Beyond diazomethane: Alternative approaches to analyzing non‐esterified fatty acids

Abstract

In many branches of lipid science, researchers are interested in non-esterified fatty acid (NEFA) content and composition. For many years, diazomethane was the reagent of choice to selectively derivatize and then detect NEFA due to its highly specific methylation of the carboxylic acid functional group. While the activity of this derivatizing reagent is very defined, it is dangerous and can be difficult to obtain. In this brief review, we have compiled a collection of methods which allow for the detection of NEFA and hydroxy NEFA without the use of diazomethane. We have concentrated on methods that employ three distinct approaches of selective quantification/extraction, purification from total lipids and derivatization techniques.

Considerations about the in situ derivatization and fractionation of EFA and NEFA in biological and food samples

“…The mains drawback in the GC analysis of EFA and NEFA in biological and food samples is the need to include isolation and fractionation steps while its preparation or the utilization of hazardous reagents as diazomethane during the esterification of NEFA [2] . However, Yi et al [1] reported in 2007 a direct derivatization/fractionation procedure avoiding such cumbersome and time-consuming steps on the basis that acylglycerols can be transesterified using mild conditions together with an alkali-catalyst while NEFA can be transformed into FAME using an acid catalyst [3] .…”

iTrEnDi: In Situ Trimethylation Enhancement Using Diazomethane: Improved and Expanded Glycerophospholipid and Sphingolipid Analyses via a Microscale Autonomous Derivatization Platform

“…14 Lipid chemical derivatization techniques must be rapid, have high conversion rates, afford minimal side products that do not interfere with MS analysis, as well as function on a very small scale (≃10 nmol). Diazomethane (DZM) is a reagent that has long been implemented in gas chromatography MS analysis of fatty acids 15 due to its ability to rapidly, completely, and chemoselectively alkylate free fatty acids. Diazoalkanes are highly reactive reagents, also reacting with other acidic functional groups to produce tetraalkylammonium species, methyl esters, and alkyl phosphates with N 2 (g) being the sole byproduct formed.…”