BIOL 3120 Cell Biology Lab Lab2 Using Spectrophotometers PDF
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Texas Tech University
Rubaia Tasmin
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This document is a laboratory instruction for BIOL 3120 (Cell Biology Lab) on using spectrophotometers to measure the intensity of light passing through a methylene blue sample. It explains the principles of spectrophotometers, the Beer-Lambert Law, and the procedure to create a standard curve to determine the concentration of an unknown sample. The report also includes requirements for the lab report, such as introduction, materials, methods, results, discussion, and lab questions.
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BIOL 3120 (Cell Biology Lab) Lab2 Using Spectrophotometers Rubaia Tasmin Teaching Assistant Email: [email protected] Contents Principals of Spectrophotometers Today’s Lab Procedures Lab 2 Report Requirements...
BIOL 3120 (Cell Biology Lab) Lab2 Using Spectrophotometers Rubaia Tasmin Teaching Assistant Email: [email protected] Contents Principals of Spectrophotometers Today’s Lab Procedures Lab 2 Report Requirements 2 Principals of Spectrophotometers An instrument that enables us to measure the intensity of light passing through a sample Components: - Light source - Monochromator: selects suitable wavelength of light - Sample chamber - Detector: measures the intensity of light that passes through the sample A basic diagram of the elements in a single beam UV-Visible spectrophotometer. 3 The Beer-Lambert Law The absorbance is decided by cuvette pathlength and sample concentration. 4 Standard curve To build a direct relationship between concentration and absorbance (methylene blue). According to the standard curve, you can know the concentration of an unknown methylene blue. The concentration should be in the concentration range of your standard curve. Unknown sample 5 Today’s Lab Procedures Set the spectrophotometer to 660 nm Read the absorbance of a blank Read the absorbance of a methylene blue unknown Preparation of a standard curve of methylene blue concentrations Determine the concentration of the methylene blue unknown 6 Lab 2 Report Requirements 1. Introduction: Principal of the spectrophotometer. 2. Materials: All the chemicals used along with concentration, and instruments used. 3. Methods: Brief steps for the experiment you did. 4. Results: Raw data in the tables. Standard curve graph including suitable axis names and concentration unit. Standard curve equation and calculations for the unknown concentration. 5. Discussion/conclusion: What improvements can you make? How can you justify the results? What is your conclusion? 6. Lab manual questions & underlined questions Page 15 File name for your lab report submission- BIOL3120_Section_Lastname_Firstname_ LabN # Send me the Word document by email: [email protected] 7
