{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,1]],"date-time":"2026-03-01T03:32:46Z","timestamp":1772335966602,"version":"3.50.1"},"reference-count":54,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2016,12,23]],"date-time":"2016-12-23T00:00:00Z","timestamp":1482451200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100011011","name":"Junta de Andaluc\u00eda","doi-asserted-by":"publisher","award":["FQM-2310"],"award-info":[{"award-number":["FQM-2310"]}],"id":[{"id":"10.13039\/501100011011","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["MAT2013-40852-R"],"award-info":[{"award-number":["MAT2013-40852-R"]}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["MAT2013-42900-P"],"award-info":[{"award-number":["MAT2013-42900-P"]}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["MAT2014-57652-C2-2-R"],"award-info":[{"award-number":["MAT2014-57652-C2-2-R"]}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["MAT2015-69035-REDC"],"award-info":[{"award-number":["MAT2015-69035-REDC"]}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["MINECO-CSIC 201560E055"],"award-info":[{"award-number":["MINECO-CSIC 201560E055"]}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["PCIN-2015-169-C02-02"],"award-info":[{"award-number":["PCIN-2015-169-C02-02"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin\/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UV\u2013vis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonation\u2013deprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film.<\/jats:p>","DOI":"10.3390\/s17010024","type":"journal-article","created":{"date-parts":[[2016,12,23]],"date-time":"2016-12-23T09:47:26Z","timestamp":1482486446000},"page":"24","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":47,"title":["Optical Gas Sensing of Ammonia and Amines Based on Protonated Porphyrin\/TiO2 Composite Thin Films"],"prefix":"10.3390","volume":"17","author":[{"given":"Pedro","family":"Castillero","sequence":"first","affiliation":[{"name":"Instituto de Ciencia de Materiales de Sevilla, CSIC\u2013Universidad de Sevilla, Am\u00e9rico Vespucio 49, Sevilla 41092, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2110-5023","authenticated-orcid":false,"given":"Javier","family":"Roales","sequence":"additional","affiliation":[{"name":"Departamento de Sistemas F\u00edsicos, Qu\u00edmicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, Sevilla 41013, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"T\u00e2nia","family":"Lopes-Costa","sequence":"additional","affiliation":[{"name":"Departamento de Sistemas F\u00edsicos, Qu\u00edmicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, Sevilla 41013, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juan","family":"S\u00e1nchez-Valencia","sequence":"additional","affiliation":[{"name":"Instituto de Ciencia de Materiales de Sevilla, CSIC\u2013Universidad de Sevilla, Am\u00e9rico Vespucio 49, Sevilla 41092, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Angel","family":"Barranco","sequence":"additional","affiliation":[{"name":"Instituto de Ciencia de Materiales de Sevilla, CSIC\u2013Universidad de Sevilla, Am\u00e9rico Vespucio 49, Sevilla 41092, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6417-1437","authenticated-orcid":false,"given":"Agust\u00edn","family":"Gonz\u00e1lez-Elipe","sequence":"additional","affiliation":[{"name":"Instituto de Ciencia de Materiales de Sevilla, CSIC\u2013Universidad de Sevilla, Am\u00e9rico Vespucio 49, Sevilla 41092, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8750-6220","authenticated-orcid":false,"given":"Jos\u00e9","family":"Pedrosa","sequence":"additional","affiliation":[{"name":"Departamento de Sistemas F\u00edsicos, Qu\u00edmicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, Sevilla 41013, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,12,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1913","DOI":"10.1016\/S1352-2310(00)00544-6","article-title":"Instrument development and application in studies and monitoring of ambient ammonia","volume":"35","author":"Erisman","year":"2001","journal-title":"Atmos. Environ."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1055\/s-2007-971096","article-title":"Respiratory ammonia output and blood ammonia concentration during incremental exercise","volume":"20","author":"Ament","year":"1999","journal-title":"Int. J. Sports Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2523","DOI":"10.1023\/A:1020568227868","article-title":"Breath ammonia measurement in Helicobacter pylori infection","volume":"47","author":"Kearney","year":"2002","journal-title":"Dig. Dis. Sci."},{"key":"ref_4","unstructured":"Sabbioni, G., and Richter, E. (1999). Toxicology, Elsevier."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/0168-1605(95)00032-1","article-title":"Biogenic amines: Their importance in foods","volume":"29","author":"Santos","year":"1996","journal-title":"Int. J. Food Microbiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/S0956-5663(01)00180-4","article-title":"Biosensors in fish production and quality control","volume":"17","author":"Venugopal","year":"2002","journal-title":"Biosens. Bioelectron."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1547","DOI":"10.1080\/19440049.2011.600728","article-title":"Biogenic amines in fish, fish products and shellfish: A review","volume":"28","author":"Prester","year":"2011","journal-title":"Food Addit. Contam. Part A Chem. Anal. Control. Expo. Risk Assess."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1016\/j.talanta.2005.10.046","article-title":"Development of a volatile amine sensor for the monitoring of fish spoilage","volume":"69","author":"Pacquit","year":"2006","journal-title":"Talanta"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/S0040-6090(01)00987-7","article-title":"Mixed oxides as gas sensors","volume":"391","author":"Zakrzewska","year":"2001","journal-title":"Thin Solid Films"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"8158","DOI":"10.3390\/s91008158","article-title":"Semiconducting metal oxide based sensors for selective gas pollutant detection","volume":"9","author":"Kanan","year":"2009","journal-title":"Sensors"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5469","DOI":"10.3390\/s100605469","article-title":"Metal oxide semi-conductor gas sensors in environmental monitoring","volume":"10","author":"Fine","year":"2010","journal-title":"Sensors"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2904","DOI":"10.1021\/cm049457o","article-title":"Detection and classification of volatile organic amines and carboxylic acids using arrays of carbon black-dendrimer composite vapor detectors","volume":"17","author":"Gao","year":"2005","journal-title":"Chem. Mater."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Lobnik, A., \u0160pela, K.U., Turel, M., and Fran\u010di\u010d, N. (2011). Sol-gel based optical chemical sensors. SPIE Proc., 8073.","DOI":"10.1117\/12.886819"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"5099","DOI":"10.3390\/s90705099","article-title":"Applications and advances in electronic-nose technologies","volume":"9","author":"Wilson","year":"2009","journal-title":"Sensors"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1021\/cm025677v","article-title":"Conductive polymer foams as sensors for volatile amines","volume":"15","author":"Wang","year":"2003","journal-title":"Chem. Mater."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1002\/adom.201300516","article-title":"An Optical Sensor for Volatile Amines Based on an Inkjet-Printed, Hydrogen-Bonded, Cholesteric Liquid Crystalline Film","volume":"2","author":"Stumpel","year":"2014","journal-title":"Adv. Opt. Mater."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/0925-4005(94)01278-P","article-title":"Recent developments in semiconducting thin-film gas sensors","volume":"23","author":"Sberveglieri","year":"1995","journal-title":"Sensors Actuators B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/S0925-4005(99)00506-7","article-title":"Gas-sensing characteristics of modified-MoO3 thin films using Ti-overlayers for NH3 gas sensors","volume":"64","author":"Imawan","year":"2000","journal-title":"Sens. Actuators B Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/0250-6874(82)80026-7","article-title":"Characteristics of semiconductor gas sensors I. Steady state gas response","volume":"3","author":"Clifford","year":"1982","journal-title":"Sens. Actuators"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/S0925-4005(99)00413-X","article-title":"Selective detection of NH3 over NO in combustion exhausts by using Au and MoO3 doubly promoted WO3 element","volume":"65","author":"Xu","year":"2000","journal-title":"Sens. Actuators B Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2659","DOI":"10.1039\/B204984H","article-title":"The optical gas-sensing properties of an asymmetrically substituted porphyrin","volume":"12","author":"Pedrosa","year":"2002","journal-title":"J. Mater. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1007\/s13320-011-0025-4","article-title":"Review on recent developments of fluorescent oxygen and carbon dioxide optical fiber sensors","volume":"1","author":"Chu","year":"2011","journal-title":"Photonic Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"710","DOI":"10.1038\/35021028","article-title":"A colorimetric sensor array for odour visualization","volume":"406","author":"Rakow","year":"2000","journal-title":"Nature"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"5147","DOI":"10.1021\/am3010169","article-title":"Selective Detection of Volatile Organic Compounds by Spectral Imaging of Porphyrin Derivatives Bound to TiO2 Porous Films","volume":"4","author":"Roales","year":"2012","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.snb.2014.12.080","article-title":"Optical detection of amine vapors using ZnTriad porphyrin thin films","volume":"210","author":"Roales","year":"2015","journal-title":"Sens. Actuators B Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"11278","DOI":"10.1021\/jp803577d","article-title":"Alkylamine sensing using langmuir-blodgett films of n-alkyl-N-phenylamide-substituted zinc porphyrins","volume":"112","author":"Brittle","year":"2008","journal-title":"J. Phys. Chem. B"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1515\/REVCE.2007.23.2.65","article-title":"Tunable diode laser absorption spectroscopy (TDLAS) in the process industries\u2014A review","volume":"23","author":"Lackner","year":"2007","journal-title":"Rev. Chem. Eng."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1016\/S0928-4931(02)00194-7","article-title":"Characterization and fast optical response to NO2 of porphyrin LB films","volume":"22","author":"Pedrosa","year":"2002","journal-title":"Mater. Sci. Eng. C"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2025","DOI":"10.1016\/j.tsf.2010.10.038","article-title":"Optimization of mixed Langmuir-Blodgett films of a water insoluble porphyrin in a calixarene matrix for optical gas sensing","volume":"519","author":"Roales","year":"2011","journal-title":"Thin Solid Films"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"373","DOI":"10.4028\/www.scientific.net\/KEM.543.373","article-title":"Room Temperature Fluorescence Gas Sensor Based on Coated TiO2 Nanoparticles","volume":"543","author":"Yusoff","year":"2013","journal-title":"Key Eng. Mater."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Milgrom, L.R. (1997). The Colours of Life, Oxford University Press.","DOI":"10.1093\/oso\/9780198553809.001.0001"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.snb.2006.07.021","article-title":"Dye-doped inorganic\/organic composite films as fluorescence sensors for methanol vapor","volume":"123","author":"Stevens","year":"2007","journal-title":"Sens. Actuators B Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2543","DOI":"10.1039\/b809631g","article-title":"Optical explosives detection: From color changes to fluorescence turn-on","volume":"38","author":"Germain","year":"2009","journal-title":"Chem. Soc. Rev."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"712","DOI":"10.1021\/am900746q","article-title":"Active and optically transparent tetracationic porphyrin\/TiO2 composite thin films","volume":"2","author":"Castillero","year":"2010","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"764","DOI":"10.1016\/j.snb.2010.07.059","article-title":"A transparent TMPyP\/TiO2 composite thin film as an HCl sensitive optochemical gas sensor","volume":"150","author":"Cano","year":"2010","journal-title":"Sens. Actuators B Chem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"3775","DOI":"10.1021\/jp805708w","article-title":"Wetting angles on illuminated Ta2O5 thin films with controlled nanostructure","volume":"113","author":"Rico","year":"2009","journal-title":"J. Phys. Chem. C"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"9460","DOI":"10.1021\/la800773v","article-title":"Preillumination of TiO2 and Ta2O5 photoactive thin films as a tool to tailor the synthesis of composite materials","volume":"24","author":"Barranco","year":"2008","journal-title":"Langmuir"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.pmatsci.2015.06.003","article-title":"Perspectives on oblique angle deposition of thin films: From fundamentals to devices","volume":"76","author":"Barranco","year":"2016","journal-title":"Prog. Mater. Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"721","DOI":"10.1063\/1.1744225","article-title":"Enhancement of phosphorescence ability upon aggregation of dye molecules","volume":"28","author":"Mcrae","year":"1958","journal-title":"J. Chem. Phys."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/0009-2614(70)80220-2","article-title":"Extended dipole model for aggregates of dye molecules","volume":"6","author":"Czikklely","year":"1970","journal-title":"Chem. Phys. Lett."},{"key":"ref_41","unstructured":"Kuhn, H., and Foersterling, H.-D. (2000). Principles of Physical Chemistry, John Wiley & Sons Inc."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/0009-2614(70)80062-8","article-title":"Light absorption and structure of aggregates of dye molecules","volume":"6","author":"Czikkely","year":"1970","journal-title":"Chem. Phys. Lett."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"12302","DOI":"10.1021\/j100149a034","article-title":"Influence of molecular orientation and proximity on spectroscopic line shape in organic monolayers","volume":"97","author":"Evans","year":"1993","journal-title":"J. Phys. Chem."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/S0927-7757(99)00551-8","article-title":"\u03c0-Electron systems - Building blocks of supramolecular machines","volume":"171","author":"Kuhn","year":"2000","journal-title":"Colloids Surfaces A Physicochem. Eng. Asp."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"7594","DOI":"10.1021\/la026004u","article-title":"Influence of molecular organization of asymmetrically substituted porphyrins on their response to NO2 gas","volume":"18","author":"Pedrosa","year":"2002","journal-title":"Langmuir"},{"key":"ref_46","first-page":"265","article-title":"Spectral detection of J-aggregates of cationic porphyrin and investigation of conditions of their formation","volume":"744","year":"2005","journal-title":"J. Mol. Struct."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/S1388-2481(00)00013-8","article-title":"Determination of porphyrin dimer in a mixed monolayer of porphyrin\/phospholipid transferred on ITO electrodes","volume":"2","author":"Pedrosa","year":"2000","journal-title":"Electrochem. Commun."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"11118","DOI":"10.3390\/s150511118","article-title":"Free-Base Carboxyphenyl Porphyrin Films Using a TiO2 Columnar Matrix: Characterization and Application as NO2 Sensors","volume":"15","author":"Roales","year":"2015","journal-title":"Sensors"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1142\/S1088424611003380","article-title":"Resonance Raman spectroscopic examination of ferrochelatase-induced porphyrin distortion","volume":"15","author":"Franco","year":"2011","journal-title":"J. Porphyr. Phthalocyanines"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"386","DOI":"10.1021\/ic50204a021","article-title":"Porphyrins. 40. Electronic spectra and four-orbital energies of free-base, zinc, copper, and palladium tetrakis(perfluorophenyl)porphyrins","volume":"19","author":"Spellane","year":"1980","journal-title":"Inorg. Chem."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/j.aca.2008.08.032","article-title":"Optochemical sensing of hydrogen chloride gas using meso-tetramesitylporphyrin deposited glass plate","volume":"627","author":"Kalimuthu","year":"2008","journal-title":"Anal. Chim. Acta"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"99","DOI":"10.5923\/j.materials.20120204.01","article-title":"A Novel Method for Evaluation of Band Width of MEMS-Based Embedded Gas Sensor","volume":"2","author":"Kumar","year":"2012","journal-title":"Am. J. Mater. Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1974","DOI":"10.1039\/C3RA42443J","article-title":"Anchoring effect on (tetra)carboxyphenyl porphyrin\/TiO2 composite films for VOC optical detection","volume":"4","author":"Roales","year":"2014","journal-title":"RSC Adv."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.molstruc.2013.04.045","article-title":"Aqueous ammonia and ammonium chloride hydrates: Principal infrared spectra","volume":"1046","author":"Max","year":"2013","journal-title":"J. Mol. Struct."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/1\/24\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:29:13Z","timestamp":1760210953000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/1\/24"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,12,23]]},"references-count":54,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2017,1]]}},"alternative-id":["s17010024"],"URL":"https:\/\/doi.org\/10.3390\/s17010024","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,12,23]]}}}