Table 1.
Methodology details for mass-spectrometry-based analysis
| Laboratory | Sample vol. | Sample enrichment |
|---|---|---|
| 2 (HPLC-MS/MS) | 500 μl (0.5 μl injected) | SPE with Isolute® Env + SPE (Kinesis, St. Neots, UK); eluate evaporated under vacuum and reconstituted in 50 μl mobile phase |
| 4 (HPLC-MS/MS) | 50 μl (5 μl injected) | None |
| 4 (LC-GC/MS) | 750 μl (500 μl injected) | LC-prepurification followed by freeze-drying of collected fractions, hydrolysis in 60% formic acid, and derivatization with BSTFA |
| 9 (UPLC-MS/MS) | 40 μl | Sample diluted with 0.1 M LiAc, pH 6.4 (40:60, v/v) |
| 11 (HPLC-MS/MS) | 120 μl (20 μl injected) | Online SPE with ODS-3 column, 5 μm, 4.6 × 33 mm (Inertsil; GL Sciences Inc., Tokyo, Japan) |
| 14 (GC-MS) | 800 μl | Sample diluted 1:10 with formic acid buffer (10% pH 2.75), SPE Oasis HLB columns (Waters); freeze-dried extract derivatized with BSTFA +1% TMCS |
| 15 (HPLC-MS/MS) | 20 μl | Online SPE with ODS-3 C18 column, 5 μm, 4.6 × 50 mm (Inertsil) |
| 16 (HPLC-MS/MS) | 100 μl (10 μl injected) | None |
| 18 (HPLC-MS/MS) | 50 μl (10 μl injected) | SPE (Oasis HLB) |
All techniques LC-MS/MS, unless indicated otherwise. Literature references for methodology are provided, where available. NH4Ac, ammonium acetate; SPE, solid phase extraction.