Abstract
The authors describe a silicon nanoparticle-based fluorometric method for sensitive and selective detection of Cu2+. It is based on the catalytic action of Cu2+ on the oxidation of cysteine (Cys) by oxygen to form cystine and the by-product H2O2. The generated H2O2 is catalytically decomposed by Cu2+ to generate hydroxyl radicals which oxidize and destroy the surface of SiNPs. As a result, the blue fluorescence of the SiNPs is quenched. The method has excellent selectivity due to the dual catalytic effects of Cu2+, which is much better than most previously reported nanomaterial-based assays for Cu2+. Under the optimal conditions, the method has low detection limit (29 nM) and a linear response in a concentration range from 0.05 μM to 15 μM. The method has been successfully applied to the determination of Cu2+ in spiked real water samples, and the results agreed well with those obtained by the Chinese National Standard method (GB/T 7475-1987; AAS).
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
Introduction
Copper is widely used in agriculture and industry, and also plays an important role in the environment and in human physiology. High concentrations of Cu2+ may be toxic to the human body [1, 2] and lead to liver or kidney diseases [3]. For this reason, Cu2+ is listed as a priority pollutant by the Environmental Protection Agency (EPA) [4]. Therefore, the detection of the concentration of Cu2+ in environmental water samples has important practical value in the water pollution monitoring and management. Many analytical methods have been developed and utilized to detect Cu2+ including electrochemical method [5], atomic emission spectrometry [6], atomic absorption spectrometry [7], colorimetry [8,9,10,11], fluorometry [12] and so on. Among these methods, fluorometry has been proved to be an ideal technique for the trace analysis due to its advantages of easy operation and high sensitivity.
Various fluorometric methods for the detection of Cu2+ have been designed by utilizing fluorescence dyes or fluorescence nanomaterials as fluorescent probes [13,14,15]. However, many of them still suffer from some drawbacks, such as complicated synthetic procedures, poor water solubility and toxicity, which limit their further applications [16, 17]. On the other hand, most methods are based on the interaction between Cu2+ and the functional groups of fluorescence probes. However, some metal ions may influence the selectivity due to their similar chemical properties and ionic radii. For instance, utilizing the affinity effect between the amino group at the surface of carbon quantum dots and the Cu2+, Chi et al. developed a fluorescence method to detect Cu2+ [18]. However, some cations, such as Ni2+, Fe2+ and Hg2+, seriously disturb the detection of Cu2+ due to the combinations of Ni2+, Fe2+ and Hg2+ with amino groups. Based on the chelation of Cu2+ and the “N” and “O” atoms, Sun et al. developed a polymer nanodots-based fluorescence method to detect Cu2+. Although satisfactory results were obtained, the selectivity results indicated that Fe3+ influence the selectivity [19]. Furthermore, similar phenomena are also found in some of the reported literatures [4, 19,20,21]. Therefore, smart design should be introduced for the construction of Cu2+ detection method with better selectivity.
It has been demonstrated that Cu2+ can not only catalyze the cysteine (Cys) to cystine and produce H2O2 under the O2 atmosphere [22, 23], but also catalyze decomposition of as-produced H2O2 into hydroxyl radicals through Fenton-like reaction [24, 25]. In the present work, using silicon nanoparticles (SiNPs) which with low cytotoxicity, high biocompatibility, good hydrophilicity and stable fluorescence as fluorophore [26], the authors developed a novel method to detect Cu2+ based on the strong oxidizing properties of hydroxyl radicals which were produced by the dual catalytical effects of Cu2+. The fluorescence of SiNPs was quenched significantly by hydroxyl radicals for oxidizing and destroying the surface state of SiNPs, which was proportional to the concentration of Cu2+. This novel method shows high selectivity and sensitivity toward Cu2+ due to the unique dual catalytical effects of Cu2+. Furthermore, the application of this method to detect Cu2+ in real water samples is also demonstrated successfully.
Experimental section
Reagents
(3-Aminopropyl)trimethoxysilane (APTMS) (97%) was purchased from Shanghai Energy Chemical Co., Ltd. (http://www.energy-chemical.com/). Other reagents were purchased from Sinopharm Chemical Reagent Co., Ltd. (http://www.reagent.com.cn:666/ScrcBackGroup/reagent/newindex.jsp), and used directly without further purification. HEPES (10 mM) buffer was prepared by dissolving 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid in ultrapure water and adjusting the pH value to 8.0 with 1 M NaOH. The ultrapure water from a Millipore system (resistance ≥18.2 MΩ cm) was used throughout the experiments.
Apparatus
The UV-vis absorption spectra were measured on a UV2450 spectrophotometer (Shimadzu CO., LTD, Japan). The fluorescence (FL) emission spectra were collected on an F-7000 spectrophotometer (Hitachi CO., LTD, Japan). The Fourier transform infrared (FT-IR) spectra were performed from Nicolet Nexus 670 FT-IR spectrometer (Nicolet Instrument CO., U.S.A.). The microstructures of the SiNPs were examined using a JEOL-1230 transmission electron microscope (JEOL CO., LTD, Japan).
Preparation of silicon nanoparticles and detection of Cu2+
SiNPs were prepared according to the literature [26] (The detailed synthesis process was presented in supplementary material). The detection of Cu2+ was performed at environment temperature (about 20 °C) in pH 8.0, 10 mM HEPES buffer. Firstly, 20 μL SiNPs (600 μg mL−1) solution and 10 μL Cys (50 mM) solution were mixed with 960 μL HEPES buffer. Then, 10 μL of varied concentrations of Cu2+ were added into the mixed solution. The above solutions were incubated for 30 min at environment temperature (about 20 °C). After that, the fluorescence emission spectra were recorded immediately under excitation wavelength at 350 nm. For comparison, other ions including Na+, K+, Ag+, Mg2+, Ni2+, Zn2+, Ca2+, Co2+, Cd2+, Hg2+, Pb2+, Mn2+, Fe2+, Fe3+ and Al3+ were also tested by the same conditions. Each experiment was repeated three times. The error bars represent standard deviation from 3 replicates.
Real water samples analysis
The tap water sample was collected from the lab’s tap in the authors’ institute. The mineral water was collected from the Yuelu mountain (Changsha, China). The river water was collected from the Xiangjiang river (Changsha, China). The real water samples (tap water, mineral water and river water) were simply filtered with cylinder membrane filter (0.22 μm, Pall 66,191, Pall Corporation, USA) and diluted 10 times before the analysis. The following steps were similar to that of fluorescence detection of Cu2+, and the test solutions were spiked with standard solutions including varied concentration of Cu2+. Besides, the analytical results were found by atomic absorption spectrometry (data were performed by an atomic absorption spectrophotometer, Beijing Purkinje General Instrument CO. LTD, China) and from the Chinese National Standard GB/T 7475-1987 (water quality--determination of copper, zinc, lead and cadmium--atomic absorption spectrometry).
Results and discussion
Choice of materials
The morphology and property of nanomaterials have important influence on the performance of fluorescence detection methods. Compared with semiconductor quantum dots (e.g. CdSe, CdS and ZnS etc.), which are usually composed of heavy metals, SiNPs have the advantages of good water dispersibility, low toxicity, resistance to photobleaching and good biocompatibility [27]. On the other hand, the larger specific surface area and abundant surface functional groups of SiNPs make it easy interaction with guest species. Moreover, the SiNPs also have strong fluorescence, which is helpful to improve the detection sensitivity. Therefore, based on the above advantages, the authors developed a fluorescence method to detect Cu2+ by using SiNPs as fluorophore.
Characterization of SiNPs
Transition electron microscopy (TEM) experiments were performed to investigate the morphology of the SiNPs. Fig. 1a shows that a great deal of spherical nanoparticles can be observed in the TEM image and that the SiNPs possess excellent monodispersity and uniform size.. The diameters were calculated to be about 6-8 nm (Fig. 1b). In order to demonstrate the surface structure of the SiNPs, the FT-IR spectra information was collected. As shown in Fig. 1c, the absorption peaks at 1100 cm−1, 1384 cm−1, 1577 cm−1, and 3423 cm−1 are assigned to the Si-O stretching vibration C-O bending vibrations, N-H bending vibrations and the N-H stretching vibration, respectively. The FT-IR results indicated that amino groups are rich on the surface of SiNPs, which is similar with the literature [26]. In addition, as shown in Fig. 1d, the absorption, excitation and emission spectra demonstrated that as-synthesized SiNPs were an outstanding candidate for fluorescent materials. The UV-Vis spectrum shows absorption peak at 350 nm while the maximum fluorescence emission intensity centered at 450 nm when excited at 350 nm.
Mechanism of the fluorescent detection method
The feasibility of using SiNPs for Cu2+ detection was explored. Fig. 2 shows the fluorescence spectra of SiNPs solution under various conditions. It can be seen that under the 350 nm light excitation, the SiNPs exhibits a strong fluorescence emission peak centre at 450 nm. The presence of Cu2+ or Cys alone does not affect the fluorescence of SiNPs. However, presence of both Cu2+ and Cys leads to an obvious decrease of fluorescence intensity of SiNPs, indicating that Cu2+ and Cys can quench the fluorescence of SiNPs effectively. These results indicate that it is feasible to quantify Cu2+ by measuring the fluorescence intensity of SiNPs.
The quenching mechanism was investigated. Previously study indicated that the Cu2+ can catalyze the oxidation of Cys to cystine and produce H2O2 under the O2 atmosphere [22, 23]. The overall process of Cys oxidation as:
The authors inferred that the Cu2+ can further catalyze the decomposition of H2O2 to produce hydroxyl radicals through a Fenton-like reaction [24, 25]. Similar to the reported carbon quantum dots [28, 29] and semiconductor quantum dots [30], the authors further inferred that the surface states of SiNPs may be destroyed and changed by the generated hydroxyl radicals, which results the fluorescence quenching of SiNPs. Control experiments were carried out to demonstrate the fluorescence quenching mechanism. As shown in Fig. S1, the H2O2, cystine, cystine+H2O2 cystine+Cu2+ do not affect the fluorescence of SiNPs. Conversely, as shown in Fig. S1B, the fluorescence of SiNPs was quenched effectively in the presence of both Cu2+ and H2O2. Furthermore, the fluorescence quenching efficiency was decreased to a certain degree when dimethyl sulfoxide (DMSO, a trapping agent of hydroxyl radicals) was added to the solution (Fig. S2A). These results indirectly indicated that the hydroxyl radicals are associated with the fluorescence quenching of SiNPs. Similar to the published literatures that the high activity hydroxyl radicals can destroy the original surface state of SiNPs, resulting the fluorescence quenching of SiNPs [31]. Fig. S2B shows the fluorescence recovers to a certain degree when NaBH4 is added to the solution. Therefore, the authors speculated that the fluorescence quenching of SiNPs was caused by the changes of the surface state of SiNPs through hydroxyl radicals. The detection mechanism is shown in Fig. 3.
Optimization of method
The following parameters were optimized: (a) the concentration of Cys; (b) the concentration of SiNPs; (c) pH and (d) incubation time. Respective data and figures are given in the Electronic Supporting Material (Fig. S3). The following experimental conditions were found to give the best results: (a) the concentration of Cys is 0.5 mM; (b) pH = 8; (c) the concentration of SiNPs is 12 μg mL−1 and (d) an incubation time of 30 min.
The analytical performance of the method
Under optimal conditions, the analytical performance of the method for Cu2+ detection was evaluated. Fig. 4a shows the fluorescence emission spectra of the SiNPs in the presence of various concentrations of Cu2+. It can be seen that the fluorescence of SiNPs at 450 nm decreased gradually with the increasing of Cu2+. The relationship between the fluorescence quenching rate of SiNPs [(F0-F)/F0] and the concentration of Cu2+ is shown in Fig. 4b. It is clearly seen that a good linear correlation is observed over the concentration range of 0.05 μM to 15 μM. The corresponding calibration equation is y = 0.0424× + 0.0663 (R2 = 0.9984), where y and x are the fluorescence quenching rate [(F0-F)/F0] and the concentration of Cu2+, respectively. According to the ratio of 3 times the standard deviation of the blanks to the slope of the linear equation of the calibration curve, the limit of detection (LOD) is calculated as 29 nM. The LOD is lower than the maximum concentration of Cu2+ in drinking water by the US Environmental Protection Agency (20 μM). Table 1 summarizes some nanomaterials-based fluorescence method for Cu2+ analysis [2, 18,19,20,21, 32,33,34,35,36,37,38,39]. Some metal ions with similar chemical properties or ionic radius may affect the interaction between Cu2+ and the fluorescence nanomaterials. Thus, these detection methods had lower selectivity to Cu2+. J. Hwang et al. reported a fluorescence method for the detection of Cu2+ by using electrochemically etch method synthesized porous silicon nanoparticles as a fluorescent probe [39]. However, the detection mechanism of J. Hwang and his coworker is different from the present method. The method of J. Hwang and his coworker was based on the interaction between Cu2+ and porous silicon nanoparticles, which may affected by Fe2+. Conversely, the present method has good selectivity toward Cu2+ due to the dual catalytic effects of Cu2+. Therefore, the authors believe that they provide an effective new approach for the selective detection of Cu2+.
Next, the fluorescence quenching data were further analyzed by the Stern-Volmer equation:
Where I0 and I are the fluorescence intensities of SiNPs in the absence and presence of Cu2+, respectively; cQ is the concentration of the Cu2+; KSV is the Stern-Volmer quenching constant. As shown in Fig. S4, the data do not fit a conventional linear Stern-Volmer equation, indicating both dynamic and static quenching processes occur in the present detection method [19, 36].
In order to evaluate the selectivity of this method for the detection of Cu2+, various relevant metal ions such as Na+, K+, Ag+, Mg2+, Ni2+, Zn2+, Ca2+, Co2+, Cd2+, Hg2+, Pb2+, Mn2+, Fe2+, Fe3+, and Al3+ were investigated. As shown in Fig. 5a, the fluorescence quenching rate caused by Cu2+ is greater than that of other metal ions, indicating that this method has a good selectivity for Cu2+ detection. Although the Fe2+ can react with H2O2 to generate hydroxyl radicals, the Fe2+ can not catalytic the Cys to produce H2O2. Thus, the authors speculate that the selectivity may be due to the unique catalytic reaction between Cu2+ and Cys [22, 23].
Analysis of Cu2+ in real water samples
The practicality of this method to detection of Cu2+ in real samples was further validated by a standard addition method. Certain concentration of Cu2+ standard solutions were directly spiked into the real water samples (tap water, mineral water, river water) before sample pre-treatment. The analysis results are summarized and listed in Table S1. Satisfactory recoveries (94.0%-105.8%) were obtained for all samples, implying that this method has potential application in the detection of Cu2+ in real applications.
Conclusions
In summary, a novel and effective fluorometric method for the detection of Cu2+ has been developed. It is based on the excellent fluorescence properties of SiNPs as well as the the dual catalytical effects of Cu2+. Under the optimal conditions, a relative low detection limit and a good linear for Cu2+ were obtained. Compared with other reported Cu2+ methods which commonly based on the interaction between Cu2+ and the surface groups of the nanomaterials, this method has better selectivity due to the dual catalytical effects of Cu2+. In addition, this method can be applied to the detection of Cu2+ in real samples and obtained satisfactory results, indicating its potential application in practice. This research will provide an effective new approach for the design of Cu2+ selective detection method. Nonetheless, it should be noted that this novel method also has a limitation. As the rapid and on-site detection of Cu2+ is of great significance to human health and pollution treatment. The detection time of this method is 30 min and the response is irreversible, which limits its online detection application. However, this method is still expected for sensitive and reliable detection of Cu2+ due to its high selectivity.
References
Brown DR, Kozlowski H (2004) Biological inorganic and bioinorganic chemistry of neurodegeneration based on prion and Alzheimer diseases. Dalton Trans 13:1907–1917
Zong J, Yang X, Trinchi A, Hardin S, Cole I, Zhu Y, Li C, Muster T, Wei G (2014) Carbon dots as fluorescent probes for “off–on” detection of Cu2+ and L-cysteine in aqueous solution. Biosens Bioelectron 51:330–335
Brady DC, Crowe MS, Turski ML, Hobbs GA, Yao X, Chaikuad A, Knapp S, Xiao K, Campbell SL, Thiele DJ, Counter CM (2014) Copper is required for oncogenic BRAF signalling and tumorigenesis. Nature 509(7501):492–496
Salinas-Castillo A, Ariza-Avidad M, Pritz C, Camprubi-Robles M, Fernandez B, Ruedas-Rama MJ, Megia-Fernandez A, Lapresta-Fernandez A, Santoyo-Gonzalez F, Schrott-Fischer A, Capitan-Vallvey LF (2013) Carbon dots for copper detection with down and upconversion fluorescent properties as excitation sources. Chem Commun 49(11):1103–1105
Smith SR, Zhou C, Baron JY, Choi Y, Lipkowski J (2016) Elucidating the interfacial interactions of copper and ammonia with the sulfur passive layer during thiosulfate mediated gold leaching. Electrochim Acta 210:925–934
Wu J, Boyle EA (1997) Low blank preconcentration technique for the determination of lead, copper, and cadmium in small-volume seawater samples by isotope dilution ICPMS. Anal Chem 69(13):2464–2470
Cassella RJ, Magalhães OIB, Couto MT, Lima ELS, Neves MAFS, Coutinho FMB (2005) Synthesis and application of a functionalized resin for flow injection/F AAS copper determination in waters. Talanta 67(1):121–128
Xu X, Daniel WL, Wei W, Mirkin CA (2010) Colorimetric Cu2+ detection using DNA-modified gold-nanoparticle aggregates as probes and click chemistry. Small 6(5):623–626
Song HD, Choi I, Lee S, Yang YI, Kang T, Yi J (2013) On-chip colorimetric detection of Cu2+ ions via density-controlled plasmonic core–satellites nanoassembly. Anal Chem 85(16):7980–7986
Liu L, Dan F, Liu W, Lu X, Han Y, Xiao S, Lan H (2017) A high-contrast colorimetric and fluorescent probe for Cu2+ based on benzimidazole-quinoline. Sensors Actuators B Chem 247:445–450
Tang S, Wang M, Li Z, Tong P, Chen Q, Li G, Chen J, Zhang L (2017) A novel sensitive colorimetric sensor for Cu2+ based on in situ formation of fluorescent quantum dots with photocatalytic activity. Biosens Bioelectron 89:866–870
Su Y-T, Lan G-Y, Chen W-Y, Chang H-T (2010) Detection of copper ions through recovery of the fluorescence of DNA-templated copper/silver nanoclusters in the presence of mercaptopropionic acid. Anal Chem 82(20):8566–8572
Xu G, Wang J, Si G, Wang M, Xue X, Wu B, Zhou S (2016) A novel highly selective chemosensor based on curcumin for detection of Cu2+ and its application for bioimaging. Sensors Actuators B Chem 230:684–689
Huang C-B, Li H-R, Luo Y, Xu L (2014) A naphthalimide-based bifunctional fluorescent probe for the differential detection of Hg2+ and Cu2+ in aqueous solution. Dalton Trans 43(21):8102–8108
Guo Y, Zhang L, Zhang S, Yang Y, Chen X, Zhang M (2015) Fluorescent carbon nanoparticles for the fluorescent detection of metal ions. Biosens Bioelectron 63:61–71
You Q-H, Lee AW-M, Chan W-H, Zhu X-M, Leung KC-F (2014) A coumarin-based fluorescent probe for recognition of Cu2+ and fast detection of histidine in hard-to-transfect cells by a sensing ensemble approach. Chem Commun 50(47):6207–6210
Kim MH, Jang HH, Yi S, Chang S-K, Han MS (2009) Coumarin-derivative-based off-on catalytic chemodosimeter for Cu2+ ions. Chem Commun 32:4838–4840
Dong Y, Wang R, Li G, Chen C, Chi Y, Chen G (2012) Polyamine-functionalized carbon quantum dots as fluorescent probes for selective and sensitive detection of copper ions. Anal Chem 84(14):6220–6224
Liu S, Tian J, Wang L, Zhang Y, Qin X, Luo Y, Asiri AM, Al-Youbi AO, Sun X (2012) Hydrothermal treatment of grass: a low-cost, green route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an effective fluorescent sensing platform for label-free detection of Cu(II) ions. Adv Mater 24(15):2037–2041
Tian J, Liu Q, Asiri AM, Al-Youbi AO, Sun X (2013) Ultrathin graphitic carbon nitride nanosheet: a highly efficient fluorosensor for rapid, ultrasensitive detection of Cu2+. Anal Chem 85(11):5595–5599
Ma Y-r, Niu H-y, Zhang X-l, Cai Y-q (2011) Colorimetric detection of copper ions in tap water during the synthesis of silver/dopamine nanoparticles. Chem Commun 47(47):12643–12645
Buzuk M, Brinić S, Vladislavić N, Bralić M, Buljac M, Rončević IŠ (2016) Real-time monitoring of “self-oxidation” of cysteine in presence of Cu2+: novel findings in the oxidation mechanism. Monatsh Chem 147(2):359–367
Pecci L, Montefoschi G, Musci G, Cavallini D (1997) Novel findings on the copper catalysed oxidation of cysteine. Amino Acids 13(3):355–367
Masarwa M, Cohen H, Meyerstein D, Hickman DL, Bakac A, Espenson JH (1988) Reactions of low-valent transition-metal complexes with hydrogen peroxide. Are they “Fenton-like” or not? 1. The case of Cu+aq and Cr2+aq. J Am Chem Soc 110(13):4293–4297
Ozawa T, Hanaki A (1991) The first ESR spin-trapping evidence for the formation of hydroxyl radical from the reaction of copper(II) complex with hydrogen peroxide in aqueous solution. J Chem Soc Chem Commun 5:330–332
Feng Y, Liu Y, Su C, Ji X, He Z (2014) New fluorescent pH sensor based on label-free silicon nanodots. Sensors Actuators B Chem 203:795–801
Zhong Y, Peng F, Bao F, Wang S, Ji X, Yang L, Su Y, Lee S-T, He Y (2013) Large-scale aqueous synthesis of fluorescent and biocompatible silicon nanoparticles and their use as highly photostable biological probes. J Am Chem Soc 135(22):8350–8356
Wang H, Lu Q, Hou Y, Liu Y, Zhang Y (2016) High fluorescence S, N co-doped carbon dots as an ultra-sensitive fluorescent probe for the determination of uric acid. Talanta 155:62–69
Wei J, Ren J, Liu J, Meng X, Ren X, Chen Z, Tang F (2014) An eco-friendly, simple, and sensitive fluorescence biosensor for the detection of choline and acetylcholine based on C-dots and the Fenton reaction. Biosens Bioelectron 52:304–309
Mancini MC, Kairdolf BA, Smith AM, Nie S (2008) Oxidative quenching and degradation of polymer-encapsulated quantum dots: new insights into the long-term fate and toxicity of nanocrystals in vivo. J Am Chem Soc 130(33):10836–10837
Chen Q, Liu M, Zhao J, Peng X, Chen X, Mi N, Yin B, Li H, Zhang Y, Yao S (2014) Water-dispersible silicon dots as a peroxidase mimetic for the highly-sensitive colorimetric detection of glucose. Chem Commun 50(51):6771–6774
Lin L, Song X, Chen Y, Rong M, Wang Y, Zhao L, Zhao T, Chen X (2015) Europium-decorated graphene quantum dots as a fluorescent probe for label-free, rapid and sensitive detection of Cu2+ and L-cysteine. Anal Chim Acta 891:261–268
Das P, Ganguly S, Bose M, Mondal S, Das AK, Banerjee S, Das NC (2017) A simplistic approach to green future with eco-friendly luminescent carbon dots and their application to fluorescent nano-sensor ‘turn-off’ probe for selective sensing of copper ions. Mater Sci Eng C 75:1456–1464
Lu L, Feng C, Xu J, Wang F, Yu H, Xu Z, Zhang W (2017) Hydrophobic-carbon-dot-based dual-emission micelle for ratiometric fluorescence biosensing and imaging of Cu2+ in liver cells. Biosens Bioelectron 92:101–108
Lin Y, Wang C, Li L, Wang H, Liu K, Wang K, Li B (2015) Tunable fluorescent silica-coated carbon dots: a synergistic effect for enhancing the fluorescence sensing of extracellular Cu2+ in rat brain. ACS Appl Mater Interfaces 7(49):27262–27270
Chao M-R, Hu C-W, Chen J-L (2016) Fluorometric determination of copper(II) using CdTe quantum dots coated with 1-(2-thiazolylazo)-2-naphthol and an ionic liquid. Microchim Acta 183(4):1323–1332
Deng H-H, Li G-W, Liu A-L, Chen W, Lin X-H, Xia X-H (2014) Thermally treated bare gold nanoparticles for colorimetric sensing of copper ions. Microchim Acta 181(9):911–916
Wang X, Chen L, Chen L (2014) Colorimetric determination of copper ions based on the catalytic leaching of silver from the shell of silver-coated gold nanorods. Microchim Acta 181(1):105–110
Hwang J, Hwang MP, Choi M, Seo Y, Jo Y, Son J, Hong J, Choi J (2016) Sensitive detection of copper ions via ion-responsive fluorescence quenching of engineered porous silicon nanoparticles. Sci Rep 6:35565–35565
Acknowledgments
This work was supported by the National Natural Science Foundation of China (21475043, 21675051 and 21375037).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
The authors declare that they have no competing interests.
Additional information
Research Highlights
• A fluorescence detection method for Cu2+ was developed based on the dual catalytic effects of Cu2+
• Metal ions with similar chemical properties and ionic radius do not influence the selectivity
• The dual catalytic effect of Cu2+ improves selectivity
Electronic supplementary material
ESM 1
(DOC 6.13 MB)
Rights and permissions
About this article
Cite this article
Chen, X., Lu, Q., Liu, D. et al. Highly sensitive and selective determination of copper(II) based on a dual catalytic effect and by using silicon nanoparticles as a fluorescent probe. Microchim Acta 185, 188 (2018). https://doi.org/10.1007/s00604-018-2720-y
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00604-018-2720-y