{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T23:58:52Z","timestamp":1774483132940,"version":"3.50.1"},"reference-count":56,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,6,19]],"date-time":"2020-06-19T00:00:00Z","timestamp":1592524800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Education of Korea","award":["2019R1A6C1010016"],"award-info":[{"award-number":["2019R1A6C1010016"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Carbon dots (CDs) demonstrate very poor fluorescence quantum yield (QY). In this study, with the help of a hydrothermal method, we combined CDs with nitrogen and phosphorus elements belonging to the VA group (in the periodic table) to form heteroatom co-doped CDs, i.e., nitrogen and phosphorus co-doped carbon dots (NPCDs). These displayed a significant improvement in the QY (up to 84%), which was as much as four times than that of CDs synthesized by the same method. The as-prepared NPCDs could be used as an \u201coff-on\u201d fluorescence detector for the rapid and effective sensing of ferric ions (Fe3+) and catecholamine neurotransmitters (CNs) such as dopamine (DA), adrenaline (AD), and noradrenaline (NAD). The fluorescence of NPCDs was \u201cturned off\u201d and the emission wavelength was slightly red-shifted upon increasing the Fe3+ concentration. However, when CNs were incorporated, the fluorescence of NPCDs was recovered in a short response time; this indicated that CN concentration could be monitored, relying on enhancing the fluorescence signal of NPCDs. As a result, NPCDs are considered as a potential fluorescent bi-sensor for Fe3+ and CN detection. Particularly, in this research, we selected DA as the representative neurotransmitter of the CN group along with Fe3+ to study the sensing system based on NPCDs. The results exhibited good linear ranges with a limit of detection (LOD) of 0.2 and 0.1 \u00b5M for Fe3+ and DA, respectively.<\/jats:p>","DOI":"10.3390\/s20123470","type":"journal-article","created":{"date-parts":[[2020,6,19]],"date-time":"2020-06-19T10:43:58Z","timestamp":1592563438000},"page":"3470","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Detection of Ferric Ions and Catecholamine Neurotransmitters via Highly Fluorescent Heteroatom Co-Doped Carbon Dots"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4882-8099","authenticated-orcid":false,"given":"Thi Hoa","family":"Le","sequence":"first","affiliation":[{"name":"Department of Chemical and Biological Engineering, Gachon University, Seongnam 13120, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6443-0902","authenticated-orcid":false,"given":"Hyun Jong","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biological Engineering, Gachon University, Seongnam 13120, Korea"}]},{"given":"Ji Hyeon","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biological Engineering, Gachon University, Seongnam 13120, Korea"}]},{"given":"Sang Joon","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biological Engineering, Gachon University, Seongnam 13120, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.saa.2019.117165","article-title":"One-step synthesized fluorescent nitrogen doped carbon dots from thymidine for Cr (VI) detection in water","volume":"222","author":"Ming","year":"2019","journal-title":"Spectroc. 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