The document provides safety rules and guidelines for conducting experiments in a biochemistry laboratory. It outlines general safety rules regarding protective equipment, chemical handling, glassware use, heating procedures, and first aid. It also describes the proper use of common laboratory instruments such as pipettes, pH meters, spectrophotometers, and centrifuges. The Beer-Lambert law relating absorbance, concentration, and path length is also defined.

1. BIOCHEMISTRY

2. Lab Safety
RULES
2

3. General Safety Rules
1. Listen to or read instructions
carefully before attempting to do
anything.
2. Wear safety goggles to protect your
eyes from chemicals, heated
materials, or things that might be
able to shatter.
3. Notify your teacher if any spills or
accidents occur.
3

4. General Safety Rules
4. After handling chemicals, always
wash your hands with soap and
water.
5. During lab work, keep your hands
away from your face.
6. Tie back long hair.
4

5. General Safety Rules
7. Roll up loose sleeves.
8. Know the location of the fire
extinguisher, fire blanket, eyewash
station, and first aid kit.
9. Keep your work area uncluttered. Take to
the lab station only what is necessary.
5

6. General Safety Rules
10. It is suggested that you wear
glasses rather than contact lenses.
11. Never put anything into your mouth
during a lab experiment.
12. Clean up your lab area at the
conclusion of the laboratory period.
13. Never “horse around” or play
practical jokes in the laboratory.
6

7. Glassware Safety
1. Chipped or cracked glassware should
not be used. Show it to the teacher.
2. Broken glassware should not be
disposed of in a classroom trashcan.
There is a special glass disposal
container for it.
3. When pouring liquids into glassware,
make sure the container you are
pouring into is resting on a table at
least a hands breadth from the edge.
7

8. Glassware Safety
4.If a piece of glassware gets broken, do
not try to clean it up by yourself.
Notify the teacher.
5.Do not place hot glassware in water.
Rapid cooling may make it shatter.
8

9. Chemical Safety
1. Wear protective goggles whenever
heating or pouring hazardous chemicals.
2. Never mix chemicals together unless
you are told to do so (and then only in
the manner specified).
3. Never taste any chemicals (you should
never taste anything in the lab).
9

10. Chemical Safety
4. If you need to smell the odor of a
chemical, waft the fumes toward
your nose with one hand. Do not
put your nose over the container
and inhale the fumes.
10

11. Chemical Safety
5. Follow the instructions of your
teacher when disposing of all
chemicals.
6. Wash your hands after handling
hazardous chemicals.
11

12. Heating Safety
1. Use tongs and/or protective gloves
to handle hot objects.
2. Never reach across an open flame
or burner.
12

13. Heating Safety
3. Always point the top ends of test tubes
that are being heated away from people.
4. When heating a test tube, move it
around slowly over the flame to
distribute the heat evenly.
13

14. Heating Safety
5. Only glassware that is thoroughly
dry should be heated.
6. Heat glassware by placing it on a
wire gauze platform on a ringstand.
Do not hold it in your hand.
14

15. First Aid
Injury:
To Do:
Burns
Immediately flush with cold
water until burning sensation is
lessened.
15

16. First Aid
Injury:
To Do:
Cuts, bruises
Do not touch an open wound
without safety gloves. Pressing
directly on minor cuts will stop
bleeding in a few minutes. Apply
cold compress to bruises to
reduce swelling.
16

17. First Aid
Injury:
To Do:
The eyes
Flush eyes immediately with
plenty of water for several
minutes. If a foreign object is
lodged in the eye, do not allow
the eye to be rubbed.
17

18. LAB INSTRUMENTS

19. • For student to be familiar with the
use of the following:
1. Pipettes and pipetting techniques.
2. pH meter.
3. Spectrophotometer.
4. Centrifuge
OBJECTIVES:

20. Volumetric (Bulb) pipettes:
 These are designed to deliver the exact amount
of solution. Has only one point of graduation.
Graduated pipettes:
 Which are graduated along the stem, but not at
the tip.
 They are less accurate than the volumetric
pipettes, but can deliver small fractions of the
total capacity of the pipette.
1- Pipettes:

22. Other types of pipettes:
• These include the micropipette, which are used
to measure small quantities that the regular
pipettes cannot measure, i.e. micro litter
amounts (ul.).
Fixed volume pipette:
 This delivers only the exact volume which is
written on the top of the pipette (e.g. 20 ul, 100
ul, 1000 ul, … etc.).
Adjustable or variable volume pipette:
 This can be calibrated to deliver any amount of
solution which is written on the side of the
pipette

24. Use of pipettes:
1. Never use mouth, use pipette bulbs or pipette
filters in aspirating solutions.
2. Pipettes must be clean always.
3. After aspirating the required volume, wipe off the
surface of the pipette with tissue paper.
4. Always read the bottom of the meniscus for clear
solutions, and top for colored or viscous ones.
5. The graduation point and your eyes should be in
a horizontal position.
6. When delivering solutions, let the tip of the
pipette touch the inner surface of the container,
and let the solution flow free.
7. Always choose the proper type of pipette in
measuring the required volume.

25. Beakers:
Available in different volumes.

26. Conical Flasks:
Used in titration procedures and other different uses,
also available in different volumes.

27. Graduated Cylinders:
For measuring the volume of solutions and
dilution procedures.

28. Burette:
For addition of volumes in titration procedures.

29. 2- pH meter
 The pH meter is an instrument that is
used to measure the pH (Acidity or
alkalinity) of solutions.
 It is composed of the following:
1. Glass-bulb electrode.
2. Reference electrode.
3. Sensitive meter or measuring device.

31. 4.Cenrifuges
Clinical Benchtop Centrifuges are compact, low- •
speed centrifuges ideal for the separation of whole blood
components, such as serum, plasma, buffy coat, red blood cells,
as well as other body fluids. Their speeds may range between
around 200 rpm(rotation per min.) to 6,000 rpm.
Most clinical centrifuges can accommodate common blood draw •
tubes, but be sure to check with each vendor for specific tube
sizes or tube adaptors.

32. 3-spectrophotometer
• Spectrophotometer is one of the most
commonly used instruments in the
biochemistry laboratory.
• Its main function is to measure the
absorbance or concentration of
substances.

36. components of the
spectrophotometer:
• i) Light source:
• This part of the instrument emits visible or UV
light depending on the source itself. For example
tungsten lamp emits light from 400-750 nm, while
a deuterium lamp emits light in the UV region.
• ii) Monochromator:
• This part is to a prism or a filter which functions in
isolating only one single light. i.e. one wavelength.
• iii) Slit:
• This part functions in passing a very fine beam of
isolated wavelength.

37. components of the spectrophotometer:
• iv) Cuvette holder:
• This is where the sample of the colored solution is inserted.
The cuvette can be either in the round shape like a test
tube or square form. When measuring absorbance in the
visible region the cuvette is usually made of glass, while in
measuring absorbance at the low UV region cuvettes are
made of quartz.
• v) Photo cell:
• This part converts light energy to electric energy so it can
be measured by the measured by the measuring device.
• vi ) Galvanometer:
• This is where the electric pulses are received and converted
on a scale either to absorbance or to transmittance units.

40. Beer-Lambert Law:
• Beers Law states that: when a ray of
monochromatic light passes through an
absorbing medium, the intensity decreases
as the concentration of the absorbing
medium increases.
• Lamberts law states that: when a ray of
monochromatic light (single wavelength)
passes through an absorbing medium, its
intensity decreases as the length of the
medium increases.

41. • These two laws are combined in the form of Beer-
Lambert Law and expressed as: A = abc
• Where:
 A= Absorbance.
a= Extension coefficient (constant), which is
defined as the absorbance (at a given wavelength)
of 1M solution of the pure substance through a 1cm.
Light path.
 b= Length of light path. = 1cm.
 c= Concentration of the substance in the solution.