Lab Safety and Pipeting

1. Lab Safety and Pipeting

2. Lab Saftey The laboratory environment can be a hazardous place to work. Laboratory workers are exposed to numerous potential hazards including chemical, biological, physical and radioactive hazards, as well as musculoskeletal stresses.

3. Personal Protective • goggles • Gloves • Lab coat • Shoes

4. Tie back long hair. • Never eat, drink or smoke in a laboratory • Never touch your face, mouth or eyes • Never suck pens or chew pencils • During lab work, keep your hands away from your face. • After handling chemicals, always wash your hands with soap and water. • Clean up your lab area at the end of the laboratory period

5. general hazards in a laboratory? • Fire • Sharps • Spillages • Pressure equipment & gas cylinders • Extremes of heat & cold • Chemical hazards • Biological hazards • Radiation

6. Ethidium Bromide Safety • Ethidium bromide is a potent mutagen that has been used for many years as a nucleic acid stain. • The powder form is considered an irritant to the upper respiratory tract, eyes, and skin. • Ethidium bromide is strongly mutagenic, causing living cell mutations. An example of a DNA fragments run under gel electrophoresis

7. Hazardous Symbols

8. First Aid

11. Pipetting

12. Types of pipettes There are two types of pipettes: • Air displacement pipettes are meant for general use with aqueous solutions. • Positive displacement pipettes are used for highly viscous and volatile liquids. Both pipette types have a piston that moves in a cylinder or capillary

13. How pipettes work? • The piston moves to the appropriate position when the volume is set. • When the operating button is pressed to the first stop, the piston expels the same volume of air as indicated on the volume setting. • After immersing the tip into the liquid, the operating button is released. This creates a partial vacuum, and the specified volume of liquid is aspirated into the tip. • When the operating button is pressed to the first stop again, the air dispenses the liquid. To empty the tip completely, the operating button is pressed to the second stop (blow-out).

15. Terminology • Aspirate – to draw the liquid up into the pipette tip • Dispense – to discharge the liquid from the tip • Blow-out – to discharge the residual liquid from the tip • Calibration check – to check the difference between the dispensed liquid and the selected volume

16. General Roles • Check your pipette at the beginning of your working day for dust and dirt on the outside. If needed, wipe with 70% ethanol. • Check that you are using tips recommended by the manufacturer. • Tips are designed for single use. They should not be cleaned for reuse, as their metrological characteristics will no longer be reliable. • Avoid turning the pipette on its side when there is liquid in the tip. Liquid might get into the interior of the pipette and contaminate the pipette. • Avoid contamination to or from hands by using the tip ejector.