Scanning calorimeter for nanoliter-scale liquid samples

TLDR: In this paper, a scanning calorimeter was introduced for use with a single solid or liquid sample with a volume down to a few nanoliters, which was demonstrated with the melting of 52 nL of indium, using heating rates from 100 to 1000 K/s.

Abstract: We introduce a scanning calorimeter for use with a single solid or liquid sample with a volume down to a few nanoliters. Its use is demonstrated with the melting of 52 nL of indium, using heating rates from 100 to 1000 K/s. The heat of fusion was measured to within 5% of the bulk value, and the sensitivity of the measurement was ±7 μW. The heat of vaporization of water was measured in the scanning mode to be within ±23% of the bulk value by actively vaporizing water droplets from 2 to 100 nL in volume. Results within 25% were obtained for the heat of vaporization by using the calorimeter in a heat-conductive mode and measuring the passive evaporation of water. Temperature measurements over a period of 10 h had a standard deviation of 3 mK.