2024_09_09 Cell Lab 2.pptx

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