Reaction units separation techniques based

Flow injection analysis is based on the injection of a liquid sample into a continuously flowing liquid carrier stream, where it is usually made to react to give reaction products that may be detected. FIA offers the possibility in an on-line manifold of sample handling including separation, preconcentration, masking and color reaction, and even microwave dissolution, all of which can be readily automated. The most common advantages of FIA include reduced manpower cost of laboratory operations, increased sample throughput, improved precision of results, reduced sample volumes, and the elimination of many interferences. Fully automated flow injection analysers are based on spectrophotometric detection but are readily adapted as sample preparation units for atomic spectrometric techniques. Flow injection as a sample introduction technique has been discussed previously, whereas here its full potential is briefly surveyed. In addition to a few books on FIA [168,169], several critical reviews of FIA methods for FAAS, GF AAS, and ICP-AES methods have been published [170,171]. 

Dias et al. [58] exploited the versatility of the sequential injection system through the use of a chemical reaction to convert LA and a gas diffusion unit to separate the gaseous compound formed the technique also used posterior detection by spectrophotometry. The reaction was based on a batch procedure [54] in which LA was oxidized by Ce in a strong acidic medium (4.4 mol L H2SO4) under high temperatures (90°C). With the flow conditions and operational procedure of SIA, the kinetic parameters were improved. 

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