title: Sensitive detection of atrazine in tap water using TELISA.
abstract: A highly sensitive flow injection analysis (FIA)-based thermal enzyme-linked immunoassay, TELISA, was developed for the rapid detection of atrazine (ATZ) in tap water. ATZ and β-lactamase-labeled ATZ were employed in a competitive immunoassay using a monoclonal antibody (mAb). After the off-column liquid-phase competition, the mAb was captured on the Protein G Sepharose™ 4 Fast Flow (PGSFF) column support material. Injected β-lactamase substrate ampicillin was degraded by the column-bound ATZ-β-lactamase, generating a detectable heat signal. Several assay parameters were optimized, including substrate concentration, flow rates and regeneration conditions, as well as the mAb and ATZ-β dilution ratios and concentrations. The assay linear range was 0.73-4.83 ng mL(-1) with a detection limit of 0.66 ng mL(-1). An entire heat signal requires 10 min for generation, and the cycle time is less than 40 min. The results were reproducible and stable. ATZ-spiked tap water samples exhibited a recovery rate of 103%-116%, which correlated with the UHPLC-MS/MS measurements. We attributed this significant increase in sensitivity over our previously published work to the following factors: (i) the capture of already-formed immune complexes on the column via immobilized Protein G, which eliminated chemical immobilization of the antibody; (ii) off-column preincubation allows the formation of immune complexes under nearly ideal conditions; and (iii) multiple buffers can be used to, in one case, enhance immune-complex formation and in the other to maximize enzymatic activity. Furthermore, the scheme creates a universal assay platform in which sensing is performed in the off-column incubation and detection after capture in the enzyme thermistor (ET) detector, which opens up the possibility of detecting any antigen for which antibodies were available.
authors.affiliation: Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, PR China. ningba@163.com gaozhx@163.com.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Qie
authors.forename: Jialei
authors.initials: J
authors.lastname: Bai
authors.forename: Bin
authors.initials: B
authors.lastname: Xie
authors.forename: Lin
authors.initials: L
authors.lastname: Yuan
authors.forename: Nan
authors.initials: N
authors.lastname: Song
authors.forename: Yuan
authors.initials: Y
authors.lastname: Peng
authors.forename: Xianjun
authors.initials: X
authors.lastname: Fan
authors.forename: Huanying
authors.initials: H
authors.lastname: Zhou
authors.forename: Fengchun
authors.initials: F
authors.lastname: Chen
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Baoan
authors.initials: B
authors.lastname: Ning
authors.forename: Zhixian
authors.initials: Z
authors.lastname: Gao
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D001280:Atrazine / Q000032:analysis*; D001409:Bacillus cereus / Q000201:enzymology; D060766:Drinking Water / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D017022:Flow Injection Analysis / Q000295:instrumentation; D006540:Herbicides / Q000032:analysis*; D057230:Limit of Detection; D053719:Tandem Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D001618:beta-Lactamases / Q000737:chemistry
chemical_list: D055910:Antibodies, Immobilized; D060766:Drinking Water; D006540:Herbicides; D014874:Water Pollutants, Chemical; D001618:beta-Lactamases; D001280:Atrazine