Optimized Analytical Conditions for Eicosapentaenoic and Docosahexaenoic Acids in Antarctic krill Using Gas Chromatography

Abstract

A simple method for the esterification of EPA and DHA in Antarctic krill was developed. When EPA and DHA standard solution (1.0 mg/mL in acetonitrile) reacted with equal volumes of 0.5% sulfuric acid-methanol at 60°C for 30 min, approximately 100% esterification conversion of EPA and DHA was achieved. Based on the esterification of EPA and DHA in Antarctic krill extraction solutions under these optimization conditions, the concentrations of EPA and DHA in fresh Antarctic krill were, respectively, 4.87 and 4.26 mg/g in the head, and 2.79 and 2.62 mg/g in the pleon. In the freeze-dried Antarctic krill, the amount of EPA and DHA were, respectively, 27.80 and 24.68 mg/g in the head, and 19.89 and 18.46 mg/g in the pleon.

Keywords:

• Antarctic krill
• Eicosapentaenoic and docosahexaenoic acids
• Esterification
• Methyl esters

Acknowledgments

This research was a part of the project entitled “Korea Sea Grant Program (Gyeong-gi Sea Grant)” funded by the Ministry of Land, Transport, and Maritime Affairs, Korea.

Notes

Note. Calculation curve equation expressed as follow: Y = aX + b, where Y means area (mV*sec), X means concentration (mg/mL), and R² means correlation coefficient.

Note. (1.0 mg/mL of standard EPA and DHA solution reacted with 0.5% H2SO4-CH3OH within 30 min).

nd = not detected.

Note. Amount is expressed as the amount of EPA or DHA in sample and represents means ± standard deviation of 3 separate experiments.