Abstract: Microfluidic devices and methods of quantifying fatty acids and/or specialized pro-resolving mediators and/or fatty acid metabolites present in a fluid sample on a microfluidic device are described herein. The methods include extracting fatty acid esters containing fatty acids from the fluid sample, combining the extracted fatty acid esters with a hydrolyzing agent to cleave the fatty acids from the extracted fatty acid esters and form free fatty acids, and quantifying the free fatty acids by performing a bioassay specific to the free fatty acids. Microfluidic devices and methods of quantifying fatty acid metabolites present in a fluid sample on a microfluidic device are also described herein.