Analytical Sciences

Microwave-assisted Derivatization of Fatty Acids for Its Measurement in Milk Using High-Performance Liquid Chromatography

Rojeet SHRESTHA,* Yusuke MIURA,* Ken-ichi HIRANO,**,*** Zhen CHEN,* Hiroaki OKABE,* Hitoshi CHIBA,* and Shu-Ping HUI*

*Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Sapporo 060-0812, Japan
**Laboratory of Cardiovascular Disease, Novel, Non-Invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
***Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan

Fatty acid (FA) profiling of milk has important applications in human health and nutrition. Conventional methods for the saponification and derivatization of FA are time-consuming and laborious. We aimed to develop a simple, rapid, and economical method for the determination of FA in milk. We applied a beneficial approach of microwave-assisted saponification (MAS) of milk fats and microwave-assisted derivatization (MAD) of FA to its hydrazides, integrated with HPLC-based analysis. The optimal conditions for MAS and MAD were determined. Microwave irradiation significantly reduced the sample preparation time from 80 min in the conventional method to less than 3 min. We used three internal standards for the measurement of short-, medium- and long-chain FA. The proposed method showed satisfactory analytical sensitivity, recovery and reproducibility. There was a significant correlation in the milk FA concentrations between the proposed and conventional methods. Being quick, economic, and convenient, the proposed method for the milk FA measurement can be substitute for the convention method.

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