Chemodosimeter-based fluorescent detection of l-cysteine after extracted by molecularly imprinted polymers

A chemodosimeter-based fluorescent detection method coupled with molecularly imprinted polymers (MIPs) extraction was developed for determination of l -cysteine ( l -Cys) by combining molecular imprinting technique with fluorescent chemodosimeter. The MIPs prepared by precipitation polymerization with l -Cys as template, possessed high specific surface area of 145   m 2 /g and good thermal stability without decomposition lower than 300   °C, and were successfully applied as an adsorbent with excellent selectivity for l -Cys over other amino acids, and enantioselectivity was also demonstrated. A novel chemodosimeter, rhodamine B1, was synthesized for discriminating l -Cys from its structurally similar homocysteine and glutathione as well as various possibly co-existing biospecies in aqueous solutions with notable fluorescence enhancement when adding l -Cys. As l -Cys was added with increasing concentrations, an emission band peaked at 580   nm occurred and significantly increased in fluorescence intensity , by which the l -Cys could be sensed optically. High detectability up to 12.5   nM was obtained. An excellent linearity was found within the wide range of 0.05–50   μM ( r =0.9996), and reasonable relative standard deviations ranging from 0.3% to 3.5% were attained. Such typical features as high selectivity, high sensitivity, easy operation and low cost enabled this MIPs-fluorometry to be potentially applicable for routine detection of trace l -Cys.