title: Using thermal desorption electrospray ionization mass spectrometry to rapidly determine antimicrobial preservatives in cosmetics.
abstract: BACKGROUND
  Characterization and quantification of permitted preservatives are important inspections to prevent the overuse of preservatives in authentic formulations. However, the complexity of sample matrices makes preservative determination in cosmetics a tedious process. A rapid analytical strategy to identify preservatives would insure large numbers of products are in compliance with government regulations.
  
  
  METHODS
  Thermal desorption electrospray ionization mass spectrometry (TD-ESI-MS) was used to directly detect preservative compounds in authentic formulations without sample pretreatment. The technique employs a metal probe, which was configured for sampling cosmetics in their original states and was inserted in a closed preheated oven to thermally desorb analytes. The desorbed analytes were then carried by a nitrogen gas stream into an ESI plume, where the formed ions were subsequently detected by the mass analyzer.
  
  
  RESULTS
  The TD-ESI mass and tandem mass spectra of different classes of preservative standards were rapidly obtained, and the limits of detection were far below the legal limit of their respective concentrations. The preservatives were also directly detected in different types of authentic formulations in the absence of sample preparation, and within a few seconds per sample. Calibration curves for preservatives in four common formulations yielded good linearity in the regulation-allowed range.
  
  
  CONCLUSIONS
  Due to its sensitivity, short analysis time, repeatability, and quantitative ability, TD-ESI-MS may serve as a suitable tool for large-scale screening of cosmetic preservatives to assure product safety. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Cosmetic Applications and Management, Yuh-Ing Junior College of Health Care & Management, Kaohsiung, Taiwan. ytcho@ms.yuhing.edu.tw.
authors.forename: Yi-Tzu
authors.initials: YT
authors.lastname: Cho
authors.affiliation: Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Hung
authors.initials: H
authors.lastname: Su
authors.affiliation: Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Shiang-Jiun
authors.initials: SJ
authors.lastname: Lin
authors.affiliation: Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Ban-Hsin
authors.initials: BH
authors.lastname: Wu
authors.affiliation: Department of Cosmetic Applications and Management, Yuh-Ing Junior College of Health Care & Management, Kaohsiung, Taiwan.
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Lai
authors.affiliation: Department of Cosmetic Applications and Management, Yuh-Ing Junior College of Health Care & Management, Kaohsiung, Taiwan.
authors.forename: I-Ching
authors.initials: IC
authors.lastname: Huang