Head Space Single Drop Micro Extraction Gas Chromatography Flame Ionization Detection (HS-SDME-GC-FID) Method for the Analysis of Common Fatty Acids

INTRODUCTION: The majority of the after marketing/surveillance studies shows that most of the many vegetable oils that are sold with health-promoting claims or statements with high nutritional values and are beneficial against diseases are off-limits of related monographs/criteria. Defining the oil with fast, cheap and efficient analytical method to express fatty acids in any herbal product, to authenticate, trace, specify and classify the content is needed.
METHODS: Here we define a new simple tool with headspace single drop micro extraction (HS-SDME) method coupled with gas chromatography-flame ionization detector (GC-FID) was developed for the analysis of common fatty acids (FAs) in oils. Linolenic acid, ɣ-linolenic acid, and linoleic acid in olive oil, thyme oil, and fish oil were determined. Derivatization was carried out with 0.2 mL of 2 mol/L KOH in methanol to transfer the FAs of oils into their methyl esters (FAMEs). Then FAMEs were extracted by using head space single drop which is 2.0 µL of sodium dodecyl sulfate: 1-butanol (1: 3, v/v) mixture.
RESULTS: The most suitable extraction condition was that 360 µL of the fatty acid methyl esters (FAMEs), 2.0 mL vial, 0.07 g NaCl as a salting-out effect, 45 °C extraction temperature, and 35 min extraction time. The precision of the method was below 12% with an accuracy validated by the GC-FID reference method.
DISCUSSION AND CONCLUSION: The HS-SDME can be used for effectively for extracting fatty acids from oils for improved analysis of other fatty acids while the method is direct importance and relevance for herbal, pharmaceutical, cosmetics industry.