A rapid separation technique for overcoming suppression of triacylglycerols by phosphatidylcholine using MALDI-TOF MS

Emerson, Beth; Gidden, Jennifer; Lay, Jackson O.; Durham, Bill

doi:10.1194/jlr.d003798

Cited by 36 publications

(36 citation statements)

References 29 publications

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“…Extraction using hexanes instead of chloroform/methanol provides a cleaner nonpolar extraction ( 10,24,25 ). We observed that hexane extraction reduced the level of chlorophyll present and that the hexane extraction could be directly loaded onto the SPE column without the need to remove and reconstitute the sample.…”

Section: Lipid Extractionmentioning

confidence: 84%

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Triacylglycerol profiling of marine microalgae by mass spectrometry

Danielewicz

Anderson

Franz

2011

Journal of Lipid Research

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ingly important. The methods and pursuit of algae-based fuels also have applications for bioactive lipids and highvalue, lipid-based chemical precursors ( 4,5 ), including polyunsaturated fatty acids (PUFA), carotenes, antioxidants, vitamins, and pigments, which have applications in the pharmaceutical, nutraceutical, and food industries. In all such applications, the methods of analysis, access to desired composition, total yield, and effi ciency with which lipids can be converted to usable products will be the ultimate determinants of industrial success.Previous analysis of algae lipid composition using GC/MS and MALDI-TOF mass spectrometry (MS) has shown a broad variety of lipid classes: glycerolipids, such as monogalactosyl-diacylglycerol (MGDG) and digalactosyl-diacylglycerol (DGDG); phospholipids, such as phosphatidylcholine (PC); and neutral lipids (triacylglycerols) ( 6-9 ). Many reports have focused on the analysis of polar lipids, but TAG analysis and composition have become increasingly important for biofuel applications. TAG analysis of mixed samples remains a challenge because of its lower ionization efficiency relative to polar lipids (such as phospholipids) ( 10 ). Analysis of neutral lipids in microalgae often relies on lipophilic fl uorescence and colorimetric assays ( 11, 12 ); however, these assays do not provide compositional TAG characterization. Compositional analysis of microalgal TAG primarily involves the initial separation of extracts using either liquid chromatography or thin-layer chromatography followed by MS analysis or derivatization of extracts, such as transesterifi cation, followed by analysis of fatty acid methyl esters (FAME) by GC/MS ( 13-15 ). The direct analysis of algal triacylglycerol using pyrolysis GC/MS has been reported as a promising alternative, but the purchase of specialty equipment and use of higher temperature ranges may limit the broad utility of this method ( 16,17 ).Herein, we describe the compositional analysis of intact triacylglycerol of oleaginous marine algae using MALDI-TOF MS. MALDI-TOF provides a direct method Abstract We present a method for the determination of triacylglycerol (TAG) profi les of oleaginous saltwater microalgae relevant for the production of biofuels, bioactive lipids, and high-value lipid-based chemical precursors. We describe a technique to remove chlorophyll using quick, simple solid phase extraction (SPE) and directly compare the intact TAG composition of four microalgae species ( Phaeodactylum tricornutum , Nannochloropsis salina , Nannochloropsis oculata , and Microalgae have been identifi ed as an attractive source for the production of biofuels in addition to bioactive lipids and high-value, lipid-based chemical precursors based on their ability to produce 20% or more of their mass as oil. Due to the conversion of triacylglycerols (TAG) to fatty acid alkyl esters for use as biodiesel ( 1, 2 ), current research has focused on TAG production and analysis to make biofuels from microalgae a more economically feasible option ( 3 )....

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Section: Lipid Extractionmentioning

confidence: 84%

“…2A ] + H + ) was seen at lower intensity at m/z 893.5. Phosphatidylcholine (PC), which ionizes well and is known to suppress more nonpolar lipid signals, was also observed ( 10 ).…”

Section: Lipid Extractionmentioning

confidence: 99%

Triacylglycerol profiling of marine microalgae by mass spectrometry

Danielewicz

Anderson

Franz

2011

Journal of Lipid Research

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“…Analysis of PC and TAG (and other lipid classes) together by MS is known to be difficult due to ion suppression phenomena (Emerson et al, 2010). Ion suppression makes quantitative conclusions tenable without the addition of internal standards, as is routine in directinfusion lipidomic analyses.…”

Section: Discussionmentioning

confidence: 99%

“…Cross and longitudinal sections were prepared from representative areas of mature cotton embryos (Figure 1), and a raster step size of 50 mm with a laser spot size of ;35 mm was used to sample each section, a resolution about the size of mature cotyledon cells (Chapman et al, 2008). MALDI-MSI profiles ( Figure 1D) showed multiple adducts for lipid species (primarily H + , Na + , and K + ), some substantial ion suppression of TAGs by PC (Emerson et al, 2010), and evidence of diacylglycerol fragments produced by laser-induced compound fragmentation of PC and TAG (Gidden et al, 2007). The molecular species within each lipid class were identified using predefined databases from conventional electrospray ionization-MS (ESI-MS) profiles as well as accurate mass-tocharge ratio (m/z) searches for unique or less prevalent compounds and summed to show distributions for the total classes.…”

Section: General Distribution Of Selected Lipid Classes In Cotton Embmentioning

confidence: 99%

Spatial Mapping of Lipids at Cellular Resolution in Embryos of Cotton

et al. 2012

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Advances in mass spectrometry (MS) have made comprehensive lipidomics analysis of complex tissues relatively commonplace. These compositional analyses, although able to resolve hundreds of molecular species of lipids in single extracts, lose the original cellular context from which these lipids are derived. Recently, high-resolution MS of individual lipid droplets from seed tissues indicated organelle-to-organelle variation in lipid composition, suggesting that heterogeneity of lipid distributions at the cellular level may be prevalent. Here, we employed matrix-assisted laser desorption/ ionization-MS imaging (MALDI-MSI) approaches to visualize lipid species directly in seed tissues of upland cotton (Gossypium hirsutum). MS imaging of cryosections of mature cotton embryos revealed a distinct, heterogeneous distribution of molecular species of triacylglycerols and phosphatidylcholines, the major storage and membrane lipid classes in cotton embryos. Other lipids were imaged, including phosphatidylethanolamines, phosphatidic acids, sterols, and gossypol, indicating the broad range of metabolites and applications for this chemical visualization approach. We conclude that comprehensive lipidomics images generated by MALDI-MSI report accurate, relative amounts of lipid species in plant tissues and reveal previously unseen differences in spatial distributions providing for a new level of understanding in cellular biochemistry.

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“…For example, DHB is most commonly used for the analysis of TAG, but the ion suppression of TAG by PC is well-known. 45 …”

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confidence: 99%

Large Scale Nanoparticle Screening for Small Molecule Analysis in Laser Desorption Ionization Mass Spectrometry

et al. 2016

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Nanoparticles (NPs) have been suggested as efficient matrixes for small molecule profiling and imaging by laser-desorption ionization mass spectrometry (LDI-MS), but so far there has been no systematic study comparing different NPs in the analysis of various classes of small molecules. Here, we present a large scale screening of 13 NPs for the analysis of two dozen small metabolite molecules. Many NPs showed much higher LDI efficiency than organic matrixes in positive mode and some NPs showed comparable efficiencies for selected analytes in negative mode. Our results suggest that a thermally driven desorption process is a key factor for metal oxide NPs, but chemical interactions are also very important, especially for other NPs. The screening results provide a useful guideline for the selection of NPs in the LDI-MS analysis of small molecules.

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A rapid separation technique for overcoming suppression of triacylglycerols by phosphatidylcholine using MALDI-TOF MS

Cited by 36 publications

References 29 publications

Triacylglycerol profiling of marine microalgae by mass spectrometry

Triacylglycerol profiling of marine microalgae by mass spectrometry

Spatial Mapping of Lipids at Cellular Resolution in Embryos of Cotton

Large Scale Nanoparticle Screening for Small Molecule Analysis in Laser Desorption Ionization Mass Spectrometry

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