Gas chromatography for garlic - (Aug/17/2010 )
how to prepare extraction of garlic before undergoe GC?
is this correct?
Preparation of extracts:
Fresh garlic cloves were peeled, coarsely chopped with a knife and a 10 g sample homogenised for 2 min with 100 ml distilled water in a food blender (Kenwood). The homogenate was allowed to stand at room temperature for 15 min to ensure the complete enzymatic transformation of thiosulphinates before being filtered through 4 layers of cheesecloth.
A 50 ml sample of the filtrate was pipetted to a 500 ml conical flask and 15 g sodium chloride (NaCl) added to saturate the solution. After ensuring complete dissolution of the NaCl, 50 ml cold dichloromethane (CH2Cl2) was added and the stoppered flask agitated vigorously for 3 min. The resultant emulsion was centrifuged at 4000 rpm for 15 min, the lower solvent layer removed and dried twice with anhydrous sodium sulphate (Na2SO4).
A 10 ml sample of the dry extract was then pipetted to a 10 µl measuring cylinder. This was placed in a water bath at 25ºC ± 5ºC, and the extract was rapidly concentrated by bubbling dry nitrogen through it. The solvent was evaporated to < 1 ml final volume and then adjusted accurately to 1 ml with dichloromethane. The concentrated extract was taken up in a glass syringe and injected directly through a 0.2 µm in-line nylon filter into a 10 µm fixed sample loop.
Due to the instability of thiosulphinates in organic solvents all HPLC runs were undertaken within 45 min of extraction.
Looks ok to me, but then I've only done a couple of GC runs before.
bob1 on Wed Aug 18 20:58:55 2010 said:
Looks ok to me, but then I've only done a couple of GC runs before.
really?
actually, this preparation is for HPLC analysis, but is it possible to be used on GC?
If you take the vapour off the final extract, you might get the allicin you are after. I would try a chemistry forum rather than a biology one for this though.