Dispersion behaviour of solid particles in flow-injection analysis

Abstract

In order to achieve a reproducible on-line pretreatment of slurry samples in flow-injection analysis the dispersion behaviour of these samples has to be examined. This paper reports the effects of flow rate and some configurations of reaction manifolds. The reaction manifolds were a straight tube and two helically coiled tubes with different aspect ratios and spatial orientation. The slurry samples consisted of spheres of different densities suspended in a Triton X-100/water solution, the particle diameters (up to 75 ~tm) were relatively large compared to the internal diameter of the tubing (0.75 ram). For the straight tube theoretical calculations were found to give a reasonable impression of the experimental flow behaviour of the spheres. Statistical moments were used to characterize the slurry peaks. For tightly coiled tubes it was found that the retention time of a slurry sample depends on the particle density. The spatial orientation of the coils mainly affects the retention of high density particles.

Direct Introduction of Slurry Samples in Multi-syringe Flow Injection Analysis: Determination of Potassium in Plant Samples

“…7 This approach has been applied to the direct insertion of plant samples into flow systems by means of injection valves/ commutators [8][9][10] or selection valves. 11,12 The use of pinch valves for the same aim was reported in theoretical studies using model solutions 13 and a nitrogen flow to propel the slurry samples, 14 without application to real samples. Therefore, the purpose of this work was to explore the slurry sampling approach for automatic analysis of plant materials using a MSFIA manifold equipped with pinch valves.…”