Refractive-index effect on spectral transmission factor of liquids on double-beam molecular absorption spectrometry

Abstract

The spectral transmission factor of liquids is currently determined by spectrophotometry for various applications, including spectrocolorimetry. Applications exist that require an accuracy of the order of 10(-3) or higher in the intrinsic transmission factor. This requirement brings about the exploration of the corrections made necessary by the measuring cells' lack of pairing, the reference liquid's (water or solvent) spectral nonflatness, the refractive-index difference between the sample and the reference liquid, and the multiple reflections on cell walls. An analysis is conducted, and a procedure is presented for the self-correction of the cell's lack of pairing and for the correction of systematic errors from the reference liquid's spectral nonflatness as well as for the refractive-index discrepancies between the sample and the reference liquids and for the multiple beam reflections.