Flotation Method in Determination of the Density of Low Weight Solid Samples

Abstract

A review of the known methods of density determination of low weight samples of solid substances is presented. A modification of the flotation method is developed for the samples which weigh at least 1 mg and have a density of 1 g/cm³ and more. The sample under study is coupled with a sample of a plastic material, namely crude bee wax, and placed into a working liquid consisting of the density regulator (potassium bromide), solvent (water) and wetting agent (n-propyl alcohol). After 30-min dwell a composite sample is tranformed into a suspension by changing concentration of potassium bromide at a temperature close to 20°C to measure the liquid density using the pycnometric method. The density of the studied material is calculated using an empirical expression. The results of the density determination for the variety of solid samples of different mass and density match satisfactory the reference date.