Analysis of isoproturon at trace level by solid phase competitive fluoroimmunosensing after enrichment in a sol-gel immunosorbent |
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Authors: | P. Pulido-Tofiñ o,M.C. Pé rez-Conde |
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Affiliation: | Dpto. Química Analítica, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid, Spain |
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Abstract: | Isoproturon was extracted selectively from environmental materials (water samples) using an immunosorbent column containing anti-isoproturon antibodies encapsulated in a silica matrix by a sol-gel process. A phosphate buffered saline (PBS) conditioned immunosorbent column was used to on-line preconcentrate 5 ml well and tap water containing 0.05 μg l−1 of isoproturon, which were desorbed with 75 μl of citric acid and determined with a solid phase competitive fluoroimmunoassay. The solid phase of the immunosensor, consisting of a sol-gel glass doped with anti-isoproturon monoclonal antibody, was placed on the flow-cell of the spectrofluorometer. Free isoproturon in solution competed with a fluorescent conjugated isoproturon and reduced the support bonded fluorescence in a concentration-dependent manner. The on-line method has a detection limit of 9.7 ng l−1, relative standard deviation of 4 and 3% for 0.05 and 0.5 μg l−1, respectively, and recoveries higher than 90% for tap and well water. For comparison the off-line extraction and clean up using a C18 cartridge is also reported. |
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Keywords: | Sol-gel Immunosorbent Immunosensor Isoproturon |
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