title: Elimination of isobaric interference and signal-to-noise ratio enhancement using on-line mobile phase filtration in liquid chromatography/tandem mass spectrometry.
abstract: BACKGROUND
  Liquid chromatography/tandem mass spectrometry (LC/MS/MS) instruments are selective and sensitive but can still be affected by isobaric interference or chemical noise arising from multiple sources such as the mobile phase. In this study, a high-performance liquid chromatography (HPLC) on-line mobile phase filtration setup is described and used to remove interference to allow better detection of the analyte of interest.
  
  
  METHODS
  For instance, a filtration device containing a chemical sorbent is installed at the HPLC outlet of the aqueous solvent pump A or the organic solvent pump B. This manuscript reports different case scenarios under reversed-phase and HILIC separations either in positive (ESI(+)) or negative electrospray ionization (ESI(-)) mode using selected reaction monitoring (SRM) scans as well as additional Q1 MS scans.
  
  
  RESULTS
  The filtration of the aqueous effluent of the mobile phase using a porous graphitic carbon filter eliminated the isobaric interferences and improved the detectability of gestodene and perindopril-D4. Also, a strong cation-exchange guard column installed at the acetonitrile outlet pump was found helpful on reducing the baseline intensity and improving significantly the signal-to-noise ratio (S/N) of methenamine. Moreover, the on-line mobile phase filtration was efficient at removing chemical background ions in full scan mode.
  
  
  CONCLUSIONS
  This strategy demonstrated its usefulness by removing co-eluting isobaric interference, and reducing chemical background ions from the mobile phase, while drastically improving S/N.
authors.affiliation: Algorithme Pharma Inc., 575 Armand-Frappier, Laval, Quebec, Canada, H7V 4B3.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lahaie
authors.forename: Nikolay
authors.initials: N
authors.lastname: Youhnovski
authors.forename: Milton
authors.initials: M
authors.lastname: Furtado
authors.forename: Fabio
authors.initials: F
authors.lastname: Garofolo
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D008709:Methenamine; D008956:Models, Chemical; D009652:Norpregnenes; D020913:Perindopril; D059629:Signal-To-Noise Ratio; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D009652:Norpregnenes; C033273:Gestodene; D008709:Methenamine; D020913:Perindopril