By Anonymous on Friday, May 28, 2004 - 11:43 am:
THF stabilized with BHT as an extraction solvent could improve your stability. BHT is an antioxidant it self and could be consumed preferentially in the solution.
By Chris Allen on Thursday, May 27, 2004 - 04:17 am:
I have developed a combined method for the analysis of the antioxidants BHA and Propyl Gallate in pig feed samples, with 65/35 Meoh/THF as the extraction solvent the Propyl Gallate peak will occaisonaly degrade rapidly. Has anybody got any suggestions for improving the stability of the solution (e.g. a more sacrificial antixidant) or a suitable glassware cleaning procedure.
By Consumer Products Guy on Thursday, May 27, 2004 - 07:47 am:
Dissolve in DMF, make trimethylsilyl derivatives (to make stable), GC on non-polar capillary column.
By Anonymous on Thursday, May 27, 2004 - 07:55 am:
Chris,
I wonder if there might be some trace peroxides in your THF. These might degrade the anitoxidants pretty rapidly also. Can you get just as good extraction efficiency w/o the THF? MIght be worth an experiment or 2.
Regards,
Mark
By Chris Allen on Thursday, May 27, 2004 - 11:51 am:
I am currently using HPLC grade THF which has a maximum peroxide content of 0.05%, but there is the option of using AR grade which is stabilised and has a maximum of 0.001% peroxides. The degradation does not appear across a whole batch of extraction solvent some solutions will degrade within a couple of hours whilst others are stable overnight. Any suggestions on glassware or vial contamination?