摘要
以高锰酸光度法的实例,说明化学物质(化学元素及其组成的物质)的基态是多种多样的,而且它们各自的分布比率都是确定的,物质的吸收光谱就是这一规律的真实反映。所以,吸收谱带中的任一波长,都可用于同一相关物质含量的测定,只是各自测定的灵敏度和含量范围不同;每一方法的比色体系(bc),对于它吸收谱带中一定强度的任一波长的吸收,都必然存在着一个与之相应的吸收灵敏度最大区间Lsλ,在此区间内,该波长的吸光度改变量ΔAp均正比于该体系的改变量Δ(bc)p,即ΔAp=KΔ(bc)p;分光光度法的精密度是个随机变量,它可用样本的最大离散度Pr表示。数理统计方法研究表明,它的量值大小,决定于同批测定中,各个样品测定程序运作的"相对一致性",即样本极差R=cmax-cmin的大小,而与其吸光度的大小无关。根据长期大量的实验数据统计归纳,选用了Pr(0.65R)作为评定测定精密度的标准不仅简便而且直观。
The permanganic acid spectrophotometry is taken as an example to explain that the ground state of chemical matter （ matter made up of chemical elements ） is manifold and each distribution ratio is fixed. The absorption spectrum of the matter is the real reflection of the light absorbed by its manifold ground state, therefore each wavelength of its absorption band can be used to deter- mine the content of the related matter with different sensitivity and content range in the determination. For the colorimetric matter system （bc） that absorbs a monochromatic light A with a fixed strength, there must be a highest sensitive interval absorbed L^λs related to this light absorbed . In this interval the absorbance variable △Ap is propotional to the system variable △（bc） p, namely, △Ap = K△（bc） p. The precision of spectrophotometry is a random variable and can be presented by samples maximum dispersion （Pr）. The study of mathematical statistics demonstrats that its magnitude depends on relative identity of running individual determination procedure in the same determination seris, namely the magnitude of sample limit error （R=Cmax-Cmin）, instead of the magnitude of the systems ab- sorbane （A）. The author set the value to 0.65R thought many years of study. It is not only simple and convenient but also straightfor-ward that using the Pt=0.65R as scale for determination dispersion.
出处
《化学分析计量》
CAS
2008年第3期35-38,共4页
Chemical Analysis And Meterage
关键词
高锰酸
分光光度法
基态
吸收光谱
精密度
标准偏差
permanganic acid, spectrophotometry, ground state, absorptispectrum, precision, standard error
