偏离朗伯比尔定律NaCl水溶液的红外光谱合成  

To Make a Good Infrared Spectrum in NaCl Aqueous Solution Where Lambert-Beer’s Law is Not to be Obeyed

作　　者：姚蒙 王海水[1] YAO Meng;WANG Hai-shui(School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学化学与化工学院,广东广州510640

出　　处：《光谱学与光谱分析》2021年第1期65-70,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21773072)资助。

摘　　要：氯化钠水溶液中,水分子之间的氢键相互作用随氯化钠浓度变化而发生改变,导致不同浓度的水溶液光谱形状也不同,因此NaCl溶液的光谱不满足朗伯比尔定律。如果浓度c与吸光率A不满足朗伯比尔定律,则利用光谱差减技术扣除溶剂水的吸收峰问题就会遇到瓶颈,差减效果不能令人满意。利用二元线性回归分析法和双边夹原理合成杂化光谱,期望在偏离朗伯比尔定律体系,可以理论上获得各种浓度的NaCl水溶液的杂化光谱,并且保证杂化光谱与其代表的真实光谱高度相似。主要结论如下:(1)浓度c1和c2的NaCl水溶液的红外光谱分别为Ac1和Ac2,则浓度介于c1和c2之间的溶液光谱,均可用Ahc(c1,c2)=aAc1+bAc2来表示。Ahc(c1,c2)与浓度为c(c1<c<c2)的溶液的真实光谱Ac高度类似。(2)c2和c1间隔越小,杂化光谱Ahc(c1,c2)与真实光谱Ac的相似度越高,因此可根据精度要求选择合适的Ac1和Ac2来拟合Ahc。(3)杂化光谱Ahc(2%,30%)=aA2%+bA30%,适用浓度区间2%~30%,涵盖浓度范围宽,效果令人满意。(4)回归系数a和b与浓度c关系为a=-3.592c+1.0589,b=3.565c-0.05515。在2%~30%浓度范围内,选取浓度c数值,即可获得相应回归系数a和b,再将a和b代入方程Ahc(2%,30%)=aA2%+bA30%,即可获得NaCl水溶液的杂化光谱。杂化光谱与相对应的真实光谱高度近似,Ahc(2%, 30%)≈Ac,完全可替代真实光谱。If the solution concentration c and the spectral absorbance A is not obeyed Lambert-Beer’s Law,an individual solution sample should be prepared and acquired in order to obtain its infrared spectrum.The binary linear regression analysis and hybrid spectrum were applied to NaCl aqueous solution.The following conclusions have been reached:(1)The infrared spectra of NaCl aqueous solutions with concentrations of c1,c2 are Ac1,Ac2,respectively.Then the regression equation Ahc(c1,c2)=aAc1+bAc2 is set up,where the relationship among c1,c2 and c is c1<c<c2.Hybrid spectrum Ahc(c1,c2)can be very similar to real spectrum Ac if a and b values are selected properly.(2)The smaller difference between c2 and c1,the higher similarity between Ahc(c1,c2)and Ac is.(3)The regression equation Ahc(2%,30%)=aA2%+bA30% can be applied to the concentration range 2%~30%.(4)The relationships between a and c,b and c are c=-3.592c+1.0589 and b=3.565c-0.5515.If we select c,we can easily obtain a and b then a and b are substituted into regression equation Ahc(c1,c2)=aAc1+bAc2.All hybrid spectra are very similar to the real spectra and they can even replace the real spectra.

关 键 词：NACL水溶液 朗伯比尔定律 线性回归分析 杂化光谱 

分 类 号：O657.33[理学—分析化学]