Optimization of the thiobarbituric acid-malonaldehyde reaction in non-aqueous medium. Direct analysis of malonaldehyde in oil samples by HPLC with fluorimetric detection

• Published in: Microchemical journal Vol. 159; p. 105318
• Main Authors: Durán Merás, Isabel, Periañez Llorente, Cesar, Pilo Ramajo, Jesús, Martín Tornero, Elisabet, Espinosa-Mansilla, Anunciación
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2020
• Subjects: Dermatologic oil; Malondialdehyde; Olive oil; Organic medium; Rancidity; TBA reaction; TBA reaction; Dermatologic oil; Olive oil; Malondialdehyde; Rancidity; Organic medium
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2020.105318

•Malondialdehyde (MDA) is an indicator of the lipid peroxidation in food and biological samples.•Thiobarbituric acid (TBA) reacts with MDA and other secondary lipid oxidation products.•Spectrophotometric methods measure the total thiobarbituric acid reactive substances (TBARs).•HPLC proposed method is selective for TBA-MDA and allow us the in situ determination of MDA in oil samples. The reaction of thiobarbituric acid (TBA) with saturated and unsaturated aldehydes in organic medium, 1-propanol, compatible with lipid samples, has been studied using spectrophotometric and fluorimetric techniques. With saturated aldehydes, the formation of non-fluorescence yellow derivatives was observed. Unsaturated mono-aldehydes, trans, trans-2,4-hexadienal and trans, trans-2,4-nonadienal, give fluorescent TBA-derivatives. In presence of malondialdehyde (MDA), a derivative with an absorption maximum located at 532 nm and a fluorescence maximum located at 552 nm, exciting at 532 nm, were observed. The structures of the derivatives generated in organic medium were achieved by high performance liquid chromatography (HPLC) using a mass spectrometer as detector. A heterogeneous propanol-water-oil medium was optimized for the direct analysis of MDA in oil samples by HPLC with fast scanning fluorescence detection. Good linearity over the range of 0.05–1.0 μg mL−1 was obtained. Without any pre-treatment, olive oil and dermatologic oil samples were analysed. MDA was selectively determined in presence of other potential TBARs. The proposed HPLC-fluorimetric method is more selective than the spectrophotometric method because only MDA, and no other TBARs, is determined.