1. The Basic Skills of the Biotechnology Workplace

2. Volume is a measurement of the amount of space something occupies
Liquid volume can be measured in
Liters (L)
Milliliters (mL)
Microliters (µL)

3. Converting Units
Often volumes are measured in one unit of measurement and reported in another
Using metric units
Need Conversion Factors

4. Measuring liquids
To measure larger liquid volumes, technicians usually use a graduated cylinder.

5. Pipets are available that measure volumes between 0.1 mL and 50 mL.
Serological pipettes

6. Pipets are available that measure volumes between 0.1 mL and 50 mL.
Transfer pipettes

7. Reading a graduated cylinder:
Make sure you know the total volume it will hold and the value of each of the graduations.

8. In the lab, common graduated cylinders include 10 mL, 25 mL, 100 mL, 250 mL, 500 mL, and 1 L.

9. Using Pipettes “Never mouth pipette!”
Instead, you must use one of a number of pipetting devices available (pipet fillers).

10. Using Micropipettes
Measuring units smaller than 1mL requires a micropipette.
A micropipette has four parts
Plunger button
Ejector button
Volume display
Dispensing tip

11. Picking and Using the Appropriate Micropipette
P-100 or P-200 micropipette
P-10 or P-20 micropipette
P-1000 micropipette

12. The plunger has two “stops.”
Pressing to the first stop evacuates air to the volume in the display.
Pressing to the second stop evacuates that volume plus another 50% or so.

13. P-10 micropipettes are common in biotechnology labs.
A P-10 micropipette will measure volumes as small as 0.5 mL and has precision to 0.02 mL.

14. P-100 Micropipette.
This micropipette will measure volumes as small as 10 mL and has precision to 0.2 mL.

15. 1 mL = 0.001L
1000mL = 1L
1μL = 0.001mL
1000μL = 1mL
1,000,000μL = 1L

17. Using a micropipette:P1000
Volume = 350µL
thousands of µL
hundreds
tens
0 x 1000 =
3 x =
+ 5 x =

18. Using a micropipette:P200
Volume = 95µL
hundreds of µL
tens
ones
0 x 100 =
9 x 10 =
+ 5 x =

19. Using a micropipette:P20
Volume = 2.5µL
tens of µL
ones
0 x 10 =
2 x 1 =
+ 5 x 0.1=
tenths

20. Using a micropipette:P2
Volume = 0.5µL
ones of µL
0 x = 0
5 x = 0.5
+ 0 x 0.01= 0
tenths
hundredths

21. Your Turn

22. Answers

23. The p20 is used for volumes between 2 μL and 20 μL.
Attempting to set the volume beyond the pipette’s minimum or maximum values can damage it.

25. The p200 is used for volumes between 20 μL and 200 μL
Attempting to set the volume beyond the pipette’s minimum or maximum values can damage it.

27. The p1000 is used for volumes between 200μL and 1000 μL
Attempting to set the volume beyond the pipette’s minimum or maximum values can damage it.

29. P20 1 x 10 = 10 5 x 1 = 5 + 3 x 0.1= 0.3 The volume = 15.3 μL
See how the dial is set to 153?
The volume = 15.3 μL
1 x 10 = 10
5 x 1 = 5
+ 3 x 0.1=

30. P200
See how the dial is set to 097?
Volume = 97 μL.
0 x 100 =
9 x = 90
+ 7 x = 7

33. One useful way to convert units is to use the metric "staircase"

34. Concentration is measured in several ways:
Mass/volume
Volume/volume
% mass/volume
Molarity
Normality

35. Solutions of Given Mass/Volume Concentrations
Mass/Volume Solution. Solvent is added until a volume of 10 mL is reached.
The protein solution has a concentration of 1 mg/mL and it is considered fairly concentrated.

36. Concentration in Mass/Volume Units
____ g/mL X ____ mL = ____ g of solution
concentration volume to be weighed out,
desired desired dissolved in the solvent

37. A percentage represents something that is part of 100.
Concentration % Mass/Volume Equation
____ % = _______
percent value decimal value of the g/mL
____ X ____ = ____ g of solute to
decimal total volume be measured and
value desired (mL) added to the volume desired of solvent

38. Molarity Concentration Equation
volume molarity molecular the number of grams to be
wanted (L) X desired X weight of the = dissolved in solvent, up to
(mol/L) solute (g/mol) the total volume of
solution desired

39. Periodic Table. The Period Table of Elements shows the elements (atoms) found in compounds (molecules). Each element is listed along with the atomic weight (mass) of each atom in the element. A NaCl molecule has a molecular weight of about 58.4 atu (atomic mass units) because the Na atom weighs about 23 amu, and the Cl atom weighs about 35.4 amu. Together, in the NaCl molecule, the atoms total approximately 58.4 amu. The mass of a hydrogen atom equals 1 amu.

40. Dilutes of Concentrated Solutions
Concentrating 1 L Solution.
Concentrated solutions can be prepared initially with a greater amount of solute to solvent, or a solution can be concentrated by removing water.
A diluted solution can be prepared by adding solvent to the solution.

41. Diluting a 100 mg/mL Stock Solution to 1 mg/mL.