title: Liquid chromatography-tandem mass spectrometry of porphyrins and porphyrinogens in biological materials: separation and identification of interfering poly(ethylene) glycol by travelling wave ion mobility spectrometry/tandem mass spectrometry.
abstract: Biological and clinical samples for porphyrin and porphyrinogen analyses by liquid chromatography-tandem mass spectrometry (LC-MS/MS) are often contaminated with poly(ethylene)glycol (PEG), which complicates the interpretation of mass spectra and characterisation of new porphyrin metabolites. Two contaminating PEG molecules (m/z 833 and m/z 835) were completely separated from uroporphyrin I (m/z 831) by travelling wave ion mobility spectrometry and characterised by tandem mass spectrometry. One of the PEG species (m/z 835) also co-eluted with uroporphyrinogen I (m/z 837) and was unresolvable by travelling wave ion mobility spectrometry/MS, therefore contaminating the MS/MS mass spectra owing to isotope distribution. These PEG species, with the [M + H](+) ions at m/z at 833 and/or m/z 835, co-eluted with uroporphyrin I and uroporphyrinogen I by LC-MS/MS and could be wrongly identified as uroporphomethenes.
authors.affiliation: Clinical Biochemistry, King's College Hospital, Denmark Hill, London, SE5 9RS, UK; Cancer Studies and Molecular Medicine, RKCSB, University of Leicester, Leicester, LE2 7LX, UK.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Benton
authors.forename: Chang Kee
authors.initials: CK
authors.lastname: Lim
authors.forename: Caje
authors.initials: C
authors.lastname: Moniz
authors.forename: Donald J L
authors.initials: DJ
authors.lastname: Jones
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D008099:Liver / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011165:Porphyrinogens / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D011166:Porphyrins / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D051381:Rats; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D011165:Porphyrinogens; D011166:Porphyrins; D011092:Polyethylene Glycols
keywords: poly(ethylene) glycol; porphyrinogens; porphyrins; travelling wave ion mobility spectrometry/mass spectrometry; uroporphomethene