StandardCurveProtocolandDataSheet_v5_milk_1mL.docx -...

This preview shows page 1 - 3 out of 8 pages.

1 Measurement, Pipette Use, and the Standard Curve Objectives 1. Dilute a concentrated stock solution to a working concentration. 2. Accurately and precisely use pipettes in a laboratory setting 3. Use a spectrophotometer 4. Generate and evaluate a standard curve. 5. Use a standard curve to determine the concentration of protein in milk. Safety 1. Closed-toe shoes must be worn 2. Long hair tied back 3. Goggles must be worn at all times while experiments are being conducted in the classroom. Even if you’re done. 4. Gloves should be worn while performing the experiments. 5. All pipet tips should be ejected into the tip waste bin on your bench. 6. All Bradford reagent should be poured into the acid waste container on the side bench. Remember to put the lid back on when you are done. 7. Rinse your plastic cuvettes in the sink and place them in the trash can in the front of the room. Lab Activity 1: Proper pipetting technique Your Lab Instructor will demonstrate the proper technique for using a micropipettor. 1. When instructed following the demonstration, pick up a micropipettor (it does not matter what size) and place the correct size tip on it. 2. Depress the plunger with your thumb and become accustomed to the "first stop" and the "second stop". 3. Practice depressing the plunger to the first stop and s l o w l y releasing it back to the end stop. 4. When your Lab instructor comes to visit your table and instructs you to do so, pipet the volume of water requested by your instructor from the container on your table into a microcentrifuge tube. 5. Under no circumstances should you ever dial a micropipettor above or below its stated volume range! (Look at the knob—it will tell you the range!) Doing so will damage the pipettor and likely make it extremely unreliable. 6. Your instructor may request that you repeat this process until you get it right. It's ok! It's practice and you want to become proficient.
2 Lab Activity 2: Using Standard Curves to Calculate Unknown Concentrations Both Part A and Part B should be set up and performed simultaneously. Ideally, perform the serial dilution and initial testing of the milk first, then set up the standard curve and measure the appropriate dilution of milk. You should measure your milk sample on the spectrophotometer immediately after you have measured your standard curve. Part A- the standard curve Complete Table 1 , calculating the volume of BSA, Bradford Reagent and 0.15M NaCl necessary to make a 1.0 mL solution with the final concentration shown in each row. You will be required to hand in the completed table. You should have Table 1 already filled in BEFORE LAB.

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture