Gas chromatography for garlic
Posted 17 August 2010 - 07:59 PM
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.
Posted 18 August 2010 - 12:58 PM
Posted 18 August 2010 - 10:03 PM
actually, this preparation is for HPLC analysis, but is it possible to be used on GC?
Posted 19 August 2010 - 12:50 PM
Posted 19 August 2010 - 03:01 PM