Fatty acids and their esters are found in many biological substrates. Many of these fats are unhealthy (e.g. saturated fats) while others have been found to be beneficial (e.g. unsaturated, polyunsaturated). Using flash can be challenging as the compounds are very non-polar with little or no UV chromophores. Identification is typically performed in a separate test such as GC/MS. As an alternative, mass-directed fractionation using Isolera Dalton maximized compound detection sensitivity and triggered fractionation in these difficult substrates.