Other Analytic Techniques Clinical Chemistry Review 78
METHOD PRINCIPLE COMPONENT PARTS USE
Ion-selective electrodes
Osmometry
Electrophoresis
Potential difference between 2 electrodes
directly related to concentration of analyte.
Determines osmolality (measurement of #
of dissolved particles in solution, irrespective
of molecular weight, size, density, or type)
based on freezing-point depression. (Vapor
depression osmometers not widely used in
clinical labs. Don’t measure volatile solutes.)
Separation of charged particles in electrical
field. Anions move to positively charged
pole (anode); cations to negatively charged
pole (cathode). The greater the charge, the
faster the migration.
Reference electrode, indicator
electrode, liquid junction,
measuring device
Cooling bath, thermistor
probe, stirring wire,
galvanometer
Power supply, support
medium, buffer, stain,
densitometer
pH, PCO 2 , PO 2 , Na+, K+,
Ca2+, Li+, Cl−
Serum & urine osmolality
Serum protein elec-
trophoresis, hemoglobin
electrophoresis
