Arisawa J, Misawa K
Department of Electronic Engineering, Faculty of Engineering, Hokkaido Institute of Technology, Sapporo, Japan.
Front Med Biol Eng. 1989;1(4):287-97.
The surface structure of an artificial membrane composed of a Millipore filter and a synthetic lipid analogue, dioleylphosphate (DOPH), immersed in KCl solution changes when the CaCl2 concentration reaches a critical value. Using a photomultiplier mounted on the eyepiece of a stereoscopic microscope the structural change can be measured quantitatively as an intensity variation of reflected light of the membrane surface. Calcium ions decreased the intensity to about 50% of the original hydrophilic state whose solution was only KCl. However, the degree of structure change was dependent on adsorbed DOPH density, solution temperature and pH value. On the other hand, using the light reflectance curves obtained from the structural observations, an unknown CaCl2 concentration in a KCl solution can be determined. Since the reflectance curve shifts widely with various densities of DOPH adsorbed in the Millipore filter, it is possible to measure the CaCl2 concentration over a wide range. The detection range was from 0.1 to 50 mM CaCl2.
由微孔滤膜和合成脂质类似物二油酰磷酸酯（DOPH）组成的人工膜浸入氯化钾溶液中，当氯化钙浓度达到临界值时，其表面结构会发生变化。使用安装在立体显微镜目镜上的光电倍增管，结构变化可以作为膜表面反射光强度变化进行定量测量。钙离子使强度降低至仅含氯化钾溶液的原始亲水状态强度的约50%。然而，结构变化程度取决于吸附的DOPH密度、溶液温度和pH值。另一方面，利用从结构观察获得的光反射曲线，可以测定氯化钾溶液中未知的氯化钙浓度。由于反射曲线会随着微孔滤膜上吸附的各种密度的DOPH而大幅移动，因此有可能在很宽的范围内测量氯化钙浓度。检测范围为0.1至50 mM氯化钙。
