Optical immunosensor for fast and sensitive detection of DDT and related compounds in river water samples.
A surface plasmon resonance (SPR) based immunosensor has been developed for the monitoring of environmentally persistent pollutants like DDT, its metabolites and analogues in real water samples. A reusable immunosurface is provided via the covalent attachment of the analyte derivative to a self-assembled alkanethiol monolayer formed onto the SPR gold-thin layer. The regeneration of the sensor surface allowed the performance of 270 assay cycles within an analysis time of 20 min for each assay cycle. Immunoassays based on a binding inhibition format were performed by using two monoclonal antibodies (MAbs) with different selectivity. Low limits of detection (LODs), in the sub-nanogram per litre range, were attained for DDT-selective (15 ng L-1) and DDT group-selective immunoassays (31 ng L-1). Both assays were carried out in spiked river water samples without significant effect of the matrix. SPR measurements were validated using gas-chromatography-mass spectrometry. The comparison between methods was in good agreement showing an excellent correlation coefficient (r2=0.995). The SPR analysis of DDT proved to be three times more sensitive than colorimetric ELISAs without the need of labelling and a much lower time of response. Our SPR biosensor portable platform (beta-SPR) is already commercialised by the company SENSIA, S.L. (Spain).
Mauriz
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Microelectronics National Centre CNM-CSIC, Isaac Newton, 8, 28760 Tres Cantos, Madrid, Spain. elba@imm.cnm.csic.es
Calle
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Manclús
J J
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Montoya
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Hildebrandt
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Barceló
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Lechuga
L M
LM
D000906:Antibodies; D015374:Biosensing Techniques / Q000295:instrumentation*; D003634:DDT / Q000032:analysis* / Q000737:chemistry; D045483:Rivers / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation
D000906:Antibodies; D003634:DDT