Volume 24, Issue 2 (April 1979)
A Liquid Gradient Density Screening System for Soil Sample Identification Studies Using a Minicomputer
The use of density gradient systems for the identification and comparison of soil samples is a well-recognized procedure [1,2]. In the usual manual method, liquid from a series of mixtures consisting of various ratios of high and low density liquids, such as 1,1,2,2-tetrabromoethane and bromobenzene, is added to a glass tube positioned vertically in a stand having a ruled background. The liquid is added up to each line and two or more identical tubes are prepared for comparison of the unknown against the reference material. A simple 8- to 10-step gradient is usually sufficient to obtain a usable resolution for most soil samples.