{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,21]],"date-time":"2026-06-21T05:37:11Z","timestamp":1782020231970,"version":"3.54.5"},"reference-count":24,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2021,11,10]],"date-time":"2021-11-10T00:00:00Z","timestamp":1636502400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["analyticalsciencejournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Drug Testing and Analysis"],"published-print":{"date-parts":[[2022,2]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>During routine urine drug testing for cannabis use targeting delta\u20109\u2010tetrahydrocannabinol carboxylic acid (delta\u20109\u2010THC\u2010COOH) at the Karolinska University Laboratory in Sweden, an unknown interfering peak was observed in the liquid\u2010chromatographic\u2013tandem mass\u2010spectrometric (LC\u2013MS\/MS) confirmative analysis. The peak showed the same exact mass and most abundant fragments as delta\u20109\u2010THC\u2010COOH but a slightly shorter retention time, thereby not fulfilling all requirements for a positive identification. The analytical results suggested that it was a similar compound, and with access to reference material, it could be identified as the double bond isomer delta\u20108\u2010THC\u2010COOH. Delta\u20108\u2010THC has recently become popular as a recreational drug, although its legality varies and is sometimes unclear. In Sweden, all THC isomers are classified substances. The slight difference in retention times was sufficient to distinguish the THC\u2010COOH isomers in the routine LC\u2013MS\/MS method, but another LC method allowed better peak separation and individual quantification. At the Karolinska University Laboratory, delta\u20108\u2010THC\u2010COOH was first observed in April 2020, and the highest incidence was noted in June 2020 when it was present in 5.3% of all THC\u2010COOH\u2010positive samples. The incidence later decreased to today only occasional findings. Large differences in the relative presence of the isomers in the urine samples indicated different origin, for example, synthetically produced pure delta\u20108\u2010THC, or mixtures of both THC isomers formed during combustion of cannabidiol (CBD). In conclusion, the appearance of delta\u20108\u2010THC and other isomers on the recreational drug market risks causing analytical and medico\u2010legal problems, due to confusion with delta\u20109\u2010THC.<\/jats:p>","DOI":"10.1002\/dta.3190","type":"journal-article","created":{"date-parts":[[2021,11,3]],"date-time":"2021-11-03T22:59:25Z","timestamp":1635980365000},"page":"371-376","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Analytical and medico\u2010legal problems linked to the presence of delta\u20108\u2010tetrahydrocannabinol (delta\u20108\u2010THC): Results from urine drug testing in Sweden"],"prefix":"10.1002","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7480-8078","authenticated-orcid":false,"given":"Anders","family":"Helander","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine Karolinska Institutet  Stockholm Sweden"},{"name":"Department of Clinical Pharmacology Karolinska University Laboratory  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Malin","family":"Johansson","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology Karolinska University Laboratory  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Annika","family":"Andersson","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology Karolinska University Laboratory  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomas","family":"Vill\u00e9n","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology Karolinska University Laboratory  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2021,11,10]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.lfs.2005.09.011"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tplants.2020.05.005"},{"key":"e_1_2_7_4_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.168.3936.1159"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00213-020-05712-8"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/jms.1624"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1111\/jnc.15369"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.1093\/jat\/16.5.276"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1097\/01.ftd.0000197091.07807.22"},{"key":"e_1_2_7_10_1","doi-asserted-by":"publisher","DOI":"10.1093\/jat\/25.7.538"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00216-014-8301-y"},{"key":"e_1_2_7_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/cpt1973143353"},{"key":"e_1_2_7_13_1","unstructured":"WebsterGRB SarnaLP MechoulamR.United States Patent Application Publication. 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