{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,18]],"date-time":"2026-06-18T03:21:50Z","timestamp":1781752910060,"version":"3.54.5"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2018,5,1]],"date-time":"2018-05-01T00:00:00Z","timestamp":1525132800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Rapid, global technological development has caused the food industry to use concentrated food component sources like dietary supplements ever more commonly as part of the human diet. This study analysed the menaquinone-7 (MK-7) content of dietary supplements in oil capsule and hard tablet forms. A novel method for separating and measuring geometric isomers of MK-7 in dietary supplements was developed and validated. Eleven different isomers of cis\/trans- menaquinone-7 were identified. Identification of cis\/trans isomers was performed by combination of HPLC, UPLC and HRMS-QTOF detection, whereas their quantities were determined by DAD detection. The content of menaquinone impurities was ascertained, including cis\/trans- menaquinone-6 isomers (5.5\u201316.9 \u00b5g per tablet\/capsule) and cis\/trans-menaquinone-7 isomers (70.9\u2013218.7 \u00b5g tablet\/capsule), which were most likely formed during the chemical synthesis of the menaquinone-7. The all-trans MK-7 content was lower than the isomeric form and often lower than what the labels declared. A new method of quantification, developed and validated for menaquinones in oil capsules, provided on average 90% recovery and a limit of quantification (LOQ) of approximately 1 \u00b5g mL\u22121.<\/jats:p>","DOI":"10.3390\/molecules23051056","type":"journal-article","created":{"date-parts":[[2018,5,3]],"date-time":"2018-05-03T03:20:27Z","timestamp":1525317627000},"page":"1056","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Analysis of Menaquinone-7 Content and Impurities in Oil and Non-Oil Dietary Supplements"],"prefix":"10.3390","volume":"23","author":[{"given":"Arkadiusz","family":"Szterk","sequence":"first","affiliation":[{"name":"Department of Spectrometric Methods, National Medicines Institute, 30\/34 Che\u0142mska, 00-725 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6544-5412","authenticated-orcid":false,"given":"Katarzyna","family":"Bus","sequence":"additional","affiliation":[{"name":"Department of Spectrometric Methods, National Medicines Institute, 30\/34 Che\u0142mska, 00-725 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam","family":"Zmys\u0142owski","sequence":"additional","affiliation":[{"name":"Department of Spectrometric Methods, National Medicines Institute, 30\/34 Che\u0142mska, 00-725 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karol","family":"Ofiara","sequence":"additional","affiliation":[{"name":"Department of Spectrometric Methods, National Medicines Institute, 30\/34 Che\u0142mska, 00-725 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.ics.2006.08.024","article-title":"Role of vitamin K in the regulation of calcification","volume":"1297","author":"Shea","year":"2007","journal-title":"Int. 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