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MB Sample ID: SA021826
| Local Sample ID: | sample41 |
| Subject ID: | SU000455 |
| Subject Type: | Animal |
| Subject Species: | Homo sapiens |
| Taxonomy ID: | 9606 |
| Species Group: | Human |
Select appropriate tab below to view additional metadata details:
Combined analysis:
| Analysis ID | AN000684 |
|---|---|
| Analysis type | MS |
| Chromatography type | Reversed phase |
| Chromatography system | Cohesive TX2 liquid chromatography system |
| Column | Ascentis C18 (150 x 2.1mm,2.7um) |
| MS Type | ESI |
| MS instrument type | Triple quadrupole |
| MS instrument name | ABI Sciex API 5000 QQQ |
| Ion Mode | NEGATIVE |
| Units | micromolar |
Chromatography:
| Chromatography ID: | CH000496 |
| Chromatography Summary: | Concentration and isotopic enrichment of palmitic acid from extracted plasmas were simultaneously measured against an extracted concentration standard curve as well as an enrichment standard curve on the Applied Biosystem API5000 mass spectrometer-MS (Foster City, CA) coupled with a Cohesive TX2 liquid chromatography system-LC (Franklin, MA). This system provides two LCs connected in parallel to the mass spectrometer, allowing twice the number of samples to be analyzed by using tandem sample injection. The LCs were controlled by Aria software (Cohesive Technology). Palmitic and heptadecanoic acids were separated on the LCs using an Ascentis C18, 2.7 μm, 2.1 × 150 mm column using two buffers. Buffer A was 80% acetonitrile, 0.5 mM ammonium acetate; buffer B was 99% acetonitrile, 1% 0.5 mM ammonium acetate. The flow rate was 0.4 ml/min, and the gradient conditions were as follows: 0–8 min isocratic at 55% B, 8–8.5 min 55⇒95% B, 8.5–10 min isocratic at 95% B, 10–10.5 min 95⇒55% B, and 10.5–12 min isocratic at 55% B. One tenth of the volume of each concentration standard and each plasma sample were resuspended in 400 μl of buffer A prior to injecting 10 μl onto the LC/MS. The chromographic separation of linoleic acid, palmitic acid, oleic acid, eladic acid, and heptadecanoic acid (internal standard) are depicted in Fig. 1A. Although palmitic and oleic acid peaks overlap, they are distinguishable by MS, whereas eladic acid, which is indistinguishable from oleic acid by MS, is easily separated by chromatography. Fig. 1B depicts the M+2 peaks for palmitate and heptadecanoate and the M+16 peak for palmitate of a plasma sample from a volunteer receiving a [U-13C]palmitate infusion. Palmitate elutes at 6.2 min and heptadecanoate acid at 7.1 min; however, in Fig. 1B the retention times are shown as 1.2 and 2.9 min because of the 3 min delay set in the LC method before diverting the flow to the MS for acquisition. The MS was set to acquire for only 5 min, allowing MS data acquisition from the second LC to begin while the first LC finishes its 12 min gradient. The MS was equipped with a turbo ion spray interface with the heater set at 60°C, spray voltage at 5500 V, sheath gas at 50, sweep gas at 40, and transfer capillary at 270°C. Palmitate, [13C16]palmitate and heptadecanoate were selectively monitored at m/z 257, m/z 271 in negative mode. Palmitate was monitored as [M+2−H]− and [M+16−H]−. Heptadecanoic was also monitor as [M+2−H]− . Therefore m/z 271 was either [13C16]palmitate or heptadecanoate, depending on where it eluted in the LC gradient. |
| Instrument Name: | Cohesive TX2 liquid chromatography system |
| Column Name: | Ascentis C18 (150 x 2.1mm,2.7um) |
| Flow Gradient: | 0–8 min isocratic at 55% B, 8–8.5 min 55⇒95% B, 8.5–10 min isocratic at 95% B, 10–10.5 min 95⇒55% B, and 10.5–12 min isocratic at 55% B. |
| Flow Rate: | 0.4 ml/min |
| Solvent A: | 80% acetonitrile/20% water; 0.5 mM ammonium acetate |
| Solvent B: | 99% acetonitrile/1% water; 0.5 mM ammonium acetate |
| Chromatography Type: | Reversed phase |
