Fast simultaneous determination of BHA and TBHQ antioxidants in biodiesel by batch injection analysis using pulsed-amperometric detection.

We report the first amperometric method for the simultaneous determination of butylated hydroxyanisole (BHA) and tert-butylhydroquinone (TBHQ) in biodiesel using batch-injection analysis (BIA) coupled to pulsed-amperometry. A sequence of potential pulses was selected in order to detect TBHQ and BHA separately in a single injection step at a glassy-carbon electrode. Samples were diluted in 50% v/v hydroethanolic solution with 0.1 mol L(-1) HClO(4) (supporting electrolyte) before injection using an electronic pipette. The method is highly precise (RSD<1%, n=10), fast (170 injections h(-1)), accurate (recovery between 100 and 110%), presents low detection limits (73 and 75 nmol L(-1) BHA and TBHQ, respectively), and can be easily adapted for on-site determinations.