BUCHI Melting Point M-565 - Manual (Page 42)

6 Operation
42 Melting Point M-565 Operation Manual, Version D
6 .4 Calibration
NOTE
BUCHI recommends calibrating each new instrument after installation. Furthermore it is recom-
mended that the instrument be recalibrated every year.
6 .4 .1 Calibration principle
NOTE
The instrument is calibrated using melting point standards. The calibration is valid for boiling points
as well.
Use the calibration set (11055018). This calibration set contains the melting point standards listed
below. Each standard is shipped with a certificate of analysis and an MSDS (material safety data
sheet).
The calibration set contains the following substances:
• 4-Nitrotoluene:
approx. 52 °C
• Diphenyl acetic acid: approx. 148 °C
• Caffeine: approx. 237 °C
• Potassium nitrate: approx. 335 °C
From each substance, a minimum of 6 have to fulfill a standard deviation of less than +/- 0.2 °C.
Otherwise the instrument will not move on to the next substance. The maximum number of samples
for each substance to reach the deviation of +/- 0.2 °C is limited to 12 samples. The instrument auto-
matically chooses the best 6 results from the determinations performed.
After a successful calibration is done, it may be checked using the verification set (11055019). Each
standard of the set contains a certificate of analysis and the MSDS.
The verification set contains the following substances:
• Benzil:
approx. 94 °C
• p-Anisic acid: approx. 182 °C
• Phenolphthalein: approx. 261 °C