Balances Flashcards
Qualitative analysis
Detects the presence of a substance
Uses chemical reaction or antibody/antigen detection
Amount NOT quantified
Reported as positive or negative
Antigen
“Other” protein-not recognized by the body
Quantitative analysis
Measures exact amount of analyte - three methods:
- Gravimetric
- volumetric
- colorimetric
Gravimetric
Uses the measurement of mass
Volumetric
Uses reaction with a known, standardized solutions liberations
Colorimetric
Uses a chemical reaction with a coloured end product, colour intensity = concentration
Mass
Amount of matter present in an object
Remans constant in different environments
SI units: kilogram (kg)
Weight
The force of gravity acting upon an object
Change depending on the environment an object is in
SI unit: newton (N)
Balance
Instrument used to measure mass
Capacity
Maximum load A balance can accurately measure
Sensitivity
Smallest load a balance can accurately measure
#Of dermal points displayed in measurement
Accuracy
Refers to the degree to which the mass displayed agrees with the actual mass of the object being weighed
Tare
Set the balances to read zero; useful when using measuring containers
Mechanical balances
Single pan- uses counterweights moved along a beam to measure weight
Double pan- compares an objects mass to another - can be useful to balance centrifuge buckets
Electronic balances
Uses electrostatic force to balance objects instead of counter weights
Classified bases on capacity and sensitivity:
- Course or rough
- Precision (top load)
-Analytical
- semi microanalytical I
