title: Rapid extraction and quantitative detection of the herbicide diuron in surface water by a hapten-functionalized carbon nanotubes based electrochemical analyzer.
abstract: A solid phase extraction micro-cartridge containing a non-polar polystyrene absorbent matrix was coupled with an electrochemical immunoassay analyzer (EIA) and used for the ultra-sensitive detection of the phenyl urea herbicide diuron in real samples. The EIA was fabricated by using carboxylated carbon nanotubes (CNTs) functionalized with a hapten molecule (an amine functionalized diuron derivative). Screen printed electrodes (SPE) were modified with these haptenized CNTs and specific in-house generated anti diuron antibodies were used for bio-interface development. The immunodetection was realized in a competitive electrochemical immunoassay format using alkaline phosphatase labeled secondary anti-IgG antibody. The addition of 1-naphthyl phosphate substrate resulted in the production of an electrochemically active product, 1-naphthol, which was monitored by using differential pulse voltammetry (DPV). The assay exhibited excellent sensitivity and specificity having a dynamic response range of 0.01 pg mL(-1) to 10 μg mL(-1) for diuron with a limit of detection of around 0.1 pg mL(-1) (n = 3) in standard water samples. The micro-cartridge coupled hapten-CNTs modified SPE provided an effective and efficient electrochemical immunoassay for the real-time monitoring of pesticides samples with a very high degree of sensitivity.
authors.affiliation: Institute of Microbial Technology (CSIR), Sector 39-A, Chandigarh 160036, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Sharma
authors.forename: Vijayender
authors.initials: V
authors.lastname: Bhalla
authors.forename: Satish
authors.initials: S
authors.lastname: Tuteja
authors.forename: Manil
authors.initials: M
authors.lastname: Kukkar
authors.forename: C Raman
authors.initials: CR
authors.lastname: Suri
mesh_terms: D000906:Antibodies / Q000276:immunology; D004237:Diuron / Q000032:analysis* / Q000302:isolation & purification; D055664:Electrochemical Techniques; D004566:Electrodes; D004784:Environmental Monitoring; D006241:Haptens / Q000276:immunology; D006540:Herbicides / Q000032:analysis* / Q000302:isolation & purification; D007118:Immunoassay; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009284:Naphthols / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000906:Antibodies; D006241:Haptens; D006540:Herbicides; D037742:Nanotubes, Carbon; D009284:Naphthols; D014874:Water Pollutants, Chemical; C029350:1-naphthol; D004237:Diuron