液芯光纤共振拉曼光谱法检测水中生物分子研究

Study of Biological Molecules in Water by Using the Resonance Raman Spectra in Liquid-Core Optical Fiber

拉曼光谱是研究水中生物分子重要的有效方法之一,然而由于拉曼散射截面小,特别是水分子的电子激发态能级高,因此水中生物分子的拉曼光谱测量甚为困难。将液芯光纤技术和共振拉曼技术结合起来,可大幅度提高拉曼光谱强度。实验中用可以获得最大的共振拉曼光谱强度的514.5nmAr+离子激光激发,分别用石英和Teflon液芯光纤对水中β-胡萝卜素生物分子进行了痕量检测研究。结果表明应用石英液芯光纤和Teflon液芯光纤可分别检测浓度为10-7～10-9mol.L-1和10-9～10-10mol.L-1的β-胡萝卜素。

Raman spectrum is an important and effective method for the study of biological molecules in water. Measuring the Raman spectra for biological molecules in water, however, is very difficult because of the small Raman scattering cross section and the high electronic excitation energy of water molecules. In the present paper, the authors applied both technologies of liquid-core optical fiber and the resonance Raman spectra, then the intensity of Raman spectra was enhanced to a great extent. In this experiment, we chose the laser wavelength 514. 5 of Ar^＋ ion laser as excitation laser, because we could obtain the maximal intensity of resonance Raman spectra at this wavelength. The experiment results show that, for the trace inspecting study of β-carotene biological molecules in water, the concentration in the range of 10^-7-10^-9 mol · L^-1 can be detected by quartz liquidcore optical fiber and the concentration in the range of 10^-9-10^-10 mol · L^-1 by Teflon liquid-core optical fiber. The detecting utmost will be further reduced if improving the quality of optical fiber.