Lab 3 Spectrophotmeter Flashcards
methods are widely used to quantify concentration of biological materials
photometric
enables accurate determination of very small quantities
sensitivity
physical basis to determine the physical characteristsics of chemicals to absorb what… at specific …. depending on atomorc structure
light ,wavelength
lesser light leaves the solution
true, because most are absorbed
uniform absorbing solution proportion of light passing is called
transmittance
transmittance expressed as
T-l/lo
light absorbed by substance
absorbance
light not absorbed
transmittance
absorbance unit
optical density OD - absorbance per unit length
absorbance / thickness fo sample
OD
transmittance and absorbance are
linear interdependent
OD =
log10(1/T)
transmittance ranges from
1-100%
absorbance ranges
0-infinity
states that absorbance is proportional to the composition of the concentration of the substance and the length of material that the light travels through
beer lamber law
exceptions are
ionizing compounds, out of range concentration (high)
amount of light transmitted at any given wavelength is a function of
concentration
relationship b/t concentration and light
straight line
simplified spectrophotometer use filters to segregate specific wavelengths
colorimeter
measures turbidity
turbidometer
measures concentration by the flourescence of materials
fluorometer
measures concentration by the excitation of materials by heat and flame with consequent development of color
flame photometer
when extremes are reached it is called
topping or bottoming out
colorimeter usable range
0.01-1.0 OD units
dilution factor =
total end volume/ volume of stock solution (used)
final concentration=
original concentration/dilution factor
