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MB Sample ID: SA016154
Local Sample ID: | 21999U |
Subject ID: | SU000383 |
Subject Type: | Animal |
Subject Species: | Homo sapiens |
Taxonomy ID: | 9606 |
Species Group: | Human |
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Sample Preparation:
Sampleprep ID: | SP000390 |
Sampleprep Summary: | Sphingomyelins, dihydrosphingomyelins, ceramides and dihydroceramides: A modified Bligh-Dyer extraction method was used in the presence of internal standards (IS). Sample analysis was performed in four batches using a Shimadzu 10A HPLC system coupled to a TSQ Quantum Ultra triple quadrupole mass spectrometer operated in SRM mode under ESI(+). A Thermo Betasil C18 column was employed to achieve the optimal sensitivity and separation. Data processing was conducted with Xcalibur software (Thermo) to obtain the peak area ratios of analytes to the corresponding internal standards (Supplemental Table 2). A pooled lipid extract from study samples was used as a quality control (QC) sample, and was injected between every 6 study samples to verify the instrument consistency. The peak area ratios were then normalized to the average of QC peak area ratios in the same batch, so that the results for different batches were brought to the same baseline. Sphingoid bases, ceramide-1-phosphate, monohexosylsphingosine, monohexosylceramides, dihexosylceramides, trihexosylceramides, monohydroxylated monohexosylceramides, monohydroxylated dihexosylceramides, sulfatides, and gangliosides: Plasma protein was precipitated with methanol, followed by supernatant collection, drying, and reconstituting with 1:1 methanol/water in the presence of internal standards. Duplicate sample analysis (1 st analysis and 2 nd analysis) was performed in four batches with an online trapping API-4000 system, (consists of a API-4000 mass spectrometer, a Leap PAL autosampler, an Agilent 1100 HPLC, and a Shimadzu HPLC) operated in multiple reaction monitoring (MRM) mode under ESI(+) for all species except sulfatides and E2gangliosides ESI(-). An Agilent Eclipse XRB-C18 column was used for sphingoid bases and ceramide-1- phosphate and a Varian Metasil C18 column was used for analysis of monohexosylsphingosine, mono-, di-, tri- hexosylceramides as well as their monohydroxylated ceramides. An Agilent Zobax Eclipse Plus C18 column was used for analysis of sulfatides and gangliosides. A Thermo Betasil C18 trapping column was also used for all analytes. Data processing was conducted with Analyst software (Applied Sciences) to obtain the peak area ratios of analytes to the corresponding internal standards. A pooled lipid extract from study samples was used as a quality control (QC) sample, and was injected between every 10 study samples to verify the instrumental consistency. All duplicated sample runs were averaged. The values for each sphingolipid were peak area ratios that were normalized to internal standard and then normalized to QC standards. Values were relative peak area ratios and unitless. |