The NOESY spectra were recorded on a 700 MHz Varian NMR spectrometer (Agilent Technologies) under the following conditions: solvent: D2O; resonant frequency: 699.6 MHz; pulse width: 90°; relaxation delay: 0.500 s; scan time: 0.500 s; temperature: 25 °C; 256 increments.
Varian nmr spectrometer
Manufactured by Agilent Technologies
Sourced in United States
The Varian NMR spectrometer is a laboratory instrument used for nuclear magnetic resonance (NMR) spectroscopy. It is designed to analyze the chemical structure and properties of substances by measuring the absorption and emission of electromagnetic radiation by atomic nuclei in a strong magnetic field.
Automatically generated - may contain errors
12 protocols using varian nmr spectrometer
1
NOESY Spectroscopic Analysis of Biomolecules
2
Analytical Characterization of Compounds
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
All reagents, solvents, silica gel for TLC and silica gel for column chromatography were purchased from Sigma-Aldrich (Pty) Ltd. (Johannesburg, South Africa) and Merck (Pty) Ltd. (Johannesburg, South Africa) through a licenced local supplier, Shalom Laboratories and Supplies, South Africa. Antioxidant absorbance were measured on a 680-Bio-Rad Microplate Reader (Serial Number 14966, Irvine, CA, USA), while the anti-elastase activity was monitored on a Perkin Elmer VICTOR Nivo microplate reader (excitation: 560 nm/emission: 590 nm wavelengths). Isolated compounds were analyzed with a 600 MHz Bruker Biospin GmbH spectrometer (Bruker, Rheinstetten, Germany) and a 400 MHz VARIAN NMR spectrometer (Agilent Technologies Inc., Santa Clara, CA, USA). Chemical shift (δ) was recorded in part per million (ppm). The spectrum range was set at 0–14 ppm for 1H NMR, while that of 13C NMR was set at 0–220 ppm. Tetramethyl silane was used as the internal standard and compounds were read in deuterated chloroform and benzene, as well as benzene-d6 in trifluorotoluene (TFT). High-resolution mass spectrometry (HRMS) was performed with a Waters API Q-TOF Ultima spectrometer (Waters Corporation, Manchester, UK) situated in Stellenbosch University, Stellenbosch, South Africa.
3
Diffusion Measurements of Hydrogel Solutions
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Vortexed
hydrogel solutions are pipetted into NMR tubes (Wilmad-LabGlass, Vineland,
New Jersey) and allowed to cure in a 37 °C oven for 20 min. The
samples are kept at 25 °C until measurements are made. Diffusion
measurements were made at 25, 30, and 37 °C. The samples are
allowed to equilibrate in the instrument (600 MHz Varian NMR spectrometer,
Agilent Technologies, Santa Clara, California) at 25 °C for 10
min and at 30 and 37 °C for 1 h before measurements at each respective
temperature are started. For each temperature, the π/2 pulse
time is determined before making measurements. A stimulated spin-echo
pulse sequence, based on the sequence described by Wu et al., was
used for diffusion coefficient measurements.20 (link),21 (link) The expected signal for this measurement is a function of the Stejskal–Tanner
variable, X, defined in terms of the pulse–sequence
parameters as Experiments used gradient-pulse amplitudes, g, that varied from 0 to 61.5 G/cm with a fixed gradient-pulse
duration (δ = 2 ms) and gradient-pulse separation time (Δ
= 100 ms). The variable-time delay, τ, was computed to ensure
proper timings for a measurement and was typically 1.5 ms. A diffusion
coefficient, D, can then be calculated using where S(X) is the signal for a given value of X and S(0) is the signal without a gradient pulse. The signal
is taken from the water peak in the 1H NMR spectrum, around
4.0 ppm.
hydrogel solutions are pipetted into NMR tubes (Wilmad-LabGlass, Vineland,
New Jersey) and allowed to cure in a 37 °C oven for 20 min. The
samples are kept at 25 °C until measurements are made. Diffusion
measurements were made at 25, 30, and 37 °C. The samples are
allowed to equilibrate in the instrument (600 MHz Varian NMR spectrometer,
Agilent Technologies, Santa Clara, California) at 25 °C for 10
min and at 30 and 37 °C for 1 h before measurements at each respective
temperature are started. For each temperature, the π/2 pulse
time is determined before making measurements. A stimulated spin-echo
pulse sequence, based on the sequence described by Wu et al., was
used for diffusion coefficient measurements.20 (link),21 (link) The expected signal for this measurement is a function of the Stejskal–Tanner
variable, X, defined in terms of the pulse–sequence
parameters as Experiments used gradient-pulse amplitudes, g, that varied from 0 to 61.5 G/cm with a fixed gradient-pulse
duration (δ = 2 ms) and gradient-pulse separation time (Δ
= 100 ms). The variable-time delay, τ, was computed to ensure
proper timings for a measurement and was typically 1.5 ms. A diffusion
coefficient, D, can then be calculated using where S(X) is the signal for a given value of X and S(0) is the signal without a gradient pulse. The signal
is taken from the water peak in the 1H NMR spectrum, around
4.0 ppm.
4
Quantitative NMR Analysis of Monomer Conversion
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The conversions were determined by 1H-NMR on a Varian NMR spectrometer (Agilent technologies, Santa Clara, CA, USA) operating at 600 MHz using deuterium oxide (D2O) as the deuterated solvent. The monomer conversion (C) was calculated as reported by [29 (link)].
where C is the monomer conversion, IA is the integrated signal between 6.13 to 6.28 ppm corresponding to CH2 protons adjacent to the double bond in the monomer, and IB is the integrated signal at 3.44 ppm due to CH2 protons adjacent to the –SO3H group in the monomer and polymer (this peak was selected as a reference IB = 1).
Molecular weight (Mn) and dispersity (Ð) were determined by gel permeation chromatography (GPC) on an Agilent 1100 HPLC equipped with a refractive index detector (IR) and two columns: Zorbax PSM 60-S and PSM 1000-S (Agilent technologies, CA, USA). DMF containing LiBr (0.05%) was used as the eluent (flow rate 0.70 mL min−1) at 30 °C and PMMA was used as the calibration standard.
where C is the monomer conversion, IA is the integrated signal between 6.13 to 6.28 ppm corresponding to CH2 protons adjacent to the double bond in the monomer, and IB is the integrated signal at 3.44 ppm due to CH2 protons adjacent to the –SO3H group in the monomer and polymer (this peak was selected as a reference IB = 1).
Molecular weight (Mn) and dispersity (Ð) were determined by gel permeation chromatography (GPC) on an Agilent 1100 HPLC equipped with a refractive index detector (IR) and two columns: Zorbax PSM 60-S and PSM 1000-S (Agilent technologies, CA, USA). DMF containing LiBr (0.05%) was used as the eluent (flow rate 0.70 mL min−1) at 30 °C and PMMA was used as the calibration standard.
5
NMR Spectra Acquisition and Analysis
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
1H-NMR spectra were recorded with a Varian NMR spectrometer (Agilent Technologies) operating at 600 MHz using a 5 mm cold probe. RG-II samples were dissolved in D2O (0.2 mL, 99.9%; Cambridge Isotope Laboratories, Tewksbury, MA, USA) and placed in a 3 mm NMR tube. 1H-NMR spectra were obtained using standard Varian pulse programs. Chemical shifts were measured relative to internal DMSO (δH 2.721) or acetone (δH 2.225). Data were processed using MestReNova software (Mestrelab Research S.L., Spain).
6
Metformin and Andrographis paniculata in Metabolomics
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Nuclear magnetic resonance (500 MHz Varian NMR spectrometer (Varian Inc., Palo Alto, CA, USA) was used to identify the differentiating metabolites in the biofluids of metformin-treated, A. paniculata-extract-treated, and non-treated (control group) rats. For 1H-NMR analysis, urine samples were prepared and analyzed as described by Maulidiani et al. [63 (link)] The spectral processing of NMR data was done using Chenomx NMR Suite software (Version 7.1, Chenomx Inc., Edmonton, AL, Canada). The residual signals of water (δH 4.68–5.00), urea (δH 5.55–6.00), and imidazole (δH 7.23–7.40 and 8.43–8.46 ppm) were subtracted from the analysis. Spectral intensities were scaled to TSP and spectral region from δH 0.52–10.00 was binned into regions of 0.04 ppm width. Pareto scaling was applied to processed data and multivariate data analysis was performed using SIMCA-P+ version 12.0.1.0 (Umetrics AB, Umeå, Sweden). Statistical analysis was performed using GraphPad prism for Windows (version 5.03, Redmond, WA, USA). The NMR signals were assigned according to the existing literature databases (HMDB, http://www.hmdb.ca/ ; KEGG, http://www.genome.jp/kegg/ ; Chenomx NMR Suit Ver.7.1). Table 1 shows the identified metabolites in the urine of normal, obese, and obese–diabetic rats.
7
Serum Sample Preparation for 1H NMR Analysis
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Before 1H NMR analysis, the supernatant of serum samples were thawed at room temperature. 200 μl supernatant was mixed with 200 μl phosphate buffer solution (pH 7.4, 45 mM) and 200 μl D2O into tube. The mixture was centrifuged at 12,000 rpm at 4°C for 10 min, and 550 μl supernatant of the mixture was transferred to a 5 mm NMR tube. The 1H NMR measurements of samples were performed using a 600 MHz Varian NMR spectrometer (Varian Inc., Palo Alto, CA, USA), functioning at frequency of 599.93 MHz and maintained at 25°C. A standard water-suppressed one dimensional NMR was obtained using the Carr-Purcell-Meiboom-Gill pulse sequence (64 scans). The acquisition time of each 1H NMR spectrum was 1.5 s.
8
NMR Spectroscopy of Acetylated Compounds
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
ACM samples (300 μL) were prepared by the addition of 250 μL deuterium oxide and 10 μL sodium trimethyl [2,2,3,3-2H4] propionate (TSP) (0.005 g/mL). 1H NMR spectra were acquired on a 600-MHz Varian NMR spectrometer (Varian Limited, Oxford, United Kingdom) by using the first increment of Nuclear overhauser effect spectroscopy pulse sequence at 25°C. Spectra were acquired with 16384 data points and 256 scans. Water suppression was achieved during the relaxation delay (2.5 s) and the mixing time (100 ms). All spectra were referenced to TSP at 0.0 ppm. 1H NMR ACM spectra were processed manually with Chenomx software (version 7.5; Chenomx Edmonton, Canada) and were phase and baseline corrected. Spectra were converted into 8000 spectral regions of 0.001 ppm width. The water region was excluded (4–6 ppm), and data were normalized to the total area of the spectral integral. Discriminating metabolites were identified using libraries of pure metabolites developed in house and the Chenomx database library. Metabolites of interest were semi-quantified using Chenomx.
9
Sodium Hypochlorite-Mediated Organic Synthesis
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Unless otherwise noted, all reactants or reagents including dry solvents were obtained from commercial suppliers and used as received. NaClO (Sodium hypochlorite solution reagent grade, available chlorine 4.00–4.99%) was purchased from Lingfeng reagent company, Shanghai, China. All the reactions were conducted using reaction tube (10 mL) under argon atmosphere. Analytical thin layer chromatography (TLC) was performed using Silica Gel 60 F25 plates. Column chromatograph was performed on silica gel 100~200 mesh. 1H and 13C NMR spectra were obtained in CDCl3 or DMSO using 300 MHz, 400 MHz Varian NMR spectrometer. Chemical shifts in 1H NMR spectra are reported in parts per million (ppm) on the δ scale from an internal standard of residual CDCl3 (7.26 ppm). Data are reported as follows: chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet), integration, and coupling constant in Hertz (Hz). Chemical shifts in 13C NMR spectra are reported in ppm on the δ scale from the central peak of residual CDCl3 (77.16 ppm).
10
Synthesis and Characterization of HA-SS-NH2 Polymer
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The HA-SS-NH2 polymer was synthesized following a previously described procedure 25 . Briefly, 60 kDa-sodium hyaluronate (1% w/v in MES buffer) was activated with N-(3-(dimethylamino)propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) at a 1:4:2 molar ratio and reacted at room temperature for 30 min. The activated hyaluronic acid (HA) was then mixed with cysteamine dihydrochloride at a 1:10 molar ratio and reacted at room temperature for 12 h. HA-SS-NH2 was purified by dialysis, freeze-dried, and stored at -20° C. HA-SS-NH2 molecular structure was characterized by 1H-NMR using D2O as a solvent (400 MHz Varian NMR spectrometer).
About PubCompare
Our mission is to provide scientists with the largest repository of trustworthy protocols and intelligent analytical tools, thereby offering them extensive information to design robust protocols aimed at minimizing the risk of failures.
We believe that the most crucial aspect is to grant scientists access to a wide range of reliable sources and new useful tools that surpass human capabilities.
However, we trust in allowing scientists to determine how to construct their own protocols based on this information, as they are the experts in their field.
Ready to get started?
Sign up for free.
Registration takes 20 seconds.
Available from any computer
No download required
Revolutionizing how scientists
search and build protocols!