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Optical Engineering • Open Access

Nondestructive evaluation of crystallized-particle size in lactose-powder by terahertz time-domain spectroscopy
Author(s): Satoshi Yamauchi; Sakura Hatakeyama; Yoh Imai; Masayoshi Tonouchi

Paper Abstract

Transmission-type terahertz time-domain spectroscopy is applied to evaluate crystallized lactose particle of size below 30 μm, which is far too small compared to the wavelength of incident terahertz (THz)-wave. The THz-absorption spectrum of lactose is successfully deconvoluted by Lorentzian to two spectra with peaks at 17.1  cm[sup]−1 (0.53 THz) and 45.6  cm 1 (1.37 THz) derived from α -lactose monohydrate, and a spectrum at 39.7  cm1 (1.19 THz) from anhydrous β-lactose after removal of the broad-band spectrum by polynomial cubic function. Lactose is mainly crystallized into α -lactose monohydrate from the supersaturated solution at room temperature with a small amount of anhydrous β-lactose below 4%. The absorption feature is dependent on the crystallized particle size and the integrated intensity ratio of the two absorptions due to α-lactose monohydrate is correlated in linear for the size.

Paper Details

Date Published: 2 December 2013
PDF: 6 pages
Opt. Eng. 53(3) 031203 doi: 10.1117/1.OE.53.3.031203
Published in: Optical Engineering Volume 53, Issue 3
Show Author Affiliations
Satoshi Yamauchi, Ibaraki Univ. (Japan)
Sakura Hatakeyama, Ibaraki Univ. (Japan)
Yoh Imai, Ibaraki Univ. (Japan)
Masayoshi Tonouchi, Osaka Univ. (Japan)


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