First Grading Flashcards
required for preparation of any primary standard.
Analytical balances
Single pan enclosed by sliding transparent doors.
Analytical balances
Uses an electromagnetic force to
counterbalance the weighed sample’s sample.
Electronic balances
Consists of a head or rotor, carriers, or shields that are attached to the vertical shaft of a motor or air compressor and enclosed in a metal covering
Clinical centrifuge
process in which centrifugal force is used to separate solid matter from a liquid suspension; also separate two liquid phases of different densities.
Centrifugation
RCF in grams=
1.118 x 10-5 x r x (rpm)2 ; or use nomogram
RPM =
tachometer or strobe light TYPES: 1.
tubes placed in the cups of the rotor assume a horizontal plane when the rotor is in motion and vertical position when at rest.
Horizontal-head or swinging-bucket centrifuge
During centrifugation, particles travel in a constant manner along the tube while the tube is at right angle to the shaft of the centrifuge.
Horizontal-head or swinging-bucket centrifug
Angle-head or fixed angle centrifuge
Tubes are held at a fixed angle from
25-40 degrees to the vertical axis of rotation.
Particles are driven outside and bottom of the tube and the surface of the sediment packs against the side and bottom of the tube and the surface of the sediment is parallel to the shaft of the centrifuge.
Angle-head or fixed angle centrifuge
- High-speed centrifuge; mainly fixed angle rotorsq
- requires a refrigerated chamber
Ultracentrifuge
circulating or noncirculating.
Water bath
Water bath maintenance
Type II (or Type I)
water
MEASURING DEVICES: PIPETS
Classification According to Graduations
Graduated or Measuring Pipets
C. “Blow Out”
D. “Between Two Marks”
Transfer pipets
Volumetric pipets
Ostwald-folin pipet
Pasteur pipet
Automatic pipet
used to transfer aqueous solutions & non-viscous samples self-draining
Volumetric pipet
has the greatest degree of accuracy and precision
Volumetric pipet
read at the lower meniscus
Volumetric pipet
bulb at the center
Volumetric pipet
used for biologic fluids having viscosity greater than water; blowout pipet
Ostwald folin
read on the upper meniscus
bulb is closer to the delivery tip
Ostwald folin
no calibration mark; used to transfer solutions or biologic fluids without consideration of a specific volume
Pasteur piper
Graduated or Measuring Pipets
Mohr pipet
Serological pipet
calibrated between two marks; deliver between their calibration marks
Mohr pipet
- Tip should NOT touch the receiving vessel
- self-draining; with smaller orifice
Mohr pipet
graduated down to the tip
Serological pipet
blow-out pipet; with larger orifice
Serological pipet
exact volume is calibrated to fill the volume between two calibration points on the pipet
Between Two Marks
Holds the particular volume but
does not dispense the exact
volume
To-Contain” (TC)