REGIONAL BIOTECH AT THE UNIVERSITY OF TEXAS-PAN AMERICAN

1. REGIONAL BIOTECH AT THE UNIVERSITY OF TEXAS-PAN AMERICAN BIOSCIENCE EDUCATION FOR THE RIO GRANDE VALLEY

2. AN INTRODUCTION TO USING A DIGITAL MICROLITER PIPETTE PIPETMAN & EAGLE BRANDS

3. FUNCTION OF THE MICROLITER PIPETTE • In the biotechnology laboratory, scientists use an instrument called a microliter pipette or micropipette to measure and transfer precise amounts of liquid reagents • The micropipette is a precision instrument calibrated in microliters (mL). 1ml = 1000 (mL)

4. CAREFUL HANDLING OF THE MICROPIPETTE • The micropipette must be handled with great care, to avoid damage. • A damaged micropipette may produce imprecise measurements and this could affect the results from an experiment. • Do not rough-handle or drop the micropipette

5. CAREFUL HANDLING OF THE MICROPIPETTE • Do not adjust the micropipette volume above or below that recommended. If you encounter resistance while turning the volume adjustment wheel, stop and inform your instructor immediately. • When not using the micropipette, lay it flat on the workbench or hang it on the pipette stand in front of you.

6. PARTS OF A MICROPIPETTE (EAGLE BRAND)

7. PARTS OF A MICROPIPETTE (PIPETMAN BRAND)

8. SETTING THE VOLUME ON THE P20 & E20 • In the digital volume indicator window are three vertical numbers read from top to bottom • The top number indicates “tens” microliters (mL) • The middle number indicates “units” microliters (mL) • The bottom number indicates “tenths” microliters (mL)

9. SETTING THE VOLUME ON THE P200 & E100 • In the digital volume indicator window are three vertical numbers read from top to bottom • The top number indicates “hundreds” microliters (mL) • The middle number indicates “tens” microliters (mL) • The bottom number indicates “units” microliters (mL)

10. SETTING THE VOLUME ON THE P1000 & E1000 • In the digital volume indicator window are three vertical numbers read from top to bottom • The top number indicates “thousands” microliters (mL) • The middle number indicates “hundreds” microliters (mL) • The bottom number indicates “tens” microliters (mL)

11. SETTING THE VOLUME ON THE MICROPIPETTE • Hold the micropipette in one hand and with the other hand, turn the volume adjustment knob until the volume indicator displays the desired volume. See tables and pictures in the next slide for examples • IF THE VOLUME ADJUSTMENT KNOB IS HARD TO TURN, STOP AND CALL THE INSTRUCTOR. DO NOT TRY TO FORCE THE KNOB TO TURN BECAUSE YOU WILL DAMAGE THE MICROPIPETTE

12. P20 P1000 P200 E20 E1000 E100 TENS THOUSANDS HUNDREDS 1 0 1 1 0 1 TENS UNITS HUNDREDS 0 8 8 0 8 8 TENS TENTHS UNITS 0 7 3 7 3 0 THIS EXAMPLE IS A SETTING FOR 18.3 MICROLITERS (mL) THIS EXAMPLE IS A SETTING FOR 100 MICROLITERS (mL) THIS EXAMPLE IS A SETTING FOR 870 MICROLITERS (mL)

13. MEASURING AND TRANSFERRING LIQUID REAGENTS • Turn the volume adjustment knob to the desired volume • Hold the micropipette so that the tip ejector button is facing the user and the thumb is free to depress the push button

14. MEASURING AND TRANSFERRING LIQUID REAGENTS • Select and open a box containing the correct size tips to be used. • Place the pointed end of the micropipette shaft into one of the tips and press down firmly, then lift-up the micropipette with tip attached. • YOU MUST NEVER USE THE MICROPIPETTE WITHOUT A TIP ATTACHED !!!

15. MEASURING AND TRANSFERRING LIQUID REAGENTS • Using your thumb, depress the pushbutton to the first stop. • Immerse the micropipette tip about half-way into the reagent you are measuring. • Make sure the reagent does not touch the micropipette shaft

16. MEASURING AND TRANSFERRING LIQUID REAGENTS • With the pipette tip immersed in the reagent, draw the reagent into the tip by slowly raising your thumb and releasing the pushbutton • Remove the tip from the reagent by lifting the micropipette • Visually examine the tip to make sure it contains reagent and that there are no bubbles present.

17. MEASURING AND TRANSFERRING LIQUID REAGENTS • Move the micropipette towards the transfer container which is to receive the measured reagent • Expel the reagent inside the tip into the transfer container by placing the tip in the transfer container and slowly depressing the pushbutton with your thumb as far as it will go. • With your thumb still holding down the depressed push button, lift the micropipette and tip out of the transfer container

18. MEASURING AND TRANSFERRING LIQUID REAGENTS • With the micropipette and tip out of the transfer container, slowly raise your thumb, releasing the pushbutton. • Position the micropipette on top of the waste container • Dispose of the tip by using your thumb to press down on the tip ejector