Simple and fast fluorescence detection of benzoyl peroxide in wheat flour by N-methoxy rhodamine-6G spirolactam based on consecutive chemical reactions

Benzoyl peroxide (BPO) as a brightener is often added to wheat flour, and excessive use of this food additive is receiving increasing concern. Herein, a simple and fast method for fluorescence detection of BPO is proposed based on consecutive chemical reactions. In this approach, BPO first oxidizes Fe2+ into Fe3+ and the resulting Fe3+ then induces the opening of the spirolactam ring of a new rhodamine derivative, N-methoxy rhodamine-6G spirolactam, switching on fluorescence of the detection system. More importantly, the fluorescence response of the reaction system to BPO is rather rapid and sensitive, with a detection limit of 6 mg kg−1 (k = 3), which makes it to be of great potential use in food safety analysis. The applicability of the proposed method has been successfully demonstrated on the determination of BPO in wheat flour samples.

Graphical abstractA simple and fast method for fluorescence detection of benzoyl peroxide in wheat flour by N-methoxy rhodamine-6G spirolactam (1) is proposed based on consecutive chemical reactions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Benzoyl peroxide can oxidize Fe2+ into Fe3+. ► Fe3+ selectively induces the opening of rhodamine spirolactam ring. ► The two reactions led to the development of a new fluorescent method for benzoyl peroxide. ► The method is simple and fast, and is used to detect benzoyl peroxide in wheat flour.