Steven Schoenfeld

6 Questions 43 Answers 0 Followers

Questions related from Steven Schoenfeld

What is the best method for determining amino acids on HPLC C18 column DAD?

So I have a GC method with ethyl chloroformate that works for almost all amino acids except it doesn't do arginine, and serine and threonine smear badly due to the active hydroxyls. I tried OPA...

12 May 2022 9,372 4 View

Need a way to separate nucleotides from NaCl SPE?

I have been using capillary electrophoresis to quantitate I+G in flavors. The one problem I cannot seem to overcome is that I need my samples have less ionic strength than the CE running buffer or...

21 July 2021 1,716 4 View

What is causing Agilent G1600 EL 5207 CE pressure problem?

I am going crazy trying to figure out why I keep getting EL 5207 &5500 on my Agilent 1600 CE. I checked the buffer bottles they seem fine I get a pretty good pop when I undo the cap. The air...

01 March 2017 8,232 14 View

For NDA amino acids is there any substitute for cyanide?

I am interested in doing some of the amino acids on my CE that are troublesome or impossible using GC (arginine serine threonine). I am looking at the NDA protocol and the problem I see is the use...

14 July 2016 441 0 View

I anyone doing GC of amino acids using trifluoroacetylacetone and isobutyl or ethyl chloroformate?

http://www.omicsonline.org/open-access/gas-chromatographic-determination-of-amino-acids-and-polyamines-in-human-skin-samples-using-trifluoroacetylacetone-2157-7064.1000248.pdf I am attempting to...

12 August 2015 4,118 6 View

What is the best way to go about the capillary electrophoresis separation of very small peptides to get a size profile?

I am looking to get into CE (mainly because I don't have the budget for an HPLC). One of the things I am looking at doing is separating peptides by size. I have read about CGE mode but it seems...

18 March 2015 6,963 4 View