FURTHER OBSERVATIONS ON THE DETERMINATION OF PHOSPHATE BY PHOTOELECTRIC COLORIMETRY

1939 ◽  
Vol 17b (6) ◽  
pp. 178-191 ◽  
Author(s):  
G. R. Smith ◽  
W. J. Dyer ◽  
C. L. Wrenshall ◽  
W. A. De Long
Keyword(s):  
Ferric Iron ◽  
Stannous Chloride ◽  
Reducing Agent ◽  
Factors Affecting

A study of factors affecting the ceruleomolybdate reaction for phosphate is reported. The concentrations of stannous and stannic ions, the presence of extraneous salts, and temperature are important factors affecting the intensity and stability of the blue colour.The stannous chloride reagent should be preserved from oxidation by storing it under hydrogen.The interference by ferric iron is due largely to its reaction with the reducing agent, and may be avoided by diluting the sample to contain 0.1 p.p.m. of phosphorus and using two or three times the usual quantity of stannous chloride.

THE DETERMINATION OF NUCLEOTIDE PHOSPHORUS WITH A STANNOUS CHLORIDE - HYDRAZINE SULPHATE REAGENT

1964 ◽  
Vol 42 (2) ◽  
pp. 287-292 ◽  
Author(s):  
R. O. Hurst
Keyword(s):  
Light Absorption ◽  
Stannous Chloride ◽  
Reducing Agent ◽  
Accurate Estimation ◽  
Molybdenum Blue ◽  
Colorimetric Measurement ◽  
Highly Sensitive ◽  
Hydrazine Sulphate

Stabilization of stannous chloride as reducing agent for the analysis of phosphorus by the molybdenum blue method has been achieved by combining it with hydrazine sulphate. Application of the procedure to the determination of inorganic and nucleotide phosphorus is described. Colorimetric measurement of light absorption is made at 700 mμ, permitting a highly sensitive and accurate estimation of phosphorus.

scholarly journals Iron as a disturbing factor in the determination of phosphate by the molybdenum blue method

1954 ◽  
Vol 26 (1) ◽  
pp. 159-168
Author(s):  
Armi Kaila
Keyword(s):  
Hydrochloric Acid ◽  
Sulphuric Acid ◽  
Ferrous Iron ◽  
Ferric Iron ◽  
Stannous Chloride ◽  
Phosphorus Concentration ◽  
Colour Intensity ◽  
Molybdenum Blue ◽  
Fading Effect

The interference of ferric and ferrous iron in the determination of phosphate by the molybdenum blue method has been studied. It was found that the presence of ferric iron in the solutions could cause either an increase or a decrease in the colour intensity depending on the amount of stannous chloride applied and on the acid and molybdate concentrations in the reagent. Also the phosphorus concentration exerted its effect upon the course of the errors. If the original modification of Truog and Meyer was employed, generally, the most convenient way for the elimination of the interference of ferric iron was to dilute the solution. An increase in the amount of stannous chloride largely helped to prevent the fading effect of ferric iron, provided the phosphorus concentration was not lower than 0.25 ppm. When the effect of ferric iron upon the development of molybdenum blue at various concentrations of sulphuric acid and ammonium molybdate was studied, the observation was made that at each acidity there could be found a concentration of molybdate in which the effect of even fairly high amounts of ferric iron was almost negligible. In lower molybdate concentrations the presence of ferric iron caused an increase in the colour intensity, in higher molybdate concentrations the fading effect of ferric iron was marked. This most suitable level of the molybdate concentration depended to a certain degree on the phosphorus concentration of the solution and on the amount of stannous chloride applied. Fairly good results could be obtained, if the ratio of molybdate (expressed as mg/ml) to acid (expressed as normality) in the solution to be reduced was five times as high as the acidity of the solution to be reduced (expressed as its normality), e.g. 4 in 0.8 N acid, 3.5 in 0.7 N acid, 3 in 0.6 N acid etc. Although it seemed to be fairly possible to avoid the interference of ferric iron by a proper choice of the concentrations of acid and molybdate and of the amount of stannous chloride applied, the fading effect of ferrous iron could not be prevented, if only sulphuric acid was used in the reagents. But the substitution of sulphuric acid by hydrochloric acid totally prevented the fading effect of ferrous iron. On the contrary, a slight increase in the colour intensity was demonstrated. This was true also when only one half of the acid present was hydrochloric acid. It was found that this mixture of sulphuric acid and hydrochloric acid in the molybdate reagent offers an available way for the elimination of the disturbing effect of iron.

scholarly journals Factors affecting the determination of iron species in the presence of ferric iron

2018 ◽  
Vol 8 (8) ◽  
Author(s):  
Jian Zhu ◽  
Xi Yang ◽  
Feifei Fan ◽  
Yitong Li
Keyword(s):  
Ferric Iron ◽  
Iron Species ◽  
Factors Affecting

Sodium Hypophosphite as Reducing Agent for Determination of Submicrogram Quantities of Mercury in Animal Feeds and Manures

1981 ◽  
Vol 64 (1) ◽  
pp. 9-13
Author(s):  
Amer El-Ahraf ◽  
W Van Willis ◽  
Dutt V Vinjamoori
Keyword(s):  
Analytical Procedure ◽  
Stannous Chloride ◽  
Reducing Agent ◽  
Sodium Hypophosphite ◽  
Acid Digestion ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Mineral Acids ◽  
Absolute Detection Limit

Abstract The reduction of mercury in samples of dairy cattle and chicken feed rations and manures prepared by acid digestion for determination by flameless atomic absorption is rapidly, smoothly, and quantitatively effected by sodium hypophosphite. The reducing agent is air-stable, is effective over a wide range of mercury concentrations, and is useful in the presence of many mineral acids commonly used for wet digestion of these matrices. The accuracy and precision obtained in determinations with this reagent are equivalent to those obtained using stannous chloride at the same conditions. Recovery efficiencies for the total analytical procedure were studied using cattle manure and feed rations spiked to 0.6 ppm Hg as phenylmercuric nitrate; the range of recoveries varied from 93 to 102% (97% average). The absolute detection limit of the method is 10 ng Hg, and the precision varies in the range of 2.2-6% for samples containing 3 ppt-10 ppm Hg. The advantages of sodium hypophosphite lie in the elimination of premature reduction of mercury caused by traces of stannous chloride adhering to the walls of the reaction vessel, the elimination of several wash steps in the determination, and the long shelf life of the reagent.

Modeling of dynamic mosaicism on ring chromosomes in human fibroblasts and IPSCS

2020 ◽  
pp. 12-13
Author(s):  
Т.В. Никитина ◽  
А.А. Кашеварова ◽  
М.М. Гридина ◽  
А.А. Хабарова ◽  
А.Г. Мензоров ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Human Fibroblasts ◽  
Cellular Heterogeneity ◽  
Mitotic Stability ◽  
Factors Affecting ◽  
Ring Chromosomes ◽  
Cell Clones ◽  
Mitotic Instability ◽  
Mitotic Behavior

Митотическая нестабильность кольцевых хромосом может приводить к появлению клеточных клонов с различной генетической структурой. В качестве модели нестабильности кольцевых хромосом в митозе мы использовали фибробласты от пациентов с r(8), r(13), r(18) и r(22) и полученные из них индуцированные плюрипотентные стволовые клетки (ИПСК). Линии ИПСК с r(22) имели относительно стабильный кариотип на протяжении десятков (до 60) пассажей и сохраняли неизменную структуру кольцевой хромосомы. Кариотип линий ИПСК с r(8) и r(18) на ранних пассажах стабильный, планируется его изучение на поздних пассажах. Наибольшее разнообразие кариотипа выявлено в линиях ИПСК с r(13), в которых наблюдали различные перестройки и выраженную клеточную гетерогенность. Определение факторов, влияющих на митотическую стабильность кольцевых хромосом, может иметь значение для консультирования пациентов. Mitotic instability of ring chromosomes can lead to the appearance of cell clones with different genetic structure. IPSCs from fibroblasts of patients with r(8), r(13), r(18), and r(22) were used as a model of ring chromosomes mitotic behavior. Karyotypes of iPSC lines with r(8) and r(18) have so far been evaluated only in the early passages, lines with r(22) have maintained a relatively stable karyotype up to 60 passages. The occurrence of rearrangements and cellular heterogeneity was found characteristic for r(13) iPSCs. The determination of factors affecting the ring chromosomes mitotic stability would be beneficial for the patient’s prognosis.

Examination of Conditions for the Determination of Carbamate Pesticides in Soils

1992 ◽  
Vol 57 (8) ◽  
pp. 1632-1638 ◽  
Author(s):  
Věra Tatarkovičová ◽  
Zdeněk Stránský
Keyword(s):  
Activated Carbon ◽  
Solvent Extraction ◽  
Soil Type ◽  
Extraction Procedure ◽  
Purification Procedure ◽  
Factors Affecting ◽  
Carbamate Pesticides ◽  
Rp Hplc ◽  
Extracting Solvent

The procedure for the determination of carbamate pesticides in soil was optimized. The following factors affecting the final results were investigated: extracting solvent, extraction procedure, extract purification procedure, and soil type. Triple extraction with acetone and purification of the extract on a two-stage purification column containing an activated carbon-silica gel 1+1 mixture were found optimal. The extracts after treatment were analyzed by RP-HPLC with UV detection. The method developed allows carbamate pesticides in soil to be determined at concentrations in excess of 30 μg kg-1.

Fish Price Determination Around Lake Victoria, Tanzania: Analysis of Factors Affecting Fish Landing Price

2021 ◽  
Vol 22 (2) ◽  
pp. 348-363
Author(s):  
Damian Boniface Sambuo ◽  
Stephen Kirama ◽  
Kitala Malamsha
Keyword(s):  
Lake Victoria ◽  
Regulatory Body ◽  
Price Determination ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Fish Market ◽  
Fishery Policy ◽  
The Government ◽  
And Performance

Determination of fish landing price is important, as the same contributes to the structure, conduct and performance of the fish market in Lake Victoria. Determination of relevant landing price is a gap to console between fishermen, agents (middlemen), processors and the government. The main objective of this study was therefore to examine fish price determination. Specifically, to examine the methods for fish price determination and analyse factors that affect fish landing price in Lake Victoria, a cross-sectional design was employed, and 300 respondents were randomly selected from two district councils, namely, Sengerema and Buchosa. Both qualitative and quantitative data were analysed using descriptive statistics and inferential analysis. Findings show that landing price is determined through formal negotiation with processors, consultation with other traders, informal negotiation with buyers and Beach Management Unit (BMU). The study concluded that these are the common methods used to determine landing prices. Also, distance from fishing to onshore landing centres, market information channels, age and experiences of the fishermen are the factors significantly found affecting landing price. It is recommended that the mechanism for setting up fishery price, fish market structure, fishery information and the formation of fishery regulatory body needs fishery policy and sector reforms that mark the determination of fish landing price.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

2021 ◽  
pp. 1-9
Author(s):  
Etsuo Niki
Keyword(s):  
Biological Molecules ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Beneficial Effects ◽  
Multiple Oxidants ◽  
Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

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