Drug Testing and Analysis
·
2020
·Vol. 13
·期 3
·720-728
·
IF 2.903
Cui-Mei Liu,Hong-Yuan He,Lin Xu,Zhen-Dong Hua
Performing fast qualitative identification of seized illegal drugs by Raman spectroscopy is challenging due to fluorescence interference as well as chemical complexity. Spectrometers with 785-nm excitation, 1,064-nm excitation, and sequentially shifted excitation (SSE) were compared for their effect on fluorescence reduction. The characteristic peaks method, which is independent of cutting agents, was tested as a new strategy to broaden the application of the Raman technique. The suitability of the characteristic peaks method was fully examined by analyzing a large amount of seized illegal drugs, including 72 methamphetamine hydrochloride (concentration range of 13.9%–99.4%), 68 ketamine hydrochloride (17.7%–99.8%), 176 heroin hydrochloride (5.2%–79.5%), 51 cocaine hydrochloride (21.1%–94.5%), and 33 cocaine base (30.9%–92.5%) samples. The results showed that seized methamphetamine, ketamine, and cocaine samples had no or little fluorescence. Hence, in regard to detection of these samples, the advantage of using 1,064-nm excitation and SSE compared with 785-nm excitation was quite limited. Regarding the heroin samples, a significant improvement of the “high” confident positive detected rate was evident for 1,064 nm excitation (60.8%) and SSE (61.4%), compared with 785-nm excitation (13.1%). However, it was also seen that even if 1,064-nm excitation and SSE were applied, the fluorescence of heroin samples was still unable to be fully overcome. By using the characteristic peaks method, low LOD results of 5%–20% were acquired for 40 types of drug mixtures, and lower LODs were obtained for the 60% of the drug mixtures compared with library searching method. Raman spectroscopy in conjunction with the characteristic peaks method was shown to be fast, simple, accurate, and sensitive in the qualitative analysis of seized drug samples.
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Natural Product Communications
·
2020
·
IF 0.468
Qiushan Zhang,Jin Shao,Tong Zhao,Lei He,Huiping Ma,Linlin Jing
In the present study, the antioxidant property of 4 flavones (moslosooflavone, wogonin, isowogonin, and norwogonin) was evaluated using 6 different assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH·), superoxide (O2 •−), and nitric oxide (NO) radical scavenging assays, ferrous iron chelation, reducing power, and total antioxidant capacity. The 4 flavones exhibited antioxidant activities with decreasing order as norwogonin > isowogonin >> wogonin> moslosooflavone. The present results demonstrated that norwogonin and isowogonin exhibited excellent antioxidant activity, which was mainly based on the presence of C-8 hydroxyl group.
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Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 30
·16411-16417
·
IF 12.732
You Xu,Mingzhen Wang,Kaili Ren,Tianlun Ren,Mengying Liu,Ziqiang Wang,Xiaonian Li,Liang Wang,Hongjing Wang
The development of efficient catalysts for electrocatalytic selective conversion of nitrate pollutants into valuable ammonia is a project of far-reaching importance. This work demonstrated the in situ electroreduction of pre-synthesized CuO nanoplates into defect-rich metallic Cu nanoplates and evaluated their electrocatalytic nitrate-to-ammonia activity. Concentrated atomic defects in the as-converted Cu nanoplates could favor the adsorption, enrichment and confinement of nitrate ions and pivotal reaction intermediates, selectively promoting eight-electron reduction (NH3 formation). Consequently, the resultant defect-rich Cu nanoplates exhibit a significant ammonia production rate of 781.25 μg h−1 mg−1, together with excellent nitrate conversion (93.26%), high ammonia selectivity (81.99%) and good electrocatalytic stability, superior to the defect-free Cu nanoplate counterpart. Isotope labelling experiments demonstrated that the source of ammonia was from nitrate. Both 1H NMR and colorimetric methods were used to quantify the ammonia yield.
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ENVIRONMENTAL POLLUTION
·
2021
·
IF 8.071
Chen Sun,Tong Chen,Qunxing Huang,Xiaoguang Duan,Mingxiu Zhan,Longjie Ji,Xiaodong Li,Jianhua Yan
Porous carbons are appealing low-cost and metal-free catalysts in persulfate-based advanced oxidation processes . In this study, a family of porous biochar catalysts (ZnBC) with different porous structures and surface functionalities are synthesized using a chemical activation agent (ZnCl 2 ). The functional biochars are used to activate persulfate for sulfamethoxazole (SMX) degradation. ZnBC-3 with the highest content of ketonic group (C O, 1.25 at%) exhibits the best oxidation efficiency, attaining a rate constant ( k obs ) of 0.025 min −1 . The correlation coefficient of the density of C O to k obs ( R 2 = 0.992) is much higher than the linearity of the organic adsorption capacity to k obs ( R 2 = 0.694), implying that C O is the intrinsic active site for persulfate activation. Moreover, the volume of mesopore ( R 2 = 0.987), and Zeta potential ( R 2 = 0.976) are also positive factors in PS adsorption and catalysis. In the mechanistic study, we identified that singlet oxygen is the primary reactive oxygen species . It can attack the –NH 2 group aligned to the benzene ring to form dimer products which could be adsorbed on the biochar surface to reach complete removal of the SMX. The optimal pH range is 4–6 which will minimize the electrostatic repulsion between ZnBCs and the reactants. The SMX degradation in ZnBC/PS system was immune to inorganic anions but would compete with organic impurities in the real wastewater . Finally, the biochar catalysts are filled in hydrogel beads and packed in a flow-through packed-bed column. The continuous system yields a high removal efficiency of over 86% for 8 h without decline, this work provided a simple biochar-based persulfate catalyst for complete antibiotics removal in salty conditions.
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ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Hongjing Wang,Qiqi Mao,Tianlun Ren,Tongqing Zhou,Kai Deng,Ziqiang Wang,Xiaonian Li,You Xu,Liang Wang
Achieving high efficiency in nitrate (NO3–) to ammonia (NH3) electrocatalysis requires the exploration of advanced electrocatalysts with a well-designed composition and architecture. In this work, a facile one-step hydrothermal approach was developed for the construction of novel Cu/oxygen vacancy-rich Cu-Mn3O4 heterostructured ultrathin nanosheet arrays on Cu foam (Cu/Cu-Mn3O4 NSAs/CF). Two-dimensional ultrathin nanosheet arrays could increase the exposure of catalytically active centers, and the heterogeneous nanointerface and oxygen vacancies synergistically improve the nitrate-to-ammonia activity over the active centers. Due to the desirable compositional and structural advantages, the Cu/Cu-Mn3O4 NSAs/CF demonstrated excellent performance for the electrocatalytic nitrate reduction to ammonia with high ammonia selectivity (87.6%) and Faradic efficiency (92.4%).
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Advanced Materials Interfaces
·
2021
·Vol. 8
·期 19
·2100588
·
IF 6.147
Jie Guan,Ying-zhuo Shen,Yun Shu,Dangqin Jin,Qin Xu,Xiao-Ya Hu
The high photoluminescence quantum yield (PLQY) of perovskite nanocrystals (PNCs) makes them promising candidates in optoelectronics. However, the easy loss of structural integrity and fast chemical degradation upon exposure to moisture influence their reliable applications in aqueous solutions. Here, a hierarchical surface construction strategy is rationally designed to fulfill an internal–external stabilization of PNCs. Carbon quantum dots (CQDs) and cetyltrimethyl ammonium bromide (CTAB) have been demonstrated stabilized PNCs internally by eliminating the proton transfer-induced ligand desorption. Meanwhile, CTAB acts as a cationic surfactant in consolidating the subsequent SiO 2 coating to prevent the PNCs from external environments. Based on the resulted PNCs, a sensitive and selective fluorescence film sensor for Fe 3+ detection is successfully constructed. The fluorescence of PNCs at 525 nm is quenched after the addition of Fe 3+ in the concentration range from 770 p m to 411 µ m . As Fe 3+ ions attached to the surface of the film are removed with water, the fluorescence of the film can be easily recovered. Owing to this character, the application of the PNCs toward the confidential information encryption has been proved. This work provides an effective design strategy to improve the stability of PNCs and extends their applications in sensing and encryption areas.
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Journal of Functional Foods
·
2021
·
IF 4.451
Liangmiao Luo,Yi Wang,Yihai Wang,Jingwen Xu,Xiangjiu He
Mango is one of the most popular fruit in tropical and subtropical regions of the world. In this study, previously undescribed two sterols ( 1 – 2 ) and one terpenoid ( 10 ), as well as ten known phytochemicals ( 3 – 9 , 11 – 13 ), were isolated and identified from mango fruits. In vitro anti-neuroinflammatory activity of the purified compounds was evaluated and most of them exhibited pronounced bioactivity. Among them, compounds 2 and 5 exhibited the most significant anti-neuroinflammatory effects, which were comparable to that of indomethacin (positive control) and suggested that the sterols in the fruits of mango played important roles for the anti-neuroinflammatory activity. Further, Western blotting, quantitative PCR and immunofluorescence staining assays were performed to confirm that compounds 2 and 5 exerted the anti-neuroinflammatory through the NF-κB pathway. The study provided a phytochemical evidence for further development and utilization of the fruits of mango in health products.
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JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Guifen Zhu,Guohao Cheng,Tong Lu,Zhiguo Cao,Lifang Wang,Qianjin Li,Jing Fan
An ionic liquid functionalized polymer (IL-P) was prepared feasibly and simply by grafting1-butyl-3-vinylimidazolium bromide onto the silica surface. The IL-P was fully characterized, and the results showed that IL-P has a rough surface with a lower specific surface area (205.49 m 2 g −1 ), and the involvement of ionic liquid significantly improved the adsorption performance of IL-P. The pH, initial concentration, adsorption time and temperature were investigated to discuss the adsorption behaviors of IL-P in aqueous solution. The adsorption process of 2,4-dichlorophenol (2,4-DCP), bisphenol A (BPA) and 2,4-dinitrophenol (2,4-DNP) onto IL-P better fitted the pseudo-second-order model, while that of 2-isonaphthol (2-NP) followed the pseudo-first-order model. The adsorption behaviors of IL-P towards 2,4-DCP and 2,4-DNP fitted well with Liu isotherm model, and that of BPA and 2-NP can be described by Langmuir model. The maximum adsorption capacities of 2,4-DCP, BPA, 2,4-DNP and 2-NP bound on IL-P was 239.7, 68.39, 56.86 and 64.28 mg g -1 , respectively, and the adsorption of IL-P is a spontaneous physical process. Comparing with other adsorbent, the as-prepared IL-P showed excellent recognition ability towards the phenolic compounds and can be applied to adsorb and remove trace 2,4-DCP, 2-NP, 2,4-DNP and BPA simultaneously in complicated wastewater and soil samples.
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RSC Advances
·
2019
·Vol. 9
·期 40
·23267-23275
·
IF 3.049
Jianhua Wang,Lishen Zhang,Xiaochun Li,Xiaoliang Zhang,Hua-Zhong Yu
Nowadays quantitative chemical analysis is usually costly, instrument-dependent, and time-consuming, which limits its implementation for remote locations and resource-limited regions. Inspired by the ancient papercutting art (kirigami), we herein introduce a novel cut-and-paste protocol to fabricate 3D microfluidic paper-based analytical devices (μPADs) that are suitable for on-site quantitative assay applications. The preparation of the device is fast, simple, and independent of any lithographic devices or masks. Particularly designed reaction “channels” were pre-cut from a piece of filter paper, then assembled back to the silanized, superhydrophobic paper pads. The different layers of the device were assembled using a chemically-inert adhesive spray. The fabricated device has high efficiency of liquid handling (up to 60 times faster than conventional methods) and it is particularly inexpensive. Beyond the benchtop fabrication advantage, in conjunction with a custom mobile app developed for colorimetric analysis, we were able to quantify representative environmental contaminants (i.e., the amount of Cr(VI) and nitrite ions) in various water samples with the cut-and-paste μPADs (namely kPADs). Their detection limits (0.7 μg mL−1 for Cr(VI) and 0.4 μg mL−1 for nitrite ions, respectively) are comparable with conventional spectrophotometric methods, which confirm the potential of kPADs for on-site environmental/sanitary monitoring and food toxin pre-screening.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Zhen Li,Mei Li,Cong Wang,Xinhui Zhou,Jianfeng Li,Daoliang Li
Based on modified diazo reaction, a novel surface-enhanced resonance Raman scattering (SERRS) method employed for ultrasensitive, highly selective, and ultra-trace determination of nitrite in aquaculture water was demonstrated. The azo dyes, which are formed by 4-aminothiophenol, nitrite, and N-(1-naphthyl) ethylenediamine dihydrochloride in acid conditions, can exhibit high SERS signal on Ag nanoparticles. Subsequently, the concentration of nitrite can be determined from the intensity of SERRS of derivative. Under optimal conditions, a linear relationship between Raman intensity and the nitrite concentration was found in the range of 0.1–15.0 μmol L −1 with a good correlation coefficient (R 2 = 0.9921) at 1380 cm −1 , and the limit of detection can reach as low as 16.4, 24.0, 9.0, and 24.6 nmol L −1 at 1138, 1332, 1380 and 1418 cm −1 , respectively. Additionally, the results indicate that the present method can be applied to detect nitrite in real aquaculture water samples without influence of interfering ions. This study provides a feasible method for accurate, trace, and fast field detection of nitrite in aquaculture water with strong potential to be used for on-line and on-site optical sensors of nitrites.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 12
·1-7
·
IF 5.479
Li Shuhuai,Ma Xionghui,Pang Chaohai,Tian Hai,Xu Zhi,Yang Yan,Lv Daizhu,Ge Huilin
A fluorometric assay is described for the determination of Cd(II) in environmental and agricultural samples. It is making use of a molecularly imprinted polymer (MIP) and aptamer as dual recognition units, while carbon quantum dots (co-doped with sulphur and nitrogen) and gold nanoparticles (SN-CQD/Au) act as the fluorophores. The aptamer-modified MIP was placed on an SN-CQD/Au-modified indium tin oxide glass electrode. Cd(II) was detected with high selectivity by the recognition sites of the aptamer in the MIP. Fluorescence, with excitation/emission peaks at 370/430 nm, is quenched by Cd(II). Response is linear in the 20 pM to 12 nM concentration range. The detection limit is 1.2 pM. The sensor is selective for Cd(II), and recoveries from spiked waters, soils and vegetables real-world samples range between 82.1 and 113.9%.
A fluorescence sensor composed of a molecularly imprinted polymer and an aptamer as a dual identification system for Cd 2+ coupled with and carbon quantum dots (co-doped with sulphur and nitrogen) and gold nanoparticles (SN-CQDs/Au) as fluorescent element that can detect Cd 2+ with high selectivity by a dual-recognition mechanism.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Yunlei Zhou,Fei Li,Hanwen Wu,Yan Chen,Huanshun Yin,Shiyun Ai,Jun Wang
A selective and sensitive electrochemical aptasensing strategy was developed for kanamycin detection based on target-triggered single-strand DNA adsorption on MoS 2 nanosheets and enzymatic signal amplification. Firstly, a Y-shape double-stranded DNA (dsDNA) was designed containing probe DNA, assist DNA (labeled with biotin at its 3′-terminal) and aptamer DNA. Then, in the presence of kanamycin, aptamer DNA can be released from the Y-shape dsDNA structure due to its interaction with kanamycin to form stable conjugate, which will destroy the Y-shape dsDNA structure and lead to the presence of two-fragment of single-stranded DNA (ssDNA) on the remained half-hybrid DNA structure (containing probe DNA and assist DNA). Based on the strong interaction between ssDNA and MoS 2 nanosheets, the half-hybrid DNA structure can be captured on MoS 2 nanosheets modified electrode surface, which triggers the subsequent immobilization of streptavidin-alkaline phosphatase (SA-ALP) compound. Under the catalysis of ALP, p -nitrophenol phosphate (PNPP) is hydrolyzed to produce p -nitrophenol (PNP). Based on the linear relationship between the electrochemical oxidation signal of PNP and kanamycin concentration, kanamycin can be detected with the detection limit of 0.029 nM (S/N = 3). The aptamer-MoS 2 nanosheets based electrochemical biosensor shows good selectivity, reproducibility for kanamycin detection.
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