Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
What are the layers involved in a dry reagent reaction? |
Spreading layer, analytical layer(s), reflective layer, support layer |
|
|
What is the structure and function of a spreading layer? |
It is made of a fibrous material which spreads the analyte laterally, ensuring uniform diffusion |
|
|
What is dry chemistry? |
The use of dry strips impregnated with analyte so as to bring about a physical change which gives information about the analyte (e.g. pH strips) |
|
|
What is the usual structure of an analytical layer? |
A thin porous gelatine film in which reagents have been added during production |
|
|
When might fibrous material be used in an analytical layer? |
When filtration is needed (e.g. separating RBCs from serum, separating reaction products) |
|
|
What must be true of reagents in analytical films? |
They must be stable and must not cross-react with one another |
|
|
What is the structure and purpose of a reflective layer? |
Generally composed of a pigment or metal foil, it is meant to reflect back as much of the chemically produced light as possible |
|
|
What is the structure and purpose of a support layer? |
Generally made of thin plastic which transmits light, acts as a mechanical foundation for the reagents |
|
|
How might the reflective and support layers be combined? |
If the support layer is made of a reflective plastic |
|
|
What is the advantage of using reagent strips to test samples? |
They are stable, portable, and ready-to-use |
|
|
What type of complex assay is generally not performed using dry reagents? |
Immunoassays |
|
|
What is the basic process of immunoassays? |
--Antibody binds analyte --Unbound substances are washed away --Bound analytes are quantified using antibody detection system |
|
|
Urine pregnancy and fecal occult blood tests are examples of what kind of dry reagent chemistries? |
All or nothing (positive or negative) |
|
|
Urine analysis strips are examples of what kind of dry reagent chemistries? |
Semi-quantitative (results compared to control spectrum) |
|
|
How does absorption spectrophotometry work? |
Like a stained-glass window-- white light passing through is filtered by reflective pigments, and this light's intensity is based on the concentration of pigment |
|
|
What type of photometry is used in dry reagent chemistry? |
Reflectance photometry |
|
|
How is reflectance photometry used to measure analyte concentration? |
Complex algorithms relate the light reflected from analyte chromophores to the concentration of analyte |
