Journal: Molecules

Article Title: Comparison of Strategies for the Determination of Sterol Sulfates via GC-MS Leading to a Novel Deconjugation-Derivatization Protocol

doi: 10.3390/molecules24132353

Figure Lengend Snippet: Strategies for sterol sulfate determination utilizing gas chromatography-mass spectrometry (GC-MS). “Two step” methods make use of a prior deconjugation step to form the free (unconjugated) sterol and a subsequent derivatization of the hydroxyl and, for methyloxime-trimethylsilyl (MO-TMS) derivatives, also the keto group. Direct derivatization refers to simultaneous cleavage of the sterol sulfate and derivatization. The deconjugation and derivatization strategies are shown with pregnenolone sulfate ( 6 ) here. TMS = derivatization to pregnenolone trimethylsilyl ether, MO-TMS = deconjugation/derivatization to pregnenolone methyloxime-trimethylsilyl ether, TFA = deconjugation/derivatization to pregnenolone trifluoroacetyl ester.

Article Snippet: Derivatization reagents trifluoroacetic anhydride (TFAA), 1-(trimethylsilyl)imidazole (TSIM), and N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA) were from Macherey-Nagel (Düren, Germany).

Techniques: Gas Chromatography, Mass Spectrometry, Gas Chromatography-Mass Spectrometry

Journal: Molecules

Article Title: Comparison of Strategies for the Determination of Sterol Sulfates via GC-MS Leading to a Novel Deconjugation-Derivatization Protocol

doi: 10.3390/molecules24132353

Figure Lengend Snippet: ( a ) Total ion chromatogram (TIC) of pregnenolone-TMS derivatives (containing cholestane (IS)). ( b ) Mass spectra of resulting pregenolone TMS ethers peaks (I)–(IV) after derivatization with N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA)/ N -trimethylsilylimidazole (TSIM) (9:1). ( c ) Structures of pregnenolone-mono-TMS ether (I) and pregnenolone-bis-TMS ethers (II–IV) ; for chromatographic and mass spectral characteristics see .

Article Snippet: Derivatization reagents trifluoroacetic anhydride (TFAA), 1-(trimethylsilyl)imidazole (TSIM), and N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA) were from Macherey-Nagel (Düren, Germany).

Techniques:

Journal: Molecules

Article Title: Comparison of Strategies for the Determination of Sterol Sulfates via GC-MS Leading to a Novel Deconjugation-Derivatization Protocol

doi: 10.3390/molecules24132353

Figure Lengend Snippet: ( a ) Bar chart with mean base peak areas and standard deviations (n = 6) of the sterol TFA esters obtained by treatment of sterol sulfates 1 – 8 with trifluoroacetic anhydride. ( b ) Total ion chromatogram (TIC) of the eight sterol TFA esters and the internal standard, derived from: 1 androsterone sulfate, 2 dehydroepiandrosterone sulfate, 3 epiandrosterone sulfate, 4 allopregnanolone sulfate, 5 pregnanolone sulfate, 6 pregnenolone sulfate, 7 cholesterol sulfate, 8 25-hydroxycholesterol sulfate, and 9 cholestane (IS). ( c ) Mass spectrum of pregnenolone TFA ester ([M] + m/z 412). ( d ) Mass spectrum of cholesterol TFA ester ([M] + m/z 482). For chromatographic and mass spectral characteristics see .

Article Snippet: Derivatization reagents trifluoroacetic anhydride (TFAA), 1-(trimethylsilyl)imidazole (TSIM), and N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA) were from Macherey-Nagel (Düren, Germany).

Techniques: Derivative Assay

Journal: Molecules

Article Title: Comparison of Strategies for the Determination of Sterol Sulfates via GC-MS Leading to a Novel Deconjugation-Derivatization Protocol

doi: 10.3390/molecules24132353

Figure Lengend Snippet: Determination of (keto-)sterol sulfates 1–8 as (MO-)TMS derivatives ( a ) with and ( b ) without previous sulfate solvolysis step (with 1% acetic acid in 1,4-dioxane). The indicated time refers to the duration of solvolysis prior to MO-TMS derivatization (for ”Solvolysis and derivatization”, ( a )) or to the incubation with O -methylhydroxylamine solution (for ”Simultaneous deconjugation/MO derivatization”, ( b )). The results obtained for each individual sterol sulfate under the different conditions are shown as relative peak areas [%] ± standard deviation (n = 6); the mean value of all steroids for every time point is shown in the background (grey), the best conditions for all tested sterol sulfates are marked as “Best condition”. The maximum recorded peak area for each sterol derivative within this experiment was set as 100%. Analyzed sterols: 1 androsterone sulfate, 2 dehydroepiandrosterone sulfate, 3 epiandrosterone sulfate, 4 allopregnanolone sulfate, 5 pregnanolone sulfate, 6 pregnenolone sulfate, 7 cholesterol sulfate, and 8 25-hydroxycholesterol sulfate.

Article Snippet: Derivatization reagents trifluoroacetic anhydride (TFAA), 1-(trimethylsilyl)imidazole (TSIM), and N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA) were from Macherey-Nagel (Düren, Germany).

Techniques: Incubation, Standard Deviation

Journal: Molecules

Article Title: Comparison of Strategies for the Determination of Sterol Sulfates via GC-MS Leading to a Novel Deconjugation-Derivatization Protocol

doi: 10.3390/molecules24132353

Figure Lengend Snippet: Overview of derivatization methods for analysis of sterol sulfates.

Article Snippet: Derivatization reagents trifluoroacetic anhydride (TFAA), 1-(trimethylsilyl)imidazole (TSIM), and N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA) were from Macherey-Nagel (Düren, Germany).

Techniques: