Segmented flow injection

In 1985, mono-segmented flow analysis was proposed [64] as a means of achieving extended sample incubation times without excessive sample dispersion. The sample was inserted between two air bubbles into an unsegmented carrier stream therefore the innovation combined the favourable characteristics of both segmented and unsegmented flow systems. Further development revealed other potential applications, especially with regard to relatively slow chemical reactions, flow titrations, sample introduction to atomic absorption spectrometers, liquid-liquid extraction and multi-site detection (Chapters 7 and 8). This innovation was also referred to as segmental flow injection analysis [65]. 

L. Solujic, E.B. Milosavljevic, M.R. Straka, Total cyanide determination by a segmented flow injection-on-line UV digestion-amperometric method, Analyst 124 (1999) 1255. 

J.A. Borzitsky, A.V. Dvinin, O.M. Petrukhin, Y.I. Urosov, Segmental flow injection with ion-selective electrodes for the determination of fluoride in waters, Anal. Chim. Acta 274 (1993) 125. 

Z.-L. Zhi, Segmental flow injection analysis, a hybrid technique of segmented continuous flow analysis and flow injection analysis, Trends Anal. Chem. 17 (1998) 411. 

Y.-S. Hsieh, S.R. Crouch, Flow reversal and flow recycle air-segmented flow injection for simultaneous determination of a binary mixture, Anal. Chim. Acta 304 (1995) 333. 

ASTM D7511-09e2, Standard test method for total cyanide by segmented flow injection analysis, in-line ultraviolet digestion and amperometric detection, ASTM International. 

Since 1970, new analytical techniques, eg, ion chromatography, have been developed, and others, eg, atomic absorption and emission, have been improved (1—5). Detection limits for many chemicals have been dramatically lowered. Many wet chemical methods have been automated and are controlled by microprocessors which allow greater data output in a shorter time. Perhaps the best known continuous-flow analy2er for water analysis is the Autoanaly2er system manufactured by Technicon Instmments Corp. (Tarrytown, N.Y.) (6). Isolation of samples is maintained by pumping air bubbles into the flow line. Recently, flow-injection analysis has also become popular, and a theoretical comparison of it with the segmented flow analy2er has been made (7—9). 

E. Fogelqvist, M. Krysell and L-G. Danielsson, On-line liquid-liquid extr action in a segmented flow directly coupled to on-column injection into a gas cliromatograph , A a7 Chem. 58 1516-1520(1986). 

Sulphate In Waters, Effluents and Solids (2nd Edition) [including Sulphate in Waters, Effluents and Some Solids by Barium Sulphate Gravimetry, Sulphate In waters and effluents by direct Barium Titrimetry, Sulphate in waters by Inductively Coupled Plasma Emission Spectrometry, Sulphate in waters and effluents by a Continuous Flow Indirect Spectrophotometric Method Using 2-Aminoperimidine, Sulphate in waters by Flow Injection Analysis Using a Turbidimetric Method, Sulphate In waters by Ion Chromatography, Sulphate in waters by Air-Segmented Continuous Flow Colorimetry using Methylthymol Blue], 1988... 

Flow injection analysis has been adapted to automatic air-segmented continuous flow systems, e.g., the Technicon AutoAnalyzer system. Several reducing... 

Flow injection analysis is a rapid method of automated chemical analysis that allows for quasi-continuous recording of nutrient concentrations in a flowing stream of seawater. The apparatus used for flow injection analysis is generally less expensive and more rugged than that used in segmented continuous flow analysis. A modified flow injection analysis procedure, called reverse flow injection analysis, was adopted by Thompson et al. [213] and has been adapted for the analysis of dissolved silicate in seawater. The reagent is injected into the sample stream in reverse flow injection analysis, rather than vice versa as in flow injection analysis. This results in an increase in sensitivity. 

FLOW INJECTION ANALYSIS VERSUS SEGMENTED FLOW... 

In this technique, which was developed in the 1970s, microlitre volumes of liquid sample are injected, at intervals, into a continuously flowing carrier stream which is not air-segmented. Various reagent streams are introduced as required and controlled mixing of reagents and sample occurs. The fact that flow injection analysis does not involve air-segmented streams makes it possible to include such separation steps as solvent extraction and gas diffusion. 

Figure 3.10 — Flow manifolds for implementation of flow-through biosensors. (A) Flow injection merging-zones manifold for the bioluminescence detennination of ATP. ATP standards (30 fiL) and luciferin (30 fiL) are injected into the buffered carrier streams, each pumped at 0.7 mL/min and synchronously merged 12.5 cm downstream. Distance from merging point to immobilized enzyme coil, 2.2 cm. (Reproduced from [59] with permission of Elsevier Science Publishers). (B) Completely continuous flow manifold for the determination of NADH. (Reproduced from [71] with permission of the Royal Society of Chemistry). (C) Segmented-flow manifold for the determination of L-(+)-lactate. (Reproduced from [65] with permission of Marcel Dekker, Inc.). (D) Single-channel flow injection manifold with immobilized reagent for the detennination of glucose. (Reproduced from [77] with permission of Elsevier Science Publishers).

Flow injection analysis (FIA) is a continuous flow method in which highly precise sample volumes are introduced into a stream that is segmented or non-segmented. The... 

Flow injection analysis is a continuous flow method in which highly precise sample volumes are introduced into a stream using segmented or unsegmented flow. The method must be accurate, precise and reproducible before it can be considered as a useful technique and the following test proves that this technique does meet all the requirements. Tyson [3], carried out several studies involving flow injection techniques and atomic spectroscopy with considerable success. 

Two types of continuous flow analyzers are the segmented flow analyzer and the flow injection analyzer. 

In continuous flow methods, the sample is inserted into a flowing stream, where a number of operations can be performed before it is transported to a flow-through detector. Hence, these systems behave as automated analyzers in that they can perform not only sample processing operations but also the final measurement step. Such sample processing operations as reagent addition, dilution, incubation, mixing, dialysis, extraction, and many others can be implemented between the point of sample introduction and detection. There are two different types of continuous flow systems segmented flow analyzers and flow injection analyzers. 

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