A simple, economical and selective method employing ion pair dispersive liquid−liquid microextraction
(DLLME) coupled with spectrophotometric determination of carbamazepine (CBZ) in pharmaceutical
preparations and biological samples was developed. The method is based on reduction of Mo(VI) to
Mo(V) using a combination of ammonium thiocyanate and ascorbic acid in acidic medium to form a red
binary Mo(V) thiocyanate complex. After addition of CBZ to the complex, extraction of the formed CBZ−
Mo(V)−(SCN)6 was performed using a mixture of methylene chloride and methanol. Then, the measurement
of target complex was performed at the wavelength of 470 nm. The important extraction parameters affecting
the efficiency of DLLME were studied and optimized in detail. At the optimum conditions, the linear range
was 0.02–0.2 μg/mL. Moreover, the limits of detection and quantification were 0.01 and 0.04 μg/mL, respectively.
High enrichment factor was obtained (118). Good recoveries at 0.06, 0.15 and 0.2 μg/mL ranging from
93 to 102% were achieved. The proposed method was successfully applied to the determination of CBZ in
pharmaceutical formulations and biological samples.