Shuming Ke:
While our paper that the quote is from deals with TMAO and TMA, you might find some of the precautions concerning the volatility of TMA in organic solvents of interest. Depending on temperature the TMA diffuses from the solvent and care must be taken to minimize that.A stock picric acid/toluene solution was prepared by dissolving 2.9 grams picric acid (containing about 30% water; Warning: the picric acid must not be dried before use) in 100 mL toluene yielding a 2% picric acid solution. The clear yellow toluene phase was carefully decanted from the small aqueous phase, filtered through a Whatman No. 1 filter paper, and stored at room temperature in a brown bottle equipped with a Teflon lined cap. The stock toluene solution is stable for at least a year. A working solution was always prepared daily by diluting 1.0 mL of the stock solution with 100 mL toluene.
hi, I plan to use picrate method described by Dyer (j fish res bd can, 1945:351- 358) to determine TMA content in marine fish tissue. The basic concept is to react TMA extracted in toluene with 0.02% picric acid and measure absorbance at 410nm. In Dyer' method, dry picric acid is disolved in toluene to prepare 2% picric acid stock solution in toluene. Since dry picric acid is highly explosive and shock sensitive, this raises the question-- how to prepare picric acid solution in toluene? Do I just order dry (moisture free) picric acid solid and disolve in toluene? Any one has practical ideas on how to carry on the analysis? Many thanks.
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