title: Characterisation and quantification of liposome-type nanoparticles in a beverage matrix using hydrodynamic chromatography and MALDI-TOF mass spectrometry.
abstract: This paper describes the characterisation of liposome-type nanoparticles (NPs) dispersed in a beverage matrix. Characterisation is based on a two-step procedure: first, liposomes are separated on the basis of size in the nanometre range by use of hydrodynamic chromatography (HDC); second, chemical characterisation is performed by use of MALDI-TOF mass spectrometry (MS). Characterisation of three types of Coatsome liposome, a commercially available type of empty liposome, was investigated. All three liposome types, Coatsome A = anionic, N = neutral, and C = cationic, gave single peaks in HDC, reflecting diameters of 153, 187, and 205 nm, respectively. Subsequent MALDI-TOF MS in positive mode furnished major signals at m/z = 734.5 ([M + H](+) adduct) and m/z = 756.6 ([M + Na](+) adduct) of L-(α)-dipalmitoylphosphatidylcholine (DPPC) monomer and dimeric adducts at m/z = 1468.1 and m/z = 1490.1, respectively. MALDI-TOF MS in negative mode gave a signal at m/z = 721.3 ([M - H](-) adduct) of L-(α)-dipalmitoylphosphatidylglycerol (DPPG), except for Coatsome C which lacks this phospholipid. After HDC separation of Coatsome A NPs the major DPPC and DPPG signals can be detected in the expected fractions by use of MALDI-TOF MS in positive and negative modes, respectively. Validation of the analytical strategy revealed linearity (R(2) > 0.99), repeatability (relative standard deviation <10 %), and reproducibility (relative standard deviation between days <10 %) were good, recovery was 61 ± 5 %, and the limit of quantification was 1 mg mL(-1) in this matrix. With 4 mg Coatsome A mL(-1) 20 out of 20 samples furnished the 734.5 and 756.6 signals typical of DPPC in MALDI-TOF MS characterisation.
authors.affiliation: RIKILT Wageningen UR, Wageningen, The Netherlands. hans.helsper@wur.nl
authors.forename: Johannes P F G
authors.initials: JP
authors.lastname: Helsper
authors.forename: Ruud J B
authors.initials: RJ
authors.lastname: Peters
authors.forename: Lambertus
authors.initials: L
authors.lastname: Brouwer
authors.forename: Stefan
authors.initials: S
authors.lastname: Weigel
mesh_terms: D001628:Beverages / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D008081:Liposomes / Q000032:analysis; D053758:Nanoparticles / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D008081:Liposomes