| Mass Spectra Information for Method: m[1] |
| method name |
M[1] (EITTMS) |
| sampling |
shock freezing in liquid nitrogen |
| extraction |
hot (70°C) methanol/water/chloroform (approx. 4:1:2; v/v/v) |
| fractionation |
polar metabolites
liquid partitioning into methanol/water (approx. 1:1; v/v), and chloroform (chloroform phase is discarded) |
| derivatization |
=N-O-CH3 (methoxyamine hydrochloride/ pyridine reagent, 20 mg / ml) - Si(CH3)3 (N-methyl-N-(trimethylsilyl)-trifluoroacetamide, MSTFA reagent) |
| ri system |
n-dodecane (RI 1200)
n-pentadecane (RI 1500)
n-nonadecane (RI 1900)
n-docosane (RI 2200)
n-octacosane (RI 2800)
n-dotriacontane (RI 3200)
n-hexatriacontane (RI 3600) |
| gas chromatograph |
GC 6890 (Agilent Technologies, Palo Alto, CA, USA) |
| injection |
1 µl splitless, 230°C, 2 min pulse at 110 psi |
| column |
Rtx-5Sil MS, 30 m x 0.25 mm ID with 10 m integrated guard column, 0.25 µm film thickness (Restek GmbH, Bad Homburg, Germany) |
| temperature program |
2 min at 80 °C, 15 min ramp to 350 °C, 2 min at 350 °C |
| carrier gas |
Helium, 1 ml min-1, operated by electronic pressure control |
| mass spectrometer |
Pegasus II TOF-MS system (Leco, St. Joseph, MI, USA), transfer line 250°C, ion source 200°C |
| ionization |
electron impact |
| scanning |
6 spectra s-1 (m/z = 70-600) |
| deconvolution |
AMDIS (Automated Mass Spectral Deconvolution and Identification System, National Institute of Standards and Technology, Gaithersburg, MD, USA) |
| settings |
adjacent peak subtraction (2), resolution (medium), sensitivity (high), shape requirements (high) |
| remarks |
Pure reference substances are processed without extraction and fractionation |
| method variants |
-Omission of fractionation for the analysis of a mixed polar and lipophilic fraction
-Omission of methoxyamination |
