The Analysis of Overlapping Spectral Absorption Bands by Derivative Spectrophotometry

Abstract

In the measurement of absorption spectra, it is difficult to detect low intensity bands overlapped by bands of higher intensity. Their detection is greatly facilitated by measuring the first derivative of the transmission curve with respect to wavelength. A machine is under development in this laboratory to plot this derivative. A graphical study is here made of the behavior of the derivative curves for overlapping absorption bands of differing heights, widths and separation intervals and the derivatives are compared with the corresponding extinction and percent transmission curves. The curves here presented are intended as illustrations of the possibilities inherent in derivative spectrophotometry and for the identification of extinction or transmission curve types from measured derivatives.

Near-infrared spectroscopy and imaging in food quality and safety

“…Generally, smoothing is done by using a running average, i.e., boxcar smooth or a Savitzky-Golay smooth, with binomial filtering and FT as alternative methods [89,90]. The first and second derivatives of spectra are used to remove constant or sloping baselines with added effect in resolution enhancement and S/N ratio deterioration [91,92]. The linearization of spectra is necessary because measured signals are often not proportional to sample properties of interest and concentrations of chemical compound.…”

A new simple long‐path‐length thin‐layer spectroelectrochemical cell in various uses

“…The derivative spectrophotometric technique can distinguish the overlapping absorption peaks, identify and enlarge the 'shoulder peaks', accurately determine the location of a maximum absorbance, and greatly increase the selectivity of a monitoring system [22,231. With these unique characteristics, the derivative spectroelectrochemical method (DSEC) is quite useful for studying a redox system that possesses complicated absorption spectra changes (especially for biological molecules).…”

Digestibility and growth performance of feedlot cattle fed pelleted grain screenings

“…Derivative spectra were used to emphasize small or large absorption peaks, and minimize overlapping peaks and baseline correction (Giese and French 1955). Both the standard normal variate, and detrend functions were applied (Barnes et al 1989).…”