{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T10:49:41Z","timestamp":1776854981404,"version":"3.51.2"},"reference-count":57,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2017,1,14]],"date-time":"2017-01-14T00:00:00Z","timestamp":1484352000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation","award":["61671433"],"award-info":[{"award-number":["61671433"]}]},{"name":"National Basic Research Program of China (973 Program)","award":["2015CB352100"],"award-info":[{"award-number":["2015CB352100"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Water contamination is a main inducement of human diseases. It is an important step to monitor the water quality in the water distribution system. Due to the features of large size, high cost, and complicated structure of traditional water determination sensors and devices, it is difficult to realize real-time water monitoring on a large scale. In this paper, we present a multi-parameter sensor chip, which is miniature, low-cost, and robust, to detect the pH, conductivity, and temperature of water simultaneously. The sensor chip was fabricated using micro-electro-mechanical system (MEMS) techniques. Iridium oxide film was electrodeposited as the pH-sensing material. The atomic ratio of Ir(III) to Ir(IV) is about 1.38 according to the X-ray photoelectron spectroscopy (XPS) analysis. The pH sensing electrode showed super-Nernstian response (\u221267.60 mV\/pH) and good linearity (R2 = 0.9997), in the range of pH 2.22 to pH 11.81. KCl-agar and epoxy were used as the electrolyte layer and liquid junction for the solid-state reference electrode, respectively, and its potential stability in deionized water was 56 h. The conductivity cell exhibited a linear determination range from 21.43     \u03bc S \/ cm     to 1.99     mS \/ cm    , and the electrode constant was 1.566 cm\u22121. Sensitivity of the temperature sensor was 5.46     \u03a9 \/ \u00b0 C    . The results indicate that the developed sensor chip has potential application in water quality measurements.<\/jats:p>","DOI":"10.3390\/s17010157","type":"journal-article","created":{"date-parts":[[2017,1,16]],"date-time":"2017-01-16T09:44:02Z","timestamp":1484559842000},"page":"157","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":35,"title":["Fabrication of a Miniature Multi-Parameter Sensor Chip for Water Quality Assessment"],"prefix":"10.3390","volume":"17","author":[{"given":"Bo","family":"Zhou","sequence":"first","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100080, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chao","family":"Bian","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jianhua","family":"Tong","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shanhong","family":"Xia","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,1,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1016\/j.snb.2013.12.002","article-title":"Miniaturized water quality monitoring pH and conductivity sensors","volume":"193","author":"Banna","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_2","unstructured":"Yosemitech Yosemitech Homepage: Y4000. Available online: http:\/\/www.yosemitech.com\/product-20."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3400","DOI":"10.1109\/JSEN.2014.2332513","article-title":"Development of a low-cost hemin-based dissolved oxygen sensor with anti-biofouling coating for water monitoring","volume":"14","author":"Hsu","year":"2014","journal-title":"IEEE Sens. J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"063102","DOI":"10.1063\/1.4907631","article-title":"A carbon nanotube based resettable sensor for measuring free chlorine in drinking water","volume":"106","author":"Hsu","year":"2015","journal-title":"Appl. Phys. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"095201","DOI":"10.1088\/0957-0233\/20\/9\/095201","article-title":"Water quality assessment by an integrated multi-sensor based on semiconductor RuO2 nanostructures","volume":"20","author":"Zhuiykov","year":"2009","journal-title":"Meas. Sci. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.bios.2015.04.092","article-title":"Simultaneous detection of multiple bioactive pollutants using a multiparametric biochip for water quality monitoring","volume":"72","author":"Guijarro","year":"2015","journal-title":"Biosens. Bioelectron."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"6658","DOI":"10.1016\/j.tsf.2012.07.020","article-title":"Acid\/L-cysteine\/gold nanoparticle modified microelectrode for simultaneous detection of copper and lead","volume":"520","author":"Wang","year":"2012","journal-title":"Thin Solid Films"},{"key":"ref_8","unstructured":"Organization, World Health Guidelines for Drinking-Water Quality: Fourth Edition. Available online: http:\/\/www.who.int\/water_sanitation_health\/publications\/dwqguidelines-4\/en."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"69086","DOI":"10.1039\/C5RA11291E","article-title":"Microfabricated electrochemical pH and free chlorine sensors for water quality monitoring: Recent advances and research challenges","volume":"5","author":"Qin","year":"2015","journal-title":"RSC Adv."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1109\/JSTQE.2015.2497438","article-title":"Miniature pH Optical Fiber Sensor Based on Fabry\u2013Perot Interferometer","volume":"22","author":"Zheng","year":"2016","journal-title":"IEEE J. Sel. Top. Quantum Electron."},{"key":"ref_11","unstructured":"Bahari, N., Zain, A.M., Abdullah, A.Z., Bien, D., Sheng, C., and Othman, M. (2010, January 28\u201330). Study on pH sensing properties of RF magnetron sputtered tantalum pentoxide (Ta2O5) thin film. Proceedings of the 2010 IEEE International Conference on Semiconductor Electronics (ICSE), Malacca, Malaysia."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5647","DOI":"10.1016\/j.electacta.2010.04.102","article-title":"A pH sensor based on the TiO2 nanotube array modified Ti electrode","volume":"55","author":"Zhao","year":"2010","journal-title":"Electrochim. Acta"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1016\/j.snb.2005.03.040","article-title":"Chemical and pH sensors based on the swelling behavior of hydrogels","volume":"111\u2013112","author":"Gerlach","year":"2005","journal-title":"Sens. Actuators B Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/j.sna.2014.04.007","article-title":"Physical The effects of sensing electrode thickness on ruthenium oxide thin-film pH sensor","volume":"214","author":"Sardarinejad","year":"2014","journal-title":"Sens. Actuators A. Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1016\/j.talanta.2015.10.011","article-title":"Miniaturized metal oxide pH sensors for bacteria detection","volume":"147","author":"Uria","year":"2016","journal-title":"Talanta"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1016\/j.snb.2004.11.087","article-title":"Development of the real-time pH sensing system for array sensors","volume":"108","author":"Pan","year":"2005","journal-title":"Sens. Actuators B Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1016\/j.snb.2013.11.109","article-title":"A precise pH microsensor using RF-sputtering IrO2 and Ta2O5 films on Pt-electrode","volume":"193","author":"Kuo","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/j.elecom.2013.12.012","article-title":"Iridium oxide based coaxial pH ultramicroelectrode","volume":"40","author":"Huang","year":"2014","journal-title":"Electrochem. Commun."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1016\/S0925-4005(01)00972-8","article-title":"A long-term stable iridium oxide pH electrode","volume":"81","author":"Wang","year":"2002","journal-title":"Sens. Actuators B Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3857","DOI":"10.1109\/JSEN.2012.2236551","article-title":"Sol-gel iridium oxide-based pH sensor array on flexible polyimide substrate","volume":"13","author":"Nguyen","year":"2013","journal-title":"IEEE Sens. J."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"945","DOI":"10.1109\/TNANO.2014.2332871","article-title":"Micro pH Sensors Based on Iridium Oxide Nanotubes","volume":"13","author":"Nguyen","year":"2014","journal-title":"IEEE Trans. Nanotechnol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1016\/j.electacta.2012.04.143","article-title":"Influence of oxidation state on the pH dependence of hydrous iridium oxide films","volume":"76","author":"Steegstra","year":"2012","journal-title":"Electrochim. Acta"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.snb.2014.02.004","article-title":"Fabrication method and characterization of electrodeposited and heat-treated iridium oxide films for pH sensing","volume":"196","author":"Kim","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"632","DOI":"10.1143\/JJAP.28.632","article-title":"Anodically electrodeposited iridium oxide films (AEIROF\u2019s) from alkaline solutions for electrochromic display devices","volume":"28","author":"Yamanaka","year":"1989","journal-title":"Jpn. J. Appl. Phys."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"8733","DOI":"10.1021\/ac801413b","article-title":"Simultaneous detection of pH changes and histamine release from oxyntic glands in isolated stomach","volume":"80","author":"Bitziou","year":"2008","journal-title":"Anal. Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"8070","DOI":"10.1021\/ac401883n","article-title":"Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping","volume":"85","author":"Nadappuram","year":"2013","journal-title":"Anal. Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"5726","DOI":"10.1021\/ac020326l","article-title":"Fabrication of Anodically Electrodeposited Iridium Oxide Film pH Microelectrodes for Microenvironmental Studies","volume":"74","author":"Bezbaruah","year":"2002","journal-title":"Anal. Chem."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.electacta.2012.02.058","article-title":"Involvement of nanoparticles in the electrodeposition of hydrous iridium oxide films","volume":"68","author":"Steegstra","year":"2012","journal-title":"Electrochim. Acta"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"F1","DOI":"10.1149\/1.3001924","article-title":"Effects of Electrodeposition Conditions and Protocol on the Properties of Iridium Oxide pH Sensor Electrodes","volume":"156","author":"Elsen","year":"2009","journal-title":"J. Electrochem. Soc."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2087","DOI":"10.1002\/smll.201100485","article-title":"Anodic Deposition of Colloidal Iridium Oxide Thin Films from Hexahydroxyiridate(IV) Solutions","volume":"7","author":"Zhao","year":"2011","journal-title":"Small"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1021\/jz200051c","article-title":"A High Yield Synthesis of Ligand-Free Iridium Oxide Nanoparticles with High Electrocatalytic Activity","volume":"2","author":"Zhao","year":"2011","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"B485","DOI":"10.1149\/2.0391609jes","article-title":"Electrodeposition of Iridium Oxide Nanoparticles for pH Sensing Electrodes","volume":"163","author":"Khalil","year":"2016","journal-title":"J. Electrochem. Soc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1016\/j.electacta.2011.09.086","article-title":"Improvement in the long-term stability of screen-printed planar type solid-state Ag\/AgCl reference electrode by introducing poly (dimethylsiloxane) liquid junction","volume":"58","author":"Shitanda","year":"2011","journal-title":"Electrochim. Acta"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1016\/j.snb.2005.09.005","article-title":"A miniaturized electrochemical system with a novel polyelectrolyte reference electrode and its application to thin layer electroanalysis","volume":"115","author":"Kim","year":"2006","journal-title":"Sens. Actuators B Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/S0040-6090(01)01783-7","article-title":"Fabrication and characterization of a new planar solid-state reference electrode for ISFET sensors","volume":"406","author":"Huang","year":"2002","journal-title":"Thin Solid Films"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1016\/j.snb.2011.04.025","article-title":"Dynamic feedback regulation of the potential of a microfabricated liquid-junction Ag\/AgCl reference electrode","volume":"156","author":"Adachi","year":"2011","journal-title":"Sens. Actuators B Chem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"341","DOI":"10.4028\/www.scientific.net\/KEM.483.341","article-title":"The Fabrication and Experiment of a Four-Electrode Conductivity Sensor for Fresh Water","volume":"483","author":"Li","year":"2011","journal-title":"Key Eng. Mater."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"577","DOI":"10.1109\/TIM.2007.911703","article-title":"A Four Terminal Water Quality Monitoring Conductivity Sensor","volume":"57","author":"Ramos","year":"2008","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"166","DOI":"10.1016\/j.desal.2013.03.007","article-title":"Integrated micro fluidic-based sensor module for real-time measurement of temperature, conductivity, and salinity to monitor reverse osmosis","volume":"317","author":"Kim","year":"2013","journal-title":"DES"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1185","DOI":"10.1109\/JSEN.2005.855596","article-title":"Micromachined Silicon Electrolytic Conductivity Probes with Integrated Temperature Sensor","volume":"5","author":"He","year":"2005","journal-title":"IEEE Sens. J."},{"key":"ref_41","unstructured":"Hyldg\u00e5rd, A., \u00d3lafsd\u00f3ttir, \u00cd., Olesen, M., Hedegaard, T., Hansen, O., and Thomsen, E. (November, January 30). V FISH & CHIPS: Four Electrode Conductivity\/Salinity Sensor on a Silicon Multi-sensor Chip for Fisheries Research. Proceedings of the IEEE SENSORS, Irvine, CA, USA."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"722","DOI":"10.1088\/0960-1317\/17\/4\/008","article-title":"Fabrication of a LCP-based conductivity cell and resistive temperature device via PCB MEMS technology","volume":"17","author":"Broadbent","year":"2007","journal-title":"J. Micromech. Microeng."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3295","DOI":"10.1088\/0957-0233\/18\/11\/005","article-title":"A miniature, low cost CTD system for coastal salinity measurements","volume":"18","author":"Broadbent","year":"2007","journal-title":"Meas. Sci. Technol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"138","DOI":"10.4236\/jst.2012.23020","article-title":"Morphology and Electrochemical Properties of Activated and Sputtered Iridium Oxide Films for Functional Electrostimulation","volume":"2","author":"Negi","year":"2012","journal-title":"J. Sens. Technol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1016\/j.apcatb.2015.05.027","article-title":"Development of electrodeposited IrO2 electrodes as anodes in polymer electrolyte membrane water electrolysis","volume":"179","author":"Lee","year":"2015","journal-title":"Appl. Catal. B Environ."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1860","DOI":"10.1021\/ic301968j","article-title":"Characterization of an Amorphous Iridium Water-Oxidation Catalyst Electrodeposited from Organometallic Precursors","volume":"52","author":"Blakemore","year":"2013","journal-title":"Inorg. Chem."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.snb.2008.10.030","article-title":"Morphology of Pt-doped nanofabricated RuO2 sensing electrodes and their properties in water quality monitoring sensors","volume":"136","author":"Zhuiykov","year":"2009","journal-title":"Sens. Actuators B Chem."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.jelechem.2014.11.012","article-title":"Anodic electrodeposition of iridium oxide particles on glassy carbon surfaces and their electrochemical\/SEM\/XPS characterization","volume":"736","author":"Casella","year":"2015","journal-title":"J. Electroanal. Chem."},{"key":"ref_49","first-page":"1034","article-title":"Amperometric Detection of Isoprenaline Based on Glassy Carbon Electrode Modified by Iridium Oxide Nanoparticles","volume":"26","author":"Roushani","year":"2015","journal-title":"J. Braz. Chem. Soc."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"H29","DOI":"10.1149\/1.1353582","article-title":"A pH Electrode Based on Melt-Oxidized Iridium Oxide","volume":"148","author":"Yao","year":"2001","journal-title":"J. Electrochem. Soc."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.sna.2011.05.016","article-title":"A flexible pH sensor based on the iridium oxide sensing film","volume":"169","author":"Huang","year":"2011","journal-title":"Sens. Actuators A Phys."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"6469","DOI":"10.3390\/s150306469","article-title":"A solid-state thin-film Ag\/AgCl reference electrode coated with graphene oxide and its use in a pH sensor","volume":"15","author":"Kim","year":"2015","journal-title":"Sensors"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"664","DOI":"10.1039\/C0LC00293C","article-title":"Nanoporous platinum solid-state reference electrode with layer-by-layer polyelectrolyte junction for pH sensing chip","volume":"11","author":"Noh","year":"2011","journal-title":"Lab Chip"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.snb.2014.07.067","article-title":"Fabrication of thick film sensitive RuO2-TiO2 and Ag\/AgCl\/KCl reference electrodes and their application for pH measurements","volume":"204","author":"Manjakkal","year":"2014","journal-title":"Sens. Actuators B Chem."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"085008","DOI":"10.1088\/0960-1317\/20\/8\/085008","article-title":"A miniature rigid\/flex salinity measurement device fabricated using printed circuit processing techniques","volume":"20","author":"Broadbent","year":"2010","journal-title":"J. Micromech. Microeng."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"398","DOI":"10.1016\/j.sna.2007.02.024","article-title":"Direct media exposure of MEMS multi-sensor systems using a potted-tube packaging concept","volume":"142","author":"Birkelund","year":"2008","journal-title":"Sens. Actuators A Phys."},{"key":"ref_57","unstructured":"Standards Press of China (2011). Test Solutions of Electrolytic Conductivity Analyzer\u2013Preparation Method of Sodium Chloride Solutions (GB\/T 27503-2011), Standards Press of China."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/1\/157\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:26:14Z","timestamp":1760207174000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/1\/157"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,1,14]]},"references-count":57,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2017,1]]}},"alternative-id":["s17010157"],"URL":"https:\/\/doi.org\/10.3390\/s17010157","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,1,14]]}}}