Flow Injection Analysis Techniques in Atomic Spectroscopy

Abstract

Flow injection analysis (FIA), developed originally for the automation of serial assays, has become a powerful tool most adequate for performing on‐line any sample preparations before final measurement (e.g. sample dissolution, dilutions, matrix removal, preconcentration, etc.). It is not surprising that the combination of FIA with atomic spectrometric techniques has enlarged the analytical potential of atomic methods and expanded their wide field of applications. The collection of sample manipulation processes which can be covered today by flow operation procedures is amazing and therefore the general instrumentation required is reviewed in this contribution. The description of the different flow strategies is carried out according to a hierarchy going from simple dilutions (including isotopic dilution of particular interest when using mass spectrometric detection), reagent mixing or standard additions, to more sophisticated flow manifolds such as those based on the use of two phases (e.g. gas–liquid, liquid–liquid or solid–liquid) for separation/preconcentration purposes. Modern approaches allowing for on‐line decomposition/dissolution of solid samples (e.g. on‐line chemical oxidation, photo‐oxidation and microwave heating) are also described. Finally, manifolds for the in situ uptake of the sample and its complete on‐line pretreatment are discussed. The coupling of the above flow methodologies to a variety of atomization/excitation/ionization sources (flames, quartz tubes, graphite furnaces, inductively coupled plasmas (ICPs), microwave coupled plasmas, glow discharges (GDs), etc.) is detailed, in order to understand the usefulness of this combination both in atomic techniques based on photon measurements (absorption, emission and fluorescence spectrometry techniques) and on ions measurement mass spectrometry (MS).