{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:23:30Z","timestamp":1760243010566,"version":"build-2065373602"},"reference-count":44,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2015,4,1]],"date-time":"2015-04-01T00:00:00Z","timestamp":1427846400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The liquid junction potential (LJP), the phenomenon that occurs when two electrolyte solutions of different composition come into contact, prevents accurate measurements in potentiometry. The effect of the LJP is usually remarkable in measurements of diluted solutions with low buffering capacities or low ion concentrations. Our group has constructed a simple method to eliminate the LJP by exerting spatiotemporal control of a liquid junction (LJ) formed between two solutions, a sample solution and a baseline solution (BLS), in a flow-through-type differential pH sensor probe. The method was contrived based on microfluidics. The sensor probe is a differential measurement system composed of two ion-sensitive field-effect transistors (ISFETs) and one Ag\/AgCl electrode. With our new method, the border region of the sample solution and BLS is vibrated in order to mix solutions and suppress the overshoot after the sample solution is suctioned into the sensor probe. Compared to the conventional method without vibration, our method shortened the settling time from over two min to 15 s and reduced the measurement error by 86% to within 0.060 pH. This new method will be useful for improving the response characteristics and decreasing the measurement error of many apparatuses that use LJs.<\/jats:p>","DOI":"10.3390\/s150407898","type":"journal-article","created":{"date-parts":[[2015,4,7]],"date-time":"2015-04-07T03:47:46Z","timestamp":1428378466000},"page":"7898-7912","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["A Simple Method for Decreasing the Liquid Junction Potential in a Flow-through-Type Differential pH Sensor Probe Consisting of pH-FETs by Exerting Spatiotemporal Control of the Liquid Junction"],"prefix":"10.3390","volume":"15","author":[{"given":"Akira","family":"Yamada","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa Cho, Toyota City, Aichi Prefecture 470-0392, Japan"},{"name":"Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama Prefecture 700-8558, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Satoshi","family":"Mohri","sequence":"additional","affiliation":[{"name":"Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama Prefecture 700-8558, Japan"},{"name":"First Department of Physiology, Kawasaki Medical School, 577 Matsushima, Kurashiki-City,  Okayama Prefecture 701-0192, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michihiro","family":"Nakamura","sequence":"additional","affiliation":[{"name":"Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama Prefecture 700-8558, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keiji","family":"Naruse","sequence":"additional","affiliation":[{"name":"Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama Prefecture 700-8558, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,4,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1515\/zpch-1909-6720","article-title":"\u00dcber elektrische phasengrenzkr\u00e4fte","volume":"67","author":"Haber","year":"1909","journal-title":"Z. Phys. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1109\/TBME.1970.4502688","article-title":"Development of an ion-sensitive solid-state device for neurophysiological measurements","volume":"BME-17","author":"Bergveld","year":"1970","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0925-4005(02)00301-5","article-title":"Thirty years of ISFETOLOGY what happened in the past 30 years and what may happen in the next 30 years","volume":"88","author":"Bergveld","year":"2003","journal-title":"Sens. Actuators B-Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1002\/andp.18782390204","article-title":"Ueber galvanische str\u00f6me, verursacht durch concentrationsunterschiede; Folgerungen avs der mechanischen w\u00e4rmetheorie","volume":"3","author":"Helmholtz","year":"1878","journal-title":"Ann. Phys. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1661","DOI":"10.1007\/s10008-011-1373-0","article-title":"Salt bridge in electroanalytical chemistry: Past, present, and future","volume":"15","author":"Kakiuchi","year":"2011","journal-title":"J. Solid State Electrochem."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1515\/zpch-1888-0274","article-title":"Zur kinetik der in l\u00f6sung befindlichen k\u00f6rper","volume":"2","author":"Nernst","year":"1888","journal-title":"Z. Phys. Chem."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1515\/zpch-1889-0412","article-title":"Die elektromotorische wirksamkeit der jonen","volume":"4","author":"Nernst","year":"1889","journal-title":"Z. Phys. Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1002\/andp.18902750202","article-title":"Uber die erregung von electricit\u00e4t und w\u00e4rme in electrolyten","volume":"39","author":"Planck","year":"1890","journal-title":"Ann. Phys. Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1002\/andp.18902760802","article-title":"Ueber die potentialdifferenz zwischen zwei verd\u00fcnnten l\u00f6sungen bin\u00e4rer electrolyte","volume":"40","author":"Planck","year":"1890","journal-title":"Ann. Phys. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1515\/zpch-1907-5907","article-title":"Zur thermodynamik der fl\u00fcssigkeitsketten","volume":"59","author":"Henderson","year":"1907","journal-title":"Z. phys. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1515\/zpch-1908-6320","article-title":"Zur thermodynamik der fl\u00fcssigkeitsketten","volume":"63","author":"Henderson","year":"1908","journal-title":"Z. phys. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"737","DOI":"10.1002\/andp.18912801211","article-title":"Experimentaluntersuchungen \u00fcber potentialdifferenzen an den ber\u00fchrungsfl\u00e4chen sehr verd\u00fcnnter l\u00f6sungen","volume":"44","author":"Negbauer","year":"1891","journal-title":"Ann. Phys. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2563","DOI":"10.1021\/ja01445a011","article-title":"The potentials at the junctions of monovalent chloride solutions","volume":"43","author":"MacInnes","year":"1921","journal-title":"J. Am. Chem. Soc."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1021\/ja01353a021","article-title":"Electromotive-force measurements with a saturated potassium chloride bridge or with concentration cells with a liquid junction","volume":"53","author":"Scatchard","year":"1931","journal-title":"J. Am. Chem. Soc."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1515\/zpch-1895-1803","article-title":"Studien \u00fcber superoxyd-elektroden","volume":"18","author":"Tower","year":"1895","journal-title":"Z. Phys. Chem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1515\/zpch-1896-2014","article-title":"Ueber potentialdifferenzen an den ber\u00fchrungsfl\u00e4chen verd\u00fcnnter l\u00f6sungen","volume":"20","author":"Tower","year":"1896","journal-title":"Z. Phys. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"428","DOI":"10.1515\/zpch-1905-5325","article-title":"\u00dcber die elimination des diffusionspotentials zwischen zwei verd\u00fcnnter w\u00e4sserigen l\u00f6sungen durch einschalten einer konzentrierten chlorkaliuml\u00f6sung","volume":"53","author":"Bjerrum","year":"1905","journal-title":"Z. Phys. Chem."},{"key":"ref_18","first-page":"389","article-title":"\u00dcber die elimination des fl\u00fcssigkeitspotentials bei messungen von elektrodenpotentialen","volume":"17","author":"Bjerrum","year":"1911","journal-title":"Z. Electrochem. Angew. Phys. Chem."},{"key":"ref_19","first-page":"58","article-title":"\u00dcber die g\u00fcltigkeit der planckschen formel f\u00fcr das diffusionspotential","volume":"17","author":"Bjerrum","year":"1911","journal-title":"Z. Electrochem. Angew. Phys. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1291","DOI":"10.1021\/ja02242a001","article-title":"Planck\u2019s formula for the potential difference between solutions and the values of certain important cells","volume":"40","author":"Fales","year":"1918","journal-title":"J. Am. Chem. Soc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/B978-0-08-031492-1.50006-1","article-title":"Reference electrodes and liquid junction effects in ion-selective electrode potentiometry","volume":"5","author":"Covington","year":"1983","journal-title":"Ion-Sel. Electrode Rev."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.2116\/analsci.7.1","article-title":"Electrochemical approach to ion solvations. Applications of ion-selective electrodes as sensors for ion solvations and the problem of the liquid junction potential between different solvents","volume":"7","author":"Izutsu","year":"1991","journal-title":"Anal. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1059","DOI":"10.1039\/tf9686401059","article-title":"Liquid junction potential between dilute electrolytes and saturated potassium chloride","volume":"64","author":"Picknett","year":"1968","journal-title":"Trans. Faraday Soc."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1528","DOI":"10.1039\/an9830801528","article-title":"Procedures for the measurement of pH in low ionic strength solutions including freshwater","volume":"108","author":"Covington","year":"1983","journal-title":"Analyst"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1021\/ja01447a004","article-title":"Reproducible liquid junction potentials: The flowing junction","volume":"42","author":"Lamb","year":"1920","journal-title":"J. Am. Chem. Soc."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1203","DOI":"10.2116\/analsci.26.1203","article-title":"Stability of a Ag\/AgCl reference electrode equipped with an ionic liquid salt bridge composed of 1-methyl-3-octylimidazolium bis(trifluoromethanesulfonyl)-amide in potentiometry of pH standard buffers","volume":"26","author":"Shibata","year":"2010","journal-title":"Anal. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1021\/ac1021216","article-title":"Determination of the activity of hydrogen ions in dilute sulfuric acids by use of an ionic liquid salt bridge sandwiched by two hydrogen electrodes","volume":"83","author":"Shibata","year":"2011","journal-title":"Anal. Chem."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3613","DOI":"10.1007\/s00216-011-4689-9","article-title":"Solid-state reference electrodes based on carbon nanotubes and polyacrylate membranes","volume":"399","author":"Kisiel","year":"2011","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"7771","DOI":"10.1021\/ac3011507","article-title":"Advantages and limitations of reference electrodes with an ionic liquid junction and three-dimensionally ordered macroporous carbon as solid contact","volume":"84","author":"Zhang","year":"2012","journal-title":"Anal. Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1315","DOI":"10.1021\/ja01367a004","article-title":"A study of cells with liquid-liquid junctions","volume":"52","author":"Guggenheim","year":"1930","journal-title":"J. Am. Chem. Soc."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"696","DOI":"10.1021\/ja01680a015","article-title":"The activities of strong electrolytes. III. The use of the flowing junction to study the liquid junction potential between dilute hydrochloric acid and saturated potassium chloride solutions; and the revision of some single-electrode potentials","volume":"47","author":"Scatchard","year":"1925","journal-title":"J. Am. Chem. Soc."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1021\/ja01353a021","article-title":"An effect of the breadth of junction of the electromotive force of a simple concentration cell","volume":"53","author":"Scatchard","year":"1931","journal-title":"J. Am. Chem. Soc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2585","DOI":"10.1021\/ac00125a053","article-title":"Reference electrode with free-flowing free-diffusion liquid junction","volume":"58","author":"Dohner","year":"1986","journal-title":"Anal. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3563","DOI":"10.1002\/elps.200305584","article-title":"Microfluidic devices fabricated in poly(dimethylsiloxane) for biological studies","volume":"24","author":"Sia","year":"2003","journal-title":"Electrophoresis"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1541\/ieejsmas.127.367","article-title":"Automation of pH measurement using a flow-through type differential pH sensor system based on pH-FET","volume":"127","author":"Mohri","year":"2007","journal-title":"IEEJ Trans. SM"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1016\/j.snb.2009.09.045","article-title":"A fully automated pH measurement system for 96-well microplates using a semiconductor-based pH sensor","volume":"143","author":"Yamada","year":"2010","journal-title":"Sen. Actuat. B-Chem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"197","DOI":"10.20965\/jrm.2010.p0197","article-title":"Optimizing the conditions for pH measurement with an automated pH measurement system using a flow-through-type differential sensor probe consisting of pH-FETs","volume":"22","author":"Yamada","year":"2010","journal-title":"J. Robot. Mechatron."},{"key":"ref_38","unstructured":"Ogata, K. (2009). Modern Control Engineering, Prentice Hall. [5th ed.]."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1246\/bcsj.61.799","article-title":"Applications of hydrogen ion sensitive FET to the kinetic study of fast reaction in solution","volume":"61","author":"Nakatsuka","year":"1988","journal-title":"Bull. Chem. Soc. Jpn."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1016\/j.snb.2005.10.029","article-title":"Measurements of CO2, lactic acid and sodium bicarbonate secreted by cultured cells using a flow-through type pH\/CO2 sensor system based on ISFET","volume":"115","author":"Mohri","year":"2006","journal-title":"Sens. Actuators B-Chem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1016\/j.snb.2008.05.021","article-title":"Application of a flow-through type pH\/CO2 sensor system based on ISFET for evaluation of the glucose dependency of the metabolic pathways in cultured cells","volume":"134","author":"Mohri","year":"2008","journal-title":"Sens. Actuators B-Chem."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1535","DOI":"10.1541\/ieejeiss.131.1535","article-title":"Glucose dependency of the metabolic pathway of HEK 293 cells measured by a flow-through type pH\/CO2 sensor system using ISFETs","volume":"131","author":"Yamada","year":"2011","journal-title":"IEEJ Trans. EIS"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2484","DOI":"10.3390\/s130202484","article-title":"Detection of Micrococcus Luteus biofilm formation in microfluidic environments by pH measurement using an ion-sensitive field-effect transistor","volume":"13","author":"Matsuura","year":"2013","journal-title":"Sensors"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1126\/science.1066238","article-title":"Chaotic mixer for microchannels","volume":"295","author":"Stroock","year":"2002","journal-title":"Science"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/4\/7898\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:44:14Z","timestamp":1760215454000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/4\/7898"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,4,1]]},"references-count":44,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2015,4]]}},"alternative-id":["s150407898"],"URL":"https:\/\/doi.org\/10.3390\/s150407898","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2015,4,1]]}}}