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ABSTRACT. The gas chromatographic method for determination of fatty acid used in VCO has been developed. Prior to GC analysis, esterification was needed by adding 1.5 ml of Na-Metanolat and then flowed by N 2 and heating at 90ºC for 5 minutes in waterbath;
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ABSTRACT The gas chromatographic method for determination of fatty acid used in VCO has been developed. Prior to GC analysis, esterification was needed by adding 1.5 ml of Na-Metanolat and then flowed by N2 and heating at 90ºC for 5 minutes in waterbath; adding 2 ml of BF3 and then flowed by N2 and heating at 90ºC for 30 minutes in waterbath; adding 4ml of hexan and vortexed; adding 5ml NaCl saturated and vortexed; the upper phase was then injected to GC. The separation was performed by GC Agilent 6890 series equipped with a HP-5 5% Phenyl Methyl Siloxane 30m x 320µm x 0.25mm column using Helium as carrier gas and a Flame Ionization Detektor (FID). Using column programmed temperature. The initial temperature of the oven was 170ºC and then increased at a rate of 4ºC/min to 180ºC and then increased 10ºC/min to 200ºC and then increased 15ºC/min to 280ºC held to 5 minutes for approximately 15 minutes analyzing time. Under this condition the response of caprylic acid was linear from concentracion 400 to 1800 µg/ml with regression equation y = 0.1131x - 8.135 (r = 0.9986) and relative process standard deviation Vxo = 3.26%. The average recoveries sample were 82.34% + 4.60. The precission method gave relative standard deviation 1.76%. Under this condition the response of lauric acid was linear from concentracion 2600 to 11100 µg/ml with regression equation y = 0.1724x - 97.95 (r = 0.9959) and relative process standard deviation Vxo = 5.25%. The average recoveries sample were 124.1% + 8.10. The precission method gave relative standard deviation 1.94%. Under this condition the response of myristic acid was linear from concentracion 800 to 3500 µg/ml with regression equation y = 0.1726x 15.03 (r = 0.9922) and relative process standard deviation Vxo = 9.04%. The average recoveries sample were 125.9% + 8.70. The precission method gave relative standard deviation 2.41%. Under this condition the response of palmitic acid was linear from concentracion 300 to 1350 µg/ml with regression equation y = 0.1783x - 5.739 (r = 0.9989) and relative process standard deviation Vxo = 3.38%. The average recoveries sample were 106.2% + 7.10. The precission method gave relative standard deviation 3.22%. Keywords: saturated acid, validation, determination, esterification, VCO, GC
