Resonance-enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry for Evaluating Emulsion Inversion via Temperature Change

Iwata, Masafumi; Uchimura, Tomohiro

doi:10.2116/analsci.19p272

Cited by 7 publications

(9 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[19][20][21][22] Recently, we applied REMPI-TOFMS to the analysis of an emulsion without pretreatment. [23][24][25] In this technique, an emulsion is flowed through a capillary column and is continuously introduced into TOFMS. Then a series of mass spectra are recorded, the peak areas of a target species are extracted from the series of mass spectra, and finally a time profile of the peak areas can be constructed.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of the Creaming of Emulsions via Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

et al. 2021

Self Cite

View full text Add to dashboard Cite

The creaming behavior of an oil-in-water (O/W) emulsion was quantitatively evaluated via resonance-enhanced multiphoton ionization time-of-flight mass spectrometry. Styrene O/W emulsions were prepared with initial styrene concentrations of 1 and 4 g/L, and the height at the center of the sample was monitored. A peak area of the molecular ion of styrene was set as the signal intensity, for which a time profile was constructed from a series of mass spectra. As a result, the averaged time profiles showed that the signal intensities increased once and then decreased with the onset of creaming. In addition, in order to fit an experimentally obtained time profile, a modified fit function was proposed. Based on the fit results, the ratios of the increases and decreases in signal intensities were different between the two emulsions-higher in the case of an O/W emulsion with a higher initial oil concentration. On the other hand, the duration of the enhancement of the signal intensity with the onset of creaming was independent of the initial oil concentration. The present method offers the possibility to quantitatively evaluate the creaming behavior of an emulsion without pretreatment, and, therefore, would be useful for confirming the stability and quality assurance of emulsions.

show abstract

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of the Creaming of Emulsions via Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) using ultraviolet (UV) pulses for ionization is a selective analytical method. 13 − 17 Namely, compounds with absorption against the laser wavelength that is applied, mainly aromatic compounds, can be sensitively and selectively detected. Until now, Zimmermann et al have reported applications in evaluating volatile flavor compounds during coffee roasting.…”

Section: Introductionmentioning

confidence: 99%

Using SPME-GC/REMPI-TOFMS to Measure the Volatile Odor-Active Compounds in Freshly Cooked Rice

et al. 2020

Self Cite

View full text Add to dashboard Cite

The volatile odor-active compounds of cooked rice were evaluated using a method that combined solid-phase microextraction (SPME) with gas chromatography–resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (GC/REMPI-TOFMS). An SPME fiber was held at the upper levels of the cooked rice and given an extraction time of 5 min. By using a nanosecond ultraviolet (266 nm) pulsed laser for ionization, two compounds, 4-vinylphenol and indole, which are considered to be important for the characteristic flavor of cooked rice, could be detected from all types of cultivars measured in the present study—nonglutinous rice, glutinous rice, and aromatic rice. In the case of fresh nonglutinous rice, the amounts of introduction for 4-vinylphenol and indole to GC were ca. 70 and 20 pg, respectively. While both peak areas decreased with increases in the time needed to maintain warmth, the decreasing behaviors differed slightly with a noteworthy rapid decrease for indole. For nonglutinous rice, the peak areas for 4-vinylphenol were almost the same, whether it was fresh (measured within 1 month from harvest) or aged (measured 6–12 months after harvest), but those of indole significantly decreased following storage. We also found differences among cultivars: the peak area for 4-vinylphenol in nonglutinous rice was somewhat strong; the peak area for indole was intensely strong in glutinous rice; however, the peak areas for both 4-vinylphenol and indole were weak in aromatic rice. Volatile odor-active compounds were detected in a sensitive and time-resolved manner; therefore, the proposed method could be useful for differentiating varieties of cooked rice from the viewpoints of cooking conditions, freshness, and cultivar types.

show abstract

“…In a previous study, we demonstrated the evaluation of an emulsion where phase inversion had occurred via a temperature change. 13 In that report, a capillary column was used for sample introduction, and when the temperature of the column was low (40 °C), several positive spikes were detected. This indicated that the emulsion was surely an O/W emulsion.…”

Section: ■ Introductionmentioning

confidence: 99%

“…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%

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Resonance-enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry for Evaluating Emulsion Inversion via Temperature Change

Cited by 7 publications

References 36 publications

Quantitative Evaluation of the Creaming of Emulsions via Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

Quantitative Evaluation of the Creaming of Emulsions via Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry

Using SPME-GC/REMPI-TOFMS to Measure the Volatile Odor-Active Compounds in Freshly Cooked Rice

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

Contact Info

Product

Resources

About