Analysis of isoproturon at trace level by solid phase competitive fluoroimmunosensing after enrichment in a sol–gel immunosorbent

• Published in: Analytica chimica acta 2006-03, Vol.562 (1), p.122-127
• Main Authors: Pulido-Tofiño, P., Barrero-Moreno, J.M., Pérez-Conde, M.C.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Applied sciences; Chemistry; Exact sciences and technology; General, instrumentation; Global environmental pollution; Immunosensor; Immunosorbent; Isoproturon; Pollution; Sol–gel; Spectrometric and optical methods
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2005.12.072

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.