1 l aboratory i nstruments and a pparatuses by the end of this topic, the student will be able to:...
TRANSCRIPT
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1
BY ALL STAFF MEMBERS
OF MEDICAL BIOCHEMISTRY DEPARTMENT
LABORATORY INSTRUMENTS AND APPARATUSES
By the end of this topic, the student will be able to: Identify and categorize the different instruments and apparatuses with their parts and uses in practice.
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Glasswares:• Beakers• Erlenmeyer flasks• Test tubes
Heating:• Tripod stand• Bunsen Burner
Experimental Apparatus:• spectrophotometers
Holding and Grabbing:• Test tube Rack• Spatula
Filtering:• Filter Paper• Funnel
:Observing• Petri Dish• Watch Glass
Outlines
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Glass wares
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*Instruments for Liquid Volume Measurements
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Liquid Volume Measurements
Instruments used for volume measurement depends on the accuracy and volumes needed. The smaller the
diameter of the instrument the more accurate it would be e.g. pipettes.
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Pipettes
A pipette measures and delivers exact volumes of liquids.
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Glass graduated pipettes
used to transfer small-volumes of liquids e.g.
(1ml-10ml)
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Automatic pipetteMost accurate of all, used to transfer micro- volumes of liquids e.g. (1l-1000l)
Automatic pipette tips
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Graduated CylindersA graduated cylinder is used to measure different volumes of liquids.
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Volumetric flasks
A volumetric flask is used for the preparation of solutions with different concentrations and
volumes.
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*Instruments For Transfer, Mixing Boiling And storage
of Chemicals
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Test tubes
-Used for performing chemical experiments and reactions in lab. e.g. -Holding liquid samples for heating, dissolution, centrifugation, and other
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Reagents and Chemicals Bottles
Used for: Storage of different chemicals, reagents, and even strong corrosives. So, they should always carry an informative label.
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Graduated Beakers
A beaker holds solids or liquids that will not release gases when reacted or are unlikely to splatter if stirred or heated.
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precise; expensive
Range:
Glassware – Precision and Cost
beaker vs. volumetric flask
When filled to 1000 mL line, how much liquid is present?
beaker 5% of 1000 mL = 50 mL
volumetric flask1000 mL + 0.30 mL
950 mL – 1050 mL 999.70 mL– 1000.30 mL
imprecise; cheap
Range:
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Erlenmeyer flasks (conical flasks) hold solids or liquids that may release gases during a reaction or that are likely to splatter if stirred or heated.
Erlenmeyer Flask (conical flask)
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Rounded Flask (Florence Flask)
Round (Florence) flask is rarely used; it is used for the mixing of chemicals. Narrow neck prevents splash exposure on heating or stirring.
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Heating
These objects are all used in the process of heating, but each one has a different function.
Bunsen Burner
Wire gauzeTripod stand Boiling Tube
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Bunsen burners are used for the heating of nonvolatile liquids and solids.
Bunsen Flame
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Crucible
Crucibles are used for heating certain solids, particularly metals, to very high temperatures.
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Evaporating Dish
The evaporating dish is made of porcelain or ceramic to withstand heat; as it’s used for the heating of stable solid compounds and elements.
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Glass Stir Rod
A glass rod is used to manually stir solutions. It can also be used to transfer a single drop of a solution.
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* Instruments used For handling
of Chemicals
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It is inserted into the end of the glass pipette to help the delivery of liquid without suction by mouth.
Pipette pump
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It resembles small paddles or teaspoons. It resists corrosions. It is
used to handle solid powdered chemicals.
Spatula
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Plastic Pasteur
transfer Pipette
Droppers & Plastic transfer
pipette
They are used to transfer small amounts or drops of liquid solutions.
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Test tube RackTest tube racks are for holding and organizing
test tubes on the laboratory counter. Plastic racks may melt in contact with very hot
test tubes.
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Test Tube Holder
A test tube holder is useful for holding a test tube which is too hot to handle.
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Rubber Stoppers
Rubber stoppers are used to close containers to avoid spillage, evaporation and /or contamination. Containers should never be heated when there is a stopper in place.
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Well Plates
Well plates are used when we want to
perform many small scale reactions at one
time.
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Washing Bottle
A wash bottle has a spout that delivers a wash solution to a
specific area. Distilled water is the only liquid that should be
used in a wash bottle.
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Test Tube Brushes
Test tube brushes are used to clean test tubes and graduated cylinders.
Forcing a large brush into a small test tube will often break the tube.
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Forceps
Forceps (or tweezers) are used to pick up small objects.
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Weighing Tray
Weighing boats are used to weigh solids that will be transferred to another vessel.
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Petri dishUsed for culture studies and for preparing
agar plates.
Observing
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Watch Glass
Used as a surface to observe powder consistency . It may be used as a beaker cover or as a weighing tray.
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*Instruments used For Filtration
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FunnelsA funnel is used to aid in the transfer of liquid from one vessel to
another.
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Filter papersOuter rough surface
Inner smooth surface
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Activity: Label the given illustrative diagram showing the filtration of magnesium carbonate.
1
2
3
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*Instruments Used For Detecting pH And Recording of Temperature And
Specific Gravity
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Litmus Paper
Red litmus paper is used to identify bases.
Blue litmus paper is used to identify acids.
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ThermometerCalibration marks along it, allow the temperature to be read by the length of mercury within it. It is used usually to measure the temperature of water bath in
lab.
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Urinometer (Hydrometer)
Used to measure the specific gravity of a
liquid e.g. urine
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*Apparatuses and their parts Used in Lab
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Lab water bath
Water Bath provides precise temperature for lab reactions control and is available with an analog or digital operating system
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Balance
Used to weigh chemicals
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Centrifuge
Spins liquid samples at different high
speeds to sediment different fractions.
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Gel electrophoresis Apparatus
Tank
combs
Glass plates
separators
Gel
Tank cover
Used to separate macromolecules as DNA , RNA and Protein
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Comb of gel-electrophoresis
Forms wells in the gel which are needed to load samples in them.
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Spectrophotometer
Used to measure the absorbance (O.D) of different substances in biological fluid; using it to calculate the
corresponding concentrations.
Cuvette
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pH meterBulb of pH
meter
Used to measure the pH of a solution.
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Measurement by glass wares
~ ~ ~ ~ ~
water ingrad. cyl.
mercury ingrad. cyl.
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There are some materials where the curve goes up. Still, you read the
horizontal center of the meniscus
(top of the meniscus).
In some plastic cylinders water has a flat surface. In that case top or bottom doesn't matter, but we can still say use
the center rather than the edges.
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A characteristic of liquids in glass containers is that they curve at the edges. This curvature is called the meniscus. You measure
the level at the horizontal center or inside part of the meniscus.
The Meniscus
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Glass Graduated Cylinder
Reading the Volume from a 100-mL Graduated Cylinder
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IMAGE. 100-mL graduated cylinder.Step 1: Determine the scale increment:
How? Answer:In shown Fig, the large graduations
are(10,20,30,40,50,60ml --- etc) between 60 mL and 50 mL = 10 mL. Next, ten small
intervals between the large labeled graduations. Therefore, the scale increment is 10 mL/10 graduations = 1 mL/graduation.
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Step 2: Use the labeled graduations and the scale increment to measure.
How? Answer The volume is greater than 50 mL, Next, use the scale increment. There are two graduation marks below the meniscus, and each graduation represents 1 mL, so the certain digits of the reading are 52 mL
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Identify each volume to two decimal places(values tell you how much you have expelled)
4.50 mL 4.8mL 5.00 mL
Activity: Reading a pipette
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Dr/ Amal Mansour