HW1-Pipetting+Practice+Spreadsheet

You will measure one volume with two of the pipettes and measure two different volumes with the P-200-type pipette. 1. Place a weigh boat on the metal pan inside the balance, close side and top doors, and zero (tare) the balance. ** Please ask Dr. Hrabak or Ian if you want us to confirm that you have the pipette set correctly. It's better to ask than to break this $250 piece of equipment. 3. Use your best pipetting technique to draw up water from your beaker and dispense the water into the weigh boat. ** Feel free to do a few practice runs before you start recording the weights. 5. You must take at least 6 readings with each pipette at each volume, but you may take up to 10 readings. 200.0 uL 20.0 uL 20.0 uL 3 or 4? 3 or 4? 3 or 4? 3 or 4? 201 199 20.0 20.0 200 200 19.0 20.0 202 201 20.0 20.0 200 200 20.0 20.0 201 200 20.0 19.0 200 201 19.0 20.0 201 201 20.0 20.0 200 201 20.0 19.0 200 200 20.0 20.0 200 200 19.0 20.0 Mean (mg) 201 Mean (mg) 200 20 Mean (mg) 19.8 Accuracy Accuracy Accuracy Mean (uL) 201 Mean (uL) 200.3 19.7 Mean (uL) 19.8 Specs(uL) 197-203 Specs(uL) 198.4-201.6 19.5-20.5 Specs(uL) 19.8-20.2 Precision Precision Precision St Dev (uL) 0.7 St Dev (uL) 0.7 0.5 St Dev (uL) 0.42 Specs (uL) Specs (uL) Specs (uL) The goal for this pipetting practice is to fill in the table below. The data that you collect will be used to calculate the accuracy and precision of THREE of your four pipettes as part of this week's homework. 2. Follow the steps in the lab manual reading to set the desired volume on your pipette. Remember to unlock the pipette before adjusting the volume if applicable! 4. Close side and top doors of the balance and record the weight in milligrams (NOTE THAT THE BALANCE READ OUT IS USUALLY SET TO GRAMS BUT CAN BE CHANGED ON SOME BALANCES) IMPORTANT: if the display on your balance has 4 decimal places, then your milligram value in the table below should have one decimal place. If your balance's display has 3 decimal places, your milligram value will have no decimal places. In Excel, you can adjust the number of decimal places by selecting <Format>, <Cells>, <Number>, then changing the number of decimal places. 6. The spreadsheet is set up to automatically calculate the mean and standard deviation. You will be comparing your mean and standard deviation with the "Specs" or manufacturer's specifications for the instrument as part of this week's Homework assignment. IMPORTANT : Email yourself this spreadsheet but also save to the desktop (including your name in the filename) on the G51 laptop and make note of the laptop number. That way if your emailing doesn't work, we can try to retrieve the file for you. Type of pipette (choosed 1): P-1000 or SL-1000 or XLS-1000 200 uL or 0.2 mL Circle type of pipette: P-200 or SL-200 or XLS-200 Circle type of pipette: P-20 or SL-20 Type of balance (choose 1): balance type of balance: balance? type of balance: balance? + 0.6 + 0.3 + 0.2 + 0.06