MNL-1007 REV A
7
Measurement Steps
The spectrum (
S
) of a sample is given by the ratio of the spectrum of the beam transmitted or reflected from the sample (
I
)
to the
spectrum of the beam at the front face of the sample (
I
o
) over the spectral range of interest
𝑺
(𝝀
𝟏
→𝝀
𝟐
)
=
𝑰
(𝝀
𝟏
→𝝀
𝟐
)
𝑰
𝒐
(𝝀𝟏→𝝀𝟐)
To measure the sample’s spectrum (
S
), the background spectrum should be measured (
I
o
)
(background measurement), as well as the
light transmitted or reflected from the sample (
I
)
(sample measurement). The NanoQuest software enables the acquisition of the
background measurement and stores it to be used as a reference spectrum in further sample measurements.
It is recommended that the background spectrum be measured as frequently as possible, and ideally before each sample
measurement. This ensures the most accurate results from the device.
Transmission Measurements
The background measurement
I
o
is obtained by measuring the spectrum of the transmitted beam without placing any material in the
light path (e.g. an empty cuvette), under the same conditions at which the measurement of the sample will be conducted. Once the
background measurement has been made, the sample measurement
I
is made by placing the sample in the sample holder.
Reflection Measurements
The background measurement (
I
o
) is obtained by measuring the spectrum of the reflected beam from an appropriate reflection
reference standard with nearly flat spectral response across the spectral range of interest under the same conditions at which the
measurement of the sample will be conducted. The sample spectrum (
I
)
is then obtained by measuring the beam reflected from the
sample.