[Sample distribution of inner ear fluids in the submicroliter range]

Abstract

Biochemical analysis of inner ear fluids is fraught with numerous problems. After developing accurate techniques to measure inorganic and organic substances in fluid amounts of 0.1 microliter the problem of measuring and handling series of samples arose. It became necessary to develop methods to handle inner ear fluid taken without sophisticated techniques, i.e. to measure, to store and to dispatch inner ear fluid samples. The fluid volume is measured with a "nanocap" technique and is then transferred to cellulose acetate membranes. A 3 mm long glas capillary tube held by a special device is dipped into the inner ear fluid sample. The capillary tube is then placed on a membrane piece that adheres to the tube. The higher capillary forces of the membrane transfer the fluid out of the glass tube into the membrane which is put into a plastic reaction tube and stored. The reproducibility of the method was tested by flame photometric assays of standard sodium solutions and of perilymph from the scala tympani of guinea pigs. The variation coefficient is below 3% for a standard solution and below 5% for perilymph. The method developed to measure and handle inner ear fluids with the aid of "nanocap" and membrane pieces is easier and faster than the conventional techniques.