title: Fast screening of terpenes in fragrance-free cosmetics by fluorescence quenching on a fluorescein-bovine serum albumin probe confined in a drop.
abstract: A headspace single drop microextraction procedure is proposed for terpene screening in fragrance-free cosmetics. The drop is composed by an aqueous solution of a fluorescence probe formed by bovine serum albumin and fluorescein. Extracted volatile terpenes produce a fluorescence quenching that can be monitored by microvolume-fluorospectrometry. This quenching is observed on the fluorescein fluorescence only when it is linked to bovine serum albumin. A mechanism of contact quenching is proposed. Variables related to the terpene microextraction procedure were carefully studied, namely drop composition and volume, microextraction time, sample volume and temperature, stirring rate and salt addition. The only sample treatment is the dilution of cosmetic with 40% (v/v) ethanol. Citronellol was selected as a representative terpene for calibration purposes. According to the European legislation, the probability-concentration graph of the screening system was established using 0.001% (w/w) as the cut-off level. Low limits of detection with simple instrumentation, absence of matrix effects and high sample throughput can be emphasized.
authors.affiliation: Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Cabaleiro
authors.forename: Inmaculada
authors.initials: I
authors.lastname: de la Calle
authors.forename: Carlos
authors.initials: C
authors.lastname: Bendicho
authors.forename: Isela
authors.initials: I
authors.lastname: Lavilla
mesh_terms: D000818:Animals; D002417:Cattle; D003358:Cosmetics / Q000737:chemistry*; D019793:Fluorescein / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D057230:Limit of Detection; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000191:economics / Q000379:methods*; D013729:Terpenes / Q000032:analysis*
chemical_list: D003358:Cosmetics; D005456:Fluorescent Dyes; D013729:Terpenes; D012710:Serum Albumin, Bovine; D019793:Fluorescein