A Rapid Method for Dry Weight Determination of Proteins on a Micro Scale with an Electrobalance

Abstract

A method to determine the dry weight (0.25-2 mg) of aqueous protein solutions within 1 h, using an electrobalance, is described. The drying of 50-200 .mu.l solution pipetted onto a glass fiber disc is carried out in vacuo at 70.degree. C until the recorded dry weight becomes constant (within 25-40 min). The dried residue can subsequently be used for other purposes, e.g., quantitative amino acid analyses and the determination of moisture content in lyophilized protein samples.