Matthew David Wolhowe

4 Questions 8 Answers 0 Followers

Questions related from Matthew David Wolhowe

Reason for loss of sterol esters during GC analysis?

I've got an intractable issue with loss (apparently) of sterol acetates (cholesterol acetate, stigmasterol acetate, etc) when trying to quantify them via GC-FID. I routinely get 60-70% of what I...

23 December 2019 6,202 7 View

Why are TEA/DMAP/n-methylimidazole turning yellow or red in acetic anhydride?

I've been running acetylation reactions with acetic anhydride using pyridine as the base with with either DMAP or n-methylimidazole as catalysts (or acetic anhydride and TEA with no catalyst). The...

15 August 2019 3,286 3 View

How am I losing sterols during acetylation?

I'm working with trace amounts (say, 1 microgram) of sterols such as dinosterol, stigmasterol, and cholesterol, and have been trying to acetylate with acetic anhydride and pyradine. This is a...

14 August 2019 7,033 2 View

What is the best work-up for acetic anhydride/pyradine acetylation?

I'm working with trace amounts (say, 1 microgram) of sterols, and trying to acetylate with acetic anhydride and pyradine. What we've typically done is at 70C for half an hour with 20 ul of acetic...

31 July 2019 5,077 13 View