Bio Spectroscopy Lab
Introduction: This investigation used spectroscopy to evaluate light absorption in different solutions. A spectrophotometer was used in the lab to determine these values. A spectrophotometer is an apparatus used to “measure the absorption of radiation in the visible and UV regions of the spectrum and allows precise at a particular wave length” (Jones et al., 2007). The amount of light absorbed by a substance is directly in relation to the concentration of the solute and also the wavelength moving through the solute (Jones et al., 2007). This is commonly referred to as Beer’s Law and can be expressed as A= εl [C]. Beer’s Law equation measures the absorbency of light, making it an effective measure as spectrophotometers give exact values for absorbency (Jones et al., 2007).
The purpose of this lab is to identify the concentration of unknown 276 using absorption values obtained from the spectrophotometer. When using these absorbance values in relation to similar fast green dilution solutions, the concentration of unknown 276 was achieved by drawing a line of best fit on a scatter plot (refer to figure 2 within this lab). By using absorption values of other solutions such as fast green stock solution and chloroplast pigments, information about high absorbency wavelengths was gained. By plotting this information in an “absorption spectrum” graph, the maximum absorption was easily identified for fast green, chlorophyll A and chlorophyll B (refer to figures 1 and 4 within this lab). The graphs in general can be closely related and compared to Beer’s Law stated above. For example, when referring to figure 2 (within this lab) concentration curve for fast green, absorption is in relation to concentration, where as when the concentration of a substance is increased, higher values of light was absorbed (Jones et al., 2007).
Materials and Methods:
Please refer to Lab 4 in manual
Results:
Dilution concentration calculation:
(Using CiVi= CfVf formula) Test
The purpose of this lab is to identify the concentration of unknown 276 using absorption values obtained from the spectrophotometer. When using these absorbance values in relation to similar fast green dilution solutions, the concentration of unknown 276 was achieved by drawing a line of best fit on a scatter plot (refer to figure 2 within this lab). By using absorption values of other solutions such as fast green stock solution and chloroplast pigments, information about high absorbency wavelengths was gained. By plotting this information in an “absorption spectrum” graph, the maximum absorption was easily identified for fast green, chlorophyll A and chlorophyll B (refer to figures 1 and 4 within this lab). The graphs in general can be closely related and compared to Beer’s Law stated above. For example, when referring to figure 2 (within this lab) concentration curve for fast green, absorption is in relation to concentration, where as when the concentration of a substance is increased, higher values of light was absorbed (Jones et al., 2007).
Materials and Methods:
Please refer to Lab 4 in manual
Results:
Dilution concentration calculation:
(Using CiVi= CfVf formula) Test
References: Tanaka, R., & Tanaka, A. (2011 August). Chlorophyll cycle regulates the construction and destruction of the light-harvesting complexes. Biochimica et Biophysica Acta - Bioenergetics. 1807(8), 968-976. doi: 10.1016/j.bbabio.2011.01.002 Morel, A. & Bricaud, A. (1981). Theoretical results concerning light absorption in a discrete medium, and application to specific absorption of phytoplankton. Deep Sea Research Part A. Oceanographic Research Papers. 28(11), 1375-1393. doi: 10.1016/0198-0149(81)90039-X Freeman, S., Harrington, M. & Sharp, J. (2011). Biological Sciences. Ontario: Toronto. pp 209-215. Jones, A., Reed, R. & Weyers, J. (2007). Practical Skills in Biology (4th ed.). England: Harlow. pp. 366