Analysis of Organoselenium and Organic Acid Metabolites by Laser Desorption Single Photon Ionization Mass Spectrometry

Chen, Yanfeng; Sullards, M. Cameron; Hoang, Tiffany T.; May, and Sheldon W.; Orlando, Thomas M.

doi:10.1021/ac060827x

Cited by 24 publications

(29 citation statements)

References 86 publications

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“…For example, 10.5-eV LDPI-MS was used to detect organoselenium and organic acid metabolites that ranged up to 500 Da in human urine (47). Detection limits were in the range of 20 ng/mL for several of the organoselenium compounds.…”

Section: Biological Applicationsmentioning

confidence: 99%

Light and Molecular Ions: The Emergence of Vacuum UV Single-Photon Ionization in MS

Hanley¹,

2009

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Thanks to recent technological advances and singlephoton ionization's (SPI's) ability to detect all organics,Because the human eye does not detect IR radiation, we cannot see a warm object in the dark without an IR camera or other "transformation method". MS has the same problem: it cannot directly detect the objects of intereststhe analyte moleculessbut only their ionized counterparts. Therefore, the transformation methods that ionize the analyte molecules are of particular importance to MS. The invention of new ionization methods such as MALDI or ESI for MS detection of biomolecules has had an enormous influence on the development of MS and its applications in analytical chemistry.However, many ionization methods result in the formation not only of intact molecular ions but also of ion fragments. This is particularly true for electron impact (EI) ionization, the classical ionization method for smaller molecules ranging in mass up to ∼500 Da. EI uses electrons of 70-eV kinetic energy, near where maximal ionization efficiency occurs, 1 which makes it a "hard" ionization technique because the analytes are heavily fragmented upon ionization. The molecular peak is often barely visible in the mass spectra of labile compounds, although the fragment patterns do supply information about the presence of distinct functional groups in the investigated molecules. Furthermore, the fragment patterns of unknown substances can be used for a statistically based identification by comparison with EI-MS library data. The benefits of the latter feature made MS with EI the routine spectrometric detection method for GC. However, the frequent absence of information on the molecular weight of labile compounds is a severe disadvantage of EI, hampering the identification of unknowns. Furthermore, for complex mixtures of organic compounds, EI-MS requires a preseparation method such as GC; otherwise, the overlapping complex fragment patterns cannot be deconvoluted into mass spectra of individual compounds.These shortcomings of EI have led to a continuing demand for robust fragmentation-free or "soft" ionization methods for MS. Several soft ionization techniques have been developed, including methods based on chemical ionization (CI), field ionization (FI), and photoionization (PI). More recently, MALDI and ESI emerged and became the dominant soft ionization methods for polar

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Section: Biological Applicationsmentioning

confidence: 99%

Light and Molecular Ions: The Emergence of Vacuum UV Single-Photon Ionization in MS

Hanley¹,

2009

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“…Furthermore, the optimized lasers desorption and ionization conditions were controlled and kept constant during the whole measurements. 16 In order to make the results as accurate as possible, we measured the signal intensities of at least three points located on the different places of the sample surface for each concentration. S3, Supporting Information).…”

Section: 4semi-quantification and Estimation Of The Limit Of Detecmentioning

confidence: 99%

“…14 Dimov detected the quantitative elemental analysis of Rhodium (Rh) and Palladium (Pd) in minerals. 16 Additionally, Sabbah and Pomerantz analysed the composition and molecular-mass distribution of asphaltenes. 16 Additionally, Sabbah and Pomerantz analysed the composition and molecular-mass distribution of asphaltenes.…”

Section: Introductionmentioning

confidence: 99%

Direct and fast detection of chlorothalonil in soil samples using laser desorption VUV single photon post-ionization mass spectrometry

Liu

Zhu

et al. 2015

Anal. Methods

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Wide and abusive applications of fungicides (such as chlorothalonil) in agricultural production have caused various adverse effects on the environment, especially on the soil. Herein, a novel laser desorption VUV single photon postionization mass spectrometry (LDPI-MS) has been firstly applied to the direct and fast detection of chlorothalonil in soil. In the experiment, three different wavelength lasers were used as the ionization sources (SPI at 118 nm, REMPI at 266 nm and 355 nm) and the results showed that only SPI at 118 nm could achieve expected "soft" ionization. The limit of detection in 118 nm ionization was determined to be 0.5 pmol per spot, ca. 1 mg/kg of chlorothalonil in soil. Moreover, no other additives were needed to assistant desorption/evaporation of chlorothalonil from soil samples and the detecting process could be rapidly completed on the basis of a time-saving sample pretreatment. The results demonstrated that LDPI-MS method held a great potential for detecting real natural soil contaminated with chlorothalonil.

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“…The L2MS uses laser for desorption followed by the resonance-enhanced multiphoton ionisation (REMPI) with laser or single-photon ionisation (SPI) with laser/discharge lamp to produce ions [32]. Due to the 'soft' ionisation, especially for SPI, the L2MS requires almost no sample preparation [33] and has proven to be a powerful analytical technique for characterising a wide range of molecular systems with high sensitivity [34][35][36][37][38][39][40][41][42][43][44][45][46].…”

Section: Laser Desorption-based Mass Spectrometrymentioning

confidence: 99%

Photoionisation and photodissociation studies of nonvolatile organic molecules by synchrotron VUV photoionisation mass spectrometry and theoretical calculations

Pan

Zhang

Guo

et al. 2010

International Reviews in Physical Chemistry

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The importance of photo-induced ionisation and dissociation of organic molecules has been recognised for several decades. Many studies have been carried out with different techniques and methods. However, introducing nonvolatile and thermally labile compounds into the gas phase in an ionisation chamber under high vacuum is still a great challenge. In this review, we present our recent work on the photoionisation and photodissociation of a series of nonvolatile organic molecules using IR laser desorption combined with tunable synchrotron vacuum ultraviolet photoionisation mass spectrometry. The fundamental fragmentation pathways of these compounds are discussed in detail. Theoretical calculations are employed in order to compare theoretical and experimental outcomes. We also give the potential application of this method in the qualitative analysis of complex mixtures.

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Analysis of Organoselenium and Organic Acid Metabolites by Laser Desorption Single Photon Ionization Mass Spectrometry

Cited by 24 publications

References 86 publications

Light and Molecular Ions: The Emergence of Vacuum UV Single-Photon Ionization in MS

Light and Molecular Ions: The Emergence of Vacuum UV Single-Photon Ionization in MS

Direct and fast detection of chlorothalonil in soil samples using laser desorption VUV single photon post-ionization mass spectrometry

Photoionisation and photodissociation studies of nonvolatile organic molecules by synchrotron VUV photoionisation mass spectrometry and theoretical calculations

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