Lab02-Spectrophotometry - BSCI330 Laboratory Manual Spring...

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BSCI330 Laboratory Manual Spring 2012 Carpenter et al. 2011. BSCI330 Laboratory Manual. University of Maryland, College Park. 1 LAB EXERCISE 2: SPECTROPHOTOMETRY Review of Laboratory Technique From your previous experience in other biology courses, you should have been introduced to several important laboratory techniques. Although they should therefore already be familiar, we wish to review them briefly, as optimal success in many of the laboratory exercises this semester will depend upon their proper implementation. 1. Use of the spectrophotometer Spectrophotometry is a useful technique that can be used to follow the course of biological events by monitoring the change in either the amount of light absorbed or the percentage of light transmitted by a sample over time. We will be using the spectrophotometers in several of the labs this semester. The spectrophotometer is a comparatively simple device, basically consisting of a light source ( spectrometer ) a light diffractor or filter, and a light detector ( photometer ), as shown in Figure 1.1 below. Chemical compounds that absorb light are called chromophores and absorb light energy at particular wavelengths, based on their electronic structures. Structurally, chromophores generally consist of either conjugated pi systems as found in beta carotene, or of metal complexes , as found in chlorophyll (look up the chemical structures for these pigments – what do they have in common that is likely contributing to their ability to absorb/reflect visible light?). Figure 1.1
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This note was uploaded on 02/27/2012 for the course BSCI 330 taught by Professor Payne during the Spring '08 term at Maryland.

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Lab02-Spectrophotometry - BSCI330 Laboratory Manual Spring...

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