This article provides a basic overview of the principles of sequential injection analysis. This is followed by a discussion of the instrumental requirements. A brief overview of some of the diverse analytical applications of SIA is also presented.

Sequential injection analysis

The selective detection of a specific target molecule in a complex environment containing potential contaminants presents a significant challenge in chemical sensor development. Utilizing phage display techniques against trinitrotoluene (TNT) and dinitrotoluene (DNT) targets, peptide receptors have previously been identified with selective binding capabilities for these molecules. For practical applications, these receptors must be immobilized onto the surface of sensor platforms at high density while maintaining their ability to bind target molecules. In this paper, a polymeric matrix composed of poly(ethylene-co-glycidyl methacrylate) (PEGM) has been prepared. A high density of receptors was covalently linked through reaction of amino groups present in the receptor with epoxy groups present in the co-polymer. Using X-ray photoelectron spectroscopy (XPS) and gas-chromatography/mass spectroscopy (GC/MS), this attachment strategy is demonstrated to lead to stably bound receptors, which maintain their selec...

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Polymer-oligopeptide composite coating for selective detection of explosives in water.

Designing an ultra-sensitive aptasensor based on an AgNPs/thiol-GQD nanocomposite for TNT detection at femtomolar levels using the electrochemical oxidation of Rutin as a redox probe.

Square-wave cathodic stripping voltammetric analysis of RDX using mercury-film plated glassy carbon electrode.

The second generation of flow-injection analysis (FIA), so-called sequential injection (SI), has already been consolidated as an attractive flowing-stream approach in several analytical fields, with advantages over the first generation of FIA in terms of automation, miniaturization, and sample and reagent consumption. A further noteworthy feature is the inherent versatility of the flow network to implement unit operations at will with no need for manifold re-configuration. The present review discusses the potential of SI to accommodate solid reactors and packed columns in the flow set-up for environmental applications, aiming to facilitate on-line chemical derivatization, chromatographic separation of target species, removal of interfering matrix compounds, or determination of trace levels of analyte via sorptive preconcentration procedures. In this context, the concept of renewable surfaces, so-called SI-bead injection (SI-BI), used in either the jet-ring or lab-on-valve (LOV) configurations, is presented as a front-end to many detectors. This article also outlines recent trends focused on exploiting SI as an automated tool for handling solid samples of environmental concern and accommodating dynamic fractionation schemes for trace elements.

Solid reactors in sequential injection analysis : recent trends in the environmental field

A rapid sequential injection spectrophotometric method for the selective determination of 2,4,6-trinitrotoluene (TNT) in soil samples is presented. The method is based on a derivatization reaction of TNT with sodium sulfite in a basic acetone medium. The reaction conditions, namely the percentage of acetone used in the reaction, the sample and reagent volumes, the mixing coil volume, and the reaction time, were optimized. The reaction was found to be particularly sensitive to the concentration of acetone; an acetone/water medium of 88% (v/v) acetone was found to be optimal. A study of the response of the method to other explosives demonstrated that the method is selective for TNT. In particular, it was shown that the method had little (<2%) or no response to other secondary explosives such as 2,4- or 2,6-dinitrotoluene (DNT). An average precision of 6.1% RSD was established for five soil samples (n = 4). The limit of detection was 0.5 μg mL-1 for aqueous standards and 80 μg g-1 for ∼300 mg soil samples. A...

Marcy M. Christensen

Papers

Selective determination of TNT in soil extracts by sequential injection spectrophotometry