New Method for the Determination of Uranium (4), Uranium(4) and Total Uranium In Solutions Obtained During Leaching of Phosphate ores by Hydrochloric Acid

Author(s):  
L.A. GUIRGUIS ◽  
M.A. WASSEF
2021 ◽  
Vol 20 ◽  
pp. e210971
Author(s):  
Cristiane Brandão Santos Almeida ◽  
José Augusto Rodrigues ◽  
Valéria Souza Freitas ◽  
Ynara Bosco de Oliveira Lima-Arsati

Aim: To propose a new method to determine in vitro potentially bioavailable fluoride (F) in diet and toothpaste after ingestion. Methods: Diet samples (D) were obtained from 15 portions of a meal served to children in a day care centre. To simulate the ingestion of toothpaste during brushing after meals, a specific amount of toothpaste was added to the diet samples (D + T). F was determined in D and D + T after incubation in a solution that simulated “gastric juice” (0.01 M hydrochloric acid) at 37oC for 30, 60 and 120 min. Microdiffusion facilitated by HMDS was used to determine the total F concentrations in samples D and D + T. The analyses were performed using an ion specific electrode. Results: For D samples, incubation in “gastric juice” for 30, 60 and 120 min resulted in F concentrations (μg F/mL) of 0.75 ± 0.06c, 0.77 ± 0.07c and 0.91 ± 0.09b, corresponding to 75.3, 77.3 and 90.7% of the total F (1.02 ± 0.12a), respectively (p = 0.0001; ANOVA + Tukey). For D + T samples, these values of F concentrations (μg F/mL) were 2.55 ± 0.46b, 2.83 ± 0.44ab and 3.15 ± 0.37a, corresponding to 86.9, 94.8 and 106.7% of the total F (2.99 ± 0.34a), respectively (p = 0.0023; ANOVA + Tukey). Conclusion: Then, it can be concluded that the proposed method of “gastric juice” is a promising protocol for determining potentially bioavailable fluoride in the diet and toothpaste after ingestion. However, additional studies are desirable.


1965 ◽  
Vol 48 (5) ◽  
pp. 892-897 ◽  
Author(s):  
Len Kamm ◽  
G G Mckeown ◽  
D Morison Smith

Abstract A new method for the determination of nitrite and nitrate in foods will accurately determine concentrations as low as 1 ppm. 1-Naphthylamine is diazotized by nitrite and coupled with excess amine to give 4-(lnaphthylazo)-l-naphthylamine. The compound is extracted into CHCI3, the extract is acidified with methanol-hydrochloric acid, and absorbance is measured at 555 mµ. Nitrate is quantitatively reduced by passage through a cadmium column and determined as nitrite; nitrite passes through the column unaltered. Therefore, in samples containing both forms of nitrogen, nitrate is determined by difference. The method was applied to 194 samples of baby foods. Spinach, beets, wax beans, squash, “garden vegetables,” green beans, carrots, and “mixed vegetables” were found to contain, on the average, more than 20 ppm nitrate nitrogen.


1937 ◽  
Vol 15b (2) ◽  
pp. 65-74 ◽  
Author(s):  
P. Larose ◽  
A. S. Tweedie

A modification of Pregl's micromethod for the determination of sulphur in organic compounds has been found to be satisfactory and convenient when applied on a macro scale to wool.The investigation of various methods of cleaning the samples shows that the best results are obtained when the wool wax is extracted with a solvent before washing with water. It is shown that a treatment with dilute hydrochloric acid is not necessary in preparing the sample.Three different procedures have been followed in determining the dry weight of the sample and the differences in the results are discussed. Results obtained by the new method are compared with those obtained by other recognized methods, and the agreement with the results of the Benedict-Denis-Barritt method is shown to be very good.


1960 ◽  
Vol 23 ◽  
pp. 227-232 ◽  
Author(s):  
P WEST ◽  
G LYLES
Keyword(s):  

1977 ◽  
Vol 37 (02) ◽  
pp. 210-215 ◽  
Author(s):  
R Margalit ◽  
E Gidron ◽  
Y Shalitin

SummaryThe term “effective activator” of plasminogen is proposed, to denote the resultant of activator-antiactivator interaction, and a method for the determination of the level of these activators is described. By adding axcess plasminogen to the euglobulin fraction of plasma the influence of the level of endogenous plasminogen and of the antiplasmin is eliminated. It is shown that the level of fibrinogen has very little bearing on the results. An effective activator unit is defined as equal to 1 CTA unit of urokinase activity on a fibrinogen-plasminogen substrate.


1964 ◽  
Vol 12 (01) ◽  
pp. 119-125 ◽  
Author(s):  
Y Shamash ◽  
A Rimon

SummaryA new method for the assay of plasmin inhibitors in human plasma is described. The method consists of determination of the caseinolytic activity of a standard plasmin solution before and after incubation with the inhibitor, with lysine added to the mixture as a stabilizer of plasmin. Using this method, it was found that plasma contains enough inhibitors to inactivate 30 caseinolytic units of plasmin, or 10 times the normal amount of plasminogen in human plasma.


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