PAHs possess very characteristic UV absorbance spectra. These may involve absorbance or fluorescence measurements. RNA quality is measured using UV spectrometry with an absorbance peak of 260nm. Additionally, Spectrophotometers are specialized to measure either UV or Visible light wavelength absorbance values. The greater the absorbance at a certain wavelength of light, the greater the potency. The concentration of amino acid is proportional to the absorbance of the resulting solution. This should not be confused with absorbance and absorption coefficient. It has the appearance of a red powder with an absorbance maxima at 518 nanometers. Tartrazine is water-soluble and has a maximum absorbance in an aqueous solution at 425 nm. HABA dye is bound to avidin or streptavidin and yields a characteristic absorbance. Greater the formazan concentration the deeper the purple colour and thus the higher the absorbance. The detergents will cause a swelling effect which could be measured by an absorbance change. The extended pi-electron conjugation gives mCherry its red-shifted absorbance and emission. The optical depth equals the absorbance times ln(10). In this case, the greater the absorbance, the higher the protein concentration.