{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,24]],"date-time":"2026-10-24T04:13:51Z","timestamp":1792815231403,"version":"4.5.0"},"reference-count":40,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,3,14]],"date-time":"2019-03-14T00:00:00Z","timestamp":1552521600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Foods"],"abstract":"<jats:p>Melatonin (MEL) is an indoleamine produced mainly by the pineal gland in vertebrates. It plays a significant role in the regulation of circadian rhythms, mitigation of sleeping disorders, and jet lag. This compound is synthetized from tryptophan (TRP) and it has been found in seeds, fruits, and fermented beverages, including wine. Wine is also a source of other tryptophan derivatives, the tryptophan ethylester (TEE) and MEL isomers (MISs), for which the biological properties need to be elucidated. An analytical method for the simultaneous quantification of TRP, TEE, and MEL was developed by a Solid Phase Extraction (SPE) of a preconcentration of wine followed by high performance liquid chromatography (HPLC) analysis either with fluorescence or mass spectrometer detectors. The analytical method showed a relative standard deviation (RSD) lower than 8%, except for TRP (RSD 10.5% in wine). The recovery was higher than 76%. The versatility of SPE preconcentrations allowed for the adequate preconcentration of wine sample as well as detection of low concentrations, an important aspect especially for MEL (detection limit 0.0023 \u00b5g\/L). The proposed method proved to be suitable for assessing the investigated compounds in some red wine samples, where 74.4\u2013256.2 \u00b5g\/L and 0.038\u20130.063 \u00b5g\/L of TEE and MEL were detected, respectively. Five MISs were also found in wine samples in concentrations up to 1.97 \u00b5g\/L.<\/jats:p>","DOI":"10.3390\/foods8030099","type":"journal-article","created":{"date-parts":[[2019,3,15]],"date-time":"2019-03-15T04:12:09Z","timestamp":1552623129000},"page":"99","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":30,"title":["Assessment of Tryptophan, Tryptophan Ethylester, and Melatonin Derivatives in Red Wine by SPE-HPLC-FL and SPE-HPLC-MS Methods"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0525-7123","authenticated-orcid":false,"given":"Daniela","family":"Fracassetti","sequence":"first","affiliation":[{"name":"Department of Food, Environmental and Nutritional Sciences, Universit\u00e0 degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ileana","family":"Vigentini","sequence":"additional","affiliation":[{"name":"Department of Food, Environmental and Nutritional Sciences, Universit\u00e0 degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alfredo","family":"Lo Faro","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, Universit\u00e0 degli Studi di Milano, Via Mangiagalli 37, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrizia","family":"De Nisi","sequence":"additional","affiliation":[{"name":"Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Universit\u00e0 degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3937-5355","authenticated-orcid":false,"given":"Roberto","family":"Foschino","sequence":"additional","affiliation":[{"name":"Department of Food, Environmental and Nutritional Sciences, Universit\u00e0 degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonio","family":"Tirelli","sequence":"additional","affiliation":[{"name":"Department of Food, Environmental and Nutritional Sciences, Universit\u00e0 degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marica","family":"Orioli","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, Universit\u00e0 degli Studi di Milano, Via Mangiagalli 37, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5063-1236","authenticated-orcid":false,"given":"Marcello","family":"Iriti","sequence":"additional","affiliation":[{"name":"Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Universit\u00e0 degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,3,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1210\/edrv-1-2-109","article-title":"The pineal and its hormones in the control of reproduction in mammals","volume":"1","author":"Reiter","year":"1980","journal-title":"Endocr. 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