Characterisation of humic substances using atmospheric pressure chemical ionisation and electrospray ionisation mass spectrometry combined with size-exclusion chromatography

Pfeifer, Thomas; Klaus, Uwe; Hoffmann, Ralf; Spiteller, Michael

doi:10.1016/s0021-9673(01)00805-6

Cited by 45 publications

(52 citation statements)

References 34 publications

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Section: Maldi-tof-mssupporting

confidence: 93%

“…This result is in good agreement with other literature data (Lingbo et al, 2005;Pfeifer et al, 2001;Rostad and Leenheer, 2004). Similarly to our results, Persson et al (2000) and Pfeifer et al (2001) observed at least one order of magnitude higher total ion current in the negative mode when analysing aquatic humic substances by ESI-MS. Furthermore, in positive ion mode, metal ion adduction (Leenheer et al, 2001;Plancque et al, 2001) and cluster formation of charged molecules with neutral ones (Klaus et al, 2000) have been suggested to bias the ion distribution towards higher values, while these processes were less pronounced in negative ion mode.…”

Section: Maldi-tof-mssupporting

confidence: 93%

“…The most intensive peak is at m/z 307.269, which corresponds to double charged fragment. The spacing between this peak and the most intensive one in the previous spectra is due to the fragmentation of CO 2 -group (m/z -44 for single chraged and m/z -22 for double charged fragment (Pfeifer et al, 2001). It is also possible that this difference is due to the fragmentation of Na + .…”

Section: Cinnamonic Forest Soil Spiked With Pt Ionsmentioning

confidence: 80%

“…They are negatively charged and tend to bind heavy metals and various organic compounds. Therefore it is of great interest to obtain more information about this class of compounds (Pfeifer et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Up to now, few attempts have been made to characterise humic substances by molecular weight using "soft" ionisation techniques such as electrospray ionisation (ESI), laser desorption (LDI) and matrix assisted laser desorption ionisation (MALDI). ESI is finding the most widespread application because it is considered to be the softest ionisation method (Brown and Rice, 2000;Kiss et al, 2003;Persson et al, 2000;Pfeifer et al, 2001;Reemtsma and These, 2003;Stenson et al, 2002;Varga et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Mass spectrometric techniques for characterisation of platinum–humic substance complexes in soil and street dust samples

Lyubomirova

Djingova

2013

Chemical Speciation & Bioavailability

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Increased platinum concentrations have been detected in environmental samples since the introduction of catalytic converters in Europe. It was previously believed that PGE are relatively inert and that the soluble fraction of automobile catalyst emitted PGE is only a few percent. However, new studies suggested that metallic Pt is oxidised in the soil and that the majority of the Pt species could be humic substance complexes.The aim of the present paper is the characterisation of platinum-humic acid complexes in spiked soil and street dust samples. A number of different soft ionisation mass spectrometric techniques, such as ESI-Q-MS, ESI-ION TRAP-MS and MALDI-TOF-MS have been tested. The ESI mass spectra of the soil humic acids were characterised by high complexity and irreproducibility.MALDI-TOF-MS was used for humic acid complexes characterisation in positive and negative modes. Positive ionisation was less effective and produced more simple and less informative spectra than negative ionisation. Two different MALDI matrices (CHCA, DHBA) were tested for use with humic substances. DHBA yielded better results, exhibiting superior ionisation efficiency, low spectral background and the matrix peaks were almost completely suppressed causing no interferences with identified analyte peaks. The application of MALDI-TOF-MS shows its suitability for humic substance characterisation. The comparison of the MALDI-spectra of humic acids, extracted from spiked and native soil proved that Pt undergoes transformation in the environment to humic acid complexes.

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Section: Maldi-tof-mssupporting

confidence: 93%

Section: Maldi-tof-mssupporting

confidence: 93%

Section: Cinnamonic Forest Soil Spiked With Pt Ionsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mass spectrometric techniques for characterisation of platinum–humic substance complexes in soil and street dust samples

Lyubomirova

Djingova

2013

Chemical Speciation & Bioavailability

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Development of liquid chromatography/mass spectrometry methods for the quantitative analysis of herbal medicine in biological fluids: a review

Gray

Chang

Zhang

et al. 2009

Biomedical Chromatography

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The development of liquid chromatography-mass spectrometry (LC-MS) and tandem MS/MS for the analysis of bioactive components and their metabolites of herbal medicines in biological fluids is reviewed with the aim of providing an overview of the current techniques and methods used. The issues and challenges associated with various stages of the analytical method development are discussed using Ginkgo biloba and Panax ginseng as case studies. LC-MS offers selectivity and specificity in both the chromatographic separation and detection steps. This is necessary in order to measure compounds at extremely low concentrations as is often observed in plasma and urine samples. Traditional methods of detection (UV-visible) do not offer sufficient selectivity and specificity needed. The strategies and pitfalls involved with the measurement of such compounds are discussed in this review. Matrix effects, 'unseen' matrix suppression and enhancement ionization effects can significantly reduce the accuracy and precision of the measurement. The impact of the correct choice of chromatography column formats on signal-to-noise ratio is also discussed. Analytical methods from sample preparation to mass spectrometric detection is outlined in order to provide good direction for analysts intent on the measurement of bioavailable compounds from herbal medicines in plasma and urine samples.

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Current literature in mass spectrometry

2002

J. Mass Spectrom.

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In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (4 Weeks journals ‐ Search completed at 14th. Nov. 2001)

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Characterisation of humic substances using atmospheric pressure chemical ionisation and electrospray ionisation mass spectrometry combined with size-exclusion chromatography

Cited by 45 publications

References 34 publications

Mass spectrometric techniques for characterisation of platinum–humic substance complexes in soil and street dust samples

Mass spectrometric techniques for characterisation of platinum–humic substance complexes in soil and street dust samples

Development of liquid chromatography/mass spectrometry methods for the quantitative analysis of herbal medicine in biological fluids: a review

Current literature in mass spectrometry

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