My processed fish extract samples is evaporated to dryness and a residue is obtained which is not getting dissolved in MSTFA+TMCS silylating reagent. I am worried if the problem is in the final evaporation procedure or should I use pyridine as solvent before adding MSTFA+TMCS? Can anyone suggest me ideas to sort this out?
Hello Indumathi,
What are the compounds you would like to separate and analyze? Probably you need to use a solvent (as you said, pyridine), or use more time/temperature using the derivatization reagents to get the expected results.
Regards.
I need to derivatize tetrodotoxin and analyse it through GC-MS mam. The residue which I obtained finally from the processed fish tissue extract is not getting dissolved in the silylating reagent. Please so suggest me some idea.
I´ve just read a paper saying that " To the resulting residue, a mixture of N , O-bis acetamide, trimethylchlorosilane and pyridine (2: 1: 1) is added to
generate trimethylsilyl (TMS) ‘‘C9-base’’ compounds " (APPLIED AND ENVIRONMENTAL MICROBIOLOGY , Sept. 1995, p. 3468–3470).
So, probably you can try to add pyridine (1 part, i.e. 100 uL) to dissolve the sample (try to mix and stir the vial very well!), and then N , O-bis acetamide (2 parts, i.e. 200 uL) and trimethylchlorosilane (1 part, 100 uL). But first of all, you should observe that pyridine gets to dissolve the sample...
Let me know if you succeed!
Regards.
Thank you so much mam. Let me try it out and get back to you.
Thanks and regards
Indumathi
If your dried extract residue doesn't dissolve in the derivatization solution, the derivatization will likely not proceed much if at all. If pyridine doesn't work, you could try ethyl acetate. Your compound looks to have basic/acidic functionalities. Have you thought about adjusting the pH to neutralize the analyte to facilitate their dissolution in the solvent?
Just add MeOX-Pyridine (Methoxylamine HCl - 20mg/ml dissolved in pyridine..freshly prepared) to the dried extract and incubate the mixture at 37 oC on a thermomixer for 30 mins or 1 hour (If you use heat block, intermittent shaking should do). Followed by this add MSTFA+TMCS and incubate at 37oC for 60 mins. Spin down (in case there is still some undissolved extract) and transfer the supernatant to GC-MS vials. Run GC-MS. Good Luck
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