Flow Injection Analysis FIA

FIA has the advantage of working for low sample volumes (25-200 III) and at a speed that is limited only by the response time of 

When a very small quantity of sample is injected into a large volume of liquid then dispersion must be taken into account. EHspersion is represented by  

Once the enzyme sensor has been in contact with the inhibitor, it is rinsed with a solution containing a reactivating agent. In principle, the injection of substrate should give the reference peak again. 

When enzyme sensors are combined with FIA they have applications in medicine and the food produce industry. For example, FIA has been combined with the glucose oxidase electrode to determine glucose in blood [270], with the choline oxidase electrode for the determination of cholinesterase in serum [271], and with a bienzyme electrode that uses choline oxidase and phospholipase for the determination of phospholipids in serum [272]. The technique has also been used with an alcohol oxidase electrode to determine alcohol in drinks (for example, beers) [273], or with a glucose oxidase electrode to determine glucose [274] in various foodstuffs [275] or in fermentation processes [276]. 

The application of FIA and biosensors in environmental analysis is attractive because enzyme biosensors operate on the principle of inhibition. The process is economical because only small quantities of substrate are required and because the incubation, reaction and reactivation times can be controlled. The process can therefore yield high reproducibility. This method has been used to measure insecticide levels in sea water [269], Finally, FIA is particularly suitable for the construction of automated systems. 

Ruzicka and Hansen [359] characterized flow injection analysis (FIA) as ... information gathering from a concentration gradient formed from an injected, well-defined zone of a fluid, dispersed into a continuous unsegmented stream 

FIA easily permits validation requirements to be met because alternative measuring principles can be run in parallel. This helps to exclude systematic errors which might originate from the complex matrix. For instance, Carlsen et al. [54] reported an example in which two different FIA methods for penicillin V monitoring have been compared. 

Biosensors are being increasingly used as detectors in FIA systems [284,285, 322, 379, 476]. The drawbacks of biosensors as direct in situ sensors, namely their low dynamic range, their lack of ability to survive sterilization, their limited lifetime, etc. are no longer valid ex situ because the analyzer interfaces the biosensor which can be changed at any time and FIA can provide samples in optimal dilution. The need for chemicals and reagents can be drastically reduced when employing biosensors, specifically when the entire system is miniaturized [48]. 

Only recently, flow injection has been used as an interface to the first on-line application of flow cytometry [480]. Gorlach et al. [137] used flow injection for high throughput mass spectrometric mapping. 

Interestingly, FIA can also be operated without an injection and gives valuable results. To this end we stained the DNA within yeast cells removed at a minute flux from a reactor and were able to quantify the amount of DNA online thus giving evidence for the cell-cycle dependence of oscillations [397]. 

---

Flow injection analysis (FIA) was developed in the mid-1970s as a highly efficient technique for the automated analyses of samples. °> Unlike the centrifugal analyzer described earlier in this chapter, in which samples are simultaneously analyzed in batches of limited size, FIA allows for the rapid, sequential analysis of an unlimited number of samples. FIA is one member of a class of techniques called continuous-flow analyzers, in which samples are introduced sequentially at regular intervals into a liquid carrier stream that transports the samples to the detector. ... 

DEVELOPMENT OF INFRARED DETECTION IN FLOW INJECTION ANALYSIS (FIA) AND CAPILLARY ELECTROPHORESIS (CE)... 

The ion pair extraction by flow injection analysis (FIA) has been used to analyze sodium dodecyl sulfate and sodium dodecyl ether (3 EO) sulfate among other anionic surfactants. The solvating agent was methanol and the phase-separating system was designed with a PTFE porous membrane permeable to chloroform but impermeable to the aqueous solution. The method is applicable to concentrations up to 1.25 mM with a detection limit of 15 pM [304]. 

Another interesting development, in which continuous flow was combined with discrete sample titration, is continuous flow titration by means of flow injection analysis (FIA) according to Ruzicka and co-workers70. Fig. 5.16 shows a schematic diagram of flow injection titration, where P is a peristaltic pump, S the sample injected into the carrier stream of diluent (flow-rate fA), G a gradient chamber of volume V, R the coil into which the titrant is pumped (flow-rate fB), D the detector and W waste. 

Flow injection analysis (FIA) (Ruzicka and Hansen), since 1975 In continuous flow, stopped flow or with merging zones (FIA scanning or intermittent pumping) Adapted voltammetric electrodes Membranes for Partial dialysis Membrane amperometry (Clark) Differential techniques (Donnan) Computerization, including microprocessors Special measuring requirements in plant control (to avoid voltage leakage, etc., Section 5.5)... 

The various methods that have been outlined in the previous sections are not exclusive and other analytical methods have been used for the determination of methylxanthines in food systems. One of the most widely used methods for food analysis is flow injection analysis (FIA). In a study by Numata,43 a flow injection analysis method for the determination of hypoxanthine in meat was described. 

Table 2. Performances of batchwise and flow injection analysis (FIA) bioluminescence-based optical fibre sensors.

Some coupled systems allow measurement of the main N and P forms (nitrate, ammonia and orthophosphates) [22,27,29], among which is a system based on membrane technology in combination with semi-micro continuous-flow analysis (pCFA) with classical colorimetry. With the same principle (classical colorimetry), another system [30] proposes the measurement of phosphate, iron and sulphate by flow-injection analysis (FIA). These systems are derived from laboratory procedures, as in a recent work [31] where capillary electrophoresis (CE) was used for the separation of inorganic and organic ions from waters in a pulp and paper process. Chloride, thiosulphate, sulphate, oxalate,... 

Flow injection analysis (FIA), 0 587 Flow-injection immunoanalysis, 6 400 Flow maldistribution effect, 13 258, 270-271... 

Flow-injection analysis (FIA) is a rapidly growing analytical technique. Since the introduction of the original concept in 1975, about 1000 papers have been published. 

Flow injection analysis FIA star 5020 FIA star 5032 FIA star 5025 ion selective electrode meter FIA star 5010 The Aquatec System UK Supplier EDT Analytical Ltd 14 Trading Estate Road London NW10 7LN UK FIA System LGCI Tecator AB Box 70 S 26301 Hanagas Sweden... 

Several authors have reported the identification and determination of APEOs in industrial blends, wastewaters and environmental samples by APCI-MS using flow injection analysis (FIA) [2,3] or preceded by LC, using both RP [4-9] and NP [10,11] separation. 

Flow injection analysis (FIA) ESI-MS and APCI-MS spectra for an EO/PO polyether modified silicone surfactant (PEMS) used as a personal care product have been obtained in positive and negative ionisation modes with the positive ionisation mode yielding the best results [41]. The spectra obtained in both modes were highly complicated, and thus no assignment was given. Significant differences in the ionisation results were obtained from the two interfaces, with those ions observed in the ESI-MS spectrum appearing in the lower... 

For the identification of surfactants in influent and effluent samples from German and Greek wastewater treatment plants, Schroder and co-workers [4,5] employed an analytical approach comprising SPE, selective elution and screening analysis by flow-injection analysis (FIA)-MS(MS) in combination with liquid chromatography-(tandem)... 

The structural integrity of M2D-C3-0-(E0)ra-CH3 was maintained for all solid media investigated, as confirmed by qualitative analysis of the flow injection analysis (FIA) API-MS spectra (example shown in Fig. 2.8.10a). Intercalation of the surfactant solution between the clay layers was considered as the likely cause of the reduced recovery on montmorillonite (74%), according to experimental observations and... 

Because of its advantages (high sensitivity and selectivity, low cost and miniaturization) amperometric detection has been frequently used in flow injection analysis (FIA) and RP-HPLC. However, it has been established that the peak area (detector response) considerably depends on the flow rate. A general approach has been proposed to predict the effect of flow rate on the peak area in FIA and RP-HPLC. The general form of the correlation describing the flow in a parallel plate cell with short rectangular electrodes is... 

Routine analyses of large numbers of similar samples can readily be automated and the sample throughput considerably increased (sometimes up to about 200 samples per hour) by carrying out the analyses in a continuously flowing medium. At present there are two basic approaches to the problem, the older technique of continuous-flow analysis (CFA) introduced more than 25 years ago [145] and widely developed by the Technicon Company (Auto-Analyzer), and more recent flow-injection analysis (FIA for a recent literature review see [123]). For a brief comparative survey of the two methods see [148]. 

As a process analytical solution, these extrinsic reactive approaches necessitate an extrinsic optode (see later discussion), an on-line sample conditioning system or an at-Une solution such as a flow injection analysis (FIA) system or other autonomous solutions. Reaction kinetics, post analysis cleanup such as rejuvenating a substrate (optode, immobilized based immunoassays, etc.) among other complexities are additional considerations for these types real-time analysis methods. ... 

By injection Sequential Continuous Flow-injection analysis (FIA)... 

---