EVALUATION AND APPLICATION OF A NEW HIGH PRECISION NULL-POINT ANALYTICAL TECHNIQUE IN FLAME SPECTROMETRY
EVALUATION AND APPLICATION OF A NEW HIGH PRECISION NULL-POINT ANALYTICAL TECHNIQUE IN FLAME SPECTROMETRY
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DOI：
10.1021/ac60334a023
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发表时间：
1973-01-01
影响因子：
7.4
通讯作者：
HIEFTJE, GM
中科院分区：
文献类型：
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作者：
BASTIAANS, GJ;HIEFTJE, GM
一种将样品引入火焰的新方法已被用来开发火焰光谱测定中的高精度“零点”分析技术。样品引入技术采用均匀液滴流，以受控的可变速率注入火焰中。在零技术中，通过改变样品和标准品的液滴引入速率来获得相等的信号强度，从而获得火焰中相等的原子浓度来进行测定。然后通过涉及标准浓度和液滴注射速率的简单计算来确定未知的样品浓度。与更传统的技术相比，从汽化干扰、自吸收、精度和样品灵活性方面讨论了该技术的优点和缺点。以血清中钙和钠的分析为例来评估该技术的能力。考虑并讨论了该技术向原子吸收、原子荧光和实验室自动化的扩展。与许多分析技术一样，火焰光谱法非常适合常规样品的测定。具有明确浓度范围和恒定基质的重复样品对于技术人员执行的或全自动火焰分析来说并不困难。通过先前的调查，可以优化这些测定，以针对所调查的特定样品类型提供所需的准确度和精密度水平 (I, 2)。在最终选择技术时还考虑了可能的干扰 (3-5) 和非线性效应 (6, 7)。然后仔细建立必要的分析程序，以尽量减少操作员或仪器的困难和错误。不幸的是，并非所有样品都符合常规分析程序设定的边界条件。一个意想不到的样本可能会导致许多新的、复杂的系统崩溃。工作中经常需要什么
A novel method of sampleintroduction into a flame has been utilized to develop a high precision “null point” ana-lytical technique in flame spectrometry. The sample introduction technique employs a stream of uniform droplets which are injected into the flame at a controlled, variable rate. In the null technique, determinations are made by varying the droplet introduction rates of sample andstandard to obtain equal signal intensities and, therefore, equal atom concentrations in the flame. Unknown sam-ple concentrations are then determined from simple calculations involving the standard concentration and the droplet injection rates. The advantages and disadvantages of this technique are discussed in terms of vaporization interferences, self absorption, precision, and sam-ple flexibility in comparison to more conventional tech-niques. The analysis of calcium and sodium in blood serum is used as an example to evaluate the capabilities of the technique. Extensions of the technique to atomic absorption, atomic fluorescence, and laboratory automation are considered and discussed.Flame spectrometry, like many analytical techniques, lends itself well to the determination of routine samples. Repetitive samples having a well-defined concentration range and constant matrix present no difficulty to technician-performed or fully automated flame analyses. By prior investigations, these determinations can be opti-mized to provide the desired level of accuracy and preci-sion on the specific sample type investigated (I, 2). Possible interferences (3-5) and nonlinear effects (6, 7) are also considered in the final choice of technique. The necessary analytical routine is then carefully established to minimize operator or instrument difficulty and error. Unfortunately, not all samples fall within the boundary conditions set for the routine analytical procedure. An unexpected sample can be the downfall of many of the new, sophisticated systems. What is often required in the