MICRO DIST Temperature Validation Procedure
The temperature shown in the display of the MICRO DIST Distillation Block corresponds to the temperature in the block, where the thermocouple is located. During the heating phase, the real block temperature in the vicinity of the heater may be slightly higher or lower than the temperature shown on the display. This is due to the surface area of the aluminum block, and the locations of the heat stick and thermocouple in the block.
Supplies needed to perform this test:
• An empty MicroDist™ Tube
• Glycerol (approximately 6 mL)
• Calibration stem-type thermometer (95–170 °C)
1. Turn on the MicroDist™ block, and set the temperature to 120°C. Allow the block to come to this temperature.
2. Fill the sample tube portion of a MicroDist™ tube with 7.5g (6 mL) of glycerol.
3. Break a hole in the membrane at the top of a fully assembled Microdist™ tube, large enough to insert a thermometer.
4. Push the sample tube into the collector tube assembly as you would if you were performing a distillation.
5. Snap off the top half of the MicroDist™ Tube. (See Figure 1 below)
6. Insert the thermometer until it touches the bottom of the vial. Insert the vial into the desired position of the block
7. Read the temperature after 10-15 minutes.
A template is provided in Figure 2 below for labs wishing to perform this test at different sample positions. Typically, the temperature will fall in the range of 116-123°C. This is sufficient to form HCN gas and distill across the membrane into the trapping solution. Analysis of QC samples may provide additional verification of block performance.