Development of Multiphoton Ionization Time-of-Flight Mass Spectrometry for the Detection of Small Emulsion Droplets

Fujita, Chiaki; Sugimura, Yoshiki; Uchimura, Tomohiro

doi:10.3390/app8030413

Cited by 5 publications

(7 citation statements)

References 32 publications

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“…In fact, we reported positive spikes by measuring the O/W emulsion. 10,11 This marks the first report of signals changing from negative to positive as the emulsion type changed from W/O to O/W.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…If the number of droplets would have decreased, individual droplets and/or small aggregates should have passed through the capillary column and positive spikes composed of a single plot would have been observed. In fact, we reported positive spikes by measuring the O/W emulsion. , This marks the first report of signals changing from negative to positive as the emulsion type changed from W/O to O/W.…”

Section: Resultsmentioning

confidence: 99%

“…To monitor the flow of the emulsion through the inner capillary column, a microscopic system was constructed (G plan Apo; magnification 20; numerical aperture 0.28; Mitutoyo, Kanagawa, Japan), 11 and the length between the microscopic observation point and the nozzle tip of the inner capillary column was set at 23 cm. A digital camera (DIGITAL SIGHT DS-U1, Nikon) was used to record the emulsion flow.…”

Section: ■ Experimental Sectionmentioning

confidence: 98%

“…We have reported a method for the direct analysis of an emulsion without pretreatment using resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS). − REMPI has superior spectroscopic selectivity and produces fewer contaminants, − and TOFMS is easy to clean because of the simple structure, − even when there is contamination. These advantages make REMPI-TOFMS suitable for the measurement of an emulsion where the concentrations of the constituents are inherently high.…”

Section: Introductionmentioning

confidence: 99%

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Characteristic Signal Behaviors for Water-in-Oil and Oil-in-Water Emulsions Measured by Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

et al. 2020

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Resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) was used to study the characteristic signal behaviors obtained from two types of emulsions: water-in-oil (W/O) and oil-in-water (O/W). All emulsions were prepared using phase inversion emulsification, i.e., a solution for an aqueous phase was added dropwise to an oil phase with constant stirring to obtain an emulsion. Toluene served as a detection component. When using REMPI-TOFMS to measure an emulsion, a time profile for the target component can be constructed by plotting peak areas for the corresponding component on a series of mass spectra. In the case of a W/O emulsion at a water volume fraction (f w) of 0.005, the concentration of toluene was instantaneously decreased due to the existence of water droplets, and therefore, several negative spikes were detected on the time profile while establishing a baseline. In the case of a W/O emulsion at f w = 0.3, negative peaks consisting of several plots appeared on the time profile because of the formation of aggregates of water droplets while the emulsion was flowed through a capillary column for sample introduction. An O/W emulsion at f w = 0.995 was analyzed following phase inversion, and positive peaks were detected due to the aggregates of many oil droplets. In this manner, the direct mass analysis of emulsions before and after phase inversion was achieved, and the resultant signal inversion was confirmed via REMPI-TOFMS.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characteristic Signal Behaviors for Water-in-Oil and Oil-in-Water Emulsions Measured by Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

et al. 2020

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“…Recently, we applied MPI-TOFMS to the online analysis of an emulsion. − We developed a sample introduction technique for an emulsion, and the online mass analysis of an oil phase in an O/W emulsion without pretreatment was achieved . We reported the time profile of a peak area of an analyte, which was constructed by plotting the peak areas of the corresponding ions in a series of mass spectra.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Creaming of an Emulsion via Mass Spectrometry and UV–Vis Spectrophotometry

Shinoda

Uchimura

2018

ACS Omega

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The creaming behavior of a turbid oil-in-water emulsion was observed via the processes of multiphoton ionization time-of-flight mass spectrometry (MPI-TOFMS) and ultraviolet–visible spectrophotometry (UV–vis), and the results were compared. The transmittance measurement by UV–vis showed that the turbidity of the toluene emulsion was decreased with time. However, non-negligible errors are common in the measurement of a sample with high turbidity. The online measurement by MPI-TOFMS detected many spikes in the time profile, which revealed the existence of toluene droplets in the emulsion. A smooth time profile suggested that the signal intensity had initially increased, and then decreased with time; the initial concentration of toluene was 3 g/L, which had decreased by half after 60 min. The signal behavior obtained using MPI-TOFMS differed only slightly from that obtained using UV–vis. Since a change in turbidity is not the same as a change in the local concentration of an oil component, MPI-TOFMS is useful for the analysis of a turbid emulsion and offers additional information concerning the creaming phenomenon of an emulsion.

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Correction to “Using Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry to Quantitatively Analyze the Creaming of an Emulsion”

Takezawa¹,

Iwata²,

Ueyama³

et al. 2021

ACS Omega

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Development of Multiphoton Ionization Time-of-Flight Mass Spectrometry for the Detection of Small Emulsion Droplets

Cited by 5 publications

References 32 publications

Characteristic Signal Behaviors for Water-in-Oil and Oil-in-Water Emulsions Measured by Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

Characteristic Signal Behaviors for Water-in-Oil and Oil-in-Water Emulsions Measured by Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

Evaluating the Creaming of an Emulsion via Mass Spectrometry and UV–Vis Spectrophotometry

Correction to “Using Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry to Quantitatively Analyze the Creaming of an Emulsion”

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