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        錳摻雜硫化鋅量子點室溫磷光檢測鎘離子

        2015-10-28 22:57:17趙磊等
        湖北農(nóng)業(yè)科學 2015年16期

        趙磊等

        摘要:作為一類理想的磷光探針,量子點近年來在環(huán)境污染物定性定量分析方面應用廣泛。量子點是半徑小于或接近于激子玻爾半徑的一類半導體納米晶。以巰基丙酸(MPA)為表面修飾劑制備了穩(wěn)定的水溶性摻雜型ZnS∶Mn2+量子點并應用于金屬Cd2+的檢測。在pH 7.0的PBS緩沖介質(zhì)中,Cd2+可使ZnS∶Mn2+體系磷光猝滅,強度變化與Cd2+濃度呈良好線性關(guān)系,其線性范圍為8×10-8~8×10-6 mol/L,方法檢測下限為3.86×10-8 mol/L;利用熒光光譜、紫外可見吸收光譜研究了ZnS:Mn2+納米晶結(jié)構(gòu)及其光譜特性,探討了識別Cd2+的可能機理。該方法應用于汾河水中Cd2+的檢測,回收率為93.2%~97.1%。

        關(guān)鍵詞:量子點;室溫磷光檢測(RTP);鎘離子

        中圖分類號:O657.3 文獻標識碼:A 文章編號:0439-8114(2015)16-4033-05

        DOI:10.14088/j.cnki.issn0439-8114.2015.16.052

        Phosphorescence Analysis of Cd2+ with ZnS∶Mn2+ Quantum Dots at Room-Temperature

        ZHAO Lei, MIAO Yan-ming, LI Yu-ting, LIAN Lin-wang, YAN Gui-qin

        (College of Life Science Shanxi Normal University, Linfen 041004, Shanxi, China)

        Abstract: Quantum dots (QDs) as a type of ideal phosphorescence probes have been extensively studied in qualitative and quantitative analysis of environmental pollutants. QDs are a type of semiconductor nanocrystals with radius smaller than or close to Bohr-exciton radius. In this paper, the stable water soluble QDs were prepared with mercaptopropionic acid (MPA) as a surface modifier, the prepared ZnS∶Mn2+ nanocrystal was used to detect Cd2+. In pH 7.0 PBS, Cd2+ could quench the phosphorescence intensity of the ZnS∶Mn2+ system significantly. The linear relationship between Cd2+ and phosphorescence intensity was found, and the linear range was 8×10-8~8×10-6 mol/L with detection limit of 3.86×10-8 mol/L. Then its nano-crystalline structure and the spectral properties were analyzed by fluorescence and UV-Vis spectroscopy, and the possible mechanism of Cd2+ was discussed. The recoveries of 93.2%~97.1% Cd2+ in the water sample from Fenhe were found.

        Key words: quantum dots; room-temperature phosphorescence (RTP);Cd2+

        量子點(Quantum dots,QDs) 即半徑小于或接近于激子玻爾半徑的半導體納米晶粒,是一種零維的納米材料,尺寸在納米級的金屬或半導體材料的細小顆粒,尺寸范圍為1~100 nm。量子點具有許多塊體材料和分子級別材料所不具備的性質(zhì),如:量子尺寸效應、表面效應、宏觀量子隧道效應和介電限域效應等,并由此派生出量子點獨特的發(fā)光特性。與傳統(tǒng)的有機染料相比,量子點具有寬而連續(xù)的激發(fā)光譜、窄而對稱的發(fā)射光譜、可精確調(diào)諧的發(fā)射波長(通過控制粒徑來調(diào)整發(fā)射波長)、可忽略的光漂白等優(yōu)良特性,使得其作為一種理想的磷光探針,在生物標記、成像及檢測中應用廣泛[1-8],目前將量子點用于檢測離子[9-11],生物大分子[12-15]與小分子[16-18]正成為研究熱點。室溫磷光法較之熒光分析法,磷光壽命比熒光長,可避免自體熒光和散射光的干擾,且磷光的選擇性優(yōu)于熒光[19-25]。因此,可采用量子點的磷光特性開展檢測技術(shù)研究[26]。

        鎘是一種廣泛分布于環(huán)境中的重金屬元素[27],采礦、冶煉、化石燃料等都會導致環(huán)境中的鎘積累,并進入人類食物鏈[28],導致腎功能不全,鈣代謝異常以及引發(fā)癌癥[29]。而加強檢測環(huán)境樣品,工業(yè)廢物排放和組織樣本中的鎘含量,將有利于控制人類鎘的暴露水平。目前檢測Cd2+的主要方法有原子光譜法[30]、電化學方法[31]、毛細管電泳法[32]、電感耦合等離子體質(zhì)譜法[33]、分光光度法和熒光光譜法[34]等。本試驗通過制備水溶性摻雜型ZnS∶Mn2+量子點,初步分析了對Cd2+的檢測參數(shù),以期為開發(fā)相關(guān)快速檢測方法提供參考。

        1 材料與方法

        1.1 材料和試劑

        巰基丙酸(SPA)(北京百靈威科技有限公司),Zn(CH3COO)2·2H2O,Mn(CH3COO)2·4H2O,Cd(NO3)2,Na2S·9H2O(天津市科密歐化學試劑有限公司)均為分析純,去離子水。

        1.2 主要儀器

        JSM-7500F透射電鏡(JEOL,日本),UV-29100型分光光度計(日立,日本)紫外-可見分光光度計,Cary Eclipse熒光分光光度計(瓦里安, 美國),pH計(金鵬分析儀器有限公司)。

        1.3 方法

        1.3.1 Mn摻雜ZnS量子點的合成 取100 mL三口燒瓶,依次加入50 mL 0.04 mol/L巰基丙酸,5 mL 0.1 mol/L的Zn(CH3COO)2和2 mL 0.01 mol/L的Mn(CH3COO)2,混合后在室溫下通氬氣,用1 mol/L的NaOH調(diào)節(jié)pH至11后,攪拌30 min,然后快速注射0.1 mol/L的Na2S 5 mL,迅速攪拌20 min后,于50 ℃陳化2 h形成巰基丙酸包裹的Mn,最后通過與相同體積的乙醇沉淀進行離心純化,在室溫真空下干燥,得到高水溶性的量子點粉末[35],待用。

        1.3.2 測量 在295 nm激發(fā)波長的磷光模式下,激發(fā)和發(fā)射狹縫寬度分別為10 nm和20 nm,在一系列10 mL比色管中,依次加入500 μL 0.02 mol/L的PBS緩沖液(pH=7.0),50 μL 2 mg/mL的上述量子點溶液,然后加入相同濃度不同體積的Cd2+水溶液,并以去離子水定容至5 mL,靜置5 min后測定3次。

        2 結(jié)果與分析

        2.1 量子點性質(zhì)分析

        制備的水溶性量子點結(jié)構(gòu)式見圖1(a),其透射電鏡圖(b)表明Mn摻雜ZnS量子點具有球形形狀,直徑約為3.5 nm。其磷光激發(fā)和發(fā)射峰位于590 nm處。ZnS量子點只有缺陷態(tài)發(fā)光,而Mn摻雜ZnS量子點會發(fā)射磷光,起源于Mn2+的4T1-6A1躍遷[21]。

        2.2 Mn摻雜ZnS量子點的RTP分析

        Cd2+對Mn摻雜ZnS量子點磷光的影響見圖2,結(jié)果表明Cd2+對Mn摻雜ZnS量子點的磷光具有猝滅效應。隨著Cd2+濃度增加,量子點的RTP強度呈下降趨勢,表明該量子點可用于鎘離子的RTP探針。在最佳條件下,磷光猝滅強度與鎘離子濃度的標準曲線見圖3。由圖3計算其線性回歸方程為ΔP=0.000 4 C+1.010 2,相關(guān)系數(shù)為0.993 5,連續(xù)測定11次不含鎘離子和含有0.2 μmol/L鎘離子磷光差值的相對標準偏差為1.8%。計算該方法的Cd2+檢出限為3.86×10-8 mol/L。

        2.3 RTP探針的性質(zhì)探討

        為鑒定Cd2+在該分析體系中的特異性,分析了體系中的探針磷光特性,結(jié)果見圖4。由圖4可知,Mn摻雜ZnS量子點的磷光發(fā)射峰激發(fā)于595 nm,在Mn摻雜ZnS量子點體系中添加Cd2+,可顯著降低體系磷光強度,且隨著Cd2+濃度增加,其熒光強度有規(guī)律地降低,即Mn摻雜ZnS量子點可與Cd2+發(fā)生相互作用。

        紫外-可見光譜分析結(jié)果見圖5。由圖5可知,Mn摻雜ZnS量子點的光強度較低,但加入鎘離子后,在量子點表面形成了S-Cd鍵,增大了整個體系的發(fā)光強度[36]。

        磷光猝滅過程通常分為動態(tài)碎滅(遵從Stem-Voliner方程Eq.1)和靜態(tài)碎滅(遵從Lineweaver- Burk方程Eq.2)兩類[37,38]:

        P0/P=1+Ksvcq (1)

        1/(P0-P)=1/P0+KLB/(P0cq) (2)

        其中,P0代表磷光體磷光強度,P代表加入磷光碎滅劑后體系的磷光強度,cq為碎滅劑Cd2+濃度,Ksv是動態(tài)猝滅常數(shù),KLB是靜態(tài)猝滅常數(shù)[39-41]。P0/P和cq的關(guān)系不遵循Stern-Volmer方程,而(P0-P)-1與cq的關(guān)系符合Lineweaver-Burk方程,說明Cd2+猝滅Mn摻雜ZnS量子點是一個靜態(tài)猝滅過程(圖6),即二者相互作用后產(chǎn)生了非磷光物質(zhì)。

        2.4 檢測體系的優(yōu)化

        為優(yōu)化檢測體系,試驗研究了pH、反應時間以及NaCl濃度對40 mg/L Mn摻雜ZnS量子點RTP強度的影響。由圖7可知,當pH為4.5~9.5時,隨著pH增加,量子點RTP強度呈先增后減,并在pH 6~8.5時趨于穩(wěn)定,考慮普通環(huán)境水樣pH在7左右,故選擇反應體系pH為7。由圖8和圖9可知量子點在60 min內(nèi)和高NaCl濃度下,RTP強度基本穩(wěn)定。

        2.5 樣品分析

        取一定量汾河水,過濾后,采用加標回收法分析,結(jié)果見表1。由表1可知,樣品回收率達到93%以上,檢測相對標準偏差小于6%,初步符合檢測分析要求。

        3 結(jié)論

        采用MPA包裹的Mn摻雜ZnS量子點可為快速檢測鎘離子提供新思路,該法不需復雜的樣品預處理,操作簡單,且采用的磷光檢測體系,可有效避免生物體液的自體熒光和散射光干擾,勿需除氧劑和誘導劑,成本低,是一種簡單、快速、經(jīng)濟、靈敏和高選擇性的檢測水樣中鎘離子的方法。

        參考文獻:

        [1] GRECCO H E,LIDKE K A,HEINTZMANN R,et al. Ensemble and single particle photophysical properties (two-photon excitation, anisotropy, FRET, lifetime, spectral conversion) of commercial quantum dots in solution and in live cells[J]. Microscopy Research and Technique,2004,65(4-5):169-179.

        [2] WANG L Y,KAN X W,ZHANG M C,et al. Fluorescence for the determination of protein with functionalized nano-ZnS[J]. Analyst,2002,127(11):1531-1534.

        [3] ALIVISATOS A P.Semiconductor clusters,nanocrystals,and quantum dots[J]. Science,1996,271(5251):933-937.

        [4] PENG X G,YANG W O,WICKHAM J,et al. Shape control of CdSe nanocrystals[J]. Nature,2000,404:59-61.

        [5] PENG X G,WICKHAM J, ALIVISATOS A P.Kinetics of Ⅱ-Ⅵ and Ⅲ-Ⅴ colloidal semiconductor nanocrystal growth: “Focusing” of size distributions[J]. Journal of the American Chemical Society,1998,120(21):5343-5344.

        [6] BRUCHEZ M J,MORONNE M,ALIVISATOS A P,et al. Semiconductor nanocrystals as fluorescent biological labels[J]. Science,1998,281(5385):2013-2015.

        [7] CHAN W C W, NIE S M. Quantum dot bioconjugates for ultrasensitive nonisotopic detection[J]. Science,1998,281(5385): 2016-2018.

        [8] LAN G Y,LIN Y W,HUANG Y F,et al. Photo-assisted synthesis of highly fluorescent ZnSe(S) quantum dots in aqueous solutions[J].Journal of Materials Chemistry,2007,17(25):2661-2666.

        [9] JIN W J,F(xiàn)ERN NDEZ-ARG ELLES M T,COSTA-FERN NDEZ J M,et al.Photoactivated luminescent CdSe quantum dots as sensitive cyanide probes in aqueous solutions[J]. Chemical Communications,2005(7):883-885.

        [10] FERN NDEZ-ARG ELLES M T,JIN W J,COSTA-FERN NDEZ J M,et al. Surface-modified CdSe quantum dots for the sensitive and selective determination of Cu(II) in aqueous solutions by luminescent measurements[J]. Analytica Chimica Acta, 2005, 549(1-2): 20-25.

        [11] LI H B,ZHANG Y,WANG X Q,et al.Calixarene capped quantum dots as luminescent probes for Hg2+ ions[J]. Materials Letters,2007,61(7):1474-1477.

        [12] WANG L Y,WANG L,GAO F,et al.Application of functionalized CdS nanoparticles as fluorescence probe in the determination of nucleic acids[J]. Analyst,2002,127(7):977-980.

        [13] CHEN X D,DONG Y P,F(xiàn)AN L,et al. Resonance scattering method for the ultrasensitive determination of peptides using semiconductor nanocrystals[J]. Analytica Chimica Acta,2007, 597(2):300-305.

        [14] CHEN H Q,WANG L,LIU Y,et al. Preparation of a novel composite particles and its application in the fluorescent detection of proteins[J]. Analytical and Bioanalytical Chemistry, 2006,385(8):1457-1461.

        [15] YAO H Q,ZHANG Y,XIAO F,et al. Quantum dot/bioluminescence resonance energy transfer based highly sensitive detection of proteases[J]. Angewandte Chemie International Edition,2007,46(23):4346-4349.

        [16] HUANG C P,LI Y K,CHEN T M.A highly sensitive system for urea detection by using CdSe/ZnS core-shell quantum dots[J]. Biocatalysis and Biotransformation,2007,22(8):1835-1838.

        [17] LIANG L G, HUANG S, ZENG D Y, et al. CdSe quantum dots as luminescent probes for spironolactone determination[J]. Talanta,2006,69(1):126-130.

        [18] CORDES D B, GAMSEY S, SINGARAM B. Fluorescent quantum dots with boronic acid substituted viologens to sense glucose in aqueous solution[J]. Angewandte Chemie International Edition,2006,45(23):3829-3832

        [19] TRAVIESA-ALVAREZ J M, SANCHEZ-BARRAGA N I, COSTA-FERNA NDEZ J M. Room temperature phosphorescence optosensing of benzo[a]pyrene in water using halogenated molecularly imprinted polymers[J]. Analyst,2007,132(3):218-223.

        [20] DE MELLO DONEGA C, BOL A A, MEIJERINK A. Time-resolved luminescence of ZnS:Mn2+ nanocrystals[J]. Journal of Luminescence,2002,96(2-4):87-93.

        [21] CHUNG J H,AH C S,JANG D J. Formation and distinctive decay times of surface-and lattice-bound Mn2+ impurity luminescence in ZnS nanoparticles[J]. Journal of Physical Chemistry B,2001,105(19):4128-4132.

        [22] CHENG B C, WANG Z G. Synthesis and optical properties of europium-doped ZnS: long-lasting phosphorescence from aligned nanowires[J].Advanced Functional Materials,2005,15(11):1883-1890.

        [23] OZAWA L, MAKIMURA M, ITOH M. Improved production of ZnS blue phosphor powder[J]. Materials Chemistry and Physics,2005,93(2-3):481-486.

        [24] MANOHARAN S S,GOYAL S,RAO M L,et al., Microwave synthesis and characterization of doped ZnS based phosphor materials[J]. Materials Research Bulletin,2001,36(5-6):1039-1047.

        [25] CHEN S H,GREEFF A P,SWART H C.A comparative study between the simulated and measured cathodoluminescence generated in ZnS:Cu, Al, Au phosphor powder[J]. Journal of Luminescence,2005,113(3-4):191-198.

        [26] THAKAR R,CHEN Y C,SNEE P T. Efficient emission from core/(doped) shell nanoparticles: Applications for chemical sensing[J]. Nano Letters,2007,7(11):3429-3432.

        [27] CHANEY R L, RYAN J A, LI Y M, et al. Soil cadmium as a threat to human health[J]. Cadmium in Soils and Plants,1999(85):219-256.

        [28] FRIBERG L, ELINGER C G, KJELLSTROM T. Environmental Health Criteria 134[M]. Geneva:World Health Organization,1992.

        [29] DOBSON S. Cadmium-Environmental Aspects, Environmental Health Criteria 135[M]. Geneva: World Health Organization, Geneva,1992.

        [30] AMORIM FAC, BEZERRA M A. Online preconcentration system for determining ultratrace amounts of Cd in vegetal samples using thermospray flame furnace atomic absorption spectrometry[J]. Microchim Acta,2007,159(1-2):183-189.

        [31] LI L, XIA B H, JIANG Z C. Determination of trace Cd and Pb in environmental and biological samples by ETV-ICP-MS after single-drop microextraction[J]. Talanta,2006,70(2):468-473.

        [32] QU F, LIN J M, CHEN Z L. Simultaneous separation of nine metal Ions and ammonium with nonaqueous capillary electrophoresis[J].Journal of Chromatography A,2004,1022(1-2):217-221.

        [33] SUTEERAPATARANON S, JAKMUNEE J, VANEESORN Y, et al. Exploiting flow injection and sequential injection anodic stripping voltammetric systems for simultaneous determination of some metals[J]. Talanta,2002,58(6):1235-1242.

        [34] XUE L, LIU C, JIANG H. Highly sensitive and selective fluorescent sensor for distinguishing cadmium from zinc ions in aqueous media[J].Organic Letters,2009,11(7):1655-1658.

        [35] ZHUANG J Q, ZHANG X D, WANG G, et al. Synthesis of water-soluble ZnS:Mn2+ nanocrystals by using mercaptopropionic acid as stabilizer[J]. Journal of Materials Chemistry, 2003,13(7):1853-1857.

        [36] CHUNG J H, AH C S, JANG D J. Formation and distinctive decay times of surface and lattice bound Mn2+ impurity luminescence in ZnS nanoparticles[J]. Journal of Physical Chemistry B,2001,105(19):4128-4132.

        [37] SPANHEL L, HAASE M, WELLER H, et al. Photochemistry of colloidal semieonduetors.20. Surface modification and stability of strong luminescing CdS Particles[J]. Journal of the American Chemical Society,1987,109(19):5649-5655.

        [38] SAUER K, SCHEER H, SAUER P. F rster transfer calculations based on crystal structure data from agmenellum quadruplicatum C-phycocyanin[J]. Photochemistry and Photobiology,1987,46(3):427-440.

        [39] LAKOWICZ J R, WEBER G. Quenching of fluorescence by oxygen probe for structural fluctuations in macromolecules[J]. Biochemistry,1973,12(21):4161-4170.

        [40] JONES R M, BERGSTEDT T S, MCBRANCH D W. Tuning of superquenching in layered and mixed fluorescent polyelectrolytes[J]. Journal of the American Chemical Society,2001, 123(27),6726-6727.

        [41] MURPHY C B, ZHANG Y, TROXLER T, et al. Probing Frster and Dexter energy-transfer mechanisms in fluorescent conjugated polymer chemosensors[J]. The Journal of Physical Chemistry B, 2004(108): 1537-1543.

        [42] BAPTISTA M S, INDIG G L. Effect of BSA binding on photophysical and photochemical properties of triarylmethane dyes[J]. The Journal of Physical Chemistry B,1998,102(23): 4678-4688.

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