{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T11:49:17Z","timestamp":1791287357868,"version":"4.1.0"},"reference-count":33,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2018,8,6]],"date-time":"2018-08-06T00:00:00Z","timestamp":1533513600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Journal of Forensic Sciences"],"published-print":{"date-parts":[[2019,3]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Pregabalin is a Schedule V controlled substance which is defined as the (S) enantiomer of 3\u2010(aminomethyl)\u20105\u2010methylhexanoic acid. It is used legitimately to treat neuropathy in patients with diabetes as well as for epilepsy and fibromyalgia. Pregabalin is an amino acid and an amphoteric compound, which makes it difficult to analyze using the conventional GC\u2010MS instrumentation found in most forensic drug analysis laboratories. Problems associated with the traditional GC\u2010MS analysis of pregabalin include selective solubility, ring closure to the corresponding lactam in the GC injection port and\/or the MS transfer line and difficulty with chiral derivatization due to the presence of a carboxylic acid moiety. Here, we show that these challenges can be overcome by methylating (capping) the carboxylic acid portion of the pregabalin molecule and converting to the corresponding methyl ester. Once the methyl ester is synthesized, chiral derivatization at the amine can be achieved to identify the controlled (S) enantiomer of pregabalin via GC\u2010MS.<\/jats:p>","DOI":"10.1111\/1556-4029.13888","type":"journal-article","created":{"date-parts":[[2018,8,7]],"date-time":"2018-08-07T11:20:15Z","timestamp":1533640815000},"page":"406-412","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Enantiomeric Identification of Pregabalin by GC\u2010MS via Methylation and S\u2010TPC Chiral Derivatization"],"prefix":"10.1111","volume":"64","author":[{"given":"Michael L.","family":"Hitchcock","sequence":"first","affiliation":[{"name":"U.S. Postal Inspection Service National Forensic Laboratory 22433 Randolph Drive Dulles VA 20104"},{"name":"Department of Forensic Sciences George Washington University Washington DC 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