A highly sensitive and selective turn off-on fluorescent sensor based on Sm-MOF for the detection of tertiary butylhydroquinone

A turn off-on samarium-metal-organic-framework (Sm-MOF) fluorescence sensor for detection of tertiary butylhydroquinone (TBHQ) in edible oil was designed. It was found that the fluorescence of Sm-MOF was quenched in the presence of Fe3+ ion by forming Sm-MOF@Fe3+ complex (turn off), then it was recovered after adding TBHQ (turn on) due to the competitive formation of TBHQ@Fe3+ and release of Sm-MOF. Under the optimum Fe3+ concentration, the fluorescence turn off-on approach exhibited superior selectivity and sensitivity, wide linear range (0-120 mu g/mL) and low detection limit (5.6 ng/mL) toward TBHQ. The fluorescence recovery selectivity of TBHQ over other synthetic phenolic antioxidants was attributed to the synergistic effect of high EHomo value and a small space steric hindrance. TBHQ spiked in edible oil was quantitatively detected by the standard curve method with recoveries of 101.2%-103.0%, suggesting that the turn off-on approach has potential application for TBHQ detection in oil-containing foods.