Abstract
A differential scanning calorimeter (DSC) using small sample cells has been widely used for studies on various solid materials.
It is very convenient to use a small sample cell for precise and reproducible measurements. But it is not always true for studies of solutions and biological materials with small enthalpy changes.
From this point of view, a new DTA system using larger sample cells with the effective volume of about 1.5cm3 was designed and tested.
A semiconductor thermoelectric module with a sensitivity of about 37.2mV/°C was used as a thermal detector and in the continuous measuring mode the sensitivity of this apparatus was 0.052mcal/s.
The approximate temperature range is from 100°C to-100°C. This system, in addition, ensures a constant cooling rate in virtue of precision electrical controller and a refrigerating technique of original design. The following analytical applications were described: (1) quality assessment of alcoholic drinks, (2) putrefaction test of green pea, (3) assessment of binding forces water absorbed in soil and clay, and (4) measurements of freezing behaviours of plant leaves.
