【摘要】 光程长的选择在光谱测量方法设计中非常重要,但实际测量中很难实现精确最佳光程长.从灵敏度的角度研究了在近红外光谱测量中,光程长和测量灵敏度之间的定量关系,讨论了它们对测量结果的影响:单位光程长吸光度越小,则光程长对测量误差的影响越小,可选择光程长范围就越宽;大于最佳光程长区域相对于光程较小区域,光程长变化对测量结果影响较小,可选光程过窄,应通过减小单位光程吸光度来扩展可选区域.对于单个样品,当最佳光程长获取存在较大误差时,应使所选光程长落在大于最佳光程长区域;当一组样品分别对应不同最佳光程长时,也应选择较大光程.在10个光程长下,通过6000cm-1～5900cm-1长波段不同浓度葡萄糖水溶液光谱测量实验,对理论结果进行验证,二者吻合较好.更多还原

【Abstract】 Selection of pathlength is key to near infrared spectral measurement.In this paper,the quantitative relationship between pathlength and measuring sensitivity is studied, with their influence on measurement result discussed.The less the absorptivity of unit pathlength is,the less the influence of pathlength on the measurement error is and the larger the available pathlength range can be.The influence of pathlength variation is weaker in the range the pathlength is longer than the optimum pathlength.If acceptable pathlength range is too narrow,it should be expanded by decreasing the absorptivity of the sample.For a single sample,the pathlength should be selected in the range that is longer than optimum pathlength if a large pathlength selection error is unavoidable.As for a group of samples which correspond to different optimum pathlengths,the longer one is preferred.The experiments of NIR spectrometry of aqueous glucose solutions among wavelength of 6 000 cm^-1—5 900 cm^-1 on ten different pathlengths verify the results of above-mentioned theory.更多还原