Automation of surface cleaning and sample addition for surface balances

Abstract

An apparatus is described for surface cleaning and sample addition for the measurement of physical properties of insoluble molecules at the air/water interface. To clean the surface the subphase liquid level is increased to engage aspirators positioned above the surface. These also adjust the liquid level by reproducibly breaking contact with the liquid during aspiration. Sample is added via an autosampler of the type used in high-pressure liquid chromatography. The advantages of the apparatus are the reduced chance of surface contamination and oxidation. When used in conjunction with a computer-controlled film balance, the system can be fully automated with a 25 sample capacity.