Characterization of Fulvic Acid by Laser-Desorption Mass Spectrometry

Novotny, Frank J.; Rice, James A.; Weil, David A.

doi:10.1021/es00009a045

Cited by 38 publications

(38 citation statements)

References 10 publications

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“…For HA and FA, only sporadic high peaks between 100 and 600 Da were observed, which is consistent with the literature [13,15,28]. These observations were also in accordance with the results obtained by the ultrafiltration method (Section 3.1).…”

Section: Global Shape Approachsupporting

confidence: 92%

“…In MALDI, a protecting matrix is used to induce soft ionization due to the absorption of a large part of the laser energy by the matrix [13]. The mass spectra of Humic Substances are dominated by low molecular weight ions (usually between 500 and 3000 m/z ratio) [13][14][15][16]. According to the theory of supramolecular aggregates, individual components with low molecular weights (500-1500 Da) are bound by non-covalent bonds to form humic acid and fulvic acid [17].…”

Section: Introductionmentioning

confidence: 99%

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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF–MS) coupled to XAD fractionation: Method to algal organic matter characterization

Nicolau

Leloup

Lachassagne

et al. 2015

Talanta

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Section: Global Shape Approachsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF–MS) coupled to XAD fractionation: Method to algal organic matter characterization

Nicolau

Leloup

Lachassagne

et al. 2015

Talanta

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“…SRFA was chosen as calibration compound for a quantitative HULIS determination because it is widely used and chemically well characterized (e.g., Noyes and Leenheer, 1989;Leland et al, 1999). In addition, the molecular size distribution of SRFA is <1000 Da as determined by various methods, among them LDI-MS and MALDI-MS (Novotny and Rice, 1995;Brown and Rice, 2000;Leenheer et al, 2001;Kujawinski et al, 2002). The same molecular size range is expected for HULIS (Kiss et al, 2003).…”

Section: Methodsmentioning

confidence: 88%

Characterization of high molecular weight compounds in urban atmospheric particles

2005

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Abstract. The chemical nature of a large mass fraction of ambient organic aerosol particles is not known. High molecular weight compounds (often named humic-like substances) have recently been detected by several authors and these compounds seem to account for a significant fraction of the total organic aerosol mass. Due to the unknown chemical structure of these compounds quantification as well as a determination of their molecular weight is difficult. In this paper we investigate water soluble humic-like substances in ambient urban aerosol using size exclusion chromatography-UV spectroscopy and laser desorption/ionization mass spectrometry (LDI-MS). LDI-MS was used for the first time to investigate HULIS from atmospheric aerosols. A careful evaluation of the two method shows that both methods complement each other and that both are needed to learn more about the molecular weight distribution and the concentration of humic-like substances. An upper molecular weight limit of humic-like substances of about 700 Da and a concentration of 0.3-1.6 µg/m 3 air can be estimated, corresponding to 9-30% of the total organic carbon for an urban background site.

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“…These features were proved for ESI of humic molecules in combination with high-resolution instrumentation such as Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT IRC-MS) providing a resolving power up to 120,000 for low-mass molecules [29,30,31,32]. A possible drawback in soft ionization of humic substances was indicated by Novotny and Rice [33] who, by using laser desorption ionization (LDI), suggested that formation of multiply charged ions may represent a bias in favor of low average molecular weight of humic molecules. Plancque and coworkers [25], using quadrupole time-of-flight (Q-TOF) ESI-MS, showed that singly charged ions were by far the most abundant ions generated from a fulvic acid.…”

Section: Introductionmentioning

confidence: 99%

Electrospray ionization mass spectrometry of terrestrial humic substances and their size fractions

Piccolo

Spiteller

2003

Analytical and Bioanalytical Chemistry

100

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Electrospray ionization mass spectrometry (ESI-MS) was used to evaluate the average molecular mass of terrestrial humic substances, such as humic (HA) and fulvic (FA) acids from a soil, and humic acid from a lignite (NDL). Their ESI mass spectra, by direct infusion, gave average molecular masses comparable to those previously obtained for aquatic humic materials. The soil HA and FA were further separated in size-fractions by preparative high performance size exclusion chromatography (HPSEC) and analyzed with ESI-MS by both direct infusion and a further on-line analytical HPSEC. Unexpectedly, their average molecular mass was only slightly less than for the bulk sample and, despite different nominal molecular size, did not substantially vary among size-fractions. The values increased significantly (up to around 1200 Da) after on-line analytical HPSEC for the HA bulk sample, at both pH 8 and 4, and for the HA size-fractions when pH was reduced from 8 to 4. It was noticed that HA size-fractions at pH 8 were separated by on-line HPSEC in further peaks showing average masses which progressively increased with elution volume. Furthermore, when the HA and NDL bulk samples were sequentially ultracentrifuged at increasing rotational speed, their supernatants showed mass values which were larger than bulk samples and increased with rotational speed. These variations in mass values indicate that the electrospray ionization is dependent on the composition of the humic molecular mixtures and increases when their heterogeneity is progressively reduced. It is suggested that the dominance of hydrophobic compounds in humic supramolecular associations may inhibit the electrospray ionization of hydrophilic components. Our results show that ESI-MS is reasonably applicable to humic substances only after an extensive reduction of their chemical complexity.

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Characterization of Fulvic Acid by Laser-Desorption Mass Spectrometry

Cited by 38 publications

References 10 publications

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF–MS) coupled to XAD fractionation: Method to algal organic matter characterization

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF–MS) coupled to XAD fractionation: Method to algal organic matter characterization

Characterization of high molecular weight compounds in urban atmospheric particles

Electrospray ionization mass spectrometry of terrestrial humic substances and their size fractions

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