Instruments and measurements Flashcards
Absorbance equation?
How do we get around the fact plasma/serum have lots of things in it?
Where two compounds have same absorbence called?
A= a (constant) x b (path of light) x c (concentration)
React what we want to specific compound and use Beer-Lambert law (use a Blank) or Allen correction (measure Aborbance equodistant)
Isobestic point
What is a half band pass?
Detectors on light instruments tend to be?
Measure of width of peak at half height; measures how precise light is
Diode arrays; can measure various waves of light
What is nephelometry?
Usage?
What is turbidity?
What interfears with both?
Measure dispersion from particles; measure at an ANGLE; more precise but need whole machine
Antigen-antibodies;
Turbidity: measured decrease in light (A) by particles. use photometer
lipemia interfears
What is atomic absorption?
Element absorb light emitted by same element in cathode tube
Measure decreased intensity when passing through vaporized element
What is standard vs reverse chromotography?
How to improve resolution?
Standard: Mobile phase non-polar, stantionary polar
Reverse is mobile polar and stationary non-polar
Increase length, decrease particle size, altering mobile phase–best way to pick up speed
If seperating Anions (-) use what column?
Ion exchange in labs used for?
Positive. If (+) ions seperated use (-) column
HbA1c which binds to boronate
What test can be used to look for volitiles?
In electrophoresis what is isoelectric point?
Electrophorisis above pI makes protein’s negative so they go to?
Head space gas chromatogaphy!
pH is neutral: if pH > negative, if pH < net positive
Positive end of the strip; the anode; ANIONS GO TO ANODE
What is electroendosmosis?
Some small proteins like immunoglobulins go towards cathode (the - charged electrode)
Some electrophoretic media is charged and moves dragging the small molecules with it
How to quantify proteins in a gel?
Densitometer after staining
Proteins: Coomassie blue, Pnceau red-s
DNA: ethidium bromide
Advantages of capillary electophoresis?
Can combine with what other test to ID proteins?
Small volumes, continuous sampling, automation
Proteins seperate by charge and generate a “virtual gel”
Mass spec!
Mass spec:
Weak ionization vs strong and what are they used for?
Weak: Same charge on each molecule, seperates on mass, good for mixtures
Strong: Fragments and produces specific fragment
Can combine them
3 types of radioactivity, measured?
Half-life equation?
Alpha: He nucleus, low energy, short penetrance
Beta-particles: electrons or positrons: moderate energy, Scintillation (NI or 2,5 phenyl oxazole)
Gamma-rays: High energy photons, gas filled tubes ionized and current measured
0.693/lambda=half-life lambda=specific decay constant
