Molecular Speciation of Saturates by On-Line Liquid Chromatography−Field Ionization Mass Spectrometry

Liang, Zhenmin; Hsu, Chang Samuel

doi:10.1021/ef970216v

Cited by 36 publications

(27 citation statements)

References 14 publications

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“…Electron ionization (EI) produces severe fragmentation, which often prevents obtaining molecular weight information [20]. Field desorption (FD) and field ionization (FI) involve rapid heating of the analytes, which can cause fragmentation, especially for highly branched hydrocarbons [21]. This method also suffers from a bias against small and large analytes.…”

Section: Introductionmentioning

confidence: 99%

HPLC/APCI Mass Spectrometry of Saturated and Unsaturated Hydrocarbons by Using Hydrocarbon Solvents as the APCI Reagent and HPLC Mobile Phase

Gao

Owen

Borton

et al. 2012

J. Am. Soc. Mass Spectrom.

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Saturated and unsaturated, linear, branched, and cyclic hydrocarbons, as well as polyaromatic and heteroaromatic hydrocarbons, were successfully ionized by atmospheric pressure chemical ionization (APCI) using small hydrocarbons as reagents in a linear quadrupole ion trap (LQIT) mass spectrometer. Pentane was proved to be the best reagent among the hydrocarbon reagents studied. This ionization method generated different types of abundant ions (i.e., [M + H] , with little or no fragmentation. The radical cations can be differentiated from the even-electron ions by using dimethyl disulfide, thus facilitating molecular weight (MW) determination. While some steroids and lignin monomer model compounds, such as androsterone and 4-hydroxy-3-methoxybenzaldehyde, also formed abundant M +• and [M+H] + ions, this was not true for all of them. Analysis of two known mixtures as well as a base oil sample demonstrated that each component of the known mixtures could be observed and that a correct MW distribution was obtained for the base oil. The feasibility of using this ionization method on the chromatographic time scale was demonstrated by using high-performance liquid chromatography (HPLC) with hexane as the mobile phase (and APCI reagent) to separate an artificial mixture prior to mass spectrometric analysis.

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Section: Introductionmentioning

confidence: 99%

HPLC/APCI Mass Spectrometry of Saturated and Unsaturated Hydrocarbons by Using Hydrocarbon Solvents as the APCI Reagent and HPLC Mobile Phase

Gao

Owen

Borton

et al. 2012

J. Am. Soc. Mass Spectrom.

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“…Until now, 13 C NMR spectroscopy and field ionization (FI) and field desorption (FD) mass spectrometry (MS) have been the most common techniques employed for characterization of heavy saturated hydrocarbon mixtures in petroleum industry (light hydrocarbons can be analyzed using gas chromatography/mass spectrometry (GC/MS)). − However, 13 C NMR spectroscopy can only provide bulk (average) information on these mixtures. In contrast, MS provides molecular level information, such as molecular weight and structural as well as quantitative information, on mixture components.…”

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confidence: 99%

Comparison of Atmospheric Pressure Chemical Ionization and Field Ionization Mass Spectrometry for the Analysis of Large Saturated Hydrocarbons

Jin

Viidanoja

et al. 2016

Anal. Chem.

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Direct infusion atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was compared to field ionization mass spectrometry (FI-MS) for the determination of hydrocarbon class distributions in lubricant base oils. When positive ion mode APCI with oxygen as the ion source gas was employed to ionize saturated hydrocarbon model compounds (M) in hexane, only stable [M - H] ions were produced. Ion-molecule reaction studies performed in a linear quadrupole ion trap suggested that fragment ions of ionized hexane can ionize saturated hydrocarbons via hydride abstraction with minimal fragmentation. Hence, APCI-MS shows potential as an alternative of FI-MS in lubricant base oil analysis. Indeed, the APCI-MS method gave similar average molecular weights and hydrocarbon class distributions as FI-MS for three lubricant base oils. However, the reproducibility of APCI-MS method was found to be substantially better than for FI-MS. The paraffinic content determined using the APCI-MS and FI-MS methods for the base oils was similar. The average number of carbons in paraffinic chains followed the same increasing trend from low viscosity to high viscosity base oils for the two methods.

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“…As a result, FD and FI are the primary soft ionization methods used in petroleum analysis. However, heating the analytes during FD/FI can be problematic and may cause fragmentation of molecular ions, a problem that becomes acute for high boiling materials [2]. In addition, branched alkanes are easily fragmented in FD/FI, making quantitative measurement of isomeric paraffins very challenging [2,3].…”

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confidence: 99%

“…However, heating the analytes during FD/FI can be problematic and may cause fragmentation of molecular ions, a problem that becomes acute for high boiling materials [2]. In addition, branched alkanes are easily fragmented in FD/FI, making quantitative measurement of isomeric paraffins very challenging [2,3]. Atmospheric pressure photoionization (APPI) can be used to ionize nonpolar polycyclic aromatic hydrocarbons by producing a radical cation and/or a protonated molecule of the analyte, but it cannot be used to ionize saturated paraffins [4].…”

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Ambient analysis of saturated hydrocarbons using discharge-induced oxidation in desorption electrospray ionization

Qian

Nefliu

et al. 2010

J. Am. Soc. Mass Spectrom.

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Saturated nonfunctionalized hydrocarbons can be oxidized in situ by initiating an electrical discharge during desorption electrospray ionization (DESI) to generate the corresponding alchohols and ketones. This form of reactive DESI experiment can be utilized as an in situ derivatization method for rapid and direct analysis of alkanes at atmospheric pressure without sample preparation. Betaine aldehyde was incorporated into the DESI spray solution to improve the sensitivity of detecting the long-chain alcohol oxidation products. The limit of detection for alkanes (C 15 H 32 to C 30 H 62) from pure samples is 20 ng. Multiple oxidations and dehydrogenations occurred during the DESI discharge, but no hydrocarbon fragmentation was observed, even for highly branched squalane. Using exact mass measurements, the technique was successfully implemented for analysis of petroleum distillates containing saturated hydrocarbons. (J Am Soc Mass Spectrom 2010, 21, 261-267) N on-polar hydrocarbons, the major constituent (90%) of petroleum distillates derived from crude oil [1], are difficult to analyze by mass spectrometry using atmospheric pressure ionization methods. Saturated hydrocarbons in particular, which lack functional groups and aromatic rings, can only be ionized by high voltage electron ionization (EI), chemical ionization (CI), field desorption (FD), or field ion-ization (FI). Among these methods, EI, and CI are not ideal for hydrocarbon mixture analysis due to significant fragmentation of molecular ions. As a result, FD and FI are the primary soft ionization methods used in petroleum analysis. However, heating the analytes during FD/FI can be problematic and may cause fragmentation of molecular ions, a problem that becomes acute for high boiling materials [2]. In addition, branched alkanes are easily fragmented in FD/FI, making quantitative measurement of isomeric paraffins very challenging [2, 3]. Atmospheric pressure photoionization (APPI) can be used to ionize nonpolar polycyclic aromatic hydrocarbons by producing a radical cation and/or a protonated molecule of the analyte, but it cannot be used to ionize saturated paraffins [4]. In spite of these difficulties, traditional hydrocarbon analysis in the petroleum industry continues to be an important subject. Recently, laser-induced acoustic desorption (LIAD) coupled with gas-phase ion/molecule reactions under vacuum has shown great potential to achieve efficient ionization of saturated hydrocarbons with little [1] or no [5] fragmentation. Direct analysis of hydrocarbons under ambient conditions remains highly desirable however, because it allows easy implementation on both commercial and portable mass spectrometers of on-site analysis and has the potential for high through-put screening. This paper introduces a new method that addresses this problem. Desorption electrospray ionization (DESI) is an ambient analysis method that shares some of the properties of the electrospray (ESI) technique [6]. In particular, oxidation artifacts of analytes have been reported in ...

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Molecular Speciation of Saturates by On-Line Liquid Chromatography−Field Ionization Mass Spectrometry

Cited by 36 publications

References 14 publications

HPLC/APCI Mass Spectrometry of Saturated and Unsaturated Hydrocarbons by Using Hydrocarbon Solvents as the APCI Reagent and HPLC Mobile Phase

HPLC/APCI Mass Spectrometry of Saturated and Unsaturated Hydrocarbons by Using Hydrocarbon Solvents as the APCI Reagent and HPLC Mobile Phase

Comparison of Atmospheric Pressure Chemical Ionization and Field Ionization Mass Spectrometry for the Analysis of Large Saturated Hydrocarbons

Ambient analysis of saturated hydrocarbons using discharge-induced oxidation in desorption electrospray ionization

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