title: Microcystin-LR detection in water by the Fabry-Pérot interferometer using an optical fibre coated with a sol-gel imprinted sensing membrane.
abstract: Cyanobacteria deteriorate the water quality and are responsible for emerging outbreaks and epidemics causing harmful diseases in Humans and animals because of their toxins. Microcystin-LR (MCT) is one of the most relevant cyanotoxin, being the most widely studied hepatotoxin. For safety purposes, the World Health Organization recommends a maximum value of 1 μg L(-1) of MCT in drinking water. Therefore, there is a great demand for remote and real-time sensing techniques to detect and quantify MCT. In this work a Fabry-Pérot sensing probe based on an optical fibre tip coated with a MCT selective thin film is presented. The membranes were developed by imprinting MCT in a sol-gel matrix that was applied over the tip of the fibre by dip coating. The imprinting effect was obtained by curing the sol-gel membrane, prepared with (3-aminopropyl) trimethoxysilane (APTMS), diphenyl-dimethoxysilane (DPDMS), tetraethoxysilane (TEOS), in the presence of MCT. The imprinting effect was tested by preparing a similar membrane without template. In general, the fibre Fabry-Pérot with a Molecular Imprinted Polymer (MIP) sensor showed low thermal effect, thus avoiding the need of temperature control in field applications. It presented a linear response to MCT concentration within 0.3-1.4 μg L(-1) with a sensitivity of -12.4±0.7 nm L μg(-1). The corresponding Non-Imprinted Polymer (NIP) displayed linear behaviour for the same MCT concentration range, but with much less sensitivity, of -5.9±0.2 nm L μg(-1). The method shows excellent selectivity for MCT against other species co-existing with the analyte in environmental waters. It was successfully applied to the determination of MCT in contaminated samples. The main advantages of the proposed optical sensor include high sensitivity and specificity, low-cost, robustness, easy preparation and preservation.
authors.affiliation: INESC-Porto, UOSE, Rua do Campo Alegre, Portugal; Departamento de Física, Faculdade de Ciências, Universidade do Porto, Portugal; BIOMARK/ISEP, Instituto Superior de Engenharia do Porto, Porto, Portugal.
authors.forename: Raquel B
authors.initials: RB
authors.lastname: Queirós
authors.affiliation: INESC-Porto, UOSE, Rua do Campo Alegre, Portugal; Departamento de Física, Faculdade de Ciências, Universidade do Porto, Portugal.
authors.forename: S O
authors.initials: SO
authors.lastname: Silva
authors.affiliation: REQUIMTE/FCT-UNL, Faculdade de Ciência e Tecnologia, Universidade Nova de Lisboa, Portugal.
authors.forename: J P
authors.initials: JP
authors.lastname: Noronha
authors.affiliation: INESC-Porto, UOSE, Rua do Campo Alegre, Portugal.
authors.forename: O
authors.initials: O
authors.lastname: Frazão
authors.affiliation: INESC-Porto, UOSE, Rua do Campo Alegre, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Jorge
authors.affiliation: INESC-Porto, UOSE, Rua do Campo Alegre, Portugal.
authors.forename: G
authors.initials: G
authors.lastname: Aguilar
authors.affiliation: INESC-Porto, UOSE, Rua do Campo Alegre, Portugal; Departamento de Física, Faculdade de Ciências, Universidade do Porto, Portugal.
authors.forename: P V S
authors.initials: PV
authors.lastname: Marques
authors.affiliation: BIOMARK/ISEP, Instituto Superior de Engenharia do Porto, Porto, Portugal.
authors.forename: M G F
authors.initials: MG
authors.lastname: Sales
mesh_terms: D015374:Biosensing Techniques; D000458:Cyanobacteria / Q000737:chemistry; D060766:Drinking Water / Q000737:chemistry; D007368:Interferometry; D008387:Marine Toxins; D008566:Membranes / Q000737:chemistry; D052998:Microcystins / Q000737:chemistry / Q000302:isolation & purification*; D054802:Molecular Imprinting; D055100:Optical Fibers; D019904:Polymethyl Methacrylate; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D060766:Drinking Water; D008387:Marine Toxins; D052998:Microcystins; D014874:Water Pollutants, Chemical; D019904:Polymethyl Methacrylate; C057862:cyanoginosin LR