Molecular Devices SpectraMax M3 User Manual

0112-0115 F 19
2
Principles of Operation
Absorbance
Absorbance is the amount of light absorbed by a solution. To measure
absorbance accurately, it is necessary to eliminate light scatter. In the
absence of turbidity, absorbance = optical density:
A = –log(I/I
O
)
where I is transmitted light, and I
O
is incident light.
In this manual, we use the terms absorbance and optical density
interchangeably.
Optical Density
Optical density is the amount of light passing through a sample to a
detector relative to the total amount of light available. Optical density
includes absorbance of the sample plus light scatter from turbidity.
Transmittance
Transmittance is the ratio of transmitted light to the incident light.
T = (I/I
O
)
%T = 100T
where I is transmitted light, and I
O
is incident light.
PathCheck
®
Pathlength Measurement Technology
The Beer-Lambert law states that absorbance is proportional to the
distance that light travels through the sample:
A =
 bc
where A is the absorbance,
 is the molar absorptivity of the sample, b
is the pathlength, and c is the concentration of the sample. In short,
the longer the pathlength, the higher the absorbance.
Note: In this user guide, references to the SpectraMax
®
readers
include the M3, M4, M5, and M5
e
models. When a feature or capability
applies to only certain readers, this exception is noted.

Molecular Devices SpectraMax M3 Specifications

General

Brand	Molecular Devices
Model	SpectraMax M3
Category	Laboratory Equipment
Language	English