Scanning calorimeter for nanoliter-scale liquid samples

We introduce a scanning calorimeter for use with a single solid or liquid s ample 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. T he heat of fusion was measured to within 5% of the bulk value, and the sens itivity of the measurement was +/- 7 mu W. The heat of vaporization of wate r 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 w ithin 25% were obtained for the heat of vaporization by using the calorimet er in a heat-conductive mode and measuring the passive evaporation of water . Temperature measurements over a period of 10 h had a standard deviation o f 3 mK. (C) 2000 American Institute of Physics. [S0003-6951(00)01243-2].