Luminol standard

We have recently described a calibration procedure for the determination of excitation quantum yields on commercial fluorimeters, utilizing the luminol standard , and have thereby determined singlet excitation quantum yields for the peroxyoxalate reaction with bis(2,4,6-trichlorophenyl) oxalate (TCPO), hydrogen peroxide and imidazole, using various activators . The same calibration method has been utilized to determine the singlet quantum yields obtained in the induced decomposition of protected phenoxyl-substituted 1,2-dioxetanes 6 and and compared them to the well-investigated... 

Calibration methods I modified luminol standard II absolute calibration HI Hastings-Weber light standard IV luminol standard V mean value obtained by different determination methods, including chemical titrations VI triplet yield of 0.3 E mol for TMD, obtained with DBA. 

Basic procedure (ACL kit) Mix 2400 pL of ACL reagent 1 (diluter) with 100 pL of ACL reagent 2 (buffer) and 25 pL of photosensitizer reagent (luminol based). Start measurement after brief vortexing. Assayed solution (lipid extract) is added before addition of photosensitizer reagent. Volume of ACL reagent 1 is reduced by the volume of assayed solution. Standard substance a-tocopherol or Trolox. Duration of measurement 1 min. Measured parameter integral (area under the kinetic curve of PCL). 

Total radical trapping parameter (TRAP) assay is widely used in investigations and has various modifications [45-48]. This method presumes antioxidants capability to react with peroxyl radical 2.2-azobis (2-amidinopropane) dihydrochloride (AAPH). TRAP modifications differ in methods of registering analytical signal. Most often the final stage of analysis include peroxyl radical AAPH reaction with luminescent (luminol), fluorescent (dichlorofluorescein-diace-tate, DCFH-DA) or other optically active substrate. Trolox is often used as a standard. 

CL detection has been employed in various chemical analyses. For instance, determination of mouse IgG was based on the CL reaction of an HRP-goat antimouse IgG (HRP-Ab) and the luminol/H202 system. The amount of HRP-Ab decreased with an increasing amount of mouse IgG (10-60 ig/mL). Mouse IgG was then quantified using an internal standard (microperoxidase) after CZE separation. To enhance light collection in CL detection, an aluminum mirror was deposited on the back side of the microchip [720],... 

The experimental procedure to determine 4>wa is quite analogous to that discussed for The experimental definition is given by Eq. 38, in which all the terms have been already defined. Again the dioxetane decomposition rate constant kj) is determined by following the first-order kinetics of the DPA-enhanced chemiluminescence decay. The initial or total DPA fluorescence intensity is standardized with a suitable light standard, usually with luminol or the scintillation cocktail. The photomultiplier tube should be corrected for wavelength response. ... 

The free-radical-scavenging activity of compounds was evaluated in the TEAC and CL assays. The first measures the relative abiUty of antioxidant substances to scavenge the radical cation 2,2 -azinobis(3-ethylbenzothiozoline-6-sulfonate) (ABTS" ) as compared to a standard amount of the synthetic antioxidant Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid). The CL assay measures the inhibition of iodophenol-enhanced chemiluminescence by a horseradish peroxidase/perborate/luminol system. Trolox was used as the reference antioxidant. The results showed that xanthones exhibited free-radical-scavenging activity at potency levels comparable to those of reference antioxidant compounds quercetin and rutin, while the benzophenone and phloroglucinol type compoimds had more moderate activities [87]. 

Sample solution is diluted 40 times by 600 mmol/L sodium hydroxide, the diluted sample solution 50 /iL is poured into the plate. After addition of a luminescence solution (40 mmol/L potassium hexacyanoferrate (II ) and 0.1 mmol/L potassium hexacyanoferrate (III) containing 5 /nmol/L luminol solution), luminescence intensity was measured. Calibration curve was obtained by measurement of the chemiluminescence intensity using GPL as a standard, and the relative amount of the glycated protein in hair was computed. 

FIA conditions such as concentration of luminol, flow rates of carrier solution and CL reagent were optimized for O2 and OH by measuring blank CL intensity, respectively. In both ROS, 0.5 mL/min of carrier solution and 0.1 mL/min of CL reagent gave maximum and constant CL intensity. Luminol concentrations for O2 and OH were selected 0.08 mM and 1.2 mM as optimum, respectively. These conditions gave almost maximum and constant blank CL intensity, and the precision of 5 replicate measurements for OH and O2 as the relative standard deviation were less than 1.3%. 

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