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MB Sample ID: SA254842
| Local Sample ID: | S_94 |
| Subject ID: | SU002633 |
| Subject Type: | Human |
| Subject Species: | Homo sapiens |
| Taxonomy ID: | 9606 |
| Gender: | Female |
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Sample Preparation:
| Sampleprep ID: | SP002639 |
| Sampleprep Summary: | Samples were stored at -80 °C in the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) repository before being shipped (on dry ice) to Nutrition Research Institute, UNC-CH, for metabolomics analysis. Serum samples were thawed at 4 °C overnight. Samples were vortexed via a multiple-tube vortex mixer for 2 min at 5000 rpm and then sat on ice for 10 min before sample preparation. Quality control samples (QC pools) were made by pooling 7-µL serum from each parent sample (if sufficient volume is available). An aliquot of the sample (50-µL), including the study sample and QC pool, was transferred into a new pre-labeled tube and mixed with 400-µL methanol containing 500 ng/ml L-tryptophan-d5, vortexed at 5,000 rpm for 2 min, for protein precipitation. All samples were centrifuged at 16, 000 rcf for 10 min at 4°C. The supernatant (350-uL) was dried by a SpeedVac overnight. The dried extracts were reconstituted with 100 µl water-methanol (95:5, v/v) by thoroughly mixing on multiple tube vortex mixer for 10 min at 5000 rpm and centrifuging at 4°C for 10 min at 16,000 rcf. The supernatant (about 100 µL) was transferred to pre-labeled autosampler vials for data acquisition by LC-MS. |
| Processing Storage Conditions: | On ice |
| Extraction Method: | Vortex with methanol containing 500ng/ml tryptophan-d5 as internal standard |
| Extract Storage: | -80℃ |
| Sample Resuspension: | Water-Methanol (95:5, v/v) |
| Sample Spiking: | Tryptophan-d5 stock solution at 500 ng/mL |
