AUTOMATION Flashcards
Distance between two successive peaks
Wavelength
Visible spectrum
400-700nm
Ultraviolet
<400 nm
> 700 nm
Infrared region
Used to check wavelength accuracy
Didymium or Holmium oxide Filter
Verify absorbance accuracy
Neutral density filters and dichromate solution
Beer Lambert’s Law
A= abc = 2–log %T
A: molar absorptivity
B:length of light through the solution
C: concentration of absorbing molecules
T:transmittance
One-point calculation or calibration
Beer-Lambert’s Law
Measurement of light transmitted by a solution to determine the concentration
Spectrophotometry
Provide Polychromatic light
Light/Radiant Source
Minimizes unwanted or stray
light; prevents entrance of scattered light
Entrance slit
Isolates specific or individual
wavelength of light
Monochromator
Controls the width of light beam
bandpass
Exit slit
Holds the solution whose
concentration is to be measured
Cuvet
Detects and converts transmitted
light into photoelectric energy
Photodetector
Displays output of the detection system
Meter/Read-out device
Simple type; designed to make one measurement at a time at one specified wavelength
Single beam spectrophotometer
Splits monochromatic light into two components: one beam passes through the sample and the other through a reference solution or blank
Double beam spectrophotometer
2 photodetectors
Double-beam in space
1 photodetector and 1 chopper or rotating sector mirror
Double beam in time
Excitation of electrons from lower to higher energy state
Measures light emitted by single atom burned in flame; measures excited ions (Na+ and K+)
Flame Emission Photometry
Element is not excited but merely dissociated from its chemical bond and placed in an unionized, unexcited ground state
Measures light absorbed by atoms dissociated by heat; measures unexcited trace metals (Ca2+ and Mg2+)
Atomic Absorption Spectrophotometry
Metals measured by AAS
Ca2+ and Mg2+
Ions measured by Flame Emission Photometry
Na+ and K+
Unknown sample is made to react with known solution in the presence of an indicator
Titrimetric (Volumetric)
For chloride
Schales and schales
For Calcium
Edta titration
Determines the amount of light blocked by a particulate matter in a turbid solution
Used in measuring proteins and bacterial suspensions
Turbidimetry
Determines amount of scattered light by a particulate matter in a turbid solution
Used in measuring antigen-antibody complexes
Nephelometry
Migration of charged particles in an electric field
Separates proteins on the basis of electrical charge
Electrophoresis
Buffer used in electrophoresis
Veronal/Barbital (pH. 8.6)
Measure absorbance of stain
Scans and quantifies electrophoretic pattern; measures concentration of dye and protein fraction
Densitometry
Migration through pH gradient
Ideal for separating proteins of identical sizes but with different net charges;detects CSF oligoclonal banding
Isoelectric Focusing
Created by adding acidic to anodic area and base to the cathode area
pH Gradient
Separation of soluble components based on physical and chemical characteristics
Chromatography
for naturally volatile compounds or easily converted to volatile form
Gas Chromatography
based on fragmentation and ionization of molecules using a suitable energy source
Mass spectroscopy
gold standard for drug testing
Gas Chromatography-Mass Spectroscopy
Detects 20 inborn errors of metabolism from a single blood spot
Tandem Mass Spectrscopy
based on distribution of solutes between a liquid mobile
phase and a stationary phase
Liquid Chromatography
used in rapid HbA1c testing
High performance liquid chromatography (HPLC)
used in detecting non-volatile substances; complementary to GC-MS
Liquid chromatography-Mass Spectroscopy (LC-MS)
Determines the amount of light emitted by a molecule after excitation by electromagnetic radiation
Uses 2 monochromators; measures amount of light intensity present over a zero background; affected by quenching
FLUOROMETRY/MOLECULAR LUMINESCENCE SPECTROPHOTOMETRY
Chemical reaction yields electronically excited compound that emits light as it returns to its ground state
Emission of light is created from a chemical or electrochemical reaction; usually used in immunoassays
Chemiluminiscence
Based on measuring changes in colligative properties of solutions
Osmometry
Most commonly used method
Freezing-point Depression Osmometry
Measurement of electrical potential due to free ion activity
Use:____
Potentiometry
pH and pCO2
Measurement of electricity (Coulombs) at fixed potential
Use:
Coulometry
Use:Chloride Test
Measurement of current flow produced by oxidation reaction
Use:
Amperometry
Use: pO2, Glucose chloride and peroxidase determination
Measurement of differences in current at constant voltage
Used:
Polarography
Use: Specific for pO2 and glucose
Measurement of current after which a potential is applied to an electromechanical cell
Use:
Voltametry
Use: Lead and iron testing (Anodic stripping voltametry
Samples flow through a common reaction vessel;
uses a system of continuous tubing;
Continuous Flow Analyzer
Continuous flow analyzer is used for
Parallel Testing
Continuous flow analyzer mixing reagent of sample and reagent
Glass coil inserted into the flow path
Uses acceleration and deceleration of rotor to transfer reagents and sample from one chamber to another;
Centrifugal Analyzer
Centrifugal analyzer is used for
Batch analysis
Centrifugal analyzer mixing of sample and reagent
Centrifugal force
Uses syringe pipettes (positive-liquid displacement) to aspirate and dispense samples; most versatile and most popular;
Discrete Analyzer
Discrete Analyzer is used for
Random access capability
Discrete analyzer mixing of sample and reagent
Magnetic driven teflon stirring bar
all samples are loaded at the same time and a single test is conducted on each sample
Batch testing
more than one test is analyzed concurrently on a given clinical specimen
Parallel testing
any test can be performed on any sample in any sequence
Random access testing
multiple tests are analyzed one after another on a given specimen
Sequential testing
a system other than the manufacturer’s reagents can be utilized for measurement
Open reagent testing
a system where the operator can only use the manufacturer’s reagent
Closed reagent testing