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Method of photometric determination of iron (ii). RU patent 2511631.

Method of photometric determination of iron (ii). RU patent 2511631.
IPC classes for russian patent Method of photometric determination of iron (ii). RU patent 2511631. (RU 2511631):

G01N31/22 - using chemical indicators (G01N0031020000 takes precedence);;
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FIELD: chemistry.

SUBSTANCE: invention relates to field of analytical chemistry, namely to photocolorimetric method of analysis, and can be used for determination of iron (II) content in extract of spruce needles, containing iron (II) in very low concentration. Method includes its transfer into complex compound with organic reagent, with addition of 150-200-fold amount of organic reagent to solution of iron (II) with pH 3, as reagent used is Congo red, 0.2-0.4 ml solution of surface-active substance in form of 0.2% solution of 6-aminocapronic acid, and water to 10 ml with further heating on water bath at temperature 80-98°C for 10-15 min.

EFFECT: increased analysis sensitivity.

1 ex

 

The invention relates to the field of analytical chemistry, namely photometric method of analysis and can be used for determination of iron (II) in solutions of pure salts containing iron (II) in very small concentrations.

Known photometric method for determination of iron (II) with aluminon in binary photometric system, consisting in addition to the analyzed solution buffer solution with a specific pH and organic reagent aluminon (Babko, A., A. T. Pilipenko Photometric analysis. General information and the equipment. - M: Chemistry, 1968. - S).

The disadvantage of this method is the low sensitivity.

The technical result consists in increasing the sensitivity by photometric determination of Fe (II).

Summary of the invention consists in the fact that photometric method for determination of iron (II)including the transfer him in complex compounds with organic reagent in which the solution of iron (II) pH 3 add 150 to 200-fold amount of organic reagent, which is used Congo red, 0.2-0.4 ml solution of surface-active substances in a 0.2%solution 6-aminocaproic acid and water to 10 ml volume, followed by warming in a water bath at a temperature of about 80 to 98'c for 10-15 minutes and further photometry.

Surface-active substance (SAS) cooked in a 0.2%solution 6-aminocaproic acid:

Congo red [disodium salt 4,4'-bis(1-amino-4-sulfo-2-pattiet)biphenyl] organic reagent obtained by interaction diazotized of benzidine Neftianoy acid [Indicators. Volume 1 / Under the editorship of E. Bishop.- M: Mir, 1976. - 496 S. - S]:

Example. Determination of Fe (II) with Congo red in the presence of surfactants. In a test tube is placed on V ml 10 -4 M solution of iron (II), 2 ml of buffer solution with pH equal to 3, 0.3 ml solution of surfactants, 1 ml 10 -2 M solution of Congo red, bring the volume of diluted to 10 ml water is heated on a water bath for 10 minutes at a temperature of about 80 to 98 C. Photometrate on CPK with the wavelength of the x 400 nm and thickness of the cell

l = 0,1 with m

regarding the solution of the blank experience. The linearity of the calibration curve is observed in the range of concentrations of iron (II) (1,6-5,2)-10 -7 g/ml The molar ratio of the light absorption of the complex equal

E M R = 0,06 0,3 x 10 - 4 10 x 0,1 = 200000.

Advantages of the proposed method for photometric determination of iron (II) with Congo red in the presence of surfactants following:

1) dramatically increases sensitivity definitions compared with a known method;

2) complex metal ion with Congo red residue;

3) the reaction of complex compound formation of goes in the water environment, and therefore there is no need in organic solvents, which has a negative effect on human organism;

4) the formed complex of sustainable;

5) good reproducibility of the analysis.

The photometric method for determination of iron (II)including the transfer him in complex compounds with organic reagent, wherein to the solution of iron (II) with pH 3 add 150 to 200-fold amount organic reagent, which is used Congo red, 0.2-0.4 ml of the solution of surface-active substances in a 0.2%solution 6-aminocaproic acid and water to 10 ml volume, followed by warming in a water bath at a temperature of about 80 to 98'c for 10-15 minutes and further the photometry.

 

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