An automated viscometer based on high-precision flow injection analysis. Part II. Measurement of viscosity and diffusion coefficients

Abstract

It is shown that viscosities in the range of 0.2–190 cP can be determined on 60-µl samples, in an analysis time of about 1 min with reasonable accuracy and a precision of 0.2–0.3%. The method is based on timing a sample injected into a flowing carrier stream over a fixed distance. The factors affecting the dispersion of the sample within the carrier stream have been critically investigated. It is shown that chemical interactions, especially hydrogen bonding, between the sample slug and the carrier stream can crucially affect the dispersion pattern, so that correct choice of carrier is essential for the success of the method. It can also be used for the determination of molecular diffusion coefficients and it is possible that it could be adapted to cover a wider range of viscosities. The implications of the study to flow injection analysis are discussed.