AQ-00275-000, Rev. 3
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Transflectance or Absorbance Measurements Using the Cuvette Center Mount
Sample Holder
NOTE:
Labsphere recommends using quartz cuvettes with four clear sides. Cuvettes with frosted or
ribbed sides are not recommended.
After completing the beam alignment procedure for the cuvette sample holder, follow this proce-
dure to perform measurements.
1. Fill the cuvette with the pure solvent used for the sample solution. If a cream or
sludge is to be measured, leave the cuvette empty for this step - the empty cuvette
will be the reference.
2. Load the reference cuvette into the cuvette sample holder as shown in Figure 15.
3. Open the lid of the accessory and remove the center mount port plug.
4. Carefully insert the cuvette and sample holder into the vacated center mount port. Set
the Cuvette Center Mount Sample Holder alignment pins carefully into the alignment
holes. Take care when inserting or removing the center mount from the integrating
sphere to avoid damaging the interior of the sphere.
5. Set your instrument parameters.
6. Perform an instrument baseline correction.
7. Remove the sample holder and replace the solvent or empty cuvette with the sample-
filled cuvette. Load the sample holder into the sphere.
8. Initiate a sample scan and record the measurement data. The spectrum displayed by
the instrument is the transflectance of the sample.
Powder Cell Holder
In some cases, you may find that your samples exhibit better diffuse reflectance spectra when the
sample is ground to powder form. The PCH-Series powder sample holders are designed to fit
inside your reflectance sample holder in the same manner as the reflectance standard and light trap
devices.
The PCH-Series Powder Cell Holder is available for either UV-VIS or NIR applications. The UV-
VIS model is optimal for use across the 250-1100 nm spectrum. The NIR model is optimal in the
Figure 16.
The PCH-020 powder sample
holder features a quartz window over a 9 mm
deep cavity.