著者

Hideyuki TAKEZAWA Kengo ITADANI Ryosuke OBATA Tomonobu SUGIYAMA Tomohiro UCHIMURA

出版者

The Japan Society for Analytical Chemistry

雑誌

Analytical Sciences (ISSN:09106340)

巻号頁・発行日

vol.37, no.10, pp.1453-1457, 2021-10-10 (Released:2021-10-10)

参考文献数

30

被引用文献数

2

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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.