The medium was recovered and the products on the filter papers in the Buchner funnel were washed free from ZnCl2 solution using tap water.
Filter papers containing the samples were put on a tray and placed in an oven at 40 C for air drying.
After sufficient drying time – judged with the naked eye, but not less than 24 h – the samples were brushed off the filter papers and weighed to the nearest 1 10–4 g. The procedure was then repeated with the sinks in the next solution density until all density fractions had been separated.