A New Covalent Organic Framework of Dicyandiamide-Benzaldehyde Nanocatalytic Amplification SERS/RRS Aptamer Assay for Ultratrace Oxytetracycline with the Nanogold Indicator Reaction of Polyethylene Glycol 600

In this paper, dicyandiamide (Dd) and p-benzaldehyde (Bd) were heated at 180 ∘C for 3 h to prepare a new type of stable covalent organic framework (COF) DdBd nanosol with high catalysis. It was characterized by molecular spectroscopy and electron microscopy. The study found that DdBd had a strong catalytic effect on the new indicator reaction of polyethylene glycol 600 (PEG600)-chloroauric acid to form gold nanoparticles (AuNPs). AuNPs have strong resonance Rayleigh scattering (RRS) activity, and in the presence of Victoria Blue B (VBB) molecular probes, they also have a strong surface-enhanced Raman scattering (SERS) effect. Combined with a highly selective oxytetracycline (OTC) aptamer (Apt) reaction, new dual-mode scattering SERS/RRS methods were developed to quantitatively analyze ultratrace OTC. The linear range of RRS is 3.00 × 10−3 –6.00 × 10−2 nmol/L, the detection limit is 1.1 × 10−3 nmol/L, the linear range of SERS is 3.00 × 10−3–7.00 × 10−2 nmol/L, and the detection limit is 9.0 × 10−4 nmol/L. Using the SERS method to analyze OTC in soil samples, the relative standard deviation is 1.35–4.78%, and the recovery rate is 94.3–104.9%.

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Quantitative Determination of Acetamiprid in Pollen Based on a Sensitive Enzyme-Linked Immunosorbent Assay

Molecules ◽

10.3390/molecules24071265 ◽

2019 ◽

Vol 24 (7) ◽

pp. 1265 ◽

Cited By ~ 2

Author(s):

Qingkui Fang ◽

Quan Zu ◽

Xiude Hua ◽

Pei Lv ◽

Wanwen Lin ◽

...

Keyword(s):

Monoclonal Antibody ◽

Detection Limit ◽

Quantitative Determination ◽

Immunosorbent Assay ◽

Linear Range ◽

Enzyme Linked Immunosorbent Assay ◽

Experimental Conditions ◽

Coating Antigen ◽

Relative Standard

A sensitive biotinylated indirect competitive enzyme-linked immunosorbent assay (Bic-ELISA) was developed to detect acetamiprid pesticides in pollen, based on the heterogeneous coating antigen and biotinylated anti-acetamiprid monoclonal antibody. Under optimized experimental conditions, the detection limit for the Bic-ELISA was 0.17 ng/mL and the linear range was 0.25–25 ng/mL. The cross-reactivities could be regarded as negligible for the biotinylated antibodies with their analogues except for thiacloprid (1.66%). Analyte recoveries for extracts of spiked pollen (camellia pollen, lotus pollen, rape pollen) ranged from 81.1% to 108.0%, with intra-day relative standard deviations (RSDs) of 4.8% to 10.9%, and the average reproducibility was 85.4% to 110.9% with inter-assay and inter-assay RSDs of 6.1% to 11.7%. The results of Bic-ELISA methods for the Taobao’s website samples were largely consistent with HPLC-MS/MS. Therefore, the established Bic-ELISA methods would be conducive to the monitoring of acetamiprid in pollen.

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2D covalent organic framework thin films via interfacial self-polycondensation of an A2B2 type monomer

Chemical Communications ◽

10.1039/d0cc00758g ◽

2020 ◽

Vol 56 (22) ◽

pp. 3253-3256 ◽

Cited By ~ 1

Author(s):

Bowen Zhang ◽

Xiaoyu Song ◽

Yusen Li ◽

Yang Li ◽

Zhongxiang Peng ◽

...

Keyword(s):

Thin Films ◽

Detection Limit ◽

Rapid Response ◽

Covalent Organic Framework ◽

Low Detection Limit ◽

Good Repeatability ◽

Organic Framework

Highly crystalline and oriented 2D Py-COF thin films were readily fabricated via an elaborately designed A2B2 monomer, and served as stable acidichromism sensors with rapid response, low detection limit and good repeatability.

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A new hydrazone-linked covalent organic framework for Fe(Ⅲ) detection by fluorescence and QCM technologies

CrystEngComm ◽

10.1039/d1ce00212k ◽

2021 ◽

Author(s):

Dian-Mei Li ◽

Shu-Yuan Zhang ◽

Jia-Yi Wan ◽

Wen-Qian Zhang ◽

Yi-Lun Yan ◽

...

Keyword(s):

Detection Limit ◽

Biological Systems ◽

Covalent Organic Framework ◽

Low Detection Limit ◽

New Sensors ◽

Excellent Selectivity ◽

Organic Framework

Since Fe(III) ion is of importance in biological systems, the development of new sensors for detecting Fe(III) with excellent selectivity and low detection limit is desirable. Herein, a new stable...

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Tuning the pore structures and photocatalytic properties of a 2D covalent organic framework with multi-branched photoactive moieties

Nanoscale ◽

10.1039/d0nr02994g ◽

2020 ◽

Vol 12 (30) ◽

pp. 16136-16142

Author(s):

Xuan Wang ◽

Ming-Jie Dong ◽

Chuan-De Wu

Keyword(s):

Photocatalytic Properties ◽

Effective Strategy ◽

Covalent Organic Framework ◽

Highly Efficient ◽

Pore Structures ◽

Local Connection ◽

Organic Framework

An effective strategy to incorporate accessible metalloporphyrin photoactive sites into 2D COFs by establishing a 3D local connection for highly efficient photocatalysis was developed.

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Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽

10.1557/adv.2020.416 ◽

2020 ◽

Vol 5 (63) ◽

pp. 3353-3360

Author(s):

Susana Helena Arellano Ramírez ◽

Perla García Casillas ◽

Christian Chapa González

Keyword(s):

Gold Nanoparticles ◽

Polyethylene Glycol ◽

Room Temperature ◽

Colloidal Stability ◽

Infrared Spectrometry ◽

Ammonium Bromide ◽

Chloroauric Acid ◽

Vis Spectroscopy ◽

Seed Mediated ◽

Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

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A Three-Dimensional Tetraphenylethylene-Based Fluorescence Covalent Organic Framework for Molecular Recognition

10.26434/chemrxiv.12982019 ◽

2020 ◽

Author(s):

Junxia Ren ◽

Yaozu Liu ◽

Xin Zhu ◽

Yangyang Pan ◽

Yujie Wang ◽

...

Keyword(s):

Molecular Recognition ◽

Fluorescence Probe ◽

Three Dimensional ◽

Hazardous Substances ◽

Covalent Organic Framework ◽

Highly Sensitive ◽

Volatile Organic ◽

Polycyclic Aromatic ◽

Better Than ◽

Organic Framework

<a></a><a></a><a></a><a></a><a></a><a></a><a></a><a>The development of highly-sensitive recognition of </a><a></a><a></a><a></a><a></a><a>hazardous </a>chemicals, such as volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs), is of significant importance because of their widespread social concerns related to environment and human health. Here, we report a three-dimensional (3D) covalent organic framework (COF, termed JUC-555) bearing tetraphenylethylene (TPE) side chains as an aggregation-induced emission (AIE) fluorescence probe for sensitive molecular recognition.<a></a><a> </a>Due to the rotational restriction of TPE rotors in highly interpenetrated framework after inclusion of dimethylformamide (DMF), JUC-555 shows impressive AIE-based strong fluorescence. Meanwhile, owing to the large pore size (11.4 Å) and suitable intermolecular distance of aligned TPE (7.2 Å) in JUC-555, the obtained material demonstrates an excellent performance in the molecular recognition of hazardous chemicals, e.g., nitroaromatic explosives, PAHs, and even thiophene compounds, via a fluorescent quenching mechanism. The quenching constant (KSV) is two orders of magnitude better than those of other fluorescence-based porous materials reported to date. This research thus opens 3D functionalized COFs as a promising identification tool for environmentally hazardous substances.

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The fluorimetric determination of cerium and terbium

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890616 ◽

1989 ◽

Vol 54 (3) ◽

pp. 616-621 ◽

Cited By ~ 3

Author(s):

Záviš Holzbecher

Keyword(s):

Rare Earth ◽

Detection Limit ◽

Rare Earth Elements ◽

Fluorimetric Determination ◽

Fluorescence Maximum ◽

Relative Standard ◽

And Shifts ◽

Hcl Medium ◽

Fold Excess

It has been found that phosphoric acid decreases the first excitation maximum of Ce(III) at 256 nm, increases the second excitation maximum at 297 nm and shifts the fluorescence maximum from 350 to 346 nm. Under optimum conditions, with λexc = 297 nm and λem = 346 nm, Ce(III) can be determined fluorimetrically with a detection limit of 1.2 ng ml-1 in 12M-H3PO4 medium. No interference was observed from a 20-200 fold excess of HCl, H2SO4, Na, K, NH4+, Al and the rare earth elements. HNO3 interferes and Ce(IV) and Fe(III) interfere strongly. It follows from the stereofluorograms of Ce and Tb that the spectra of the two elements are practically independent. The detection limit for Tb(III) in 0.02-2.5M-H2SO4 medium for λexc = 222 nm and λem = 494 nm is 33 ng ml-1. No interference was observed from a 5-20 fold excess of Al3+ and the other rare earth elements. The determination is slightly less sensitive in H3PO4 or HCl medium. The relative standard deviation of the measurement for 10 ng ml-1 Ce(III) or 50 ng ml-1 Tb(III) is about 3%.

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