{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T13:41:07Z","timestamp":1770817267825,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2021,11,5]],"date-time":"2021-11-05T00:00:00Z","timestamp":1636070400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003359","name":"Generalitat Valenciana","doi-asserted-by":"publisher","award":["Prometeo 2020\/078"],"award-info":[{"award-number":["Prometeo 2020\/078"]}],"id":[{"id":"10.13039\/501100003359","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Government of Spain","award":["CTQ2017-90082-P"],"award-info":[{"award-number":["CTQ2017-90082-P"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Due to their simplicity, speed and low cost, chemical spot tests are increasingly demanded for the presumptive identification of illicit drugs in a variety of contexts such as point-of-care assistance or prosecution of drug trafficking. However, most of the colorimetric reactions used in these tests are, at best, drug class selective. Therefore, the development of tests based on chemical reactions with improved discrimination power is of great interest. In this work, we propose a new colorimetric assay for amphetamine (AMP) based on its reaction with solutions of alkaline gold bromide to form an insoluble yellow\u2013orange derivative. The resulting suspensions are then filtered onto nylon membranes and the precipitate collected is used for the visual identification of AMP. The measurement of the absorbance of the membranes by diffuse reflectance spectroscopy also allows the quantification of AMP in a simple and rapid way, as demonstrated for different synthetic and drug street samples. On the basis of the results obtained, it was concluded that the proposed procedure is highly selective towards AMP, as this compound could be easily differentiated from other common drugs such as methamphetamine (MET), ephedrine (EPH), scopolamine (SCP) and cocaine (COC).<\/jats:p>","DOI":"10.3390\/molecules26216713","type":"journal-article","created":{"date-parts":[[2021,11,7]],"date-time":"2021-11-07T20:41:14Z","timestamp":1636317674000},"page":"6713","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["A Colorimetric Membrane-Based Sensor with Improved Selectivity towards Amphetamine"],"prefix":"10.3390","volume":"26","author":[{"given":"Neus","family":"Jornet-Mart\u00ednez","sequence":"first","affiliation":[{"name":"MINTOTA Research Group, Departament de Qu\u00edmica Anal\u00edtica, Universitat de Val\u00e8ncia, Dr. Moliner 50, 46100 Burjassot, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0980-8298","authenticated-orcid":false,"given":"Pilar","family":"Camp\u00edns-Falc\u00f3","sequence":"additional","affiliation":[{"name":"MINTOTA Research Group, Departament de Qu\u00edmica Anal\u00edtica, Universitat de Val\u00e8ncia, Dr. Moliner 50, 46100 Burjassot, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5106-0826","authenticated-orcid":false,"given":"Rosa","family":"Herr\u00e1ez-Hern\u00e1ndez","sequence":"additional","affiliation":[{"name":"MINTOTA Research Group, Departament de Qu\u00edmica Anal\u00edtica, Universitat de Val\u00e8ncia, Dr. Moliner 50, 46100 Burjassot, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,5]]},"reference":[{"key":"ref_1","unstructured":"(2021, September 20). 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