Week 1: Intro to Chem/Spectrophotometry Flashcards
(30 cards)
What is clinical chemistry?
About soluble mediators in liquid portion of body, be it plasma or serum. Serum preferred
How long does it take for clot to form in whole blood?
30 minutes
Which is the most common cause of metabolic disease in the West?
Obesity
Which tests are done in BMP (basic metabolic/mini)?
- Glucose
- Albumin
- Total protein
- Sodium
- Potassium
- Chloride
- BUN (blood urea nitrogen)
- Creatinine
- CO2
Which tests are done in CMP (complete metabolic panel)?
- BMP + liver panel
Liver panel: - Alanine aminotransferase (ALT)
- Aspartate aminotransferase (AST)
- Alkaline phosphatase (ALP)
- Total bilirubin
What is the matrix?
- Plasma or serum
- Urine
- Feces
- Other body fluids (CSF, peritoneal fluid, pleural fluid, synovial fluid, amniotic fluid)
Which type of system is best for quantitating color change of reaction between reagent + compound?
Closed systems utilizing focused light
How do photometric instruments measure light intensity?
Without consideration of wavelength. Most instruments use filters (photometers), prisms, gratings (spectrometers) to isolate narrow range of incident wavelength
What is Beer’s law in words?
The concentration of a substance is directly proportional to amount of light absorbed or inversely proportional to logarithm of transmitted light
How do spectrophotometric instruments work?
Measure light transmitted by solution to find concentration of light-absorbing substance in solution
List the components of a spectrophotometer
- Light source
- Monochromator
- Sample cell (cuvette)
- Photodetector
What is the range of visible spectrum on the EM spectrum? Which colors?
400 nm (violet) to 700 nm (red)
What are the two most common incandescent light sources? Which parts of EM spectrum do they cover?
- Tungsten lamp: Visible + IR
- Deuterium: UV region
Purpose of the monochromator? What types are there?
Purpose is to disperse light. Can use prism
What is the Beer’s law equation? What do the variables stand for?
A = Ebc
A= absorbance
E = molar absorptivity
b = length of light path through solution (cm)
c = concentration
What is the equation for percent transmittance? What do the variables stand for?
%T = T/I X 100
T = radiant energy transmitted (that exits cuvette)
I = Incident radiant energy on sample
What is the %T of water and why?
100% because all energy goes through to other side of cuvette. Nothing is absorbed.
I(incident) = I(absorbed) + I(transmitted)
What does the exit slit do?
Selects wavelength of interest
List the types of photodetectors
- Photocell (self-propelled)
- Phototube (external power supply)
- Photomultiplier (amplifies light)
How does photomultiplier work?
Has dynode chain made up of anodes with successively increasing voltages.
Light -> electrons -> Amps -> Volts -> Absorbance
What are ways to maintain wavelength accuracy?
- Holmium oxide
- Didymium
- Mercury
Difference between reference range and linear range?
Reference range: what’s normal for population
Linear range: how high or low you can test
How to test for stray light effect?
Measure absorbance against true absorbance. Should have straight line
Linear dynamic range also known as…?
Sensitivity range
