X-band EPR spectra were obtained on a continuous wave performed on a Bruker Elexsys E500 CW-EPR spectrometer (Bruker, Billerica, MA, USA) equipped with a Super-X microwave bridge, operating at 9.3–9.5 GHz, and a Bruker Super High QE (SHQE) cavity resonator. The g factor was calibrated in the experimental conditions using a Bruker strong pitch (g = 2.0028). The spectra were recorded at 150 K with a variable temperature apparatus (ER4131VT). The g and A values were obtained directly from the experimental EPR spectra, calculating them from the 2nd and 3rd line to avoid second order effects [51 (link)]. The spectra were recorded as an average of 6 scans, microwave frequency 9.344–9.376 GHz, modulation frequency 100 kHz, modulation amplitude 0.2–0.6 mT, time constant 164–327 ms, sweep time 2.8 min, microwave power 20–40 mW, and receiver gain 50–60 dB. The Cu2+ peptide solutions were prepared at 1:1 and 1:2 metal-to-ligand ratios in the concentration range of 1 to 2 mM. The copper used in EPR measurements was isotopically pure 63Cu, taken from a 0.05 M 63Cu(NO3)2 stock solution. The pH of aqueous solution was adjusted by adding NaOH. 10% of methanol was added to aqueous solutions to enhance spectral resolution at low temperatures.
Elexsys e500 cw epr spectrometer
Manufactured by Bruker
Sourced in United States
The Elexsys E500 CW-EPR spectrometer is a laboratory instrument designed for continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy. It is a high-performance spectrometer that provides precise measurements of the magnetic properties of materials with unpaired electrons.
Automatically generated - may contain errors
Lab products found in correlation
Winepr simfonia program, by Bruker (2 mentions)
Er 036tm nmr teslameter, by Bruker (2 mentions)
Strong pitch, by Bruker (1 mentions)
Er 036tm, by Bruker (1 mentions)
E 41 fc, by Bruker (1 mentions)
Win epr simfonia software version 1, by Bruker (1 mentions)
Cary 50 probe spectrophotometer, by Agilent Technologies (1 mentions)
J 1500 spectropolarimeter, by Jasco (1 mentions)
E 41 fc frequency counter, by Bruker (1 mentions)
7 protocols using elexsys e500 cw epr spectrometer
1
X-band EPR Spectroscopy of Cu2+ Peptides
2
EPR Spectroscopy of CCR Saturation
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The initial high-power controlled experiment (Fig. 2 ) was performed using a vacuum line setup previously reported (12 (link), 24 (link)). X-band EPR measurements were performed on a Bruker ELEXSYS E500 CW EPR spectrometer using a Bruker ER4122 super-high-Q cavity with a liquid nitrogen flow insert (controlled by a Eurotherm 4131VT variable temperature controller, which maintained the sample at 296 K). A Bruker Teslameter (ER036M) and an EIP 548B frequency counter were used to provide calibration of the magnetic field and microwave frequencies, respectively. A spectrum was then taken at 2 mW (the optimal signal to noise for the CCR component) and 585 mW (the highest power output achievable with the power leveler off to saturate the CCR as much as possible). To obtain the high-pH spectrum, we initially exposed the sample under vacuum to an ammonia atmosphere via an attached vial of ammonia (28% concentration), leaving the system to come to equilibrium overnight. Afterward, the sample was evacuated for about 10 min to recreate a vacuum, and the spectrum was taken again at 585 mW.
3
EPR Spectroscopy of Peptide-Metal Complexes
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
EPR spectra were recorded using
a Bruker ELEXSYS E500 CW-EPR spectrometer equipped with an NMR teslameter
(ER 036TM) and a frequency counter (E 41 FC) at X-band frequency,
at 77 K and room temperature. The peptide concentration was 1 mM,
and the metal:ligand molar ratio 1:1.1. The solution for EPR experiments
was prepared using ethylene glycol (5%) as a cryoprotectant. EPR parameters
were obtained by using the Bruker WinEPR SimFonia program and Doublet
new (EPR OF S = 1/2) program
by A. Ozarowski (National High Field Magnetic Laboratory, University
of Florida, Gainesville, FL).
a Bruker ELEXSYS E500 CW-EPR spectrometer equipped with an NMR teslameter
(ER 036TM) and a frequency counter (E 41 FC) at X-band frequency,
at 77 K and room temperature. The peptide concentration was 1 mM,
and the metal:ligand molar ratio 1:1.1. The solution for EPR experiments
was prepared using ethylene glycol (5%) as a cryoprotectant. EPR parameters
were obtained by using the Bruker WinEPR SimFonia program and Doublet
new (EPR OF S = 1/2) program
by A. Ozarowski (National High Field Magnetic Laboratory, University
of Florida, Gainesville, FL).
4
Spectroscopic Characterization of Cu2+ Solutions
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The absorption spectra of Cu2+ containing solutions were recorded on a Varian Cary50 Probe spectrophotometer, in the range 350–900 nm, using a quartz cuvette with an optical path of 1 cm. To describe the species present in solution, the observed wavelength of maximum absorption at a given pH was compared with the expected λmax value obtained from literature23 (link),48 (link)–50 (link). Circular dichroism (CD) spectra were recorded on a Jasco J-1500 spectropolarimeter in the 180–800 nm range, using a quartz cuvette with an optical path of 1 cm in the visible and near-UV range, and 0.01 cm in the 180–250 nm range. Electron paramagnetic resonance (EPR) spectra were recorded in liquid nitrogen on a Bruker ELEXSYS E500 CW-EPR spectrometer at X-band frequency (9.5 GHz) and equipped with an ER 036TM NMR teslameter and an E41 FC frequency counter. Ethylene glycol (30%) was used as a cryoprotectant. The EPR parameters were analyzed by computer simulation of the experimental spectra using WIN-EPR SIMFONIA software, version 1.2 (Bruker, Billerica, MA, USA).
5
EPR Characterization of Cu2+ Complexes
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
EPR measurements were carried out by using a Bruker Elexsys E500 CW-EPR spectrometer driven by a PC running the XEpr program on Linux and equipped with a Super-X microwave bridge, operating at 9.3–9.5 GHz, and a SHQE cavity were used throughout this work. All the EPR spectra of frozen solutions of Cu2+ complexes were recorded at 150 K by means of a ER4131VT variable temperature apparatus. EPR magnetic parameters were obtained directly from the experimental EPR spectra, calculating them from the 2nd and 3rd line to avoid second order effects. The instrument settings for the EPR spectra recordings of the copper2+-peptide complexes were as follows: number of scans 1–5; microwave frequency 9.344–9.376 GHz; modulation frequency 100 kHz; modulation amplitude 0.2–0.6 mT; time constant 164–327 ms; sweep time 2.8 min; microwave power 20–40 mW; receiver gain 50–60 dB. Copper2+-peptide complexes were prepared by adding the appropriate amount of isotopically pure copper, taken from a 0.05 M 63Cu(NO3)2 solution, to the peptide solution. The copper2+-peptide complex solutions were prepared at 1:1 metal-to-ligand ratio (10–3 M concentration), with the GO concentration fixed to 0.34 mg/mL.
6
EPR Spectroscopy of Cu(II) Complexes
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
A Bruker Elexsys E500 CW-EPR spectrometer driven by a PC running the XEpr software and equipped with a Super-X microwave bridge operating at 9.3–9.5 GHz and a SHQE cavity was used throughout this work. All ESR spectra of frozen solution of Cu(II) complexes were recorded at 150 K by means of a ER4131VT variable temperature apparatus. In order to increase spectral resolution, a small amount of methanol (not exceeding 10%) was added to the Cu(II) complex aqueous solutions, after adjusting the pH to the desired value, to obtain a good quality glass upon freezing [69 (link)]. The ESR magnetic parameters g|| and A|| were extracted from the 2nd and the 3rd line to remove second order effects [70 (link)]. Some experimental spectra were simulated by the program Monoclin [71 (link)], which allows researchers to distinguish more species simultaneously present.
7
EPR Spectroscopy of Cu(II) Complexes
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The EPR spectra were recorded in liquid nitrogen on a Bruker ELEXSYS E500 CW-EPR spectrometer at X-band frequency (9.5 GHz) and equipped with an ER 036TM NMR Teslameter and E41 FC frequency counter. The ligand concentration was 1 mM and the Cu 2+ to ligand molar ratio was 1 : 1.2. Ethylene glycol (25%) was used as a cryoprotectant for EPR measurements in water solution. The EPR parameters were obtained by simulation of plots using the Bruker WinEPR SimFonia program.
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!