Please enable JavaScript.
Coggle requires JavaScript to display documents.
Spectrophotometry, ELISA, Chemiluminescence, Atomic absorption, Osmometry,…
Spectrophotometry
-
Disadvantages
Single-beam spectrophotometers need to read a blank control sample before measuring concentrations in order to remove interference from the reading.
-
-
-
ELISA
-
-
-
Two types
Direct: The target antigen is coated onto the multi-well plate and then detected by an enzyme-linked antibody.
Indirect: The target antigen is coated onto the multi-well plate, then is bound by a unconjugated antibody which in turn is detected by a enzyme-linked second antibody.
-
-
Image 
-
Description: Enzyme-Linked Immunosorbent Assay is a test that detects and/or quantifies a target antigen in a heterogeneous mixture by utilizing enzyme-linked antibodies and chromogenic measurements.
Chemiluminescence
Advantages
- Relatively simple instrumentation
- Subpicomolar detection limits
- Speed (Only measured for 10 seconds)
Disadvantages
- Lack of sufficient selectivity and sensitivity to various physiochemical factors.
- Impurities can cause a background signal that degrades sensitivity and specificity
-
Common Tests:
Enzyme Catalyzed Light Emission Reaction
and
Redox Reaction Mediated Light Emission Reaction
-
Description: The production of light from a chemical reaction. Two chemicals react to form an excited intermediate, which breaks down and releases some of its energy as photons of light to reach its ground state.
Image
-
Atomic absorption
Used to measure concentration by detecting the absorption of electrophermagnetic radiation by atoms rather than molecules
-
Disadvantage
the inability of the flame to dissociate samples into free atoms
ex phosphate may interfere with calcium analysis by formation of calcium phosphate
ionization of atoms following dissociation by the flame, which can be decreased by reducing the flam temperature
-
-
Advantages
sensitive and precise
used to measure concentration of trace metals that are not easily excited
-
Osmometry
Is used to determine the molecular mass which depends on colligative properties meaning that the number of dissolved measures is the only factor that alters the properties of a solution
-
Disadvantages
- boiling point elevation is not useful for clinical samples because proteins will coagulate causing gross changes in sample composition
- volition gases if present will increase the vapor pressures of solvent
Advantages
- simple to use, requires very little knowing or scientific background to operate systems and achieve good results
- the most widely referenced and practiced technique for osmolaitity testing have be commercially available for over 50 years
-
-
-
Electrophoresis
Advantages
- The DNA molecule used as a sample can be recovered at the end of the process
- The gel is easily poured and doesn't denature the sample.
Disadvantages
- Different forms of genetic material may run in unpredictable forms.
1.The gel electrophoresis may melt when the electric current is passed through it at too high a voltage.
-
Image
Description: Electrophoresis is a process that separates charged particles in a fluid field of electrical charge.
-
Electrochemistry
-
-
Basis for many types of analysis are used in clinical lab.
There are 2 main cells involved the galvanic and electrolytic cells
2 half cells and a salt bridge which can be a piece of filter paper saturated with electrolytes
-
Advantages
ability to access unquie reactions and transformations that are not possible by other techniques
simplicity low, cost and speed
Main tests are sodium, potassium
electrolyte panels
Nephelometry
Principle
Measures the light scattered by particles in a sample, not light that passes through it as in spectrophotometry.
-
-
-
-
Tests
Detect and measure IgM, IgG, and IgA in blood samples.
-
-
Fluorometry
-
Common Tests
Fluorometry is used in the medical field to analyze fluorescent compounds
in tissue which effectively aids in the diagnosis of diseases.
Prinicple: Fluorometry measures the concentrations of solutions that contain fluorescing molecules. One a light source is emitted, light first travels through a mechanical attenuator which controls light intensity. The light will then hit the primary filter which will select the wavelength that is best absorbed by the solution to be measured. At this point, the light has now reached the sample which will emit radiant energy in all directions. The secondary filter will now pass only longer wavelengths of fluorescent light onto the detector to be measured. The electrical output of the photodetector is proportional to the intensity of fluorescent energy in that sample.
-
-
Turbidimetry
Common testing
Turbidimetric measurements are routinely used to identify the formation of antibody-antigen immune complexes to determine protein concentrations.
C3 and C4 complement proteins are common proteins measured by this method.
Principle
Turbidimetry is a technique/device used to measure how turbid a solution is. The light source emits a wavelength in the near ultraviolet range (290-410 nm). The photodetector is lined up with the incidence source and collects the beam after passage through the solution, therefore, measuring a decrease in signal or the reduction of light intensity that occurs as a result of the combination of reflection, absorption or scatter of incident light.
-
Advantages and Disadvantages
Measuring light scatter at an angle other than 180 degrees is an advantage to using turbidimetry because it minimizes error from colored solutions and increases sensitivity.
-
-
-
-
3 mayor types of osmometer
freezing point
vapor pressure
membrane osmomter
-osmotic pressure of solution