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Melting Point Certified Reference Standards
Application Note #2
What is a Certified Reference Standard?
Certified Reference Standards (CRSs) are high-purity chemicals certified by
national, local or international standards laboratories and pharmacopeias, which
are produced and tested according to well established and easy-to-reproduce
procedures.
Use CRSs for temperature scale calibration and determination of acceptability of
melting point (MP) instruments including OptiMelt.
General Guidelines and Recommendations
Use CRSs obtained from reputable standards and pharmacopeia
Laboratories.
Use CRSs with certificates of measurement including records of:
(1) Lot/batch Identification number (for traceability)
(2) Purity specification (analysis method, purity levels, etc.)
(3) Detailed description of the instrumental setup used for the melting
point determination (i.e. type of instrument, manual or automatic
detection, hot bath or metal block oven, capillary tube dimensions,
amount/height of sample packed, compaction method, etc.)
(4) Preconditioning of the sample (i.e. drying, grinding, etc).
(5) Detailed heating conditions, including initial temperature, ramping rate
and any special comments required to properly reproduce the melting
conditions used by the standards laboratory to certify the compound.
Alternatively, a reference to a standardized MP determination method
must be included.
(6) Melting points and melting point ranges with well characterized
uncertainty errors.
Whenever possible, choose the CRSs with the smallest uncertainty errors.
Remember that the accuracy of your OptiMelt is only as good as the accuracy
of the standards used for its calibration. Note: As a general rule, avoid CRSs
leading to uncertainty errors larger than 0.5