Fig. 6. The structure of proposed major degradation products of the reactions between propofol and ABTS·+. The m /z of product I, II, III, IV, and V were 690, 677, 436, 453, and 258, respectively. These products include ABTS-propofol, a part of the ABTS molecule, and combination of propofol with a part of the ABTS molecule. ABTS·+= 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical; ABTS = 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid).