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Flow injection analysis

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File:FIALyzer-1000. A flow injection analyzer. .jpg
FIAlabs FIAlyzer-1000. A flow injection analysis instrument

Flow injection analysis (FIA) is an approach to chemical analysis that is accomplished by injecting a plug of sample into a flowing carrier stream.[1][2][3] The principle is similar to that of segmented flow analysis (SFA) but no air is injected into the sample or reagent streams.

Overview

FIA is an automated method of chemical analysis in which a sample is injected into a flowing carrier solution that mixes with reagents before reaching a detector. Over past 30 years, FIA techniques developed into a wide array of applications using spectrophotometry, fluorescence spectroscopy, atomic absorption spectroscopy, mass spectrometry, and other methods of instrumental analysis for detection. Based on computer control, FIA evolved into Sequential Injection and Bead Injection which are novel techniques based on flow programming. FIA literature comprises over 22,000 scientific papers and 22 monographs.[4]

Principles of Operation

Diagram which depicts the basics of flow injection analysis

A sample (analyte) is injected into a flowing carrier solution stream that is forced by a peristaltic pump. The injection of the sample is done under controlled dispersion in known volumes. The carrier solution and sample then meet at mixing points with reagents and react. The reaction time is controlled by a pump and reaction coil. The reaction product then flows through a detector. Most often, the detector is a spectrophotometer as the reactions usually produce a colored product. One can then determine the amount of an unknown material in the sample as it is proportional to the absorption spectrum given by the spectrophotometer. After moving through the detector, the sample then flows to waste.

Detail of Sample Dispersion

When a sample is injected into the carrier stream it has the rectangular flow. As the sample is carried through the mixing and reaction zone, the width of the flow profile increases as the sample disperses into the carrier stream. Dispersion results from two processes: convection due to the flow of the carrier stream and diffusion due to a concentration gradient between the sample and the carrier stream. Convection of the sample occurs by laminar flow, in which the linear velocity of the sample at the tube’s walls is zero, while the sample at the center of the tube moves with a linear velocity twice that of the carrier stream. The result is the parabolic flow profile, before the sample passes through a detector to a waste container. [5]

Detectors

A flow-through detector is located downstream from the sample injector and records a chemical physical parameter. Many types of detector can be used such as:[5]

Industrial Applications

Agriculture

Environemental

Pharma

Research and Education

Experiments

An experiment that is used in analytical chemistry lab courses to familiarize students with FIA is the determination of phosphate by flow injection analysis. The experiment involves calibrating an FIA system, optimizing the system for detection of phosphate and finding the amount of phosphate in an unknown sample.

See also

References

  1. ^ Xu, Weihong; Sandford, Richard; Worsfold, Paul; Carlton, Alexandra; Hanrahan, Grady (2005). "Flow Injection Techniques in Aquatic Environmental Analysis: Recent Applications and Technological Advances". Critical Reviews in Analytical Chemistry. 35 (3): 237. doi:10.1080/10408340500323362.
  2. ^ Tyson, Julian F. (1985). "Flow injection analysis techniques for atomic-absorption spectrometry. a review". The Analyst. 110 (5): 419–569. Bibcode:1985Ana...110..419T. doi:10.1039/an9851000419. PMID 4025835.
  3. ^ Anastos, N.; Barnett, NW; Hindson, BJ; Lenehan, CE; Lewis, SW (2004). "Comparison of soluble manganese(IV) and acidic potassium permanganate chemiluminescence detection using flow injection and sequential injection analysis for the determination of ascorbic acid in Vitamin C tablets". Talanta. 64 (1): 130–4. doi:10.1016/j.talanta.2004.01.021. PMID 18969577.
  4. ^ Ruscika, Jarda. "Flow Injection Tutorial". www.flowinjectiontutorial.com. Retrieved 2016-03-28.
  5. ^ a b Trojanowicz, M. (2000). Flow injection analysis : instrumentation and applications. World Scientific.

5. J. Ruzicka Flow Injection Analysis. Tutorial 2015 Edition www.flowinjectiontutorial.com

  • Trojanowicz, Marek (2000). Flow injection analysis: instrumentation and applications. Singapore: World Scientific. ISBN 981-02-2710-8.
  • Hansen, Elo Harald; Růžička, Jaromír (1988). Flow injection analysis. New York: Wiley. ISBN 0-471-81355-9.
  • Martínez Calatayud, José (1996). Flow injection analysis of pharmaceuticals: automation in the laboratory. Washington, DC: Taylor & Francis. ISBN 0-7484-0445-7.
  • Pacey, Gil E.; Karlberg, Bo (1989). Flow injection analysis: a practical guide. Amsterdam: Elsevier. ISBN 0-444-88014-3.
  • Cerdà, Víctor; Ferrer, Laura; Avivar, Jessica; Cerdà, Amalia (2014). Flow analysis: A practical guide. Amsterdam: Elsevier. ISBN 978-0-444-62606-6.
  • Cerdà, Amalia; Cerdà, Víctor (2009). An introduction to flow analysis. Mallorca: Sciware.
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