SU1732240A1 - Trichloroacetic acid qualitative test - Google Patents

Abstract

The invention relates to a method for the determination of trichloroacetic acid in aqueous solutions used in biochemical and analytical studies. The purpose of the invention is to simplify the method. To do this, the aqueous solution under investigation is mixed with a 0.001% alcohol solution of Ristel Violeta at a volume ratio of a solution of trichloroacetic acid and a solution of a crystal of 50: 0.5. 2 tab.

Description

The invention relates to a method for the determination of organic acids in aqueous solutions and can be used in biochemical and. analytical studies.

A known method for the determination of trichloroacetic acid is based on the formation of polymethine dyes by heating trichloroacetic acid with pyridine and alkali (Fujiwara reaction).

1 The disadvantage of the method is the non-selectivity of this reaction. Many di- and trihalo-substituted fatty compounds enter it, including methylene chloride, chloroform, etc.

The closest to the proposed method is the determination of trichloroacetic acid, based on the formation of a colored compound of this acid with phenanthroline ferrous sulfate.

The disadvantage of the method is its complexity associated with a multistage process and a large number of reagents.

The purpose of the invention is to simplify the method.

The goal is achieved by mixing the aqueous solution containing trichloroacetic acid with an alcohol-water solution of a crystal-violet.

The method is carried out as follows.

For the determination of trichloroacetic acid in aqueous solutions, a saturated alcoholic solution of a crystal violet is prepared (10 g of a crystal and a solvent is dissolved in 100 ml of ethyl alcohol 96). Saturated alcoholic solution of crystalHi

& $ y

317

Violet can be stored for up to 6 months. A working 0.01% aqueous solution is prepared from it immediately before the analysis. To do this, 0.1 ml of a saturated alcoholic solution of the crystal light is poured into a 100 ml volumetric flask and distilled water is added to the mark.

A series of standard solutions containing a known amount of trichloroacetic acid (0.1-50 mg / ml) are prepared. In portions of the trichloroacetic acid solution in 50 ml volumes, 0.5 ml of the working solution of the crystalio is added. After 2 hours, the color is established in the solutions, Saving for a long time (more than 2 weeks), the time is unchanged. Then, to 50 ml; The solution under study is added with 0.5 ml of the working solution of the crystal-volt, stirred, kept at room temperature for 2 hours, and comparing with standard solutions, the presence of trichloroacetic acid is determined.

The change in color of the solutions of the crystal light depending on the concentration of trichloroacetic acid is presented in Table. one.

0

The action of other acids such as formic, nitrogen, acetic acid, and sulfuric in the proposed concentrations does not cause bleaching of the crystal violet. The formic acid and acetic acid in these concentrations do not alter the color of the solutions of crystalviole at all. ta, nitric and sulfuric acids change, but do not discolor.

The effect of acids in the proposed concentrations on the color of the solutions of the crystal-volley (the volume of the working solution of the crystal-roller per portion is equal to O, 5 ml) is presented in Table. 2 Thus, the advantages of the proposed method are a reduction in the labor intensity and duration of the determination due to the exclusion of the extraction stage, butyl alcohol of the colored compound obtained in re-. As a result of the reaction of trichloroacetic acid with phenanthro-lin-ferrous sulfate 1 5 and by excluding the stage of drying, no organic solvent is dried. sodium sulfate, used

the minimum amount of reactants /. ; . . .. . .. .. l. ...

As can be seen from the table. 1, the decolouration of the crystal-light by the action of tricporcetic acid begins until the pH reaches a value of 0, In this range of pH values, the decolouration of the crystal light is also observed, but no green color transition is observed in any variant.

,15

6.5

3.2 2.7

Pale Violet Violet

summer - || Colorless

-AND.

Purple blue

 - purple blue shade

2.1

1.45 1.2

0.9

-AND.

-C- - || - - || 30

Ph o m u l a i z o b r e n e n A Method for the qualitative determination of trichloroacetic acid by treating the sample of color reagent analyzed

from that and fixing the change in coloration, tl and h; a (about and with the fact that, for the purpose of simplification with the use of both, kpMC talvishshet is used as color reagent.

. :; a b and c a .T, ..

-

th

 - Purple with a blue tint

Violet-goch bast Colorless

m -it

Violet Violet Violet Violet

.ts .and .11-H-MF violet with a blue tint

20.0 50.0

. m-hre da ct or 0. Head h

Tehred Ya.Olninyk

Order 1578 Circulation. Subscription VNIIPI of the State Committee for Inventions and Discoveries under the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab.5, 4/5

table 2

-CH-MF violet with a blue tint

Purple with blue tint Blue

Blue with green

Proofreader M "Samborska"

Claims (1)

Method of Qualitative Determination of Trichloroacetic Acid by Processing · ^{1 of the} Analyzed Sample with a Color Reagent 55 and Fixing Color Changes, Which Is Included in That, in order to Simplify the Method , as a color reagent, a crystal violet is used. . “ Trichloroacetic acid concentration Table 1 pH of solutions The amount of crystalline flying per serving, ml . ' 0, .25 | 0.5 .] .... ..... 0 6.5 Pale purple Violet Violet 0.1 3.2 .-And ’". .eleven. "eleven" 0.5 2.7 Colorless Violet Blue Purple with a blue tint 1,0 2,4 - I * "· .. '· Colorless Violet-goch bast 10.0 1.45 " eleven. - "·". '' Colorless 20,0 1,2 "eleven" _ιι. '' <. 50,0 0.9 "eleven" ·. -L and