Compartmentalizing Incompatible Tandem Reactions in Pickering

Subscriber access provided by University of South Dakota

Article

Compartmentalizing Incompatible Tandem Reactions in Pickering Emulsions Enable Visual Colorimetric Detection of Nitramine Explosives Using a Smartphone Zhenyang Xie, Huilin Ge, Jiayan Du, Tao Duan, Guangcheng Yang, and Yi He Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.8b03331 • Publication Date (Web): 28 Aug 2018 Downloaded from http://pubs.acs.org on August 28, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Analytical Chemistry

Compartmentalizing

Incompatible

Tandem

Reactions

in

Pickering Emulsions Enable Visual Colorimetric Detection of Nitramine Explosives Using a Smartphone

Zhenyang Xie a, Huilin Ge a, Jiayan Du b, Tao Duan * a, Guangcheng Yang * c, and Yi He * a

a State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, School of National Defense Science & Technology, Southwest University of Science and Technology, Mianyang, 621010, P. R. China. b School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, P. R. China. c Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, China. *Corresponding author: Prof. Tao Duan, Prof. Guangcheng Yang, and Dr. Yi He, Email: [email protected], [email protected], [email protected].

ACS Paragon Plus Environment

Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 18

ABSTRACT We report a visual colorimetric assay for detection of nitramine explosives

such

as

1,3,5-trinitro-1,3,5-triazinane

(RDX)

and

1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) using a smartphone. This assay is based on compartmentalizing incompatible tandem reactions in Pickering emulsions. The alkaline hydrolysis of RDX or HMX in one Pickering emulsion to produce nitrite ions which auto-diffuses into the other Pickering emulsion to form nitrous acid. It oxidizes the 3,3′,5,5′-tetramethylbenzidine (TMB) to generate yellow TMB diimine. The RGB component change of the optical images is applied to quantitatively determine the RDX and HMX at different reaction temperature. A distinct color change occurs at RDX and HMX concentrations of 1.2 and 12 µM, respectively. The adjusted intensity increases linearly with the increasing of the logarithms of the concentrations of RDX and HMX in range of 1.2-90 µM and 12-90 µM. The limit of detection of RDX and HMX are 96 and 110 nM. Importantly, this assay is employed for the detection of RDX and HMX in real water, proving the applicability of the assay in real-word samples.

KEYWORDS: 1,3,5-trinitro-1,3,5-triazinane, 1,3,5,7-tetranitro-1,3,5,7-tetrazocane, visual colorimetry, Pickering emulsion, smartphone


Page 3 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


INTRODUCTION The reliable detection of explosives is indispensable for public security, forensic science, and environmental monitoring.1-3 The nitramine explosives containing 1,3,5-trinitro-1,3,5-triazinane (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) are widely utilized in explosive devices, plastic bonded explosives, and also in terrorism acts.4-6 The current analytical methods for detection of HMX and RDX include ion mobility spectroscopy, surface enhanced Raman spectroscopy, immunoassays, and chromatography.7-10 However, such assays require expensive instruments and laborious preconcentration process, restricting their applicability. To meet the requirement for quick decision, visual optical detection with outstanding advantages in terms of response time, experimental operation, and instrumentation equipment,11-21 such as colorimetric methods, has been developed for detection of RDX and HMX. For instance, Apak’s group developed a visual colorimetric assay for RDX and HMX based on 4-aminothiophenol functionalized Au nanoparticles (AuNPs) and naphthylethylene diamine (NED) as a coupling agent .22 The alkaline hydrolysis of RDX produces nitrite ions (NO2-, Scheme S1), followed by neutralization with an acid. The resulting NO2- reacts with 4-aminothiophenol on the surface of AuNPs under acidic conditions to generate a diazonium salt that further reacts with NED for azo-dye formation, leading to a bathochromic shift in the absorption band of AuNPs due to charge-transfer interaction at nanoparticle surface. Despite the promising results achieved the reported colorimetric assays, some limitations still remain. Firstly, the formed AuNPs are not stable, which easily aggregates and grows with time, causing color diminution of nanoparticle dispersion.23 Secondly, the detection method involves two incompatible reactions, alkaline hydrolysis of RDX and acid-assisted azo-dye formation. The two incompatible reactions have to be separately performed, which increases the complexity and thus may affect the repeatability. In addition, they are not suitable for on-site detection because the bulky UV-vis spectrometers are employed. Recently, Pickering emulsions which are stabilized by solid particles have been



Page 4 of 18

demonstrated to play a key role in biphasic catalysis.24-26 The liquid of Pickering emulsion is compartmentalized into several micrometer-sized droplets which facilitates mass transfer through the autodiffusion.27,

28

Compared with traditional

surfactant-stabilized droplets, these micrometer-sized droplets have a better stability. More importantly, these droplets compartmentalized by particles are able to confine chemical reactions of interest to them.29 Although the Pickering emulsion-based biphasic catalysis has been extensively investigated, the construction of analytical methods for detection of explosives using Pickering emulsions has not been explored. Herein, we demonstrate a strategy to compartmentalize incompatible tandem reactions in Pickering emulsions for visual colorimetric detection of RDX and HMX using a smartphone. As illustrated in Figure 1, two parent water-in-oil (w/o) Pickering emulsions are prepared by using partially hydrophobic polystyrene (PS) nanoparticles as emulsifier. In one Pickering emulsion, 3,3′,5,5′-tetramethylbenzidine (TMB) as the chromogenic substrate and hydrochloric acid are dissolved into water droplets. In the other Pickering emulsion, NaOH and RDX or HMX are dissolved into water droplets as well. Subsequently, two parent Pickering emulsions are mixed together, the resulting NO2- from the alkaline hydrolysis of RDX or HMX in one Pickering emulsion auto-diffuses into the other Pickering emulsion, which meets acid to form nitrous acid (HNO2) with strong oxidation property. The generated HNO2 further oxidizes TMB to generate yellow TMB diimine (oxTMB) with an intense absorption, allowing for visual detection of RDX or HMX. The corresponding optical images are collected by the camera of the smartphone, the RGB component change of the images is applied to quantitatively determine the RDX or HMX. In the detection system, the acid and based are confined to different water droplets, which avoids them direct contact. In addition, RDX is hydrolyzed enough at room temperature, while HMX is only hydrolyzed at 60 °C22. Therefore, we can respectively determine the RDX and HMX by altering the reaction temperature. Moreover, the present visual colorimetric method is used to analyze RDX and HMX in real water samples.


Page 5 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 1. Schematic illustration of the visual colorimetric detection of RDX/HMX based on one-pot tandem reactions in Pickering emulsions. EXPERIMENTAL SECTION Chemicals. RDX and HMX were kindly provided by China Academy of Engineering Physics.

Styrene,

poly(vinylpyrrolidone)

(PVP,

Mw

=

40000

g/mol),

2,2-azobis(2-methylpropionamidine) (AIBA), and TMB were purchased from Aladdin Bio-Chem Technology Co., Ltd (Shanghai, China). Hydrochloric acid, n-hexane, sodium hydroxide (NaOH), hexamethylenetetramine, and other inorganic salts were received from ChengDu KeLong Co., Ltd (Chendu, China). The pure water (18.2 MΩ·cm) obtained from Yili YL-100BU water purification system (Shenzhen, China) was utilized to prepare various solutions. Preparation of polystyrene nanoparticles. The PS NPs were prepared by the reported protocol30, 31. Briefly, 0.824 g PVP and 0.01 g AIBA are dissolved in 50 mL pure water. After that, 5 g styrene was added to the above solution under stirring. The solution was heated to 70 °C. After reaction for 24 h at 70 °C, the mixture solution was cool down to room temperature. The reaction product was purified by centrifugation at 14000 rpm and rinsed repeatedly with pure water to remove the residual AIBA and styrene. Tandem reactions in Pickering emulsions for visual colorimetric detection of



RDX and HMX. One Pickering emulsion was prepared with 40 µL of NaOH solution (0.2 M), 0.3 mL of PS NP dispersion (50 mg mL-1), 0.487 mL of pure water, 0.6 mL of n-hexane, and 0.2 mL RDX solution with different concentrations (0-90 µM) through ultrasonication (1 min). The other Pickering emulsion was formulated with 0.3 mL of PS NP dispersion (50 mg mL-1), 0.513 mL of 0.5 mM TMB solution, and 0.29 mL of 0.1 M HCl solution. After mixing the two Pickering emulsions, the tandem reactions were conducted at room temperature for 5 min under static conditions. Finally, the optical image of the reaction solution was recorded with the camera of a smartphone. The RGB component values of the images were subtracted by Color Helper software. The adjusted intensity (I) was calculated by following equation. I=1- (IR + IG + IB/ IbR + IbG + IbB) Where IR, IG, IB and IbR, IbG, IbB are the RGB component intensities in the presence and absence of RDX, respectively. For detection of HMX, a similar experimental process was performed, except that the tandem reactions proceeded at 60 °C. To investigate the selectivity of this assay, hexamethylenetetramine, inorganic ions, and some camouflage materials, including mineral water, bread extract, eye drop, and shampoo are chosen as the potential interferences. The bread extract is prepared by agitating the 0.2 g bread and acetone (20 mL), followed by centrifugation and filtration. The bread extract and other liquid camouflage materials were diluted 100 times with pure water. The experimental procedure is as the same with mentioned above. Real water sample analysis. Lake water and river water samples were collected from Southwest University of Science and Technology campus and Fujiang River (Mianyang, China), respectively. The obtained water samples were filtered and diluted 100 times with pure water, which were spiked with RDX or HMX standards. The spiked samples were analyzed by the same protocol mentioned above. RDX wastewater samples were provided by Sichuan Yahua Industrial Group Co., LTD. The resulting wastewater samples were filtered and diluted 100 times with pure ACS Paragon Plus Environment

Page 6 of 18

Page 7 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


water as well, which were further determined by this assay and gas chromatography mass spectrometry, respectively. Instruments. UV-vis absorption spectra were carried out by using a UV-1800 spectrophotometer (Shimadzu, Japan). The optical image of the Pickering emulsions was collected from a ZOOM 62OE microscope (Shanghai Changfang Optical instrument Co.,Ltd., China). The surface morphology and size of the PS NPs were characterized by MAIA3LMU scanning electron microscopy (TESCAN, Czech). RESULTS AND DISCUSSION Despite the fact that small molecule surfactant-based emulsions have the capacity of compartmentalizing incompatible chemicals, the trapping time is very short, which cannot be used to perform chemical reactions.28 The PS NPs are applied as emulsifier because they are partially hydrophobic and have narrow size distribution, which are favorable for formation of w/o type Pickering emulsion.28 SEM images of the PS NPs demonstrate their size of approximate 100 nm (Figure 2a). The Pickering emulsion is prepared by ultrasonicating a mixture of pure water, n-hexane, and PS NPs, in which bulk water is compartmentalized to droplets of about 10 µm in diameter as is evident from the optical microscopy photography (Figure 2b). To infer the emulsion type, the obtained Pickering emulsion with water-soluble TMB diimine (Figure S1) is added to a certain volume of pure water. As shown in Figure S2, a yellow Pickering emulsion-water interface is clearly observed, indicating that the yellow TMB diimine is not able to diffuse into the water phase because it is confined by surrounding oil. This result demonstrate that the type of the resulting Pickering emulsione is w/o. In order to verify the feasibility of the one-pot tandem reactions in Pickering emulsions for detection of RDX, a set of experiments are conducted as illustrated in Figure 2c and 2d. The detection system is formulated by mixing two Pickering emulsions. Only when one Pickering emulsion contains RDX and NaOH, and the other Pickering emulsion includes TMB and HCl, a yellow solution is obtained (Figure 2c). In the typical two control experiments, the HCl or NaOH is absent in the Pickering emulsion system, the chromophore reaction of TMB does not occur, demonstrating the presence of the one-pot tandem reactions because both base and ACS Paragon Plus Environment


acid are essential.

Figure 2. (a) SEM image of PS NPs. (b) Optical microscopy image of PS NP-stabilized Pickering emulsions. (c, d) Optical images and the corresponding UV-vis absorption spectra of the detection system after centrifugation under different conditions: i) RDX and NaOH in one Pickering emulsion, TMB in the other Pickering emulsion, ii) RDX in one Pickering emulsion, TMB and HCl in the other Pickering emulsion, iii) RDX and NaOH in one Pickering emulsion, HCl in the other Pickering emulsion, iv) NaOH in one Pickering emulsion, TMB and HCl in the other Pickering emulsion, v) RDX and NaOH in one Pickering emulsion, TMB and HCl in the other Pickering emulsion. (e) Color change mechanism of TMB by oxidation. To identify the reaction product, we centrifugate the detection solution to remove the PS NPs and measure the UV-vis absorption spectra of the supernatant. A strong absorbance peak at 440 nm is found, which is ascribe to the absorption of TMB diimine (Figure 2e).20 The effect of NO2- and HCHO that are two hydrolysis products of RDX are further studied in Figure S3. The introduction of NO2- causes a yellow solution as well, while there is no response in the presence of HCHO, proving that the


Page 8 of 18

Page 9 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


resulting NO2- from alkaline hydrolysis of RDX induces the generation of the TMB diimine. In order to confirm the oxidizability of TMB by HNO2, different concentrations of NaNO2 solutions are injected into acidic TMB. As shown in Figure S4, with increasing NaNO2 concentration from 0 to 70 µM, the absorbance of the reaction solution at 440 nm gradually increases, confirming that HNO2 can be directly oxidize TMB to produce TMB diimine. Additionally, As Figure S5 shows, the ion chromatogram of the RDX-NaOH mixture solution provides a direct evidence for the creation of NO2- from alkaline hydrolysis of RDX. All the results reveal that the Pickering emulsion-based one-pot tandem reactions are appropriate for visual colorimetric detection of RDX. Prior to evaluate the capacity of the Pickering emulsion-based one-pot tandem reactions to quantitatively determine RDX, various experimental conditions like NaOH concentration, HCl concentration, and TMB concentration have been optimized based on the adjusted intensity (I). The hydrolysis of RDX is directly dependent on the NaOH concentration. It is found that the maximum adjusted intensity presents at the NaOH concentration of 3 mM, which is selected as optimized one for the following experiment (Figure S6). Because the NaOH with a high concentration (more than 3 mM) may partially diffuse from one Pickering emulsion to the other Pickering emulsion with HCl, which consumes HCl and restrains the oxidation of TMB. The HCl is necessary for the generation of HNO2 that oxidizes TMB in the detection system. The influence of HCl concentration on the adjusted intensity is studied and shown in Figure S7. When the HCl concentration is kept at 10 mM, the adjusted intensity shows the maximum value. The reason is that a modest HCl concentration boosts the production of HNO2, whereas a high level of HCl will cause analyte loss, because it has been well established that nitrous acid decomposes into nitrogen oxides at higher acidities. In consequence, 10 mM of HCl is chosen in the following studies. Apart from the concentrations of NaOH and HCl, the TMB concentration as the chromogenic substrate is further optimized. The adjusted intensity value increases ACS Paragon Plus Environment


with increasing concentration of TMB from 1 to 90 µM and leveled off at 90 µM (Figure S8), suggesting that 90 µM of TMB is adequate for the detection system. Consequently, 90 µM of TMB is used for the detection system. Under the above-mentioned optimal experimental conditions, the colorimetric response of the detection system toward RDX at different concentrations is investigated. Figure 3a depicts the color tonality of the detection system with various amounts of RDX. The color change in the presence of 1.2 µM RDX can be detected with the naked eye. What is more, as can be seen in Figure 3b, the adjusted intensity shows a linear relationship with the logarithm of RDX concentration in the range from 1.2 to 90 µM. The limit of detection for RDX is calculated to be 96 nM at a signal-to-noise ratio (S/N) of 3. This sensitivity is comparable to or even better than that of previously reported assays for RDX detection.5,22 In particular, the present assay is cost-effective and facile, which does not involve any bulky equipment. Accordingly, this assay is very promising for on-site detection of RDX using a portable smartphone.

Figure 3. (a) Optical images of the Pickering emulsion-based detection solution after addition of different concentrations of RDX in the range of 0-90 µM. (b) The linear relationship of the adjusted intensity (I) versus the logarithm of RDX concentration from 1.2 to 90 µM. More significantly, the detection system is also capable of being applied to


Page 10 of 18

Page 11 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


determine HMX by increasing the reaction temperature to 60 °C. The alkaline hydrolysis of HMX is triggered at 60 °C to yield NO2-, which is verified by ion chromatography as illustrated in Figure S9. Analogous to the colorimetric detection of RDX, addition of HMX with various concentrations into the detection system causes different colors (Figure 4a). The assay enables visual detection of HMX at a concentration of 12 µM. The corresponding linear range for detection of HMX is from 12 to 90 µM, which is narrow than that of the RDX detection at room temperature. This is because the alkaline hydrolysis of RDX is much easier than that of HMX thanks to their stable molecule structure. The LOD for HMX is estimated to be 0.11 µM (S/N=3).

Figure 4. (a) The photographs of the Pickering emulsion-based detection system in the presence of HMX at various concentrations within 12-90 µM. (b) Linear calibration plot for HMX detection. Furthermore, the selectivity of this Pickering emulsion-based detection system for detection of RDX and HMX is examined by using hexamethylenetetramine (HEX, the precursors of RDX and HMX), common inorganic ions, and some camouflage materials (mineral water (MW), bread extract (BE), eye drop (ED), and shampoo (SAP)) that may be used to hide explosives as the potential interferences. As indicated in Figure 5, the adjusted intensities of HEX, inorganic ions even if their concentrations are ten times higher than that of RDX or HMX, and camouflage materials are almost negligible, while the distinct adjusted intensities are obtained for RDX and HMX, testifying that this colorimetric assay has a satisfactory selectivity for ACS Paragon Plus Environment


analysis of RDX and HMX. Meanwhile, HMX does not disturb the detection of RDX (Figure 5a) because it can not be hydrolyzed at room temperature.

Figure 5. Selectivity of the Pickering emulsion-based colorimetric assay for (a) RDX and (b) HMX towards their precursors and common inorganic ions. The concentrations of RDX, HMX, HEX, and inorganic ions are 70 µM, 70 µM, 700 µM, and 700 µM, respectively. The mineral water (MW), bread extract (BE), eye drop (ED), and shampoo (SAP) are diluted 100 times with pure water. Lastly, to assess the practical application of this Pickering emulsion-based detection system, we apply it for determination of RDX and HMX in natural water samples. Different concentrations of RDX (2, 20, 50, and 70 µM) and HMX (12, 30, 50, and 70 µM) are spiked to 100-fold diluted river water and lake water, respectively, and


Page 12 of 18

Page 13 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


analyzed by the present colorimetric assay. As listed in Table 1 and Table 2, the recoveries range from 95% to 108% and from 91% to 105% for detection of RDX and HMX, respectively. The corresponding relative standard deviation (RSD) values are less than 6.0%. Besides, the RDX wastewater samples are analyzed by this assay and gas chromatography mass spectrometry (GC-MS)32, respectively. The detection results from the presenting assay are in good agreement with those measured by GC-MS (Table 3). All the results unambiguously attest that the present colorimetric assay has a great potential to monitor the RDX and HMX in real water samples. Table 1. Recovery results for detection of RDX in natural water samples Sample

River water

Lake water

Added (µM)

Determined (µM)

Recovery (%) RSD (%, n=3)

2

2.05

105

1.9

20

21.6

108

0.5

50

51

102

1.6

70

69.3

99

0.7

2

2.06

103

1.2

20

19

95

3.4

50

48.5

97

2.2

70

67.9

97

0.4

Table 2. Recovery rates for detection of HMX in real water samples Sample Added (µM) Determined (µM)

River water

Lake water

Recovery (%)

RSD (%, n=3)

12

11.7

97.5

4.4

30

27.6

92

5.8

50

49.5

99

1.5

70

73.5

105

3.8

12

11.8

98.3

4.3

30

29.1

97

5.6

50

45.5

91

0.5

70

67.9

97

2.3



Page 14 of 18

Table 3. Comparison of detection results obtained in the analysis of RDX wastewater by this assay and GC-MS Sample

RDX found by

RDX found by

this assay (µM)

GC-MS (µM)

1

3.2

3.3

2

5.6

5.8

3

8.2

8.3

4

10.3

10.8

CONCLUSIONS In summary, we compartmentalizing incompatible tandem reactions in Pickering emulsions to develop a visual colorimetric assay for nitramine explosives using a smartphone. The alkaline hydrolysis of nitramine explosives and acid-assisted chromogen of TMB are realized in a single vessel. The resulting colorimetric assay permits for visual and sensitive detection of RDX and HMX at different reaction temperature, respectively. Also, this colorimetric assay exhibits a good selectivity and has been utilized to determine RDX and HMX in real water samples with satisfactory recoveries. The innovative Pickering emulsion-based detection system is easily extended to detect other analytes based on several chemical and biological reactions, which has vast application prospects in environmental monitoring, food analysis, and disease diagnosis.

ASSOCIATED CONTENT Supporting Information Figure S1-S9. This material is available free of charge via the Internet at http://pubs.acs.org.


Page 15 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


AUTHOR INFORMATION Corresponding Author *E-mail: [email protected], [email protected], [email protected] Notes The authors declare no competing financial interests.

ACKNOWLEDGEMENTS The support of this research by the Longshan Scholars Programme of Southwest University of Science and Technology (Grant No. 18LZX204 and 17LZX449), and the China Academy of Engineering Physics Foundation (18zh005603) is gratefully acknowledged.

REFERENCES (1) Geng, Y.; Ali, M. A.; Clulow, A. J.; Fan, S.-Q.; Burn, P. L.; Gentle, I. R.; Meredith, P.; Shaw. P. E. Nat. Commun. 2015, 6, 8240. (2) Hu, Z.-C.; Deibert, B. J.; Li, J. Chem. Soc. Rev. 2014, 43, 5815-5840. (3) Khatua, S.; Goswami, S.; Biswas, S.; Tomar, K.; Jena, H. S.; Konar, S. Chem.

Mater. 2015, 27, 5349-5360. (4) Gopalakrishnan, D.; Dichtel, W. R. Chem. Mater. 2015, 27, 3813-3816. (5) Mosca, L.; Behzad, S. K.; Pabel Anzenbacher, J. J. Am. Chem. Soc. 2015, 137, 7967- 7969. (6) Peng, T.-H.; Qin, W.-W.; Wang, K.; Shi, J.-Y.; Fan, C.-H.; Li, D. Anal. Chem. 2015, 87, 9403-9407. (7) Moros, J.; Laserna, J. J. Anal. Chem. 2011, 83, 6275-6285. (8) Tabrizchi, M.; ILbeigi, V. J. Hazard. Mater. 2010, 176, 692-696. (9) Beller,H. R.; Tiemeier, K. Sci. Technol. 2002, 36, 2060-2066. (10) Babaee, S.; Beiraghi, A. Anal. Chim. Acta 2010, 662, 9-13. (11) Zhou, Y.; Zhang, J.-F.; Yoon, J.-Y. Chem. Rev. 2014, 114, 5511-5571. (12) Huang, W.; Xie, Z.-Y.; Deng, Y.-Q.; He Y. Sensor. Actuat. B-Chem. 2018, 254, 1057-1060. ACS Paragon Plus Environment


(13) Yetisen, A. K.; Montelongo, Y.; Qasim, M. M.; Butt, H.; D, T. Wilkinson, M. J. Monteiro, S. H. Yun. Anal. Chem. 2015, 87, 5101-5108. (14) Li, R.; An H.-J.; Huang, W.; He, Y. Sensor. Actuat. B-Chem. 2018, 259, 59-63. (15) Huang, W.; Zhou, Y.; Du, J.-Y.; Deng, Y.-Q.; He, Y. Anal. Chem. 2018, 90, 2384-2388. (16) Yue, G.-Z.; Su, S.; Li, N.; Shuai, M.-B.; Lai, X.-C.; Astruc, D.; Zhao, P.-X.

Coordin. Chem. Rev. 2016, 311, 75-84. (17) Huang, W.; Zhou, Y.; Deng, Y.-Q.; He, Y. Phys. Chem. Chem. Phys. 2018, 20, 4347. (18) Zhou, Y.; Huang, W.; He, Y. Sensor. Actuat. B-Chem. 2018, 270, 187-191. (19) Feng, C.-J.; Dai, S.; Wang, L. Biosens. Bioelectron. 2014, 59, 64-74. (20) Huang, W.; Deng, Y.-Q.; He, Y. Biosens. Bioelectron. 2017, 91, 89-94. (21) Yu, H.-L.; Long, D.-Y.; Huang W. Sensor. Actuat. B-Chem. 2018, 264, 164-168. (22) Üzer, A. e.; Can, Z.; Akın, I. I.; Erçağ, E.; Apak, R. Anal. Chem. 2013, 86, 351-356. (23) Guo, L.-H.; Xu, Y.; Ferhan, A. R.; Chen, G.-N.; Kim, D.-H. J. Am. Chem. Soc. 2013, 135, 12338-12345. (24) Zhang, M.; Wei, L.-J.; Chen, H.; Du, Z.-P.; Binks, B. P.; Yang, H.-Q. J. Am.

Chem. Soc. 2016, 138, 10173-10183. (25) Chen, Z.-W.; Zhao, C.-Q.; Ju, E.-G.; Ji, H.-W.; Ren, J.-S.; Binks, B. P.; Qu, X.-G.

Adv. Mater. 2016, 28, 1682-1688. (26) Lu, X.-C.; Katz, J. S.; Schmitt, A. K.; Moore, J. S. J. Am. Chem. Soc. 2018, 140, 3619-3625. (27) Chen, Z.-W.; Zhou, L.; Bing, W.; Zhang, Z.-J.; Li, Z.-H.; Ren, J.-S.; Qu, X.-G. J.

Am. Chem. Soc. 2014, 136, 7498-7504. (28) Yang, H.-Q.; Fu, L.-M.; Wei, L.-J.; Liang, J.-F.; Binks, B. P. J. Am. Chem. Soc. 2015, 137, 1362-1371. (29) Huang, J.-P.; Cheng, F.-Q.; Binks, B. P.; Yang, H.-Q. J. Am. Chem. Soc. 2015, 137, 15015-15025.


Page 16 of 18

Page 17 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(30) Yang, X.-M.; Ge, D.-T.; Wu, G.-X.; Liao, Z.-W.; Yang, S. ACS Appl. Mater.

Inter. 2016, 8, 16289-16295. (31) Kang, D. J.; Cho, H.-H.; Lee, I.; Kim, K.-H.; Kim, H. J.; Liao, K.; Kim, T.-S.; Kim, B. J. ACS Appl. Mater. Inter. 2015, 7, 2668-2676. (32) Sharma, S. P.; Lahiri, S. C. J. Energ. Mater. 2005, 23, 239-264.



Page 18 of 18

NaOH NO2-

RDX/HMX Pikering emulsion

HCl

O2N

NO2 N

TMB

O2N

N

N N

N NO2

O2N

HNO2 oxTMB

NO2

N N

RDX

HMX

NO2

Smartphone

R

G

B


Compartmentalizing Incompatible Tandem Reactions in Pickering

Recommend Documents