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A CO probe with PEGylation is synthesized, achieving the detection of CO in pure water solution with high intensity color change and fluorescence enhancement. Importantly, this probe with high affinity to paper strips and low toxicity to living cells is successfully used for sensing CO in air and in living cells. [ABSTRACT FROM AUTHOR]

Since zinc ions play an important role in various physiological activities, developing a facile detection method for Zn2+ is highly desirable. Owing to their superior optical properties, semiconductor quantum dots (QDs) have been developed as a promising alternative for organic fluorophores in fluorescence analysis. In this study, water soluble di-2-picolylamine-dithiolcarbamate (DPA-DTC)/proline-dithiolcarbamate (P-DTC) co-capped CdSe/ZnS QDs as a sensitive and selective “turn-on” fluorescence probe for Zn2+ was reported. The probe was easily obtained via ligand exchange. The initial bright fluorescence of QDs was effectively quenched by DPA-DTC that acted as an effective hole trapper. Upon complexation with Zn2+, the formation of Zn2+–DPA-DTC complex altered the energetic position of the HOMO for DPA-DTC, which rendered it unfavorable for the hole transfer. Thus the QDs PL was switched on. Under optimal conditions, a good linear relationship between the fluorescence response and Zn2+ concentration could be obtained in the range from 0.9 to 16 μM. The limit of detection for Zn2+ was found to be 0.7 μM. Furthermore, the present probe exhibited a high selectivity for Zn2+ over other common metal ions and was successfully used in the detection of Zn2+ in simulated biological fluids. [ABSTRACT FROM AUTHOR]