Determination of the macroscopic formal potentials of cytochrome c3 of Desulfovibrio vulgaris, Miyazaki F, through the combined use of 1H NMR and an optically transparent thin-layer electrode cell

1990 ◽  
Vol 278 (1-2) ◽  
pp. 295-306 ◽  
Author(s):  
Kejun Fan ◽  
Hideo Akutsu ◽  
Katsumi Niki ◽  
Naoki Higuchi ◽  
Yoshimasa Kyogoku
1992 ◽  
Vol 65 (2) ◽  
pp. 424-429 ◽  
Author(s):  
Takamasa Sagara ◽  
Tomoyuki Koide ◽  
Hiroyuki Saito ◽  
Hideo Akutsu ◽  
Katsumi Niki

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).


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