Agilent Technologies International Japan, Ltd., Hachioji Semiconductor Test Division, Hachioji, Tokyo, Japan.
Colloids Surf B Biointerfaces. 2010 Mar 1;76(1):137-44. doi: 10.1016/j.colsurfb.2009.10.027. Epub 2009 Oct 27.
Recently, inspection of chemical components like melamine plays an important role in food industry for the food safety. However, conventional analyzing methods require a lot of preparations and much of time. We propose a real-time method for investing the mean particle size and number density of concentrated suspensions without any preparations. There are several techniques of analyzing concentrated suspensions. Laser light scattering (LLS) and dynamic light scattering (DLS) are used to measure the particle size. Fourier transform infrared spectroscopy (FT-IR) is used to measure the number density. They have been successfully describing the physical and dynamics characteristics near single light scattering regions. On the other hand, they require samples to be highly diluted. This is a major disadvantage in studying real concentrated suspensions, or phenomena such as gelation. Our proposed method diffused photon density wave spectroscopy (DPDWS) is based on the multiple light scattering theory. Thus, DPDWS measures the particle size and number density of the concentrated suspensions without dilution in real time. Diffused photon density wave (DPDW) is a spherical energy wave generated from the intensity-modulated point light source in the concentrated suspensions. The absorption and scattering coefficients can be simultaneously obtained from the amplitude and phase of DPDW propagated through the concentrated suspensions. Furthermore, the particle size and number density of nanoparticles can be estimated from the obtained optical properties using the absorption and the scattering theory. In this study, we qualitatively estimated the gelation of milk from the measured particle size and number density by use of DPDWS.
近年来，在食品安全方面，对三聚氰胺等化学物质的检测在食品工业中起着重要作用。然而，传统的分析方法需要大量的准备工作和时间。我们提出了一种实时的方法，无需任何准备即可测量浓缩悬浮液的平均粒径和数密度。有几种分析浓缩悬浮液的技术。激光光散射（LLS）和动态光散射（DLS）用于测量粒径。傅里叶变换红外光谱（FT-IR）用于测量数密度。它们已经成功地描述了单光散射区域附近的物理和动力学特性。另一方面，它们要求样品高度稀释。这在研究真实浓缩悬浮液或凝胶化等现象时是一个主要的缺点。我们提出的方法——漫散光密度波光谱法（DPDWS）基于多光散射理论。因此，DPDWS 可以实时测量浓缩悬浮液的粒径和数密度，而无需稀释。漫散光密度波（DPDW）是从浓缩悬浮液中的强度调制点光源产生的球形能量波。通过传播通过浓缩悬浮液的 DPDW 的幅度和相位，可以同时获得吸收和散射系数。此外，可以使用吸收和散射理论从获得的光学性质中估计纳米颗粒的粒径和数密度。在这项研究中，我们使用 DPDWS 从测量的粒径和数密度定性估计了牛奶的凝胶化。
