{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T17:39:45Z","timestamp":1787765985091,"version":"build-2784847793"},"reference-count":52,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,30]],"date-time":"2023-01-30T00:00:00Z","timestamp":1675036800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Grants-in-Aid for Scientific Research (B)","award":["JP20H02159"],"award-info":[{"award-number":["JP20H02159"]}]},{"name":"Grants-in-Aid for Scientific Research (B)","award":["JP21H01336"],"award-info":[{"award-number":["JP21H01336"]}]},{"name":"Grants-in-Aid for Scientific Research (B)","award":["JP21K18714"],"award-info":[{"award-number":["JP21K18714"]}]},{"name":"Challenging Research (Exploratory)","award":["JP20H02159"],"award-info":[{"award-number":["JP20H02159"]}]},{"name":"Challenging Research (Exploratory)","award":["JP21H01336"],"award-info":[{"award-number":["JP21H01336"]}]},{"name":"Challenging Research (Exploratory)","award":["JP21K18714"],"award-info":[{"award-number":["JP21K18714"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Rapid detection of heavy metals in solution is necessary to ensure human health and environmental protection. Some heavy-metal compounds are present in solution as compounds instead of as ions owing to their low ionization. Therefore, the development of sensor devices for the detection of heavy-metal compounds is important. In this study, as a proof of concept, we propose a sensor device using graphene and a chelating agent, which were used to develop an identification technique for three types of cadmium compounds. Pristine-graphene and two types of chelator-modified graphene-based sensors were successfully used to detect cadmium compounds at concentrations ranging from 50 to 1000 \u03bcM. The detection time was less than 5 min. The three type of graphene-based sensors responded differently to each cadmium compound, which indicates that they detected cadmium as a cadmium compound instead of as cadmium ions. Furthermore, we successfully identified cadmium compounds by operating these three types of sensors as a sensor array on the same substrate. The results indicate that sensors that focus on heavy-metal compounds instead of heavy-metal ions can be used for the detection of heavy metals in solution.<\/jats:p>","DOI":"10.3390\/s23031519","type":"journal-article","created":{"date-parts":[[2023,1,30]],"date-time":"2023-01-30T03:31:11Z","timestamp":1675049471000},"page":"1519","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Identification of Cadmium Compounds in a Solution Using Graphene-Based Sensor Array"],"prefix":"10.3390","volume":"23","author":[{"given":"Tomoya","family":"Yoshii","sequence":"first","affiliation":[{"name":"Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fuka","family":"Nishitsugu","sequence":"additional","affiliation":[{"name":"Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazuki","family":"Kikawada","sequence":"additional","affiliation":[{"name":"Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kenzo","family":"Maehashi","sequence":"additional","affiliation":[{"name":"Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1293-5084","authenticated-orcid":false,"given":"Takashi","family":"Ikuta","sequence":"additional","affiliation":[{"name":"Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1080\/02772249009357568","article-title":"Carcinogenicity and toxicity of four cadmium compounds inhaled by rats","volume":"27","author":"Glaser","year":"1990","journal-title":"Toxicol. Environ. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1016\/j.fct.2009.11.041","article-title":"Health risk assessment of heavy metals via dietary intake of foodstuffs from the wastewater irrigated site of a dry tropical area of India","volume":"48","author":"Singh","year":"2010","journal-title":"Food Chem. Toxicol."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Melnikov, A.G., Bykov, D.A., Varezhnikov, A.S., Sysoev, V.V., and Melnikov, G.V. (2022). Toward a Selective Analysis of Heavy Metal Salts in Aqueous Media with a Fluorescent Probe Array. Sensors, 22.","DOI":"10.3390\/s22041465"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1180","DOI":"10.1016\/j.sab.2006.06.010","article-title":"Analysis of total and dissolved heavy metals in surface water of a Mexican polluted river by total reflection X-ray fluorescence spectrometry","volume":"61","author":"Zarazua","year":"2006","journal-title":"Spectrochim. Acta Part B Atomic Spectrosc."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/j.talanta.2004.01.027","article-title":"Analytical methods for inorganic arsenic in water: A review","volume":"64","author":"Hung","year":"2004","journal-title":"Talanta"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Falina, S., Syamsul, M., Rhaffor, N.A., Sal Hamid, S., Mohamed Zain, K.A., Abd Manaf, A., and Kawarada, H. (2021). Ten Years Progress of Electrical Detection of Heavy Metal Ions (HMIs) Using Various Field-Effect Transistor (FET) Nanosensors: A Review. Biosensors, 11.","DOI":"10.3390\/bios11120478"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1308","DOI":"10.1093\/ndt\/gfh169","article-title":"Acute self-poisoning by ingestion of cadmium and barium","volume":"19","author":"Hung","year":"2004","journal-title":"Nephrol. Dial. Transplant."},{"key":"ref_8","unstructured":"International Agency for Research on Cancer (1993). Beryllium, cadmium, mercury, and exposures in the glass manufacturing industry. IARC Monogr. Eval. Carcinog. Risks Hum., 58, 1\u2013415."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"27924","DOI":"10.1021\/acsomega.1c03790","article-title":"Hard\u2013Soft Interactions in Solvent Extraction with Basic Extractants: Comparing Zinc and Cadmium Halides","volume":"6","author":"Lommelen","year":"2021","journal-title":"ACS Omega"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.chemgeo.2010.03.006","article-title":"Structure and stability of cadmium chloride complexes in hydrothermal fluids","volume":"276","author":"Bazarkina","year":"2010","journal-title":"Chem. Geol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1163","DOI":"10.1351\/PAC-REP-10-08-09","article-title":"Chemical speciation of environmentally significant metals with inorganic ligands. Part 4: The Cd2+ + OH\u2013, Cl\u2013, CO32\u2013, SO42\u2013, and PO43\u2013systems (IUPAC Technical Report)","volume":"83","author":"Powell","year":"2011","journal-title":"Pure Appl. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1039\/a705212j","article-title":"Hydration and water\u2013ligand replacement in aqueous cadmium(II) sulfate solution A Raman and infrared study","volume":"94","author":"Rudolph","year":"1998","journal-title":"J. Chem. Soc. Faraday Trans."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2382","DOI":"10.1021\/j150655a040","article-title":"Investigation on the structure of cadmium nitrate aqueous solutions by x-ray diffraction and Raman spectroscopy","volume":"88","author":"Caminiti","year":"1984","journal-title":"J. Phys. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"e2100137","DOI":"10.1002\/elsa.202100137","article-title":"Recent advances in field-effect transistor sensing strategies for fast and highly efficient analysis of heavy metal ions","volume":"2","author":"Liu","year":"2022","journal-title":"Electrochem. Sci. Adv."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1038\/nmat1849","article-title":"The rise of graphene","volume":"6","author":"Geim","year":"2007","journal-title":"Nat. Mater."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"652","DOI":"10.1038\/nmat1967","article-title":"Detection of individual gas molecules adsorbed on graphene","volume":"6","author":"Schedin","year":"2007","journal-title":"Nat. Mater."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"10319","DOI":"10.1021\/acs.chemrev.1c00924","article-title":"Two-Dimensional Field-Effect Transistor Sensors: The Road toward Commercialization","volume":"122","author":"Dai","year":"2022","journal-title":"Chem. Rev."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1140","DOI":"10.1126\/science.1220527","article-title":"Graphene Barristor, a Triode Device with a Gate-Controlled Schottky Barrier","volume":"336","author":"Yang","year":"2012","journal-title":"Science"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"650","DOI":"10.1021\/nn4053099","article-title":"Complementary p- and n-Type Polymer Doping for Ambient Stable Graphene Inverter","volume":"8","author":"Yun","year":"2014","journal-title":"ACS Nano"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2283","DOI":"10.1039\/C1CS15270J","article-title":"Biological and chemical sensors based on graphene materials","volume":"41","author":"Liu","year":"2012","journal-title":"Chem. Soc. Rev."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"18012","DOI":"10.1021\/ja108127r","article-title":"Label-Free Biosensors Based on Aptamer-Modified Graphene Field-Effect Transistors","volume":"132","author":"Ohno","year":"2010","journal-title":"J. Am. Chem. Soc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"15642","DOI":"10.1021\/acsanm.2c03705","article-title":"Organic Molecular Detection without Debye-Length Limitation by Desorption of Receptor from the Surface of a Graphene Field-Effect Transistor","volume":"5","author":"Sakamoto","year":"2022","journal-title":"ACS Appl. Nano Mater."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Tang, X., Debliquy, M., Lahem, D., Yan, Y., and Raskin, J.-P. (2021). A Review on Functionalized Graphene Sensors for Detection of Ammonia. Sensors, 21.","DOI":"10.3390\/s21041443"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"14546","DOI":"10.1038\/s41598-020-71591-w","article-title":"Graphene functionalized field-effect transistors for ultrasensitive detection of Japanese encephalitis and Avian influenza virus","volume":"10","author":"Roberts","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"5793","DOI":"10.1039\/D1NA00519G","article-title":"Electrical detection of ppb region NO2 using Mg-porphyrin-modified graphene field-effect transistors","volume":"3","author":"Ikuta","year":"2021","journal-title":"Nanoscale Adv."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"45001","DOI":"10.1021\/acsami.1c09985","article-title":"Electrical Detection of Molecular Transformations Associated with Chemical Reactions Using Graphene Devices","volume":"13","author":"Sakamoto","year":"2021","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1007\/s44211-022-00073-y","article-title":"Development of an odorant sensor with a cell-free synthesized olfactory receptor and a graphene field-effect transistor","volume":"38","author":"Yoshii","year":"2022","journal-title":"Anal. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e12988","DOI":"10.1111\/apha.12988","article-title":"A practical guide to the preparation and use of metal ion-buffered systems for physiological research","volume":"222","author":"Neumaier","year":"2018","journal-title":"Acta Physiol."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"De Acha, N., Elos\u00faa, C., Corres, J.M., and Arregui, F.J. (2019). Fluorescent Sensors for the Detection of Heavy Metal Ions in Aqueous Media. Sensors, 19.","DOI":"10.3390\/s19030599"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"13427","DOI":"10.1002\/anie.201603160","article-title":"A Typical Metal-Ion-Responsive Color-Tunable Emitting Insulated \u03c0-Conjugated Polymer Film","volume":"55","author":"Hosomi","year":"2016","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Stortini, A.M., Baldo, M.A., Moro, G., Polo, F., and Moretto, L.M. (2020). Bio- and Biomimetic Receptors for Electrochemical Sensing of Heavy Metal Ions. Sensors, 20.","DOI":"10.3390\/s20236800"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2685","DOI":"10.1039\/D1MH01117K","article-title":"Harnessing selectivity in chemical sensing via supramolecular interactions: From functionalization of nanomaterials to device applications","volume":"8","author":"Ciesielski","year":"2021","journal-title":"Mater. Horiz."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4921","DOI":"10.1021\/cr900134a","article-title":"Application of Metal Coordination Chemistry To Explore and Manipulate Cell Biology","volume":"109","author":"Haas","year":"2009","journal-title":"Chem. Rev."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/S0003-2670(00)86781-1","article-title":"Compleximetric titrations with triethylenetetramine-hexaacetic acid","volume":"49","author":"Harju","year":"1970","journal-title":"Anal. Chim. Acta"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"045001","DOI":"10.35848\/1882-0786\/ac564d","article-title":"Effect of changing electronic states of molecules on frequency domain of graphene FETs","volume":"15","author":"Oketa","year":"2022","journal-title":"Appl. Phys. Express"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"025003","DOI":"10.1143\/APEX.2.025003","article-title":"Mobility Variations in Mono- and Multi-Layer Graphene Films","volume":"2","author":"Nagashio","year":"2009","journal-title":"Appl. Phys. Express"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"5031","DOI":"10.1021\/nn201115p","article-title":"Top-Gated Graphene Field-Effect Transistors with High Normalized Transconductance and Designable Dirac Point Voltage","volume":"5","author":"Xu","year":"2011","journal-title":"ACS Nano"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"045104","DOI":"10.7567\/APEX.9.045104","article-title":"Acoustic carrier transportation induced by surface acoustic waves in graphene in solution","volume":"9","author":"Satoshi","year":"2016","journal-title":"Appl. Phys. Express"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"187401","DOI":"10.1103\/PhysRevLett.97.187401","article-title":"Raman spectrum of graphene and graphene layers","volume":"97","author":"Ferrari","year":"2006","journal-title":"Phys. Rev. Lett."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.ssc.2007.03.052","article-title":"Raman spectroscopy of graphene and graphite: Disorder, electron\u2013phonon coupling, doping and nonadiabatic effects","volume":"143","author":"Ferrari","year":"2007","journal-title":"Solid State Commun."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3519","DOI":"10.1021\/nl201699j","article-title":"Synthesis and characterization of large-area graphene and graphite films on commercial Cu-Ni alloy foils","volume":"11","author":"Chen","year":"2011","journal-title":"Nano Lett."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1471","DOI":"10.1039\/C4NR05390G","article-title":"Graphene field effect transistor as a probe of electronic structure and charge transfer at organic molecule\u2013graphene interfaces","volume":"7","author":"Cervenka","year":"2015","journal-title":"Nanoscale"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1336","DOI":"10.1021\/ja8057327","article-title":"Chemical Modification of Epitaxial Graphene: Spontaneous Grafting of Aryl Groups","volume":"131","author":"Bekyarova","year":"2009","journal-title":"J. Am. Chem. Soc."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"4774","DOI":"10.1021\/acs.langmuir.6b00870","article-title":"Evidence for Charge Transfer at the Interface between Hybrid Phosphomolybdate and Epitaxial Graphene","volume":"32","author":"Huder","year":"2016","journal-title":"Langmuir"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1021\/jz301821n","article-title":"XH\/\u03c0 (X = C, Si) Interactions in Graphene and Silicene: Weak in Strength, Strong in Tuning Band Structures","volume":"4","author":"Li","year":"2013","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"787","DOI":"10.1002\/cphc.200800714","article-title":"Synthesis, Characterization, and Electro-Optical Properties of ZnII Complexes with \u03c0-Conjugated Terpyridine Ligands","volume":"10","author":"Winter","year":"2009","journal-title":"ChemPhysChem"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"990","DOI":"10.2478\/s11532-011-0087-6","article-title":"Ruthenium(II)-bis(4\u2032-(4-ethynylphenyl)-2,2\u2032:6\u2032, 2\u2033-terpyridine)\u2014A versatile synthon in supramolecular chemistry. Synthesis and characterization","volume":"9","author":"Siebert","year":"2011","journal-title":"Open Chem."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"443001","DOI":"10.1088\/0953-8984\/26\/44\/443001","article-title":"Molecular adsorption on graphene","volume":"26","author":"Kong","year":"2014","journal-title":"J. Phys. Condens. Matter"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.poly.2016.12.022","article-title":"Cadmium(II) coordination polymers constructed from a bis-functionalized ligand 4\u2032-(3-carboxyphenyl)-2,2\u2032:6\u2032,2\u2033-terpyridine: Synthesis, structure and luminescence","volume":"124","author":"Bai","year":"2017","journal-title":"Polyhedron"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1007\/s12039-015-1011-y","article-title":"Highly selective detection of Zn2+ and Cd2+ with a simple amino-terpyridine compound in solution and solid state","volume":"128","author":"Chao","year":"2016","journal-title":"J. Chem. Sci."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"588","DOI":"10.1002\/bkcs.12233","article-title":"Reactivity of a Cadmium\u2013Terpyridine Complex: [Cd(L1)(NO3)2(H2O)] (L1 = (4\u2032-(4-bromophenyl)-2,2\u2032:6\u2032,2\u2033-terpyridine)","volume":"42","author":"Lee","year":"2021","journal-title":"Bull. Korean Chem. Soc."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"877","DOI":"10.1021\/acsomega.9b03821","article-title":"Selective Detection of Cu2+ Ions by Immobilizing Thiacalix[4]arene on Graphene Field-Effect Transistors","volume":"5","author":"Takagiri","year":"2019","journal-title":"ACS Omega"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/3\/1519\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:19:43Z","timestamp":1760120383000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/3\/1519"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,30]]},"references-count":52,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["s23031519"],"URL":"https:\/\/doi.org\/10.3390\/s23031519","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,30]]}}}