1. Basic Laboratory Skills

2. LIQUID VOLUMES ARE MEASURED WITH:
Graduated Cylinders – liters
& milliliters
Beaker – liters & milliliters
Flasks – liters & milliliters
Pipettes – milliliters
Micropipets – microliters

3. To Convert Between Metric Units of Measurement
Move the decimal point left when going to a bigger unit
Move the decimal point right when going to a smaller unit
Example – L = _____ mL
(2.50 L x 1000 mL/1L = 2500 mL)
Example mL = _____L
(95 mL x 1L / 1000 mL = L)

4. Graduated Cylinders: Use to measure volumes > 10 milliliters
Read volume markings at eye level
Measurements should be at bottom of the Meniscus (lowest point of concave surface)
Graduated Cylinder Sizes: 10 mL, 25 mL,
100 mL, 250 mL, 500 mL, & 1 L

5. Pipettes (Straw with Graduations)
Use when measuring volumes < 10 mL
Select smallest pipette for job to < error
Pipettes maybe volumetric (deliver specific volume)
Serological pipettes deliver graduated amounts (i.e mL,1.3 mL,1.4 mL…)
Pipettes range in size from 1 mL – 10 mL
NEVER MOUTH PIPETTE
Use a pipette bulb or pump for
pipetting & dispensing
the solution

6. Micropipettes
Micropipettes measure volumes < 1mL or 10 – 100 microliters (μ)
1 microliter (μ)= 1,000,000 L or
1 L = 1000mL & 1 mL = 1000 microliter (μ )
Micropipettes have 2 stops controlled by a plunger:
Press to 1st stop and allow to fill.
Evacuate by pressing past 2nd stop.
Micropipette Tips are used & disposed of after each use
Micropipettes can be checked for accuracy using a balance

7. Multichannel Pipette This pipette holds 4 – 16 tips &
is controlled with one plunger
It accurately measures and dispenses identical samples at the same time
This saves time and energy

8. ACCURACY OF MICROPIPETTES
A BALANCE CAN BE USED TO DETERMINE IF A MICROPIPETTE IS ACCURATE
1.5 mL OF H20 SHOULD WEIGH 1.5 g
0.25 mL OF H20 SHOULD WEIGH 0.25 g
0.15 mL of H20 SHOULD WEIGH 0.15 g

9. Review / Practice: Which instrument would you use to perform
The following measurements:
25 μ ?
125 mL ?
2.5 mL ?
450 μ ?
8.5 mL ?
MICROPIPETTE
GRADUATED FLASK
PIPETTE

10. SECTION TWO

11. MASS OR WEIGHT IS MEASURED ON BALANCES OR SCALES
STANDARD UNIT OF MASS IS GRAM
MASS MAY ALSO BE MEASURED IN MILLIGRAM (mg) OR KILOGRAMS (kg)
1,000 MICROGRAM (μ) = 1 MILLIGRAM (mg)
1,000 MILLIGRAMS (mg) = 1 GRAM (g)
1,000 GRAMS (g) = 1 KILOGRAM (kg)

12. Preparing Solutions: Solution is one or more solutes dissolved
in a solvent
The substance being dissolved is a solute
The solvent is usually a liquid
Water is the most common solvent
Concentration is the proportion of
solute to solvent
Common units of concentration:
Mass / Volume, % Mass / Volume,
Molarity and X Concentration

13. MASS / VOLUME ____ G / mL x ____ mL = ____g of solute
concentration volume to be weighed out &
desired desired dissolved in solvent OR
0.12 g / mL x 100 mL = 12 g of NACL
Measure 12 g NACL, add to solvent up to 100 mL

14. % MASS / VOLUME __9__% = _______ OR
__9__% = _______
PERCENT VALUE DECIMAL VALUE OF g / mL OR
_______ X ________ = _______g of solute
Decimal value Volume measured & added to
(g/ mL) Desired volume desired
x mL = g NACL
decimal value desired total measure & mix with
(g/mL) (mL) solvent up to 100 mL

15. MOLARITY [# moles of solute in liter of solution]
1 mole of NACL = 58.4 (atomic mass units)
2 moles of NACL = “ “
1 mole of CACl2 = “ “
Volume X Molarity X Molecular = # grams to
wanted(L) Desired Wt. of be dissolved
(mol /L) Solute(g/mol) in solvent
to volume desired
0.02L x 0.5 mol /L x 111g / mol = 1.1 g CACL2 (w/ solvent to 20 ml)

16. C1V1 = C2 V2 - IS USED TO CALCULATE HOW TO MAKE A SPECIFIC SOLUTION –
C1 = CONCENTRATION OF STOCK SOLUTION
V1 = VOLUME TO BE USED
C2 = DESIRED CONCENTRATION OF SAMPLE
V2 = DESIRED VOLUME OF DILUTED SAMPLE
? 1 L NaCl from 100 mg/mL concentrated sol.
100mg / mL x V1 = 1 mg/mL x 1000mL
V1 = 1 mg/ml x mL or V1 =1000mL / 100 = 10mL
100mg/ml [ or 10ml to 990 ml solvent]

17. Labeling Solutions
Procedures & protocols vary slightly from lab to lab, but follow standard protocol
Laboratory techs must come up with specific procedures for developing reagents & buffers
Solutions & reagents must be labeled after they’re prepared to avoid error
All solutions are labeled with at least:
Name & concentration of reagent
Date, Time & Initials of preparer
Reagents must be stored properly & safely

18. PPE – PERSONAL PROTECTIVE EQUIPMENT
Protect yourself & avoid contamination when working with infectious agents & chemicals.
Wear eye protection, gloves, lab coat & masks.
Dispose of biohazards in proper containers.
Follow Aseptic Technique.