Specac - Model DC-3 -Diamond Compression Cell for IR microscopes
Specac’s DC-3 Diamond Compression Cell is designed for FTIR microscope analysis. The DC-3 diamond compression cell enables solid and semi-solid type samples, such as fibers, microplastics, particulates, paint chips, and other small solid matter to be compressed to an ideal thickness for transmission experiments prior to IR spectroscopic analysis.
- High Quality Diamond windows: The cell uses two single flat, parallel crystal diamond windows of circa 3.5mm diameter and 0.5mm thickness.
- Simple thumbscrew fasteners: The size and position of the thumbscrews makes the cell easy to assemble and to adjust the pressure applied to the sample.
- Large clear aperture of 1.5mm diameter gives ample room to analyse micro samples under a microscope.
- High working pressure: A compressible O-ring is used between two fixing screws that pull the plate assemblies together for even and level sample contact.
- 440C Stainless steel body construction
- Beam condenser option for mounting the DC-3 in a regular benchtop FTIR instrument. The beam condenser uses ZnSe or KRS-5 lenses to focus the beam 4x and illuminate the aperture of the DC-3 for transmission analysis.
Watch our video on how to use the DC-3 for microplastic analysis below.
Benefits of the diamond compression cell
The purpose of the DC-3 is to flatten solid fibers, flakes, particulates, and other irregularly shaped matter for transmission IR microscopy. The compression of the material causes it to become flatter and thinner, resulting in improved signal-to-noise for the IR measurement. The flattened sample scatters less light and, because it is spread over a wider field of view, may allow a larger aperture to be selected for measurement, resulting in greater total light throughput. https://www.youtube.com/watch?v=-qzyXm-fSRU
Method of preparing the cell
The DC-3 consists of two flat, stainless-steel plates each with a diamond analysis window. A sample should be placed on the bottom window, making sure to leave a portion of the window uncovered so that a background measurement of the diamond can be taken (you can also take a background of the cell prior to placing the sample). The cell is assembled by aligning the top window with the screw posts on the bottom window and inserting the thumbscrews. The screws should be tightened gently in equal amounts to ensure that the two plates remain parallel. Tightening one side more than the other will lead to uneven distribution of pressure on the sample.
Analysing the sample with an IR microscope
- Put the assembled cell under the microscope (e.g. the SurveyIR microscope) and set the focus on the sample window.
- Find an area of the window not obscured by the sample and reduce the aperture to fill this area. Take a background measurement.
- Now move the sample into view of the aperture and record the sample measurement.
Many materials remain flat after compression. For these samples there is a benefit to opening the cell before analysis and using only the plate which the sample has attached to. This means the microscope has to measure through a smaller thickness of diamond, thus the signal will be better.