Ultraviolet-visible absorption spectroscopy is a widely used technique for determining the concentration of an analyte by measuring the absorbance. There have been many studies examining the relative concentration error associated with ultraviolet-visible measurements, yet there is no information to date about the best calibration design to use that minimizes this error.The major source of this error is detector noise, which obscures and degrades the ability to interpret the response. Random instrumental noise in spectrophotometric measurements can be divided into three classes: (1) sources that are completely independent of response; (2) sources with variance that are directly proportional to the response; and (3) sources of noise with variances that are related to the square of the response. The magnitudes of these noise sources affect the signal-to-noise ratio of ultraviolet-visible absorbance measurements.The goal of this study was to design calibration strategies to optimize precision over the calibration graph for ultraviolet-visible spectrochemical analyses. Different calibration strategies, composed of different concentrations and number of replicates, have been evaluated to try to determine the calibration design that will minimize imprecision as measured by the average relative concentration error integrated over the entire calibration graph.Our research, indicates that the range of calibration imprecision, as measured by the calibration concentration error, varies over a range of 75:1, depending on the location of the standards. This information allows us to conclude that some calibration designs are superior for ultraviolet-visible absorption measurements.

Investigation of calibration strategies for ultraviolet-visible absorption spectroscopy

248th National Meeting (2014)

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