C1 02 Clinical Chemistry Laboratory Equipment PDF

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CLINICAL CHEMISTRY LABORATORY EQUIPMENTBASIC LABORATORY EQUIPMENT AND SUPPLIESA. PIPETTES Pipettes are glass or plastic tubes, usually open at both ends, which are used to transfer specific amounts of liquid from one container to another. They are usually used for volumes between 1 and 100 millilite...

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CCHM1 PRELIM02 CLINICAL CHEMISTRY LABORATORY EQUIPMENT BASIC LABORATORY EQUIPMENT AND SUPPLIES A. PIPETTES • Pipettes are glass or plastic tubes, usually open at both ends, which are used to transfer specific amounts of liquid from one container to another. • They are usually used for volumes between 1 and 100 milliliters.

− Must be held vertically and the tip placed against the side of the container and must not touch the liquid in it. − A small amount of fluid will remain in the tip of the pipette − Meet requirements of transfer pipets − Ex: Mohr, Serologic, Volumetric Transfer Pipets

CLASSIFICATION OF PIPETS • Depends on the amount of liquid needed to wet the interior surface of the ware and the amount of any residual liquid left in the pipet tip: I. BASE ON DESIGN: To Contain (TC) To Deliver (TD) II. BASE ON DRAINAGE: Blow out Self-draining III. BASE ON USE: Measuring/Graduated Volumetric/Transfer I. BASED ON DESIGN: A. TC – TO CONTAIN PIPETTE − Holds/contains a particular volume but does not dispense the exact volume − Rinse out pipet (diluting fluid) − A small amount of fluid will cling to the inside wall of the pipet. − Often used in hematology section − Example: Sahli-Hemoglobin, Lang-Levy

B. TD – TO DELIVER PIPETTE − Dispense the amount of volume indicated − Designed to be drain by gravity

II. BASED ON DRAINAGE: A. BLOW OUT − Has a continuous etched ring or two small continuous rings located near the top of the pipette − Last drop should be expelled into receiving vessel(using aspirator bulb) − Ex: Serologic, Ostwald Folin BLOW OUT PIPETTE: the frosted band should not be confused with thicker colored rings or colored dots, which are a manufacturer’s code for the maximum volume of the pipette. Remember, only blowout a serological pipette if it has a frosted band or two thin rings.

CCHM1 PRELIM02 B. SELF-DRAINING − Allows the content to drain by gravity − The tip of the pipet should not be in contact with the accumulating fluid in the receiving vessels during drainage except Mohr pipet − Ex: Volumetric, Mohr

TRANSFER PIPETS A. OSTWALD-FOLIN PIPET − For viscous fluids (proteins or whole blood standards) − Blow out − Has rounded bulb near the tip

III. BASED ON USE: A. MEASURING OR GRADUATED − Deliver the amount of liquid contained between two calibration marks − Not calibrated with sufficient tolerance to use in measuring standard or control solutions. − 2 major types: Serologic and Mohr i. Serologic ii. Mohr iii. Bacteriologic iv. Ball, Kolmer or Kahn v. Micropipet

B. VOLUMETRIC PIPET − Used to deliver a single specific volume of liquid, usually between 1 and 100 ml. − Shaped like rolling pins with a large belly, one. − Blunt end, the neck, and one tapering end, the tip. − TD, self-draining. − Cylindrical glass bulb near the center.

MEASURING PIPETS A. MOHR PIPETTES: the graduations on these always end before the tip C. PASTEUR PIPET − Do not have calibration marks. − Use to transfer solutions without consideration of a specific volume. B. SEROLOGICAL PIPETTES: the graduation marks continue to the tip

B. TRANSFER − More accurate i. Volumetric ii. Ostwald-Folin iii. Pasteur Pipets iv. Automatic Macropipets or Micropipets

TYPES OF AUTOMATIC PIPET I. AIR DISPLACEMENT • Relies on piston for suction creation to draw the sample into a disposable tip that must be changed for use. • The piston does not come in contact with the liquid • Commonly used in laboratory II. POSITIVE-DISPLACEMENT • Operates by moving the piston in the pipet tip. like syringe. • Doesn’t require different tips rinsing and blotting between samples maybe required

CCHM1 PRELIM02 III. DISPENSER AND DILUTOR/DISPENSER • Obtain the liquid from common reservoir and dispense it repeatedly. i. Bottle-top ii. Motorized iii. Handheld iv. Attached to a dilutor

A&C: Air displacement automatic pipet B&D: Positive displacement automatic pipet PIPETTING VOLUMES A. DISPENSER AND DILUTOR (AUTOMATIC PIPET) • The dilutor often combines sampling and dispensing functions

B. PIPET BULBS • A pipette bulb is used to draw liquid up into the pipette. There are many types of pipette bulbs:

Rubber Bulb

Pipet Filler

Pipet Aid

Pipet Pumper

PROCEDURE ON USING THE PIPET 1. Hold the pipette about 8 cm below the mouthpiece with one hand. Then with your other hand squeeze the bulb and touch the opening to the mouth of the pipette. 2. Insert no more than one-half cm of the pipette into the bulb. 3. Place the tip into the colored liquid and slowly release the pressure on the bulb. 4. The liquid will be drawn up into the pipette and will form a curved surface against the glass. 5. This surface is called the meniscus. Pull the bottom of the meniscus up about 1 cm past the desired level. 6. Then quickly, but carefully, remove the bulb as you slip your free index finger over the tip of the mouthpiece hole. *Never use your thumb--your index finger will allow better control and will also enable you to hold other items with your free fingers when necessary 7. Then with your finger still on the end of the pipette, gently lift the pipette out of the solution. 8. Then raise your finger just enough to allow the bottom of the meniscus to line up with the desired graduation mark. You should observe the meniscus at eye-level while doing this. *when the meniscus is at the desired level, touch the tip of the pipette to the inside of the container Holding the colored water, to remove any drops of liquid on the end of the pipette. *now, there is precisely (0.645 + 0.001) ml of colored water in your pipette. 9. Keeping your finger on the end of the pipette, wipe the sides of the pipet with tissue paper & gently move it to the waste container. 10. Touch the tip to the inside of the tilted container, lift your finger off the end and allow the liquid to drain out of the pipette. 11. Hold the pipette in this position for a few seconds after it stops draining. Wipe the pipet again before disposal or cleaning the pipet.

CCHM1 PRELIM02 MENISCUS - curvature in the top surface of the liquid. Pipette should be held that the calibration mark is at the eye level. i. LOWER MENISCUS – clear solutions. ii. UPPER MENISCUS – colored or viscous solutions.

III. BEAKER − Hold different volumes rather than one exact amount − Griffin beakers − Berzeleus beakers − Less in accuracy − Used in stocking solutions

B. LABORATORY VESSELS: • CALIBRATION – glassware or other apparatus used in quantitative measurement is checked to determine its exact volume. • NATIONAL BUREAU OF STANDARDS – calibrated by weight using distilled water and analytic balance.

IV. GRADUATED CYLINDER − Used to measure liquid when high degree of accuracy is not essential. −Calibrated to deliver − Can be used to measure specified volume of liquid − Has a higher degree of accuracy than Erlenmeyer flask

I. VOLUMETRIC FLASK − Calibrated to hold one exact volume of liquid (TC). − Flasks to contain vessels − Prepare solution of known volume

II. ERLENMEYER FLASK − Designed to hold different volumes rather than one exact amount. − Less accurate than volumetric flask − Used in preparing known volume rather than determining an unknown fluid (like volumetric flask)

V. THERMOMETER A. LIQUID-IN-GLASS − Use color liquid or mercury encased in plastic or glass material with bulb at one end and a graduated stem Usually measures temperature between 20oC to 400oC. 3 TYPES: 1. APARTIAL IMMERSION - used for measuring temp in units such as heating blocks and water bath. Should be immersed to the proper height as indicated by the continuous line etched in the thermometer 2. TOTAL IMMERSION - used for refrigeration application. 3. SURFACE THERMOMETERS for flat surface such as oven or incubator. B. ELECTRONIC THERMOMETER/ THERMISTOR PROBE • ADVANTAGE: size and millisecond response time • DISADVANTAGE: expensive C. DIGITAL THERMOMETER...