The scientific field of lipidomics has shown a constantly growing publication number in recent years, which is accompanied by an increasing need for quality standards. While the official shorthand nomenclature of lipids is a first and important step toward a reporting quality tool, an additional point score would reflect the quality of reported data at an even more detailed granularity. Thus, we propose a lipidomics scoring scheme that considers all the different layers of analytical information to be obtained by mass spectrometry, chromatography, and ion mobility spectrometry and awards scoring points for each of them. Furthermore, the scoring scheme is integrated with the annotation levels as proposed by the official shorthand nomenclature, with a point score, which roughly correlates with the annotated compound details. The merit of such a scoring system is the fact that it abstracts evidence for structural information into a number, which gives even the nonlipidomics expert an idea about the reporting, and by extension, data quality at first glance. Additionally, it could serve as an aid for internal quality control and for data quality assessment in the peer review process.

• Keywords
• chromatography, glycerophospholipids, lipidomics, lipids, mass spectrometry, sphingolipids, sterols,
• Publication type
• Journal Article MeSH
• Review MeSH

Reversed-phase ultrahigh-performance liquid chromatography-mass spectrometry (RP-UHPLC/MS) method was developed with the aim to unambiguously identify a large number of lipid species from multiple lipid classes in human plasma. The optimized RP-UHPLC/MS method employed the C18 column with sub-2-μm particles with the total run time of 25 min. The chromatographic resolution was investigated with 42 standards from 18 lipid classes. The UHPLC system was coupled to high-resolution quadrupole-time-of-flight (QTOF) mass analyzer using electrospray ionization (ESI) measuring full-scan and tandem mass spectra (MS/MS) in positive- and negative-ion modes with high mass accuracy. Our identification approach was based on m/z values measured with mass accuracy within 5 ppm tolerance in the full-scan mode, characteristic fragment ions in MS/MS, and regularity in chromatographic retention dependences for individual lipid species, which provides the highest level of confidence for reported identifications of lipid species including regioisomeric and other isobaric forms. The graphs of dependences of retention times on the carbon number or on the number of double bond(s) in fatty acyl chains were constructed to support the identification of lipid species in homologous lipid series. Our list of identified lipid species is also compared with previous publications investigating human blood samples by various MS-based approaches. In total, we have reported more than 500 lipid species representing 26 polar and nonpolar lipid classes detected in NIST Standard reference material 1950 human plasma.

• Keywords
• Human plasma, Lipidomics, Lipids, Mass spectrometry, Retention behavior, Reversed-phase, Ultrahigh-performance liquid chromatography,
• MeSH
• Chromatography, Liquid methods   MeSH
• Mass Spectrometry methods   MeSH
• Humans MeSH
• Lipids blood   chemistry   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Lipids MeSH

Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-MS/APCI) with reversed- and chiral phases was used for separation of triacylglycerols (TAG) from protozoan and mold. This study describes the separation and identification of odd numbered chains of regioisomers and enantiomers of triacylglycerols from different natural sources, i.e., the protozoan Khawkinea quartana and the mold Mortierella alpina. Using the above-mentioned separation methods and the synthesis of appropriate standards of TAG, we identified regioisomers and enantiomers of both even and odd numbered TAG. The biosynthesis of odd numbered TAG was found to be strictly stereospecific and to depend on the production microorganism, one enantiomer predominating in the protozoan and the other in the mold. It was proved that even numbered TAG are synthesized in a higher optical purity, which can be explained by a higher affinity of acyltransferases to the respective substrate, i.e., to even chain PUFA.

• MeSH
• Euglena chemistry   MeSH
• Mass Spectrometry methods   MeSH
• Mortierella chemistry   MeSH
• Triglycerides chemistry   isolation & purification   MeSH
• Chromatography, High Pressure Liquid methods   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Triglycerides MeSH

Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-MS/APCI) with a chiral phase was used for separation of triacylglycerols (TAG) obtained either by organic synthesis or isolated from different algal species. We present chromatographic characteristics and tandem mass spectra of enantiomers and positional isomers (regioisomers) of C16, C18 and C20 polyunsaturated fatty acids. The retention time was found to depend on the structure of the given TAG, increasing with increasing number of double bonds and decreasing with increasing number of the carbons in TAG, with the exception of dieicosapentaenoyl-palmitoyl-glycerols.

• MeSH
• Chlorophyta chemistry   MeSH
• Mass Spectrometry methods   MeSH
• Molecular Structure MeSH
• Fatty Acids, Unsaturated analysis   chemistry   isolation & purification   MeSH
• Stereoisomerism MeSH
• Tandem Mass Spectrometry methods   MeSH
• Triglycerides analysis   chemistry   MeSH
• Chromatography, High Pressure Liquid methods   standards   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Fatty Acids, Unsaturated MeSH
• Triglycerides MeSH