4 replies to this topic

[ikwana]

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.

[bob1]

Looks ok to me, but then I've only done a couple of GC runs before.

[ikwana]

bob1, on 18 August 2010 - 12:58 PM, 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?

[bob1]

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.

[nightingale]

check ur PM