STABLE ISOTOPES AS BIOTRACER BY NOVEL LASER METHODS

通过新颖的激光方法将稳定同位素作为生物示踪剂

• 批准号: 3299043
• 负责人: WILLIAM G. TONG
• 金额: $ 8.13万
• 依托单位: SAN DIEGO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-01-01 至 1991-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3299043
• 关键词: biomedical equipment development; dietary calcium; laser spectrometry; nutrient bioavailability; radiotracer; stable isotope

The proposed research concerns the design and application of novel, ultra-sensitive, highresolution laser spectroscopic methods in measurement of metallobiochemically-important elements. For dietary availability and mineral absorption studies, the use of stable isotopes has provided an attractive alternative to radioisotopes due to the safety and ethical reasons. Although stable isotopes have been used frequently, the currently available stable isotope determination methodologies limit severely the full use of stable isotopes in biotracer studies. Even the most often used method, mass spectrometry, has many disadvantages including slow sample throughput, chemical interference and requirement of time-consuming sample purification and chelation steps. In this proposal, innovative, powerful, laser-based methods - optical phase conjugation spectroscopy and polarization spectroscopy - are presented to overcome many of the difficulties. These Doppler-free (and Lorentzian-free) laser spectroscopic methods yield spectral resolution high enough to resolve atomic/isotopic hyperfine structures - the spectroscopic fingerprints of atoms. Hence, excellent elemental/isotopic selectivity is obtained and spectral and chemical interference is virtually eliminated even if the sample contains a number of minerals. In addition to selectivity, these nonlinear laser methods also offer one of the most sensitive detection limits, and, hence, they have potential for isotope analysis at trace concentrations (ppm, and pptr) or for simple quantitative measurement of minerals in biological samples. These nonlinear laser methods employ multiple input laser beams to induce nonlinear effects in the sample and to generate signal beams. Cubic signal dependence on laser power in optical phase conjugation spectroscopy (and quadratic dependence in polarization spectroscopy) allows extremely effective use of high photon power available from lasers. Since signal is a laser beam, optical detection is very efficient. While analytical flame can be used as an atomizer to provide fast, convenient and continuous-flow sample introduction, a low-pressure discharge cell can be used for small samples and to obtain extremely high spectral resolution. Some of the advantages of the proposed laser methods over the conventional methods include excellent sensitivity, selectivity and reproducibility, relatively inexpensive instrumentation, rapid, simple and safe operation, capability of analyzing both stable and radioisotopes in small sample sizes, and fast sample throughput. The effectiveness of these laser methods will be investigated for some of the most important elements in biological studies such as Li, Ca, Ba, Cu, Zn, Mg, Pb, Cd, V, and A1. Since all isotopes present (stable and radioactive) are measured simultaneously in a hyperfine structure, these laser methods are also applicable to studies where radioisotopes are absolutely necessary.

该研究涉及新型， 超灵敏，高分辨率激光光谱方法， 金属生物化学重要元素的测量。 为 膳食可用性和矿物质吸收研究，使用 稳定同位素提供了一种有吸引力的替代品， 放射性同位素，出于安全和伦理原因。 虽然 稳定同位素已经被频繁使用，目前可用的 稳定同位素测定方法严重限制了 在生物示踪剂研究中使用稳定同位素。 即使是最常见的 使用的方法，质谱法，有许多缺点，包括 缓慢样品通量、化学干扰和 耗时的样品纯化和螯合步骤。 在这项提案中，创新的，强大的，基于激光的方法- 光学相位共轭光谱和偏振 光谱-提出克服许多困难。 这些无多普勒（和无洛伦兹）激光光谱 方法产生足够高的光谱分辨率， 原子/同位素超精细结构-光谱 原子的指纹 因此，优秀的元素/同位素 获得选择性，光谱和化学干扰， 即使样品中含有大量 矿物 除了选择性之外，这些非线性激光器 方法还提供了最灵敏的检测极限之一，并且， 因此，它们具有痕量同位素分析潜力 浓度（ppm和pptr）或简单定量 测量生物样品中的矿物质。 这些非线性 激光方法采用多个输入激光束来诱导非线性 样品中的效应并产生信号光束。 立方信号 光学相位共轭光谱中的激光功率依赖性 (and偏振光谱中的二次依赖性）允许 非常有效地利用激光器的高光子功率。 由于信号是激光束，因此光学检测非常有效。 虽然分析火焰可以用作雾化器以提供快速， 进样方便，连续流动，低压 放电池可用于小样品， 极高的光谱分辨率。 所提出的激光方法优于 传统的方法包括优异的灵敏度、选择性 和再现性，相对便宜的仪器，快速， 操作简单、安全，分析稳定， 放射性同位素在小样品尺寸和快速样品通量。 将研究这些激光方法的有效性， 生物学研究中一些最重要的元素， Li、Ca、Ba、Cu、Zn、Mg、Pb、Cd、V和Al。 因为所有的同位素 存在（稳定和放射性）的同时测量， 超精细结构，这些激光方法也适用于 放射性同位素是绝对必要的研究。