The method of determining the concentration of components in the solution

 

(57) Abstract:

Usage: the methods of manufacture of the indicator papers used in the analytical control on the content of the various ingredients in the environment. The inventive carry out the impregnation of several strips of filter paper different structures, indicator paper consists of strips of different lengths, cover in plastic wrap, before defining a cut of 1 to 2 mm from the strip of greater length, immersed in the test solution. The fluid rises along the long strip, with the component to be determined is transformed into a reactive form, reaches strips of shorter length and forms a colored compound. Intensity of staining determine the concentration of the component. 1 C. p. F. - ly, 1 Il., 3 table.

The invention relates to methods for producing the indicator papers used in the analytical control of environmental objects (natural and waste water, extracts of soils and plants, food, liquid) test methods in the field on the content of the various ingredients.

Known methods of manufacture of the indicator papers (for example, patent GDR N 216542, CL G 01 N 33/50, 1984; ed. St. USSR N 1 31/22, 33/52, 33/02, 1992), which consist in impregnating filter paper with a mixture of substances and drying. When determining the concentration of the investigated component drop of solution is placed on prepared paper and over time compare the resulting color with a standard color scale.

The disadvantage of these methods is that the definition of conduct, as a rule, in conditions that are not optimal for this reaction. This is particularly true for reactions in two stages, for example, in the determination of nitrite. In aqueous solution nitrites first form with amines colorless diazoketone in an acidic environment, which then reacts with organic amine, or naphthol in acid or alkaline medium with the formation of colored compounds. On paper, these processes are at the same pH of the medium, which leads to a significant decrease in detection sensitivity.

In addition, if the compositions are used that are not sustainable in the air, then there are errors in the analysis, associated either with coloration oxidized forms, identical to the color of the products of the reaction component to be determined or weakening of coloring by oxidative destruction generated to the N 211873, CL G 01 N 31/22, 1984). It is that as a matrix of media use filter paper with a volume capacity of 20 mg/m2. One part of it soaked in a solution containing 6 g/l sulfanilic acid, the other in a solution containing 0.3 g/l 1-naphtylamine. Paper after impregnation is dried, cut into strips with a width of 7 mm and a length of 65 mm In the analysis, two strips coated with the first components of the first and second components of the second solution put together and immersed for 1 s in the analyzed solution, then they are placed between two cover glasses for manifestation. The intensity of the resulting colour of indicator paper is proportional to the nitrite content, which is determined by the color scale. Sensitivity definitions 1 mg/l of nitrite ions.

The disadvantage of this method is its low sensitivity. The concentration is complicated by the instability of the painting, because it is possible oxidation of compounds of paper oxygen.

The closest in technical essence and the achieved result to the invention is a method of manufacturing a multilayer paper tape for testing (U.S. patent N 3511608, CL G 01 N 31/22, 33/16, 1970). Composite liststore, contains open component passes through the first layer, the component becomes in a certain connection without changing the color, then when passing through the second layer of paper is formed colored connection with the colour intensity is proportional to the concentration of the component.

The disadvantages of this method is the low sensitivity of the definitions by spreading the solution drops and uneven coloring of the resulting spot from the center to the periphery. Paper when the concentration is not protected from exposure to oxygen, so when using unstable air will lead to errors in the analysis.

The aim of the invention is to increase the detection sensitivity of the concentration of the ingredients and increase the stability of the indicator papers during storage and display.

This is achieved by the following method of manufacture of the indicator papers. Impregnate several strips of filter paper of different compositions and dried. From the received securities cut out two strips. The band, which will be formed of a reactive form of the designated element, cut out size 3-630-120 mm (lane A). The strip on to the sa). Then strips To make two sides of the strip And placed in a polyethylene film (or adhesive type K-1) and stick with thermopolium. The location of bands In from the bottom edge of the strip And choose determined experimentally for each ingredient, and it depends on the composition of the impregnation of the strip and from the reaction, which takes place on the bar.

When determining the concentration of an ingredient in the solution is cut 1-2 mm strips And (to access the solution to the paper) and dipped in the test solution. After lifting the fluid to the end of the strip And compare the colour intensity of the band In to the standard scale.

The method of manufacture and application of indicator paper explains the drawing.

Distinctive features of the method of manufacturing paper consist in the use of strips of different lengths, soaked in various structures, their location, the replacement indicator paper in a plastic wrap.

Distinctive features of the method of determining the concentration using indicator paper lies in the fact that the fluid rises in the paper of greater length, if this turns into a reactive form and in contact with a strip of the mages was performed by visual comparison of the intensity and evenness of color zones Century The results obtained are presented in table. 1.

As follows from the table. 1, is optimal width indicator paper 3-6 mm, and the ratio of the width of the paper and the lengths of the lower and higher bands is 1:(1-2):(10-20).

As an example of using indicator paper was used compounds for the determination of nitrite and iron (III) in aqueous solutions.

Filter paper weighing 100-200 g/m2soaked for 10-15 minutes formulations listed in table. 2. Dried in a current of hot air and made indicator paper above. Before defining cut 1-2 mm from the strip of greater length, dipped in the test solution and after lifting the fluid to the end of the long strip was evaluated by the color bands of smaller length.

For comparing the determined concentration of the indicator paper prepared for the prototype. To do this, put together two strips a and b of the same size (the band And the top) and put a drop of the studied solution. After 1-2 min was evaluated coloring stains on the paper.

Evaluation of the sensitivity of indicator paper on the proposed method and the prototype are presented in table. 3.

As follows from the table. 3, the limits found the Oia indicator properties of the paper in the process of determining the concentration outdoors compared the color of the paper in the study of distilled water, not containing the component to be determined. It is established that in the determination of nitrite prototype 10-15 min after wetting the paper with distilled water it becomes pink in color. Indicator paper produced by the proposed method does not change color (after raising distilled water on the area And the area In not acquiring coloring) for more than 8 hours

Storing paper prepared for the prototype to determine nitrite outdoors paper color becomes pink after 4 PM Paper prepared by the proposed method does not change its properties in the open air for 3 months.

In the determination of iron (III) using a paper produced by the prototype, 20-30 min is the weakening of the color patches associated with the destruction of the formed complex. On the contrary, when using indicator paper on the proposed method obtained the color zone In a stable for more than 2 hours

1. The METHOD of DETERMINING the concentration of COMPONENTS IN the SOLUTION, including the impregnation of several strips of paper of different compositions, drying, folding them together, the wetting of the test solution and the determination of the intensity of Brazauskas devout from two sides on a strip of greater length, cover in plastic wrap, cut 1 to 2 mm from the strip of greater length, immersed in the test solution and after the lifting of the fluid on the paper is the concentration of the component is determined by the intensity of the color strips of shorter length.

2. The method according to p. 1, characterized in that the ratio of the width of the paper to the lengths of the lower and higher bands is 1 (1 2) (10 20) when the width of the paper 3 to 6 mm.

 

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FIELD: pulp and paper industry.

SUBSTANCE: the invention is dealt with a pulp and paper industry. The paper or cardboard laminate contains at least one forming volume layer called as a volumetric layer, consisting by 40-98 % from cellulose fibers with a milling degree equal to 550-950 ml according to the Canadian standard device, and at least one secondary layer located at least on one side of the volumetric layer and having a higher density, as compared with the volumetric layer. The secondary layer and the basic layer are fused to each other in essence by all their opposite surfaces, and the laminate has a factor of rigidity at bending exceeding 2.5 Nm7/kg3, but less than 14 Nm7/kg3, calculated as a geometric average value for a longitudinal direction and a transverse direction. According to the invention, between the volumetric layer and the secondary layer there is a thin intermediate layer, which has the bigger value of resistance to removal of water, than the volumetric layer, and the basic weight at least of 2 g/m2 but less than 20 g/m2 and which is formed together with the volumetric layer. The invention also offers a method of production of paper or cardboard laminate and ensures achievement of a high strength at the low share of a binder, and also prevention of wrinkles.

EFFECT: the invention ensures achievement of a high strength of the laminate at the low content of a binder and prevention of wrinkles.

27 cl, 17 dwg, 6 tbl, 3 ex

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