Cluster composition distribution at the liquid surface of alcohol–water mixtures and evaporation processes studied by liquid ionization mass spectrometry

Tsuchiya, Masahiko; Shida, Yasuo; Kobayashi, Kenichi; Taniguchi, Osamu; Okouchi, Shoichi

doi:10.1016/j.ijms.2004.03.014

Cited by 8 publications

(11 citation statements)

References 22 publications

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“…Thus, the intensity ratio of ethanol to water in the observed clusters, R E value, can be calculated as: Σ E /Σ W . The procedure is very similar to that reported by Tsuchiya et al [36] to calculate the ethanol/water molar ratio in gas phase. Figure 4 reports the intensity ratio (R E ) for ethanol-water clusters acquired with EI and PI at different composition of ethanol/water mixtures to quantitatively compare the different ionization methods performances.…”

Section: Cluster Composition Distribution: Molar Ratio Of Ethanol To mentioning

confidence: 52%

Insights on Clusters Formation Mechanism by Time of Flight Mass Spectrometry. 1. The Case of Ethanol–Water Clusters

Apicella

Passaro

2015

J. Am. Soc. Mass Spectrom.

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Abstract. In the present work, water clusters with the addition of an electrophilic molecule such as ethanol have been studied by time of flight mass spectrometry (TOFMS). Mass distributions of molecular clusters of ethanol, water, and ethanolwater mixed clusters were obtained by two different ionization methods: electron ionization (EI) and picosecond laser photo-ionization (PI) at a wavelength of 355 nm. It was shown that short pulse laser ionization increases the signal intensity and promotes the extension of the detected mass range of the clusters in comparison with EI. Much larger clusters were detected in our experiments with respect to the current literature. The autocorrelation function (AF) was introduced in the analysis of the composition of the water clusters in terms of fundamental periodicities for obtaining information on clusters formation mechanisms. Besides, it was found that ethanol molecules are capable of substitutional interaction with hydrogen-bonded water clusters in ethanol-water binary mixtures but the self-association of ethanol was the dominant process. Moreover, the increase of ethanol concentration promotes both the formation of hydrated ethanol clusters and the self-association of ethanol clusters in ethanol-water binary mixtures. The formation of water-rich clusters and subsequent metastable fragmentation were found to be the dominant processes determining the water-rich cluster distribution, irrespective of the ionization process, while the ionization process significantly affects the ethanol-rich cluster distribution.

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Section: Cluster Composition Distribution: Molar Ratio Of Ethanol To mentioning

confidence: 52%

Insights on Clusters Formation Mechanism by Time of Flight Mass Spectrometry. 1. The Case of Ethanol–Water Clusters

Apicella

Passaro

2015

J. Am. Soc. Mass Spectrom.

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“…26) The distribution of cluster sizes of water in the air has been measured at ambient temperature and found that the size distributions were related to the humidity, 24) suggesting that neutral clusters of water exist in the air. Alcohol aqueous solutions (20%v/v, methanol and ethanol) have been measured by LPI-MS. 27) The molar ratios of alcohol to water calculated from LPI mass spectra have been agreed with the alcohol concentration of the solution, although the flow rate of a sample solution (F s ) and the voltage applied to the needle (V E ) should be controlled. It has become clear that the method is appropriate to investigate hydrogen-bonded clusters, which exist at the surface of liquids and also in a gas phase at atmospheric pressure and at ambient temperature.…”

Section: Liquid Ionization (Lpi) Mass Spectrometrymentioning

confidence: 77%

“…In previous studies by liquid-ionization (LPI) mass spectrometry, a single quadrupole mass spectrometer has been used. [21][22][23][24][25][26][27] In this paper, a tandem mass spectrometer (Extrel CMS, TMAX 2000) equipped with an improved LPI ion source was used.…”

Section: Methodsmentioning

confidence: 99%

“…28) Results also indicate that the composition distributions of cluster ions observed by LPI-MS are likely similar to the distributions of neutral clusters. 27) It has been clear that the position of the needle tip respect to the pinhole is the most critical parameter for obtaining mass spectra showing the cluster compositions at the liquid surface, because the cluster compositions vary very quickly due to evaporation, sample ions produced at the needle tip, and these ions should go through the pinhole up to the detector. The envelope of ion source used previously was a glass cylinder, [21][22][23][24][25][26][27] so that the image around the needle tip was distorted.…”

Section: Liquid Ionization (Lpi) Mass Spectrometrymentioning

confidence: 99%

“…In other words, there is no places for occurring adiabatic condensation in this instrument. 27) Several devices for introducing sample solution have been examined and it was found that good results were obtained using a microsyringe needle (Hamilton 7780-01, inner diameter: 0.13 mm). Sample liquid was supplied to the needle tip at a constant flow rate (F s ) by an infusion pump (Kd Scientific, Holliston, USA).…”

Section: Lpi Ion Sourcementioning

confidence: 99%

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Cluster Composition Distributions of Pure Ethanol: Influence of Water and Ion–Molecule Reactions Revealed by Liquid-Ionization Tandem Mass Spectrometry

2013

Self Cite

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Studies of clusters in condensed phase at atmospheric pressure are very important for understanding the properties and structures of liquids. Liquid-ionization (LPI) mass spectrometry is useful to study hydrogen-bonded clusters at the liquid surface and in a gas phase. An improved ion source connected to a tandem mass spectrometer provides detailed information about clusters. Mass spectra of pure ethanol (99.5%) observed by the first mass analyzer (Q1) showed neat ethanol cluster ions (C2H5OH) m H(+) with m up to 10 and hydrate ions (C2H5OH) m (H2O) n H(+) with m larger than 7 and n=1, such as those with m-n=8-1 and 9-1. When the flow rate of ethanol (liquid) was increased, large ethanol cluster ions with m larger than 25 were observed by the second mass analyzer (Q3). It is interesting to note that neat ethanol cluster ions are more abundant than corresponding (with the same m) hydrate ions (n=1), and major hydrate ions contain only one molecule of water. Results indicate that ion-molecule reactions occur between Q1 and Q3, because such mass spectra have never been observed by Q1. Various results indicate that neat ethanol clusters exist at the liquid surface and are ionized to give cluster ions.

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Current literature in mass spectrometry

2005

J. Mass Spectrom.

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Cluster composition distribution at the liquid surface of alcohol–water mixtures and evaporation processes studied by liquid ionization mass spectrometry

Cited by 8 publications

References 22 publications

Insights on Clusters Formation Mechanism by Time of Flight Mass Spectrometry. 1. The Case of Ethanol–Water Clusters

Insights on Clusters Formation Mechanism by Time of Flight Mass Spectrometry. 1. The Case of Ethanol–Water Clusters

Cluster Composition Distributions of Pure Ethanol: Influence of Water and Ion–Molecule Reactions Revealed by Liquid-Ionization Tandem Mass Spectrometry

Current literature in mass spectrometry

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