Preparation And Application In Environmental Analysis Of Nanoscale Sulfides Semiconductor

With the rapid development of modern economic, the problem of environmentalpollution is growing serious. Persistent organic pollutants (POPs) was known as aclass of harmful substances which are resistant to photodegradation, durable,bioaccumulative. And those pollutants also possess endocrine toxicity,immunotoxicity, as well as other toxic effects. In this paper, with remove and rapidscreening the POPs as goal, we developed novel multifunctional nanomaterials andtheir application in the fields of removal of POPs and biosensing.We have investigated the performance of nanomaterials, it provides a new way torealize the lock and remove of POPs. Although the classic gas/liquid chromatography(GC/LC) and high performance liquid chromatography tandem mass spectrometry(HPLC tandem MS) are powerful analytical methods for POPs, the practicalapplications are limited due to its high cost, extensive sample pretreatment(purification, concentration and derivatization), and difficult to perform on-site.Economical, rapid and convenient methods are in urgent need to detect trace amountsPOPs existing in the environment in site.Electrochemiluminescence (ECL) is widely accepted in many research areas dueto its high sensitivity, low background signal and simple instrumentation. Attributedto its specific, fast, low-cost, can be applied to routine analysis of a large of samples,immunoassay is frequently used for qualitative screening and quantitativedetermination of real samples.Based on above, we developed three works as below:(1) Preparation and research on photoelectric properties of CuInSe2-TiO2NTs:We use a facile solution synthesis of chalcopyrite CuInSe2nanocrystals. Then thenanocrystals were deposited on to TiO2NTs by immersing the TiO2NTs in a CuInSe2nanocrystal ink, leading to high photoelectrical conversion efficiency in the visibleregion. Compared with the unmodified TiO2NTs, the CuInSe2modified TiO2NTs(CuInSe2-TiO2NTs) showed significantly enhanced photocatalytic activity towardsmethyl orange and2,4-D under visible light. The increased photodegradationefficiency mainly results from the improved photocurrent density as results ofenhanced visible-light absorption and decreased hole-electron recombination due tothe presence of narrow-band-gap semiconductor CuInSe2. (2) Core/shellthickCdTe/CdS QDs-TiO2NTs immunosensor was developed todetect tris-(2,3-dibromopropyl) isocyanurate (TBC): A novel cathodicelectrochemiluminescence platform is proposed based on a core/shellthickCdTe/CdSquantum dots modified TiO2nanotube array (CdTe/CdS QDs-TiO2NTs) electrode.The thick CdS shell significantly increases the QD structural stability and suppressesthe nonradiative recombination within the QDs. Strong and stable ECL signals aretherefore produced through the electron-transfer reactions between theelectron-injected CdTe/CdS QDs and reduced S2O82-. A non-labeled immunosensorfor the detection of TBC was developed by cross-linking anti-TBC antibody onto acore/shellthickCdTe/CdS QDs-TiO2NTs electrode. Upon the formation ofimmunocomplex, the ECL intensity decreases owing to that the immunocomplexhinders the transport of reactant reagents to the surface of CdTe/CdS QDs-TiO2NTs.The immunosensor shows selective and sensitive responses to TBC with a linear rangefrom10pM to50nM with a detection limit of4pM. The practical applications of theimmunosensor were also realized in the selective determination of TBC in water andsoil samples from Liuyang River.(3) CdS QDs fluoresence probe-enzyme linked immunosorbent sensor: Alkalinephosphatase is able to trigger formation of CdS QDs. Alkaline phosphatasehydrolyzes thiophosphate and yields H2S, which can instantly reacts with Cd(NO3)2togive CdS quantum dots.The formation of CdS quantum dots in above reactions wasfollowed measured by fluorescence spectroscopy and showed dependence on theconcentrations of alkaline phosphatase and substrate.The sensitivity of this novelimmuosensor showed to be better than that of the standard enzyme linkedimmunosorbent method based on colorimetry.