Abstract: A simple, rapid continuous-flow method with gas chromatography detection for the simultaneous determination of natural and synthetic antioxidants (α-tocopherol, α-tocopheryl acetate, 2,6-di-tert-butyl-p-hydroxytoluene, tert-butyl-4-hydroxyanisole and tert-Bu hydroquinone) is proposed. A solid phase extractor is coupled to the flow system to isolate antioxidants from the sample matrix. During extraction, analytes are released from ~70% of the triglycerides present in fats and oils by using XAD-7 sorbent; after selective elution with 400 µL of 2-propanol, only ~0.7-0.8% of total triglycerides originally present in the sample remain in the final ext. XAD-7 adsorbs 70-95% of the antioxidants except BHT of which only ~30% is adsorbed. The proposed method is considered an effective alternative to earlier procedures.

Abstract: A flow injection method for the determination of the antioxidant BHT using polymer modified electrodes in connection with amperometric detection is proposed. The procedure is based on the electrochemical oxidation at 0.700 V (vs. Ag/AgCl [3 M NaCl]) in phosphate buffer solution (pH 7.2). BHT is determined over the range 0.001-0.020 or 0.005-0.030 g/L. Other analysis parameters, such as electrode working potential, flow rate, electrodeposited charge, and solution pH were optimized. The proposed method was applied to the determination of BHT in electrical transformer and vegetable oils samples. The results were compared with the HPLC-UV detection standard technique.