A new HPLC method for the determination of tocopherol in rat plasma

Objective: The objective of the present work is the simplification of sample treatment for vitamin E measurements in rat plasma by high-performance liquid chromatography (HPLC), then the evaluation of the effect of cadmium treatment on the vitamin E level. Methods: A HPLC method to determine vitamin E was developed with direct extraction with n-hexane-dichloromethane. The dry residue was redissolved in methanol. The method employs a Supelco Discovery ® C18 column and methanol/water (95:5, v/v) as the mobile phase. After being developed, the method was validated with a fluorescence detector. To examine the effects of exogenous cadmium on the plasma vitamin E concentrations, male Wistar rats (weighing 150 ± 20 g) were exposed for 48 h and 10 days to oral intake of 15 and 30 mg/L cadmium (as CdCl 2 ) and vitamin E (10 mg/Kg of diet) simultaneously. Results: This method makes sample treatment easier, especially when working with a large number of samples. It has proved to be selective, linear, accurate and precise. Intoxication with cadmium was followed by a significant decrease in plasma vitamin E concentrations. The lowest level was obtained in the 30 mg/L dosing group after 10 days of cadmium administration. Conclusion: We describe a rapid reversed-phase (RP) HPLC procedure for the determination of vitamin E in plasma. This method might be useful in routine assessment because it saves on solvents and chromatographic time. Interestingly, α -tocopherol may play an important role in preventing oxidative stress induced by cadmium exposure by scavenging free radicals.