Flow Injection Analysis of Iron in Presence of Uranium

Analytical chemistry involves the science of providing information about the target in order to facilitate diagnoses and the making of educated, effective decisions. Trace level determination of metallic impunity is one of the imperative steps of chemical quality control of nuclear fuels. The spectra of U are so complex that a direct determination of the metal ions in presence of U becomes very difficult to interpret. Therefore separation becomes essential and regardless of the substantial furtherance in sensitivity using new instrumentation, conventional separation techniques are recurrently used to surmount interferences from matrix elements as well as to improve detection limits [1,2]. However separation results in increase of time of analysis and also great care is needed as there is a greater chance of contamination during reaction process. ICP-AES based method for direct determination of trace metallic constituents without any separation has been reported [3]. Another technique which is very useful is the Flow Injection Analysis (FIA) which has several advantages like small sample size, high sample throughput due to shorter reaction times, reproducibility, reliability, and ease of automation [4]. The concept of FIA depends on a combination of three factors: reproducible sample injection volumes, controllable sample dispersion, and reproducible timing of the injected sample through the flow system. The common feature of all Flow Injection (FI) methods is that the characteristics of fluid flow in closed medium are exploited for one or more of the following operations on a controlled amount of sample (a) the transport of samples, (b) the chemical pretreatment of samples and (c) the presentation of samples to a chemical instrument. As all samples and standards have identical residence times, the kinetic limitations of conventional analytical methods, in which samples and standards arc handled in parallel, do not apply. Thus it is not necessary for any of the chemical or physical processes in the system to be at equilibrium and restrictions on the stability of both the product and the reagents can be relaxed. Single Line Manifold (SLM) in which a reagent carrier stream continuously flows and a fixed volume of sample is injected into the flowing reagent carrier results in dispersion due to the combination of laminar flow (in which a parabolic velocity profile develops between the center stream line and the wall) and diffusion. Flow injection analysis of iron in various matrices has been reported [5-12].