Melting curves on less than 1 μg of nucleic acid

Abstract Two types of microcuvettes were developed for the registration of melting curves in normal uv-spectrophotometers. Nucleic acid (0.5–1 μg) is required to determine changes in absorption with an accuracy of 0.1 mA. The quartz cuvette allows the registration of equilibrium melting curves up to 100°C. The other type of cuvette made from gilded brass allows to measure slow temperature jumps up to 80°C and equilibrium melting curves up to 70°C. The time range of ∼3 s to several hours is accessible complementing the Eigen/De Mayer temperature-jump technique (1963, in Techniques of Organic Chemistry, Vol. VIII/2, pp. 895–1054, Wiley, New York). Temperature jumps of high amplitude as well as jumps to lower temperatures are possible. Examples of measurements on viroids and double-stranded viral RNA are presented.