efficient when compared to the calibration via aqueous solution, in which there is an increase in the interference of isobaric precursors with a greater formation of oxides and hydroxides, thus affecting the corrections of interferences. Correcting interference is important to generate Sm, Eu and Gd concentration results in alkaline feldspar and Gd and Tb in apatite with better approximations of the actual results as well as more accurate values for Eu anomalies. In the case studied, the corrected results Eu anomalies are consistent with independent results obtained for mafic minerals from the same rocks, ind...

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An introduction to the time-of-flight technique

Cited by 17 publications

References 0 publications

A linear matrix assisted laser desorption ionization time-of-flight mass spectrometer used in pathogenic microorganism detection

A linear matrix assisted laser desorption ionization time-of-flight mass spectrometer used in pathogenic microorganism detection

Identification of molecules in graphite furnace by laser ionization time-of-flight mass spectrometry: sulfur and chlorine containing compounds

Correção de interferências isobáricas em análises de elementos terras raras em apatita e feldspato alcalino por LA-ICP-MS

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