The Determination of Sodium in Small Volumes of Fluid by Flame Photometry

1950 ◽  
Vol 27 (3) ◽  
pp. 407-419 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Sodium Chloride ◽  
Biological Fluids ◽  
Systematic Errors ◽  
Flame Photometry ◽  
Average Error ◽  
Other Substances

1. A method of integrative flame photometry is described, by which the amount of sodium in biological fluids can be determined, using samples of the order of 10-3 cu.mm. 2. With pure solutions of sodium chloride, of concentration from 0.05 to 2.0 %, the average error of the method is about 3 % of the concentration. 3. When other substances are present systematic errors of up to 7.7 % have been recorded. 4. The possibilities of reducing these systematic errors and of extending the method to deal with other elements are discussed.

scholarly journals Simultaneous Determination of Sodium and Potassium in Small Volumes of Fluid by Flame Photometry

1953 ◽  
Vol 30 (1) ◽  
pp. 1-17
Author(s):  
J. A. RAMSAY ◽  
R. H. J. BROWN ◽  
S. W. H. W. FALLOON
Keyword(s):  
Standard Deviation ◽  
Simultaneous Determination ◽  
Biological Fluids ◽  
Ammonium Phosphate ◽  
Flame Photometry ◽  
Limits Of Detection ◽  
Other Substances ◽  
Lower Limits ◽  
Sodium And Potassium

1. A method of flame photometry is described, by which the amount of sodium and potassium in biological fluids can be determined simultaneously, using samples of the order of 10-3 cu.mm. 2. When the method is tested with quantities near the lower limits of detection (of the order 4 x 10-8 mg. sodium, 6 x 10-8 mg. potassium) the reproducibility, measured as standard deviation, is ±7 x 10-9 mg. sodium and ± 17 x 10-9 mg. potassium. 3. When larger quantities (up to certain limits) are used, the standard deviation is approximately ± 3 % of the quantity in the sample, both for sodium and for potassium. 4. As is usual in flame photometry serious errors can be caused by the presence of other substances in the sample. In the case studied for purposes of illustration it is shown that these interference errors can be reduced to the order of ± 6 % by the addition of excess ammonium phosphate.

scholarly journals Development and validation of a method for isolating stavudine from biological fluids

2021 ◽  
Vol 24 (1) ◽  
pp. 62-68
Author(s):  
Daria A. Borodina ◽  
Yulia A. Gonchikova ◽  
Elena A. Illarionova ◽  
Anastasia E. Mitina
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Blood Plasma ◽  
Ammonium Sulfate ◽  
Biological Fluids ◽  
Liquid Extraction ◽  
Uv Spectrophotometry ◽  
Liquid Liquid Extraction

Objective - study of isolating Stavudine from biological fluids (urine, blood plasma). Materials and methods. Objects of research: substance and tablets of 30 mg Stavudine. Reagents: purified water, chloroform, ethyl acetate, dichloromethane, ether, heptane, toluene, acetone, 95% ethyl alcohol, 0.1 M hydrochloric acid solution, 10% ammonium hydroxide solution, 5%solutions of sodium sulfate, 20%sodium sulfate saturated, sodium chloride, sodium chloride saturated, 20%ammonium sulfate, ammonium sulfate saturated. Universal ionomer IT-1101. Stavudine was isolated by liquid-liquid extraction. To detect and quantify Stavudine, thin - layer sorbent chromatography (TLC) and UV spectrophotometry were used. Statistical data processing was performed using the software package for Windows XP (Microsoft Excel), and using the Student's t-test. Results. When using thin-layer chromatography to identify Stavudine, it was found that the Rf value of the spots of Stavudine extracts from biological material corresponded to the Rf value range of 0.67-0.69. The Rf spot value of the standard Stavudine witness sample corresponded to (0.68±0.01). The stability study showed that the Stavudine solution is stable in a hydrochloric acid solution of 0.1 M, in which the absorption spectrum of Stavudine is characterized by absorption maxima at wavelengths of 209±1 and 267±1 nm. The wavelength of 267±1 nm was chosen as the analytical wavelength for the quantitative determination of Stavudine. In the course of the study, various factors affecting the degree of extraction of Stavudine from aqueous solutions were studied. The extractant is ethyl acetate, pH 3, the electrolyte is a saturated solution of ammonium sulfate. The extraction time is 7 minutes, twice. Conclusion. Methods of identification and quantitative determination of Stavudine in extracts from urine and blood plasma by TLC and UV spectrophotometry have been developed. Methods of isolation of Stavudine from urine and blood plasma using the liquid-liquid extraction method have been developed (93.33±2.02%; 89.77±2.02% respectively).

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

Correction. Determination of Total Biogenic Sulfur Gases by Filter/Flash Vaporization/Flame Photometry

1981 ◽  
Vol 53 (4) ◽  
pp. 752-752
Author(s):  
S Farwell ◽  
D Liebowitz ◽  
R Kagel ◽  
D Adams
Keyword(s):  
Flame Photometry

Methods for the Determination of the Purity of Exosomes

2020 ◽  
Vol 25 (42) ◽  
pp. 4464-4485 ◽  
Author(s):  
Katarzyna Kluszczyńska ◽  
Liliana Czernek ◽  
Wojciech Cypryk ◽  
Łukasz Pęczek ◽  
Markus Düchler
Keyword(s):  
Drug Transport ◽  
Biological Fluids ◽  
Drug Carriers ◽  
Biological Functions ◽  
Isolation And Purification ◽  
Pubmed Database ◽  
High Concentrations ◽  
Targeted Release

Background: Exosomes open exciting new opportunities for advanced drug transport and targeted release. Furthermore, exosomes may be used for vaccination, immunosuppression or wound healing. To fully utilize their potential as drug carriers or immune-modulatory agents, the optimal purity of exosome preparations is of crucial importance. Methods: Articles describing the isolation and purification of exosomes were retrieved from the PubMed database. Results: Exosomes are often separated from biological fluids containing high concentrations of proteins, lipids and other molecules that keep vesicle purification challenging. A great number of purification protocols have been published, however, their outcome is difficult to compare because the assessment of purity has not been standardized. In this review, we first give an overview of the generation and composition of exosomes, as well as their multifaceted biological functions that stimulated various medical applications. Finally, we describe various methods that have been used to purify small vesicles and to assess the purity of exosome preparations and critically compare the quality of these evaluation protocols. Conclusion: Combinations of various techniques have to be applied to reach the required purity and quality control of exosome preparations.

Microextraction and Chromatographic Analysis of Budesonide Epimers in Exhaled Breath Condensate

2020 ◽  
Vol 16 (8) ◽  
pp. 1032-1040
Author(s):  
Laleh Samini ◽  
Maryam Khoubnasabjafari ◽  
Mohamad M. Alimorad ◽  
Vahid Jouyban-Gharamaleki ◽  
Hak-Kim Chan ◽  
...  
Keyword(s):  
Biological Fluids ◽  
Exhaled Breath Condensate ◽  
Low Cost ◽  
Exhaled Breath ◽  
Chromatography Method ◽  
Extraction Solvent ◽  
Drug Concentrations ◽  
Dispersive Liquid Liquid Microextraction ◽  
Breath Condensate

Background: Analysis of drug concentrations in biological fluids is required in clinical sciences for various purposes. Among other biological samples, exhaled breath condensate (EBC) is a potential sample for follow up of drug concentrations. Methods: A dispersive liquid-liquid microextraction (DLLME) procedure followed by a validated liquid chromatography method was employed for the determination of budesonide (BDS) in EBC samples collected using a homemade setup. EBC is a non-invasive biological sample with possible applications for monitoring drug concentrations. The proposed analytical method is validated according to the FDA guidelines using EBC-spiked samples. Its applicability is tested on EBC samples collected from healthy volunteers receiving a single puff of BDS. Results: The best DLLME conditions involved the use of methanol (1 mL) as a disperser solvent, chloroform (200 μL) as an extraction solvent, and centrifugation rate of 3500 rpm for 5 minutes. The method was validated over a concentration range of 21-210 μg·L-1 in EBC. Inter- and intra-day precisions were less than 10% where the acceptable levels are less than 20%. The validated method was successfully applied for the determination of BDS in EBC samples. Conclusion: The findings of this study indicate that the developed method can be used for the extraction and quantification of BDS in EBC samples using a low cost method.

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