Light-scattering in absorption spectra: a literature survey of examples and corrections

Absorption spectroscopy is a simple yet robust method for qualitative and quantitative analysis. The technique is most commonly applied for molecules in solution that absorb in the ultraviolet (UV), visible (Vis), and/or near-infrared (NIR) spectral region. The presence of the particles of size comparable to or greater than the wavelength of light can cause scattering. The contribution from light scattering can overwhelm intrinsic absorption especially in the shorter wavelength, UV regions, which impedes accurate analysis. The problem of light scattering is common in absorption spectroscopy. To compensate for the alterations caused by light scattering, various correction methods have been applied over the years. The chief correction methods are based on Rayleigh or Mie light-scattering theory. Displayed here are >40 spectra drawn from spectroscopy and photochemistry journals published over 7 decades (since the 1950s) that illustrate the lightscattering problem. The displays include >25 spectra beset by light scattering and 15 examples wherein spectral corrections have been applied. The present survey of the scope of the light-scattering problem in absorption spectroscopy (200–1000 nm) serves as a prelude to the development of a systematic calculational module for spectral correction.