紫外可见分光光度计的双向导数光谱法

Bidirectional Derivative Spectrophotometry of UV-Vis Spectrophotometer

紫外可见分光光度计的导数光谱法由于相移的存在,导致导数光谱中峰值、峰谷对应的波长位置与其真实的波长位置存在偏差以及复杂频率分量的物质吸收曲线发生群时延。基于零相移滤波器原理,双向导数光谱法能够有效地消除相移。实验采用紫外可见分光光度计扫描水杨酸溶液,并用导数光谱法和双向导数光谱法分析吸光度数据。结果表明,双向导数光谱法能克服相移,提供无群时延的更精确的吸收细节,从而提高紫外可见分光光度计的分析精度。

Derivative spectrophotometry of UV-Vis spectrophotometer has phase shift which will leads to two major drawbacks.First,the wavelength positions of the derivative spectra′s peak and trough will bring about the deviations corresponding to their true wavelength position.Second,the absorption curve of the complex frequency components will cause group delay.Based on the theory of zero-phase filter,bidirectional derivative spectrophotometry can effectively eliminate the phase shift.UV-Vis spectrophotometer was used to scope the salicylic acid solution and the absorption data were analyzed by derivative spectrophotometry and bidirectional derivative spectrophotometry.Results showed that bidirectional derivative spectrophotometry can overcome the phase shift,provide no group delay and more accurately absorption details.Therefore,the proposed method can improve the analysis accuracy of UV-Vis spectrophotometer.