Term
Define the following:
Spectrometry |
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Definition
| Measurement of elecromagnetic radiation in waves |
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Term
| What are the 4 analytical Spectrometry Techniques? |
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Definition
Photometry
Spectrophotometry
Atomic Absorption
Mass Spectrometry |
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Term
| What are the 3 analytical Luminescence Techniques? |
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Definition
Fluorescence
Chemiluminescence
Nephelometry |
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Term
| With Photometry what does the instrument measure? |
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Definition
| light intensity without consideration of wavelength |
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Term
| What is a common example of photometry? |
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Definition
Urine Dipstick Readers
(Reflectance photometry) |
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Term
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Definition
mathematical relationship between Absorbance and concentration.
The concentration of a substance is directly proportional to the amount of light absorbed |
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Term
| Give the mathematical formula for Beer's Law |
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Definition
| (Concentration Unknown/Concentration Standard) = (Absorbance Unknown/Absorbance Standard) |
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Term
| What is the most widely used light source for visible and near-infrared analysis? |
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Definition
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Term
| Which lamps are used for UV? |
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Definition
| Deuterium and mercury-arc |
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Term
| What does the monochromator do? |
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Definition
| Isolates 1 particular wavelength of light |
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Term
| Where does stray light come from? (bad!) |
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Definition
| Extraneous, unwanted light caused by scratches,dust particles, open compartments |
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Term
Define the following:
Photodetector |
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Definition
| Converts transmitted light into electrical energy |
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Term
| What does the readout device do? |
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Definition
| Converts the electrical signal into a useable/readable unit |
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Term
| What is the use of blanks? |
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Definition
| Correct for any absorbance due to the color of the reagent or the sample (ex. hemolysis, lipemia) |
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Term
Define the following:
Wavelength Accuracy Check |
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Definition
| Use standard absorbing solutions or filters with known wavelengths to confirm |
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Term
Define the following:
Linearity Check |
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Definition
Commercially available sets of solutions with expected Abs readings can be run to verify the
calibration curve |
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Term
| What are the 3 parts of Spectrophotometry Quality Assurance? |
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Definition
Use of Blanks
Wavelength Accuracy Check
Linearity Check |
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Term
| Atomic Absorption Spectrophotometry |
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Definition
| Measures absorption of light energy by atoms rather than by molecules |
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Term
| What is Atomic Absorption Spectrophotometry mainly used for? |
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Definition
| Quantitation of trace metals (copper, zinc, etc)and toxins |
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Term
| What is the light source for Atomic Absorption Spectrophotometry? |
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Definition
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Term
| What does the Chopper/Modulator do for Atomic Absorption Spectrophotometry? |
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Definition
Breaks cathode lamp light into pulses per second so that the detector can
differentiate between cathode lamp
light and sample emitted light |
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Term
| What does the Burner do for Atomic Absorption Spectrophotometry? |
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Definition
-Breaks chemical bonds in the sample into free atoms (vaporized).
-When atoms absorb light from the lamp
they become excited. As they return to ground state they emit light of the same wavelength as what they absorbed |
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Term
| What are the 2 light signals that will emitted from the Atomic Absorption Spectrophotometry burner? |
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Definition
| Pulsed light from the cathode lamp and a steady signal from the patient sample |
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Term
| What does the Monochromator do in Atomic Absorption Spectrophotometry? |
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Definition
| Isolates desired wavelength |
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Term
| What are the Advantages of AA? |
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Definition
| Accurate, precise, specific. |
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Term
Which type of Spectrophotometry is capable of measuring substances that
are not easily excited (metals)? |
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Definition
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Term
| What is used primarily in conjunction with chromatography techniques? |
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Definition
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Term
| Luminescence is the production of light without the production of what? |
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Definition
|
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Term
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Definition
| The difference between the Absorbed energy wavelength and the Emitted energy wavelength |
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Term
| What is the light source for a basic fluorometer? |
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Definition
| High intensity mercury-vapor or xenon arc lamp |
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Term
| What does the Primary monochromator select for? |
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Definition
| Excitation (Absorbed) wavelength |
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Term
| What does the Secondary monochromator select for? |
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Definition
| Emission (Fluorescence) wavelength |
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Term
| What are the sensitivity advantages of Fluorometry? |
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Definition
| 1000 x more than most specs |
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Term
| What are the specificity advantages of Fluorometry? |
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Definition
| Since 2 wavelengths are selected |
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Term
| What are the Disadvantages of Fluorometry? |
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Definition
| Sensitive to pH, temperature, viscosity (quenching) |
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Term
| What is the use of Fluorometry? |
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Definition
Measuring substances in low concentrations in plasma or serum
(drugs, hormones, vitamins,
cardiac markers) |
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Term
| With Chemiluminescence, the light emissions are proportional to what? |
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Definition
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Term
| Chemiluminescence labels include (3) |
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Definition
| Luminol, acridinium esters and dioxetanes |
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Term
| With Chemiluminescence, light measures can be made in how many seconds? |
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Definition
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Term
The following are characteristic of what type of luminescence?
-Cost of reagents and instrumentation are low; easy to perform
-Extremely low detection limits (lower than fluorometry) |
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Definition
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Term
Chemiluminescence:
Low or High Sensitivity? |
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Definition
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Term
Chemiluminescence:
Low or High Specificity? |
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Definition
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Term
| What is Chemiluminescence used to detect? |
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Definition
| hormones, drugs, vitamins and cardiac markers |
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Term
Nephelometry:
Light will scatter in direct proportion to what? |
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Definition
| Amount of AGN present in the patient's sample |
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Term
| What is Nephelometry primary used for? |
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Definition
| Quantitate serum proteins |
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