Av 2 400 mhz spectrometer

Manufactured by Bruker

Sourced in United States

The AV II-400 MHz spectrometer is a nuclear magnetic resonance (NMR) instrument designed for conducting spectroscopic analyses. It operates at a frequency of 400 MHz, which is a common standard in the industry. The core function of this spectrometer is to detect and measure the resonance frequencies of atomic nuclei within a sample, providing information about the chemical structure and composition of the material.

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Lab products found in correlation

Tga 4000 thermogravimetric analyzer, by PerkinElmer (1 mentions) Sigma 300 fe sem, by Zeiss (1 mentions) Waters 1515, by Waters Corporation (1 mentions) Sta 449 c jupiter, by Netzsch (1 mentions) Drop shape analysis system dsa100, by Krüss (1 mentions) Nicolet 6700 spectrophotometer, by Thermo Fisher Scientific (1 mentions) Nicolet 670 ftir spectrometer, by Thermo Fisher Scientific (1 mentions) Nicolet is10, by Thermo Fisher Scientific (1 mentions) Sta 449c, by Netzsch (1 mentions) Aviii 500 mhz, by Bruker (1 mentions)

Close spelling variants of this product

AV 400 MHz spectrometer AV II-400 spectrometer AV-400 MHz AV-400 spectrometer 400 MHz spectrometer AV-400 AV spectrometers 400 spectrometer Bruker spectrometers

8 protocols using av 2 400 mhz spectrometer

Thermal and Mechanical Characterization of Polymeric Materials

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The 1H-NMR spectra were measured on a Bruker AV II-400 MHz spectrometer (USA) using DMSO-d₆ as a solvent at 25 °C. The FTIR spectra were recorded on a Nicolet is 50 FTIR spectrometer within the 4000–400 cm⁻¹ region with KBr matrix.
The morphology of the fractured surfaces of specimens was observed with a ZEISS Sigma 300 FESEM (Schnelldorf, Germany) with an accelerating voltage of 10 kV.
TGA and DTG analyses were carried out with a PerkinElmer TGA 4000 thermogravimetric analyzer (Waltham, MA, USA) at a heating rate of 10 °C/min from 30 to 650 °C under a nitrogen atmosphere.
LOI values were recorded on a Jiangning JF-3 oxygen index analyser (Nanjing, China) with sample dimensions of 130 mm × 6.5 mm × 3 mm according to ASTMD 2863-97. UL-94 vertical burning tests were performed using a Jiangning CZF-3 horizontal and vertical combustion tester (Najing, China) with sample dimensions of 130 mm × 13 mm × 3.0 mm in accordance with ASTMD 3801-2010.
CONE tests were carried out with a FTT cone calorimeter (East Grinstead, England) under an external heat flux of 50 kW/m². Sample dimensions were 100 mm × 100 mm × 3 mm according to ISO 5660.
Tensile properties were determined using a CMT4202 universal testing machine (Shenzhen, China) according to ASTM D638, at a test speed of 10 mm/min. Specimens were dumbbell-shaped with dimensions of 75 mm × 4 mm ×1 mm.

Zhang Q., Liu H., Guan J., Yang X, & Luo B. (2022). Synergistic Flame Retardancy of Phosphatized Sesbania Gum/Ammonium Polyphosphate on Polylactic Acid. Molecules, 27(15), 4748.

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Comprehensive Characterization of Waterborne Polyurethanes

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Proton nuclear magnetic resonance (¹H NMR, 400 MHz) spectra were obtained on a Bruker AV II-400 MHz spectrometer in DMSO (Bruker, Billerica, MA, USA).
Transmission Fourier transform infrared (FTIR) spectra were tested at 25 °C on a Nicolet-6700 spectrophotometer (Thermo Electron Corporation, Waltham, MA, USA) between 4000 and 600 cm⁻¹ (resolution of 4 cm⁻¹).
Gel permeation chromatography (GPC) was performed by Waters-1515 (Waters, Milford, CT, USA) using N,N-dimethylformamide/LiBr as eluent, and polymethyl methacrylate as reference. Test concentration of WPUn samples was 2–3 mg·mL⁻¹, and the flow rate was 1 mL·min⁻¹ at 40 °C.
Differential scanning calorimetry (DSC) was performed on a Netzsch STA 449C Jupiter (Netzsch, Selb, Germany). The heating rate was 10 °C·min⁻¹ in the range of −120 to 100 °C under a steady flow of nitrogen.
Zeta potential of WPUn emulsions (diluted with distilled water to about 0.02 wt% before the test) were tested using a Zetasizer Nano ZS dynamic light-scattering (DLS) instrument (Malvern, Worcestershire, UK) at room temperature at an angle of 90°.
Water contact angles (WCA) of WPUn surface were measured by a Drop Shape Analysis System DSA 100 (Kruss, Hamburg, Germany). Measuring parameter: 3 μL of distilled water at 25 °C. The results were the mean values of three replicates.

Zhang Y., Ge T., Li Y., Lu J., Du H., Yan L., Tan H., Li J, & Yin Y. (2023). Anti-Fouling and Anti-Biofilm Performance of Self-Polishing Waterborne Polyurethane with Gemini Quaternary Ammonium Salts. Polymers, 15(2), 317.

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Characterization of Chitosan Oligosaccharides

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The structure of the two COS was characterized by Fourier transform infrared spectra (FTIR) and ¹H nuclear magnetic resonance spectroscopy (NMR). FTIR analyses of the COSs were recorded with KBr compressed pellets on a Nicolet 670 FT-IR Spectrometer. ¹H NMR analyses were recorded on a Bruker AV II-400MHz spectrometer. The DD was calculated by ¹H NMR according to equation (1), where “A_CH3” and “A_GlcNH−2,” respectively correspond to the integral of the N-acetyl proton signal and H-2 proton signal of GlcN units.

\begin{array}{l} D D (%) = 1 - \frac{\frac{1}{3} A_{C H_{3}}}{\frac{1}{3} A_{C H_{3}} + A_{G l c N H - 2}} \times 100 \end{array}

Guo X., Sun T., Zhong R., Ma L., You C., Tian M., Li H, & Wang C. (2018). Effects of Chitosan Oligosaccharides on Human Blood Components. Frontiers in Pharmacology, 9, 1412.

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FTIR and NMR Characterization of Samples

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The products were ground with KBr powder and compressed into pellets for FTIR spectroscopy analysis. The spectra of the samples were recorded as transmittance using a Nicolet 670 FTIR Spectrometer (Thermo Fisher Scientific, Waltham, MA, United States). ¹H NMR analyses were recorded on a Bruker AV II-400 MHz spectrometer at 298 K. Each sample (10 mg) was dissolved in 1 ml D₂O before spectroscopic determination.

Xu J., Sun T., Zhong R., You C, & Tian M. (2020). PEGylation of Deferoxamine for Improving the Stability, Cytotoxicity, and Iron-Overload in an Experimental Stroke Model in Rats. Frontiers in Bioengineering and Biotechnology, 8, 592294.

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Synthesis and Characterization of GelMA

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GelMA was synthesized using methods as depicted in Fig. 1b. Briefly, under constant magnetic stirring, the type-A gelatin was dissolved in 50 ml Dulbecco's phosphate buffered saline (DPBS) at 60 °C. All methacrylic anhydride was continuously added to the solution within 10 min, and excessive DPBS was poured in to cease the reaction after 3 h of reaction. Subsequently, to remove impurities, the reacted solution was dialyzed in distilled water for 7 days. Finally, the dialyzed solution was subjected to freeze-drying for 48 h to obtain porous modified gelatin (GelMA) which was stored at −20 °C for later use.
The degree of methacryloyl modification was assessed quantifiedly via the ¹H NMR spectroscopy (Bruker AV II-400 MHz spectrometer) using the method described by Shirahama et al. [30 ]. In brief, the proton signal (d = 7.0–7.5 ppm), attributed to aromatic amino acids, was used as a reference in each spectrum. The NMR spectra were integrated over the 2.7–2.9 ppm range, near lysine amino acid, using proton signal from the methylene groups. The degree of substitution (DS) was calculated as following equation:

Equation 1.

where P_GelMA and P_gelatin were the peak area of lysine methylene protons in GelMA and gelatin at around 3.0 ppm, respectively.

Zou F., Wang Y., Zheng Y., Xie Y., Zhang H., Chen J., Hussain M.I., Meng H, & Peng J. (2022). A novel bioactive polyurethane with controlled degradation and L-Arg release used as strong adhesive tissue patch for hemostasis and promoting wound healing. Bioactive Materials, 17, 471-487.

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Physicochemical Properties of PECH and PEIL Membranes

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¹H NMR
spectra of PECH, PEIL1, and PEIL2 were recorded on an AVII-400 MHz
spectrometer (Bruker Co. Ltd., Germany) using deuterated DMSO as an
internal standard.
The chemical composition of the PECH, PEIL1,
PEIL2, and HTPB-PU membranes, HTPB-PEIL1-PU membrane, and HTPB-PEIL2-PU
membrane was analyzed using an FTIR spectrophotometer (NICOLET iS10,
Thermo Electron Corporation, USA). Each spectrum was captured by averaging
32 scans at a resolution of 4 cm^–1.
Differential
scanning calorimetry (STA 449C, NETZSCH, Germany)
was used for the evaluation of the thermal stability of the PECH,
PEIL1, PEIL2, and HTPB-PU membranes, HTPB-PEIL1-PU membrane, and HTPB-PEIL2-PU
membrane under an N₂ atmosphere at a heating rate of 20
°C min^–1 from −50 to 150 °C.
The tensile strength and elongation at break values of the membranes
were measured at room temperature using a universal mechanical testing
instrument (Instron 4465, USA) at a strain rate of 500 mm min^–1. For each membrane, at least three specimen tests
were carried out.

Tang T., Ling T., Xu M., Wang W., Zheng Z., Qiu Z., Fan W., Li L, & Wu Y. (2018). Selective Recovery of n-Butanol from Aqueous Solutions with Functionalized Poly(epoxide ionic liquid)-Based Polyurethane Membranes by Pervaporation. ACS Omega, 3(11), 16175-16183.

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Synthesis and Characterization of Anionic Polyurethanes

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A series
of anionic polyurethanes were synthesized from l-lysine diisocyanate
(LDI), mPEG, cystine, CYSD, and PCL according to our previous report.^{45 (link)} Briefly, pre-polymerization of LDI and PCL was
carried out in the presence of 0.1% stannous octoate catalyst and
under the protection of nitrogen at 60 °C for 1 h. The resulting
solution was cooled down to room temperature, after which the chain
extender CYSD and tripeptide were added to react at room temperature
for 1 h (for T0C50mE1900, the addition of 1,3-propanediol (PDO) is
needed to react at 80 °C for an extra 2 h). Subsequently, mPEG
as the terminated chain was added and reacted at 90 °C for 6
h. The final products were precipitated by diethyl ether and washed
at least three times, after which the products were dried under vacuum
at 50 °C for 2 days.
The polyurethanes were characterized
by proton nuclear magnetic resonance (¹H NMR), Fourier
transform infrared spectroscopy (FTIR), and gel permeation chromatography
(GPC). ¹H NMR spectra were obtained on a Bruker AV II-400
MHz spectrometer, using dimethyl sulfoxide (DMSO-d₆) as a solvent. FTIR spectroscopy was performed by a
Nicolet 6700 FTIR spectrometer using the KBr tablet method. GPC was
examined on Waters-1515; the mobile phase was N,N-dimethylformamide (DMF)/50 mM LiBr with a flow rate of
1 mL/min at 40 °C.

Fang D., Pi M., Pan Z., Song N., He X., Li J., Luo F., Tan H, & Li Z. (2019). Stable, Bioresponsive, and Macrophage-Evading Polyurethane Micelles Containing an Anionic Tripeptide Chain Extender. ACS Omega, 4(15), 16551-16563.

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Characterization of Chemical Compounds

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Melting points were determined by a B-540 Büchi melting-point apparatus, nuclear magnetic resonance (NMR) spectra were recorded on BRUKER AVIII 500 MHz or BRUKER AVII 400 MHz spectrometer (500 or 400 MHz for ¹H NMR, 100 MHz for ¹³C NMR). Mass spectra were obtained on the Finnigan LCQ DecaXP ion trap mass spectrometer.

Cheng W., Wang S., Yang Z., Tian X, & Hu Y. (2019). Design, synthesis, and biological study of 4-[(2-nitroimidazole-1H-alkyloxyl)aniline]-quinazolines as EGFR inhibitors exerting cytotoxicities both under normoxia and hypoxia. Drug Design, Development and Therapy, 13, 3079-3089.

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