On-Line Immunochemical Detection System for Pesticide Residue Analysis

Krämer, Petra M.; Kast, Renate; Bilitewski, Ursula; Bannierink, Stephan; Brüß, Ulrich

doi:10.1021/bk-1997-0657.ch011

Cited by 11 publications

(5 citation statements)

References 6 publications

(9 reference statements)

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“…The aim of this work is to study three different multianalyte immunosensor approaches, discussing their potential, performances, and suitability in field analysis. All are based on the use of a protein A/G immunosurface − and polyclonal antibodies for the insecticide carbaryl, the herbicide atrazine, and the antifouling agent irgarol 1051 as model targets.…”

mentioning

confidence: 99%

Comparison of Multianalyte Immunosensor Formats for On-Line Determination of Organic Compounds

2001

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Studies leading to the development of multianalyte immunosensing approaches are presented herein. Competitive capture formats are developed for carbaryl, atrazine, and irgarol 1051 as target compounds. Three proposals have been tested: sequential, additive, and simultaneous formats. For individual determinations, the best format is the sequential mode; the additive mode is useful only for qualitative analyses; and the simultaneous mode is preferable for screening purposes. The proposed systems show to be advantageous over single-analyte sensors and other multianalyte approaches. In all cases, the sensitivity reached (limit of detection) is high enough for the analysis of samples containing levels of each pesticide lower than 0.1 microg/L, and sensor reusability is very good (>600 determinations). The applicability of the multianalyte immunosensors to on-line pollution surveillance in natural waters, as well as their advantages and limitations, is discussed.

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confidence: 99%

Comparison of Multianalyte Immunosensor Formats for On-Line Determination of Organic Compounds

2001

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“…The automation of heterogeneous immunoassays is wellknown from the development of flow-through systems comprising immunoreactors as packed-bed columns [80] or as open-tubular capillaries [81] with specific capture antibodies immobilized on glass beads or on the walls of the capillary. Those capillaries were fabricated also from PDMS resulting in the first element of an heterogeneous immunoassay microchip [82].…”

Section: Immunoassaysmentioning

confidence: 99%

Biochemical analysis with microfluidic systems

Bilitewski

Genrich

Kadow

et al. 2003

Analytical and Bioanalytical Chemistry

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145

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Microfluidic systems are capillary networks of varying complexity fabricated originally in silicon, but nowadays in glass and polymeric substrates. Flow of liquid is mainly controlled by use of electroosmotic effects, i.e. application of electric fields, in addition to pressurized flow, i.e. application of pressure or vacuum. Because electroosmotic flow rates depend on the charge densities on the walls of capillaries, they are influenced by substrate material, fabrication processes, surface pretreatment procedures, and buffer additives. Microfluidic systems combine the properties of capillary electrophoretic systems and flow-through analytical systems, and thus biochemical analytical assays have been developed utilizing and integrating both aspects. Proteins, peptides, and nucleic acids can be separated because of their different electrophoretic mobility; detection is achieved with fluorescence detectors. For protein analysis, in particular, interfaces between microfluidic chips and mass spectrometers were developed. Further levels of integration of required sample-treatment steps were achieved by integration of protein digestion by immobilized trypsin and amplification of nucleic acids by the polymerase chain reaction. Kinetic constants of enzyme reactions were determined by adjusting different degrees of dilution of enzyme substrates or inhibitors within a single chip utilizing mainly the properties of controlled dosing and mixing liquids within a chip. For analysis of kinase reactions, however, a combination of a reaction step (enzyme with substrate and inhibitor) and a separation step (enzyme substrate and reaction product) was required. Microfluidic chips also enable separation of analytes from sample matrix constituents, which can interfere with quantitative determination, if they have different electrophoretic mobilities. In addition to analysis of nucleic acids and enzymes, immunoassays are the third group of analytical assays performed in microfluidic chips. They utilize either affinity capillary electrophoresis as a homogeneous assay format, or immobilized antigens or antibodies in heterogeneous assays with serial supply of reagents and washing solutions.

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“…This can be achieved by adding solutions, such as ethylene glycol, urea, thiocyanate, or buffers of varying pH (8,27). However, these regeneration protocols usually affect the binding capacity of the immobilized protein (8,(27)(28)(29), leading to a limited reusability of the system. To obtain a constant binding capacity in the system, antibodies are bound to proteins, such as protein A or protein G, allowing the removal by the regeneration protocol and a fresh loading before each assay (27)(28)(29).…”

Section: Immunosensor Systems Using Labelsmentioning

confidence: 99%

“…All solutions are pumped through or incubated in the reactor, where the affinity and enzymatic reactions occur, and the compound to be detected is generated. Various devices can serve as the reactor, including a flow-through column filled with beads; a glass capillary; a silicon-chip reactor; simple, conical propylene cells, in which antibody-containing electrodes are inserted; and microtiter wells with attached optical fibers for monitoring solution optical density or electrodes for determining the amount of electrochemically active products of the enzyme reactions (8,(27)(28)(29)(31)(32)(33). Even a membrane or the surface of an electrode can serve as affinity reactor (30,31,34,35).…”

Section: Immunosensor Systems Using Labelsmentioning

confidence: 99%

“…The antibodies can be removed from the system with the enzyme tracer, and fresh antibodies can be bound before each assay. Such systems have been used only with environmental samples and contained flow-through bead-packed columns or capillaries with a surplus of immobilized protein A or G (27)(28)(29). However, particle-filled affinity columns are likely to be blocked when systems are applied to food instead of water samples.…”

Section: Sensor Systems For Food Analysismentioning

confidence: 99%

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