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.

Case Study – Characterization of Nanomaterials in Food Products

“…68 Although these methods do not provide detailed characteristics of the NMs, they may be useful in the routine detection of NMs in foods in the future. 69 …”

“…For example, HDC coupled to MALDI-TOF-MS has been applied for the size separation and chemical analysis of liposome-type NMs dispersed in a beverage matrix, 69 and LC coupled to electrospray ionization (ESI)-MS has been used to separate and identify proteins and peptides in complex samples. 23,70,71 Inorganic NMs in complex matrices were characterized in multiple studies by separation methods coupled to ICP-MS. For example, HDC-ICP-MS was used for detection of silica NMs in coffee creamer 10 as well as detection and size estimation of silver NMs in activated sludge.…”

Measurement Methods to Detect, Characterize, and Quantify Engineered Nanomaterials in Foods

“…However, for food samples that are low‐viscosity, homogeneous mixtures (a beverage or fluids in a gastric model system, for example), the test matrix may be able to be directly analyzed by chromatography, in which case the mild sample preparation conditions can preserve the ENM integrity during the analysis. This was the general strategy of a recent study by Helsper and others () who coupled MALDI‐TOF with hydrodynamic chromatography (HDC) to separate commercially purchased nanoscale liposomes from an orange‐flavored beverage based on hydrodynamic size. MALDI‐TOF has a wide molecular weight range for chemical analysis (300 to 300000 Da) and is useful for measuring lipids, proteins, and complex sugars.…”

Challenges in the determination of engineered nanomaterials in foods

“…However, they have demonstrated interesting prospects for the determination of organic NPs in food [58,60]. As an example, Fig.…”