Determination of epoxides by high-performance liquid chromatography following derivatization with N,N-diethyldithiocarbamate

Abstract

A reversed-phase, high-performance liquid chromatography (RP-HPLC) method that allows quantitation of low levels of epoxides has been described. The method involved derivatization of epoxides using 100- to 1,000-fold excess N,N-diethyldithiocarbamate (DTC) at 60 degrees C for 20 min at neutral pH. The unreacted DTC was then decomposed to CS(2) and diethyl amine by acidification of the reaction mixture to pH 2 using orthophosphoric acid. The first two steps could be performed in the same reaction vessel by sequential addition of reagents. In the final step, an aliquot (20 microL) of the derivatized sample was analyzed for the presence of stable esters of DTC by RP-HPLC using a Supelcosil LC-18-S (150 x 4.6-mm) column and a mobile phase consisting of 40% (v/v) acetonitrile in water at a flow of 1 mL min(-1). Using UV detection at 278 nm, the epoxides gave linear responses in the concentration range of 0.25 to 50 microM. The method is robust, and as low as 5 pmol of the analyte could be successfully detected and quantified with recoveries of > or =94%. Following a minimal pretreatment such as ultrafiltration (molecular weight cutoff 5,000 Da), the method is suitable for analysis of epoxides in complex physiological fluids (e.g., fetal bovine serum). The method has been rigorously evaluated and adapted in our laboratory for routine analysis and determination of stability of epoxides of 1,3-butadiene and other alkenes added to cell cultures.

Catalytic developments in the epoxidation of vegetable oils and the analysis methods of epoxidized products

“…Numerous other methods have been presented recently to estimate epoxides in the substrate, including the use of N , N -diethyldithiocarbamate (DTC), 169 4-( p -nitrobenzyl)pyridine (NBP), 170 and transmethylation. 171 However, these methods are laborious and time-consuming because of the requirement of derivatization of the epoxides before analysis.…”

Coenzyme A-dependent Aerobic Metabolism of Benzoate via Epoxide Formation

“…The second oxygen atom is released as H 2 O. We set out to obtain a derivative with DTC, which reacts with epoxides even under gentle enzyme assay conditions under opening of the epoxide ring (20,21). DTC did not disturb the enzymatic reaction.…”

1H‐NMR Characterization of Epoxides Derived from Polyunsaturated Fatty Acids

“…Several approaches have been reported previously for the determination of epoxides in oil samples, including methods utilizing hydrogen bromide (HBr) [6], 4-(p-nitrobenzyl) pyridine (NBP) [7], N,N-diethyldithiocarbamate (DTC) [8], and gas chromatography-flame ionization detection (GC-FID) [9]. The HBr method is the most commonly used method to determine epoxides in industrial applications where they are important intermediates.…”

“…However, secondary lipid oxidation products, such as conjugated dienes and some unsaturated carbonyls, interfere with the HBr method, thereby causing the overestimation of epoxide content in oxidized oils [6]. The NBP, DTC, and GC-FID methods require derivatization and are relatively time-consuming [7][8][9].…”