the main
about the project
Medicine news
To authors
Licensed books on medicine
<< Ahead Next >>

DETERMINATION OF THE GENERAL CONTENT OF MINERAL SUBSTANCES (ASH)

The total content of mineral substances in the material under study is determined by its ashing, that is, organic substances are burned with free access of air. During combustion, carbon, hydrogen, and partially oxygen evaporate in the form of carbon dioxide and water vapor, and mineral elements in the form of oxide compounds remain in the so-called raw ash.

Course of determination

1. Take two clean porcelain crucibles and place them in a muffle furnace.

2. Turn on the muffle furnace and ignite the crucibles in it for half an hour.

3. After the specified time has elapsed, turn off the muffle furnace and, without waiting for it to cool, remove the crucibles from it with iron tongs, which you should immediately put in a desiccator for cooling.

4. Weigh the cooled crucibles on an analytical balance.

5. Put about 1 ... 5 g of air-dry matter of the sample being analyzed into the crucibles, and then weigh them separately on an analytical balance.

When conducting a quantitative determination of the total mineral content directly in the raw samples, the course of determination remains the same as in the analysis of air-dry matter. The only exception is the sample, which is taken for the ashing of raw material, it should be about 3 ... 15 g.

6. To determine in each crucible the value of the sample of the material under investigation, which can be easily determined by the difference between the mass of the crucible with the contents and the mass of the empty crucible.

7. Put the crucibles with the contents into a muffle furnace. Heating of the furnace in the first 20 ... 40 minutes of burning should not be strong; then it is gradually brought to a dark red heat.

8. After 10 ... 15 minutes after the smoke stops and the material is charred, remove the crucibles from the muffle furnace and cool them in air.

9. To speed up the burning of organic substances, add 4 ... 6 drops of concentrated nitric acid to each crucible, and then put them again in a muffle furnace, the temperature in which initially should be about 80 ... 100? С.

10. Having finished evaporation of the oxidizing agent, which lasts for 10 ... 15 minutes, increase the heating of the muffle furnace to a dark red heat.
With such heating of the muffle, organic substances, as a rule, completely burn out within 30 ... 40 minutes.

11. Remove the crucibles with the resulting ash from the muffle furnace and put them in a desiccator for cooling.

12. Weigh the cooled crucibles on an analytical balance.

13. From the difference between the mass of the crucible with the remaining mineral substances in it and the mass of the empty crucible, determine the mass of the ash.

14. Determine the percentage of ash in the air-dry matter of the analyzed sample by the formula:



a x 100

Ho = ---------------- where

P2

Ho - the percentage of ash in the air-dry matter;

a is the mass of ash in the burned sample of air-dry matter;

P2 is a sample of air-dry matter taken for ashing.

15. Compare the obtained percentage of ash in the air-dry matter of the analyzed sample with the percentage of parallel determination. Their difference should not exceed 0.15%.

16. To take the arithmetic average of two parallel determinations for the final percentage of ash in the air-dry matter of the sample being analyzed.

17. To establish by recalculation the percentage of ash in absolutely dry matter of the analyzed sample according to the formula:



Ho x 100

X = ??? where

100- B1



X is the percentage of ash in absolutely dry matter;

Ho - the percentage of ash in the air-dry matter;

B1 - the percentage of hygroscopic moisture in the air-dry substance.

18. To establish by recalculation the percentage of ash in the raw material of the analyzed sample according to the formula:

Ho x a x x a

X1 = ???? or x1 = ????? where

100 100



X1 - the percentage of ash in the raw material;

Ho - the percentage of ash in the air-dry matter;

A1 is the percentage of air-dry matter in the raw sample;

X is the percentage of ash in absolutely dry matter;

And the percentage of absolutely dry matter in the raw sample.
<< Ahead Next >>
= Go to tutorial content =

DETERMINATION OF THE GENERAL CONTENT OF MINERAL SUBSTANCES (ASH)

  1. Determination of active chlorine in chlorine-containing disinfectants
    Chlorine-containing disinfectants are considered suitable for use when the content of active chlorine in them is at least 15%. The course of determination. A portion of a chlorine-containing disinfectant weighing 1 g is triturated in a mortar with a small amount of water, then transferred to a flask per 100 ml, topped up with water to 100 ml, shaken, put in a dark place for 30 minutes. For the study take a conical flat
  2. Minerals
    Mineral substances are essential nutrients that must be ingested. The value of minerals in human nutrition is very diverse: 1. Mineral substances in the body are included in the complex of substances that make up the living protoplasm of cells, in which the main substance is protein. 2. Mineral substances are part of all the extracellular and interstitial
  3. The exchange of water and minerals
    The human body is 60% water. Adipose tissue contains 20% of water (from its mass), bones - 25, liver - 70, skeletal muscles - 75, blood - 80, brain - 85%. For the normal functioning of the body, which lives in a changing environment, it is very important the constancy of the internal environment of the body. It is created by blood plasma, tissue fluid, lymph, the main part of which is water, proteins and
  4. Minerals and trace elements (minerals)
    Minerals are inorganic constituents of food. Many of them play an important role in the body, and their constant intake with food is necessary. The mineral composition of food includes more than 60 macro-and micronutrients. ___________ __ conduction of nervous excitement to muscles Iron hematopoiesis (composed of hemoglobin, 60% of total Fe in the body), anemia, rapid fatigue
  5. Hygienic importance of minerals and vitamins in the diet of the population
    Minerals and vitamins play a very important and at the same time peculiar role in the vital activity of the organism. First of all, they are not used as energy materials, which is a specific feature for proteins, fats and carbohydrates. Another distinctive feature of these nutrients is the relatively very insignificant quantitative need for them in the body. Enough
  6. Absorption of vitamins and minerals
    Folic acid. Biologically active form of folic acid - tetrahydrofolic - the most important component in the reactions of "one-carbon" transfer in the synthesis of thymidine nucleic acid from deoxyuridine. A deficiency of folic acid leads to the development of macrocytic anemia. Folate is found in green vegetables and fruits and comes in the form of pteroyl polyglutamate. Suction occurs mostly in skinny
  7. The value of vitamins and minerals for the growth and development of the child
    For the normal development of the body, children should have enough vitamins in their diet. They not only protect the body from diseases associated with them, but also are components of the tissues. Without vitamins, enzymes are not formed, and, consequently, all reactions occurring in the body are delayed, normal metabolism is disturbed, digestion and blood formation are affected, and
  8. The value of fats, carbohydrates and minerals in human nutrition. The norms of these components of food and the sources of their entry into the human body
    As mentioned in the previous lecture, fats are substances that perform in the body mainly energy function. In this regard, fats are superior to all other components of food (carbohydrates and proteins), since their combustion releases 2 times more energy (1 g of fat forms 9.3 kcal, while 1 g of protein and the corresponding amount of carbohydrates is only 4, 3 kcal). However biological
  9. Determination of the mass fraction of proteins (crude protein)
    The macro method is based on the oxidation of organic matter by burning it in sulfuric acid in the presence of a catalyst, distilling the formed ammonia with steam, trapping it with a solution of sulfuric acid and determining the nitrogen content by a titration method. A weighed portion of the product, weighted with an absolute error of up to 0.0005 g in a tubule made of filter paper or stanoliol closed on one side,
  10. Determination of pollutant emissions from auxiliary production
    Emissions of pollutants from auxiliary production are determined according to direct measurements according to the methods included in the “List of methods for measuring the concentration of pollutants” in emissions of industrial enterprises approved for use ”or calculated by the methods included in the“ List of methodological documents on the calculation of emissions (emissions a) pollutants in
  11. Determination of cholesterol and triglycerides in plasma
    Determination of cholesterol and triglycerides in plasma or serum allows us to decide the question of what type of hyperlipidemia can we talk about. Among the numerous methods for determining serum cholesterol, the most common is the direct method, which is based on the Lieberman-Burchard reaction (Ilka method). Clinical value Normal blood cholesterol is 3.9-7.2 mmol / l.
  12. Recommended composition and content of the “Report on the inventory of emissions of harmful (polluting) substances into the atmospheric air and their sources for the enterprise”
    "The report on the inventory of emissions of harmful (polluting) substances into the air and their sources for the enterprise" (hereinafter referred to as the "Report on the inventory") should include the following sections: - Title page; - Information about the developer and the list of performers; - Abstract; - Content. Introduction 1. General information about the company. 2. Brief description of the process
Medical portal "MedguideBook" © 2014-2016
info@medicine-guidebook.com