{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T15:38:55Z","timestamp":1775144335499,"version":"3.50.1"},"reference-count":42,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2019,5,9]],"date-time":"2019-05-09T00:00:00Z","timestamp":1557360000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Seventh Framework Programme","award":["606079"],"award-info":[{"award-number":["606079"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The design, development, and evaluation of an optical fibre sensor for the detection of Hg2+ in aqueous media are discussed in detail in this paper. A novel fluorescent polymeric material for Hg2+ detection, based on a coumarin derivative (acting as the fluorophore) and an azathia crown ether moiety (acting as the mercury ion receptor), has been synthesized. The fluorophore was covalently immobilized onto the fibre surface by polymerisation using the ion imprinting technique and exhibited a significant increase in fluorescence intensity in response to Hg2+ via a photoinduced electron transfer (PET) mechanism. The sensor provided a response over a concentration range of 0\u201328 \u00b5M with an acceptable response rate of around 11 min and a recovery rate of around 30 min in a Tris-EDTA buffer solution. A detection limit of 0.15 \u00b5M was obtained with a possibility of improvement by changing the thickness of the polymer layer and using a more sensitive detector. High-quality performance is seen through a high selectivity for Hg2+ over other metal ions, excellent photo-stability and reversibility which was also demonstrated, making this type of sensor potentially well suited for in-situ monitoring of mercury in the environment.<\/jats:p>","DOI":"10.3390\/s19092142","type":"journal-article","created":{"date-parts":[[2019,5,9]],"date-time":"2019-05-09T11:22:35Z","timestamp":1557400955000},"page":"2142","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["A Turn-On Fluorescence-Based Fibre Optic Sensor for the Detection of Mercury"],"prefix":"10.3390","volume":"19","author":[{"given":"T. Hien","family":"Nguyen","sequence":"first","affiliation":[{"name":"Photonics and Instrumentation Research Centre, City University of London, London EC1V 0HB, UK"}]},{"given":"Tong","family":"Sun","sequence":"additional","affiliation":[{"name":"Photonics and Instrumentation Research Centre, City University of London, London EC1V 0HB, UK"}]},{"given":"Kenneth T. V.","family":"Grattan","sequence":"additional","affiliation":[{"name":"Photonics and Instrumentation Research Centre, City University of London, London EC1V 0HB, UK"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,9]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"Remediation of mercury contaminated sites\u2015A review","volume":"221","author":"Wang","year":"2012","journal-title":"J. Hazard. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.scitotenv.2009.09.043","article-title":"Is low-level environmental mercury exposure of concern to human health?","volume":"408","author":"Holmes","year":"2009","journal-title":"Sci. Total Environ."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"391","DOI":"10.1078\/1438-4639-00305","article-title":"Amalgam studies: Disregarding basic principles of mercury toxicity","volume":"207","author":"Mutter","year":"2004","journal-title":"Int. J. Hyg. Environ. Health."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"621","DOI":"10.1111\/j.1751-7176.2011.00489.x","article-title":"Role of Mercury Toxicity in Hypertension, Cardiovascular Disease, and Stroke","volume":"13","author":"Houston","year":"2011","journal-title":"J. Clin. Hypertens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1120","DOI":"10.1016\/j.talanta.2005.07.014","article-title":"Molecularly imprinted TiO2 thin film using stable ground-state complex as template as applied to selective electrochemical determination of mercury","volume":"68","author":"Liu","year":"2006","journal-title":"Talanta"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1016\/j.bios.2016.05.017","article-title":"Dual detection of nitrate and mercury in water using disposable electrochemical sensors","volume":"85","author":"Bui","year":"2016","journal-title":"Biosens. Bioelectron."},{"key":"ref_7","first-page":"1153","article-title":"Determination of Lead(II), Cadmium(II) and Copper(II) in Waste-Water and Soil Extracts on Mercury Film Screen-Printed Carbon Electrodes Sensor","volume":"40","author":"Noh","year":"2011","journal-title":"Sains Malays."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5910","DOI":"10.1021\/ja068879r","article-title":"Turn-on and ratiometric mercury sensing in water with a red-emitting probe","volume":"129","author":"Nolan","year":"2007","journal-title":"J. Am. Chem. Soc."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4866","DOI":"10.1016\/j.tet.2013.04.072","article-title":"Azathia crown ether possessing a dansyl fluorophore moiety functionalized silica nanoparticles as hybrid material for mercury detection in aqueous medium","volume":"69","author":"Isaad","year":"2013","journal-title":"Tetrahedron"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.inoche.2014.10.026","article-title":"An \u201coff-on\u201d optical sensor for mercury ion detection in aqueous solution and living cells","volume":"50","author":"Aydin","year":"2014","journal-title":"Inorg. Chem. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2740","DOI":"10.1021\/ac404160v","article-title":"Development of a Rhodamine-Rhodanine-Based Fluorescent Mercury Sensor and Its Use to Monitor Real-Time Uptake and Distribution of Inorganic Mercury in Live Zebrafish Larvae","volume":"86","author":"Bera","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5141","DOI":"10.1016\/j.bmcl.2011.07.085","article-title":"A water-soluble 1,8-naphthalimide-based \u2018turn on\u2019 fluorescent chemosensor for selective and sensitive recognition of mercury ion in water","volume":"21","author":"Dai","year":"2011","journal-title":"Bioorg. Med. Chem. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"4903","DOI":"10.1016\/j.tetlet.2011.07.056","article-title":"A rapid Hg2+ sensor based on aza-15-crown-5 ether functionalized 1,8-naphthalimide","volume":"52","author":"Hou","year":"2011","journal-title":"Tetrahedron Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3831","DOI":"10.1039\/C4NJ00412D","article-title":"Optical chemosensors for Hg2+ from terthiophene appended rhodamine derivatives: FRET based molecular and in situ hybrid gold nanoparticle sensors","volume":"38","author":"Kaewtong","year":"2014","journal-title":"New J. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"12578","DOI":"10.1039\/c1dt11307k","article-title":"Facile synthesis of rhodamine-based highly sensitive and fast responsive colorimetric and off-on fluorescent reversible chemosensors for Hg2+: Preparation of a fluorescent thin film sensor","volume":"40","author":"Kaewtong","year":"2011","journal-title":"Dalton Trans."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.aca.2012.09.016","article-title":"An acyclic, dansyl based colorimetric and fluorescent chemosensor for Hg(II) via twisted intramolecular charge transfer (TICT)","volume":"751","author":"Tharmaraj","year":"2012","journal-title":"Anal. Chim. Acta"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2055","DOI":"10.1039\/c3cc47915c","article-title":"An unusual OFF-ON fluorescence sensor for detecting mercury ions in aqueous media and living cells","volume":"50","author":"Tian","year":"2014","journal-title":"Chem. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.snb.2013.11.111","article-title":"Simple hydrazide-based fluorescent sensors for highly sensitive and selective optical signaling of Cu2+ and Hg2+ in aqueous solution","volume":"193","author":"Wang","year":"2014","journal-title":"Sens. Actuator B Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1007\/s10895-012-1044-2","article-title":"Highly Selective and Sensitive Chemosensor for Hg2+ Based on the Naphthalimide Fluorophore","volume":"22","author":"Yang","year":"2012","journal-title":"J. Fluores."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1021\/ac0109218","article-title":"An optical fiber chemical sensor for mercury ions based on a porphyrin dimer","volume":"74","author":"Zhang","year":"2002","journal-title":"Anal. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.measurement.2018.01.071","article-title":"Optical fibre turn-on sensor for the detection of mercury based on immobilized fluorophore","volume":"121","author":"Ruan","year":"2018","journal-title":"Measurement"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/j.envpol.2004.02.019","article-title":"Biosensors for detection of mercury in contaminated soils","volume":"131","author":"Bontidean","year":"2004","journal-title":"Environ. Pollut."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1439","DOI":"10.1016\/S0038-0717(02)00088-3","article-title":"Construction and use of specific luminescent recombinant bacterial sensors for the assessment of bioavailable fraction of cadmium, zinc, mercury and chromium in the soil","volume":"34","author":"Ivask","year":"2002","journal-title":"Soil Biol. Biochem."},{"key":"ref_24","unstructured":"Grattan, K.T.V., and Meggitt, B.T. (1999). Chemical and Environmental Sensing, Kluwer Academic Publishers."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"523","DOI":"10.1002\/bio.1264","article-title":"A highly selective fluorescent sensor for mercury ion (II) based on azathia-crown ether possessing a dansyl moiety","volume":"26","author":"Dai","year":"2011","journal-title":"Luminescence"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1107","DOI":"10.1351\/pac198860071107","article-title":"Reference materials for fluorescence measurement","volume":"60","author":"Eaton","year":"1988","journal-title":"Pure Appl. Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"389","DOI":"10.6028\/jres.080A.038","article-title":"Fluorescence quantum yield measurements","volume":"80","author":"Birks","year":"1976","journal-title":"J. Res. Nat. Bur. Stand. Sect. A"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1016\/S0076-6879(82)87029-8","article-title":"Determination of binding stoichiometry by the continuous variation method\u2015The Job plot","volume":"87","author":"Huang","year":"1982","journal-title":"Methods Enzymol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2651","DOI":"10.1021\/ac980027p","article-title":"Photobleaching of fluorescent dyes under conditions used for single-molecule detection: Evidence of two-step photolysis","volume":"70","author":"Eggeling","year":"1998","journal-title":"Anal. Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"421","DOI":"10.6028\/jres.080A.044","article-title":"Fluorescence efficiency of laser-dyes","volume":"80","author":"Drexhage","year":"1976","journal-title":"J. Res. Nat. Bur. Stand. Sect. A"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1016\/j.snb.2004.10.017","article-title":"Phenol red immobilized PVA membrane for an optical pH sensor with two determination ranges and long-term stability","volume":"107","author":"Liu","year":"2005","journal-title":"Sens. Actuators B Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1305","DOI":"10.1039\/C0CS00062K","article-title":"Determining association constants from titration experiments in supramolecular chemistry","volume":"40","author":"Thordarson","year":"2011","journal-title":"Chem. Soc. Rev."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1109\/JSEN.2015.2490583","article-title":"Intrinsic Fiber Optic pH Sensor for Measurement of pH Values in the Range of 0.5\u20126","volume":"16","author":"Nguyen","year":"2016","journal-title":"IEEE Sens. J."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1812","DOI":"10.1002\/anie.199518121","article-title":"Molecular Imprinting in Cross-Linked Materials with the Aid of Molecular Templates\u2015A Way towards Artificial Antibodies","volume":"34","author":"Wulff","year":"1995","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2495","DOI":"10.1021\/cr990099w","article-title":"Molecularly Imprinted Polymers and their use in biomimetic sensors","volume":"100","author":"Haupt","year":"2000","journal-title":"Chem. Rev."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1016\/j.reactfunctpolym.2013.03.021","article-title":"Recent advances on ion-imprinted polymers","volume":"73","author":"Branger","year":"2013","journal-title":"React. Funct. Polym."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1007\/BF01056090","article-title":"Mercury in Soil\u2014A Method for assessing Acceptable Limits","volume":"19","author":"Revis","year":"1990","journal-title":"Arch. Environ. Contam. Toxicol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1007\/BF01066411","article-title":"A Method for Determining an Allowable Concentration of Mercury in Soil","volume":"15","author":"Bashor","year":"1986","journal-title":"Arch. Environ. Contam. Toxicol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1007\/s10653-014-9628-1","article-title":"Mercury concentrations and distribution in soil, water, mine waste leachates, and air in and around mercury mines in the Big Bend region, Texas, USA","volume":"37","author":"Gray","year":"2015","journal-title":"Environ. Geochem. Health"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"18020","DOI":"10.1021\/ja906500m","article-title":"A Turn-On Fluorescent Sensor for Detecting Nickel in Living Cells","volume":"131","author":"Dodani","year":"2009","journal-title":"J. Am. Chem. Soc."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1279","DOI":"10.1016\/j.snb.2017.11.129","article-title":"Ratiometric fluorescent and colorimetric BODIPY-based sensor for zinc ions in solution and living cells","volume":"258","author":"Xia","year":"2018","journal-title":"Sens. Actuator B Chem."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2131","DOI":"10.1007\/s00216-006-1061-6","article-title":"Novel coumarin-based fluorescent pH indicators, probes and membranes covering a broad pH range","volume":"387","author":"Vasylevska","year":"2007","journal-title":"Anal. Bioanal. Chem."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/9\/2142\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:50:20Z","timestamp":1760187020000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/9\/2142"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,5,9]]},"references-count":42,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2019,5]]}},"alternative-id":["s19092142"],"URL":"https:\/\/doi.org\/10.3390\/s19092142","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,5,9]]}}}