title: Determination of trace copper ions with ultrahigh sensitivity and selectivity utilizing CdTe quantum dots coupled with enzyme inhibition.
abstract: A fluorescent transducer with the combination of the unique property of CdTe quantum dots (QDs) and enzymatic inhibition assays was successfully constructed for the purpose of ultrasensitive determination of Cu(2+) ions. Alcohol oxidase (AO) catalyzed the oxidation of methanol to produce hydrogen peroxide (H(2)O(2)), inducing the quenching of QDs fluorescence. In the presence of Cu(2+) ions, the activity of AO was inhibited and therefore, the quenching of QDs fluorescence was decreased. Other metal ions showed no intensive inhibition to the AO activity even at 10 or 100 times Cu(2+) ions concentration, presenting a high selectivity of this fluorescent sensor. Using this QDs-enzyme hybrid system, the detection limit for Cu(2+) ions was found to be as low as 0.176 ng/mL (2.75 nM) due to the superior fluorescence property of QDs. Practical application of the QDs-enzyme hybrid system has been demonstrated by domestic waste water, agricultural irrigation water and lake water analysis. Results of Cu(2+) determinations were in good agreement with those obtained by inductively coupled plasma analytical method. The coupling of efficient quenching of QDs photoluminescence by H(2)O(2) generated from oxidase-catalyzed reaction and the effective enzymatic inhibition make this a simple and sensitive method for heavy metal ions detection.
authors.affiliation: Nanomedicine and Biosensor Laboratory, School of Life Science and Technology, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150080, China.
authors.forename: Caixin
authors.initials: C
authors.lastname: Guo
authors.forename: Jinliang
authors.initials: J
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Cheng
authors.forename: Zhifei
authors.initials: Z
authors.lastname: Dai
mesh_terms: D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D019187:Cadmium Compounds / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000032:analysis; D007477:Ions / Q000032:analysis; D045663:Quantum Dots; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D007477:Ions; D003300:Copper; D006861:Hydrogen Peroxide; D000429:Alcohol Oxidoreductases; C019643:alcohol oxidase; D013691:Tellurium; C028337:cadmium telluride