简介:Protein concentration is commonly estimated by measuring the absorb
ance at 280nm and calculating the concentration using the extinctio
n coefficient of the protein.The procedure is feasible because exti
nction coeffi简介:Protein concentration is commonly estimated by measuring the absorb
ance at 280nm and calculating the concentration using the extinctio
n coefficient of the protein.The procedure is feasible because exti
nction coefficients are typically obtained using standard cuvettes
with a fixed 1 cm pathlength. Extinction-based protein assays can a
lso be done in microplates, but they have not been widelyused becau
se of the inconvenience of compensating for variable pathlengths of
samples in microplate wells. The introduction of the Molecular Devi
ces’ SPECTRAmax PLUS microplate spectrophotometer marks the first
time that photometric measurements made in a microplate format can
be automatically normalized such that the resultant values are iden
tical to those obtained with the corresponding solutions in a stand
ard 1 cm pathlength cuvette. The following application note outline
s the use of the pathlength correction feature “Pathcheck”, compa
res absorbance results obtained in cuvettes and microplate, and giv
es an example where Pathcheck is applied to column chromatographic
fractions and the elution profile displayed.详细>