Reference Material
High-purity metallic element used as a primary benchmark for verifying the temperature and enthalpy scales in differential scanning calorimetry. Utilizing an indium calibration standard ensures that the instrument provides accurate data for melting points and heat of fusion. The metal is chosen for its stable chemical properties and a melting point that falls within the typical operating range of polymer analysis.
Physical Property
Melting occurs at exactly 156.6 degrees Celsius under standard atmospheric pressure. This transition is highly reproducible and produces a sharp endothermic peak that is easily identified by automated software. Calibration involves comparing the measured onset of this peak against the certified value.
Certification Requirement
Samples must be accompanied by a certificate of analysis from a recognized body like NIST or an equivalent national laboratory. These documents specify the purity level, which is typically 99.999 percent or higher. Contamination from other metals or surface oxidation leads to a broadening of the melting peak.
It also creates a measurably shift in the recorded temperature.
Handling Procedure
Technicians encapsulate the metal in a clean aluminum pan to prevent reaction with the furnace environment. Small sample masses, usually between five and ten milligrams, minimize thermal lag during the scan. Accurate weighing is essential for heat flow verification.
