Investigation of the interaction of metal-centered free radicals with ?-diketones, containing perfluoro-tert-butyl and 1-methyl-o,m-carboranyl groups using the epr method

1989 ◽  
Vol 38 (5) ◽  
pp. 1034-1037
Author(s):  
B. L. Tumanskii ◽  
S. P. Solodovnikov ◽  
N. N. Bubnov ◽  
S. A. Postovoi ◽  
Yu. V. Zeifman ◽  
...  
Keyword(s):  
Free Radicals ◽  
Epr Method ◽  
Tert Butyl

Pyrylocyanines. 32. Free radicals of a series of tert-butyl-substituted pyrylocyanines and their heteroanalogs

1993 ◽  
Vol 29 (12) ◽  
pp. 1414-1417
Author(s):  
A. V. Shpakov ◽  
O. Yu. Okhlobystin ◽  
A. D. Kachkovskii ◽  
V. V. Kurdyukov ◽  
A. I. Tolmachev
Keyword(s):  
Free Radicals ◽  
Tert Butyl

scholarly journals The role of the liver in the production of free radicals during halothane anaesthesia in the rat. Quantification of N-tert-butyl-alpha-(4-nitrophenyl)nitrone (PBN)-trapped adducts in bile from halothane as compared with carbon tetrachloride

1991 ◽  
Vol 277 (3) ◽  
pp. 795-800 ◽  
Author(s):  
H M Hughes ◽  
I M George ◽  
J C Evans ◽  
C C Rowlands ◽  
G M Powell ◽  
...  
Keyword(s):  
Free Radicals ◽  
Spin Trap ◽  
Halothane Anaesthesia ◽  
Perfused Liver ◽  
Radical Species ◽  
Tert Butyl ◽  
Biliary Elimination ◽  
Ccl4 Administration ◽  
Liver Preparation

Halothane or CCl4 was co-administered with the spin trap N-tert-butyl-alpha-(4-nitrophenyl)nitrone (PBN) to rats fitted with bile duct cannuli or to isolated perfused liver preparations. Rats maintained under halothane anaesthesia generated significant amounts of free radicals, and 5-9 nmol was excreted in bile over 1 h. No adducts were detected in urine or plasma. The hepatic origin of these free radicals was confirmed by studies on isolated perfused livers where the addition of halothane to the perfusate resulted in the biliary elimination of the same PBN-trapped radical adducts. Similarly, following CCl4 administration, the same radical species were eliminated in bile in the whole animal and the perfused liver preparation. In the perfused liver, over 3 h the total biliary elimination of radicals derived from halothane or CCl4 (administered at equimolar concentrations) was approximately the same (5-7 nmol); however, the elimination of halothane-derived radicals was more rapid over the first 1 h.

Quantitative Electron Paramagnetic Resonance: The Importance of Matching the Q-Factor of Standards and Samples

2001 ◽  
Vol 55 (10) ◽  
pp. 1375-1381 ◽  
Author(s):  
Richard L. Blakley ◽  
Dwight D. Henry ◽  
Walter T. Morgan ◽  
William L. Clapp ◽  
Carr J. Smith ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Free Radicals ◽  
Free Radical ◽  
Spin Trapping ◽  
Microwave Energy ◽  
Q Factor ◽  
Paramagnetic Resonance ◽  
Tert Butyl ◽  
Electron Paramagnetic ◽  
Stable Free Radicals

Electron paramagnetic resonance (EPR) quantification of free radicals from different samples facilitates comparison of free radical concentrations. Stable free radicals, such as 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), in a suitable solvent (e.g., benzene) can be used as a quantification standard. Free radicals found in samples can be shorter lived than radicals in prepared standards and require stabilizing spin-trapping agents such as N-tert-butyl-α-phenylnitrone (PBN) in an appropriate solvent (e.g., benzene). Analysis in our laboratory showed that free radicals from spin-trapped samples quantified against a standard of TEMPO in benzene displayed large differences among identical samples measured on either a Micro-Now 8300, Micro-Now 8400, or Bruker EMX EPR instrument. The Bruker instrument reported that the typical TEMPO in benzene standard had a Q-factor of ∼4400 while the Q-factor of our PBN-containing samples was ∼2500. (The Q-factor is inversely proportional to the amount of dissipated microwave energy in an EPR cavity.) By placing the TEMPO standard in a PBN/benzene solvent matrix we were able to match the Q-factor of our standards and samples, resulting in each of the three EPR instruments giving the same quantified free radical yields for the samples. This result points out the importance of matching the Q-factor between samples and standards for any quantitative EPR measurement.

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