Studies in automated microanalysis

Many benefits can be derived fi-om automation and miniaturization of analytical systems: compact size, high efficiency, high speed, low reagent consumption and low cost.

Flow injection analysis technique represents a breakthrough in automated microanalysis. Some persistent problems in this technique have been investigated. A dual-wavelength/dual-cell optical detection system has been used to compensate simultaneously for the effects of refi-active index change and sample turbidity effect. A dual-wavelength optical detector has been used for flow injection extraction analysis without phase separation.

Liquid drops formed at the tip of a small tube have some unique features useful for automated microanalysis, namely, reproducibility, renewability and the lack of windows in an optical cell. A liquid drop has been used as a sampler for the sample gas flowing around it; the color change of the drop due to the uptake of the analyte is optically monitored in-situ. Deposition of precipitate on the windows of a conventional flow cell, usually a vexing problem in automated process analysis, is avoided by using a liquid drop as windowless optical cell. Solvent extraction is performed by suspending a micro organic drop inside a "flowing" aqueous drop.