title: A new screening method for flunitrazepam in vodka and tequila by fluorescence spectroscopy.
abstract: A new screening method for flunitrazepam in colourless alcoholic beverages based on a spectroscopic technique is proposed. Absorption and steady-state fluorescence of flunitrazepam and its protonated form with various acids were investigated. The redshift of the wavelength of maximum absorption was distinctively observed in protonated flunitrazepam. An emissive fluorescence at 472 nm was detected in colourless spirits (vodka and tequila) at room temperature. 2-M perchloric acid was the most appropriated proton source. By using electron ionization mass spectrometry and time-dependent density functional theory calculations, the possible structure of protonated flunitrazepam was identified to be 2-nitro-N-methylacridone, an acridone derivative as opposed to 2-methylamino-5-nitro-2'-fluorobenzophenone, a benzophenone derivative.
authors.affiliation: Department of Chemistry and Center for Innovation in Chemisty, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. nararak.le@psu.ac.th
authors.forename: Nararak
authors.initials: N
authors.lastname: Leesakul
authors.forename: Sirintip
authors.initials: S
authors.lastname: Pongampai
authors.forename: Proespichaya
authors.initials: P
authors.lastname: Kanatharana
authors.forename: Pravit
authors.initials: P
authors.lastname: Sudkeaw
authors.forename: Yuthana
authors.initials: Y
authors.lastname: Tantirungrotechai
authors.forename: Chittanon
authors.initials: C
authors.lastname: Buranachai
mesh_terms: D000434:Alcoholic Beverages / Q000032:analysis*; D005445:Flunitrazepam / Q000032:analysis*; D006993:Hypnotics and Sedatives / Q000032:analysis*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D006993:Hypnotics and Sedatives; D005445:Flunitrazepam