over convenonar tun reduce the warm up time, do not heat up the instrument or sample, and have a lamp life of over 10 ye the SmartSpecTM 3000 the lamp pulses light only when a sample is being measured, thus extending the m. Xenon flash lamps have additional advantages ey pan of the lamp. Absorption Spectrum Because solutions of pure substances do not absorb the energy of all wavelengths of light equally, a substa may be identified by the unique pattern of wavelengths absorbed. By measuring the absorbance of an uncharacterized solution over a range of wavelengths and plotting the absorbance value on the Y-axis and wavelength on the X-axis, one can determine the absorption spectrum of a sample. The absorption maximum of any pure substance in solution is the wavelength where absorption is the greatest Figure 3-2 shows absorption spectra of three plant pigments: chlorophyll a, chlorophyll b, and carotenoids i the range of wavelengths 400 to 700 nm. Each of them exhibits a unique spectrum, and an aid in its identification. thus, may be used Chlorophyll a Carotenoids 600 Wavelength of light (nm) FIGURE 3-2. The absorption spectrum of chlorophyll a, chlorophyll b, and carotenoids. Q3-1. What are the two approximated absorption maxima of each of the following plant pigments? 1. chlorophyll a? 2 chlorophyll b? Exercise 1. Dilution of Solutions and Spectrophotometry Unit 3: Page 3