Naked eye detection of benzoyl peroxide in wheat flour using 3,3′,5,5′-tetramethylbenzidine as a chromogenic agent

In this work, we first discover that 3,3',5,5'-tetramethylbenzidine (TMB) can be used as a novel chromogenic agent for sensitive, convenient and rapid determination of benzoyl peroxide (BPO) in wheat flour. A simple colorimetric method based on the color reaction between TMB and BPO was developed. Factors influencing the color reaction were examined. Under the optimum conditions, the calibration linear range for detecting BPO was 0.67-16.00 mu g mL(-1) with a detection limit of 0.45 mu g mL(-1) in aqueous solution. The method was successfully applied to detect BPO in wheat flour, with recoveries between 97% and 118%. More significantly, the existence of BPO can be evaluated by the naked eye easily without the aid of any instrumentation and requiring no sample preparation operation. TMB was proved to be an efficient and robust chromogenic reagent for the detection of BPO in wheat flour.