FTIR accessories: gas & solid cells
Transmission cells for measurement of solid specimens
Apart from the traditional KBr powder pressing technology, a number of advanced methods are available for transmission spectroscopy. The variable-temperature cell enables samples to be analysed in transmission over a temperature range from -190 °C to 250 °C . The electrical heating jacket is suitable for transmission measurements from room temperature to 250 °C. The high pressure/high temperature cell permits IR spectroscopic analysis at temperatures up to 800 °C and pressures up to 66 bar. Compression cells with diamond window are ideally suited to the analysis of micro solid samples. The cell is placed in an IR microscope or beam condenser for measurement.
Gas cells & long-path gas cells
Transmission cells with considerably higher path length are required for gaseous samples, due to their low density, and for trace analysis. As far as their construction is concerned, gas measurement cells are standard transmission cells offering the required path length.
Long-path gas cells feature a compact design and are based on the White Cell principle, in which the effective path length amounts to several meters. This is achieved by means of three internal mirrors for multiple reflection of the IR light. Heated versions are available to avoid condensation or for analysis, e.g., of decomposition processes.
Many IR windows become dull and their surface scratched after an extended period of use. This kit contains all of the essential materials required to clean and re-polish windows to within a flatness of a few fringes. Re-polishing can be achieved efficiently and economically . The kit is accommodated in a handy case.
The high-pressure high-temperature cell enables IR spectroscopic analysis at temperatures up to 800 °C. The cell can be used at pressures from vacuum up to 66 bar and is also suited to the analysis of flowing gases.
Due to the hygroscopic nature of the materials of many IR cell windows and other accessories, storage in a dry atmosphere, such as a drying cabinet, is essential. The drying cabinet has a temperature control range of 30 °C to 80 °C. A desiccant with colour indication enables constant monitoring of humidity.
Long-path gas cells work according to the White principle, in which IR light is reflected several times within a three-mirror-system in order to increase the path length. The cells are available in various basic sizes.
The variable temperature cell enables solid and liquid samples to be analysed for transmission over a temperature range from -190 °C up to 250 °C. Cooling of the cell is achieved by means of a cooling dewar. The selection of coolant is determined by the desired temperature; for -190 °C, liquid nitrogen is required. The cell holder is mounted directly on the floor of the dewar, the holder accommodates one liquid cell or one solid sample holder. The cell can also be used for analysis in UN/VIS spectroscopy.
The electric heating jacket is designed for transmission measurements on liquids and solids from RT to 250 °C. The heating jacket accomodates a liquid cell (static or flow) or a solid sample holder. The structure of the water heating jacket is basically equivalent to the electrical jacket, except that heating of the flow takes place e.g. with the help of a heat recirculation thermostat.
Compression cells with diamond window are designed for analysis of micro solid samples for transmission. The sample to be analysed is placed between two diamond windows and compressed to the ideal thickness for transmission analysis by applying pressure from outside. For measurment, the cell is then placed in an IR microscope or in the microfocus 4x.beam condensor.