title: ColiSense, today's sample today: A rapid on-site detection of β-D-Glucuronidase activity in surface water as a surrogate for E. coli.
abstract: A sensitive field-portable fluorimeter with incubating capability and triplicate sample chambers was designed and built. The system was optimised for the on-site analysis of E. coli in recreational waters using fluorescent based enzyme assays. The target analyte was β-D-Glucuronidase (GUS) which hydrolyses a synthetic substrate 6-Chloro-4-Methyl-Umbelliferyl-β-D-Glucuronide (6-CMUG) to release the fluorescent molecule 6-Chloro-4-Methyl-Umbelliferyl (6-CMU). The system was calibrated with 6-CMU standards. A LOD of 5 nM and a resolution of less than 1 nM was determined while enzyme kinetic tests showed detection of activities below 1 pmol min(-1) mL(-1) of sample. A field portable sample preparation, enzyme extraction protocol and continuous assay were applied with the system to analyse freshwater and marine samples. Results from a one day field trial are shown which demonstrated the ability of the system to deliver results on-site within a 75 min period.
authors.affiliation: DCU Water Institute, Marine and Environmental Sensing Technology Hub (MESTECH), NCSR, Dublin City University (DCU), Glasnevin, Dublin 9, Ireland.
authors.forename: Brendan
authors.initials: B
authors.lastname: Heery
authors.affiliation: DCU Water Institute, Marine and Environmental Sensing Technology Hub (MESTECH), NCSR, Dublin City University (DCU), Glasnevin, Dublin 9, Ireland.
authors.forename: Ciprian
authors.initials: C
authors.lastname: Briciu-Burghina
authors.affiliation: School of Electronic Engineering, Dublin City University, Ireland.
authors.forename: Dian
authors.initials: D
authors.lastname: Zhang
authors.affiliation: DCU Water Institute, Marine and Environmental Sensing Technology Hub (MESTECH), NCSR, Dublin City University (DCU), Glasnevin, Dublin 9, Ireland.
authors.forename: Gillian
authors.initials: G
authors.lastname: Duffy
authors.affiliation: School of Mechanical and Manufacturing Engineering, Dublin City University, Ireland.
authors.forename: Dermot
authors.initials: D
authors.lastname: Brabazon
authors.affiliation: School of Electronic Engineering, Dublin City University, Ireland.
authors.forename: Noel
authors.initials: N
authors.lastname: O'Connor
authors.affiliation: DCU Water Institute, Marine and Environmental Sensing Technology Hub (MESTECH), NCSR, Dublin City University (DCU), Glasnevin, Dublin 9, Ireland. Electronic address: fiona.regan@dcu.ie.
authors.forename: Fiona
authors.initials: F
authors.lastname: Regan
mesh_terms: D004789:Enzyme Activation / Q000502:physiology; D004926:Escherichia coli / Q000737:chemistry* / Q000201:enzymology*; D005470:Fluorometry / Q000379:methods; D005618:Fresh Water / Q000032:analysis* / Q000382:microbiology; D005966:Glucuronidase / Q000032:analysis* / Q000378:metabolism*; D012623:Seawater / Q000032:analysis* / Q000382:microbiology; D014871:Water Microbiology
chemical_list: D005966:Glucuronidase
keywords: E. coli; Enzyme assay; Fluorescence; On-site; Recreational water; β-d-glucuronidase