SU1564523A1 - Method of quantitative determination of anioning surfactants - Google Patents

Abstract

This invention relates to analytical chemistry, in particular to the quantitative determination of anionic surfactants. The goal is to simplify the method and reduce the time spent on the determination. The determination is carried out by treating an aqueous solution of the analyte with a mixture of cerium chloride, methylthymol blue and cetylpyridinium bromide at a molar ratio of components 1: / 1-4 /: / 1.5-6 / in the presence of a surfactant based on polyoxyethylene synthetic fatty alcohols syntanol ACCE -12 at PH 3.7-4.9. The process is conducted with the subsequent measurement of the optical density of the resulting solution. 3 tab.

Description

This invention relates to anapiti-. The chemical chemistry of organic compounds, in particular, methods for the determination of anionic surfactants, can be used to quantify various alkyl sulphates, alkyl sulphonates and sodium alkylaryl sulphonates used as the basis for synthetic detergents, emulsifiers, flotation agents.

The aim of the invention is to simplify the method and reduce the time spent on the determination.

Example 1. In a volumetric flask of 25 ml is placed 5 ml of urotropin buffer solution with a pH of 4.9, 5 nl 2, M aqueous solution of cetylpyridinium bromide, 1 ml of 2.5% aqueous solution of syntanol ACTS-12, 2 ml of M solution methylthymol blue, 2 ml of M solution of cerium chloride and an aliquot part of the analyzed solution containing 0.15-1.5 mg of anionic surfactant. Reduce the solution to the mark with distilled water and measure it on the spectrophotometer, for example, SF-5, SF-16. -. The density of the solution at A 610 nm in a cuvette with 1 "1 cm relative to the comparison solution, which does not contain an anionic surfactant, is compared. The content of anionic surfactants in the analyzed solution is determined by the calibration curve. The construction of the calibration curve is carried out in a similar way using a standard solution determined by an anionic surfactant. Content of aPAV

in the final volume, when constructing the calibration curve, it should be 0.15-1.5 mg.

In tab. The results of determination of anionic surfactants of the type of alkyl sulfates, alkyl sulfonates and alkylaryl sulfonates by the proposed method are presented.

Thus, the data presented in Table 1 shows that it is possible for the proposed method to carry out the determination of anionic surfactants such as alkyl sulfates, sodium alkyl sulfonates and sodium alkyl aryl sulfonates with a content of 0.15-1.5 mg per 25 ml of final volume with relative with an error of 0.5 - 8.7%. At the same time, the total number of operations when performing a single determination is 16, instead of 80 of the prototype, which results in at least fivefold reduction of the time for analysis. Thus, the average time taken to perform a single determination of the anti-alcoholic surfactants according to the prototype is 8-15 minutes, and according to the proposed method, 1.5-3 minutes.

PRI mme R 2. The rationale for the proposed range of pH. Table 1 shows the results of the determination of anionic antioxidants by the proposed method at pH 4.9. Table 2 shows the results of the determination of the anionic antioxidant agent at other pH values of the proposed range, as well as at pH values beyond the proposed range. The determination is carried out as in Example 1 using buffer solutions with the corresponding pK values.

The data given in Table 1 "2" shows that the determination of the anti-pavement agent by the proposed method in the pI range of 3.7-4.9 allows one to achieve the purpose of the invention. Thus, the linearity of the calibration schedule for the determination of sodium dodecyl sulfate in the proposed pH range is observed in the range of 0.15-1.50 mg SDS with a relative error not exceeding 8.6%. The implementation of the method at pH values beyond the proposed interval leads to the absence of a difference in the nature of the light absorption of the color reagent in the absence and in the presence of an AALO. As a consequence, the purpose of the invention is not achieved.

(g

At-merz. Justification of the proposed ratio of chlorine concentrations

 ,

Q with

0

five

cerid, methylthymol blue (MTS) and cetylpyridinium bromide (S1B).

The data presented in Tables 1 and 2 show the possibility of determining the anionic surfactants by the proposed method with a ratio of CeClj: MTC: CPB 1: 2: 3.

Table 3 shows the results of the determination of the AELC at other ratios of the concentrations of GeC19, MTS and CPB of the proposed interval, as well as with the values of GeC1 $: MTS: CPB, which are outside the proposed interval. The determination is carried out analogously to example 1 using a constant concentration of MTS and variable concentrations of CeCl and CPB. Sulfonic acid was used as an anionic surfactant in experiments to establish the optimal ratio of color reagent components.

The data presented in Table 3 shows that the implementation of the proposed method for determining ALAB using CeClj, MTS and CPB, taken in a 1: (1-4) (1.5-6) ratio, allows to achieve the purpose of the invention. Going beyond the proposed interval of ratios in a number of cases leads to the absence of a difference in the nature of the light absorption of the color reagent c-presence and in the absence of an AALV or h. This leads to the formation of insoluble precipitates in the system, with the result that the purpose of the invention is not achieved.

I

F ooo Mula Invention

Method for quantitative determination of anionic surfactants by treating an aqueous solution of an analyte with a color reagent followed by measuring the optical density of the solution obtained, characterized in that, in order to simplify the method and shorten the time spent for determination, a mixture of cerium chloride, methylthymol blue is used as a color reagent and cetylpyridinium bromide with a molar ratio of components of 1: 1–4: 1.5–6, respectively, and the treatment is carried out in the presence of surfactant in exists based on synthetic polyoxyethylated fatty alcohols - synthanol ATSSE-12 at pH 3,7-4,9.

Table 1

Table3

1: 1.5

4: 6

6: 2

: 3: 6

: 2: 8

0.30 0.60

 v

0.90 1.50 0.30 0.60 0.90 1.50 0.30 0.60 0.90 1.50 0.30 0.60 0.90 1.50 0.30 0.60 0, 90 1.50

5.0

7.1 10.4

1.3 10.9 8.3 4.0 3.0

Not determined

and

.

Undefined Undefined

"- - Undefined Undefined

.- -

Claims (1)

Claim A method for the quantitative determination of anionic surfactants by treating an aqueous solution of the analyte with a color45 reagent, followed by measuring the optical density of the resulting solution, characterized in that, in order to simplify the method and reduce the time it takes to determine, a mixture of cerium chloride, methyl thymol is used as a color reagent blue and cetylpyridinium bromide in a molar ratio of components of 1: 1-4:: 1.5-6, respectively, and the treatment is carried out in the presence of surface-active components based on polyoxyethylated synthetic fatty alcohols syntanol ACSE-12 at a pH of 3.7-4.9. ’1564523 Table 1 APAV Introduced AAS,. Found APAV, Relative error,% mg mg (n = 6) (n = 6) Dodecyl sulfate sodium (DDS) 0.15 0.17 5.7 0.29 0.27 3.2 0.58 0.57 2.6 0.86 0.85 1.3 1.15 1.13 1.8 1.44 1.46 0.5 Pentadecylsul sodium phonate (VDSN) 0.15 0.14 2.6 0.60 0.60 6.8 0.90 0.91 1.4 1,50 1, 49 2.2 Alkylarylsul sodium phonate (sulfonol) 0.15 0.16 8.7 0.30 0.29 8.6 0.60 0.59 5.5 0.90 0.87 1.3 1, 50 1, 52 1,0 Table 2 APAV 'pH Introduced AAS, mg (n = 6) Found AAP, mg (n = 6) Relative error,% DDSN Gj 1 0.15 0.15 8.6 . 0.86 0.83 0.9 1.44 1.46 1.3 3.0 0.15 Undefined Not determined 0.86 1,50 _ || _ 6.1 0.15 Undefined Not determined 0.86 - ’I— 1,50 - 9.0 0.15 Undefined Not determined 0.86 1,50 PDS 8.6 0.15 Undefined Not determined 0.86 1,50 Sulfonol AND 0.15 Undefined Not determined 0.86 - ^and - 1,50 - - 7 1564523 8 Table 3 СеС1 ₄ : MTS: CPB Introduced AAS, mg (p ⁱⁿ 6) Found AAS, mg (p - 6) Relative error % 1: 1: 1,5 0.30 0.27 5,0 0.60 0.61 7.1 0.90 0.89 10,4 1,50 1.47 1.3 1: 4: 6 0.30 0.32 10.9 0.60 0.60 8.3 0.90 0.86 4.0 1,50 1,62 3.0 1: 6: 2 0.30 Not defined Not defined 0.60 0.90 1,50 2: 3: 6 0.30 0.60 Not defined Not defined  —T. ..... ♦ 0.90 ; ... · 1,50 1: 2: 8 0.30 Not defined Not defined 0.60 0.90 1,50 Editor T. Parfenova Compiled by S. Khovanskaya '* Tehred M. Khodanich - Corrector E. Lonchakova Circulation 510 Subscription Order 1155 / VNIIIPI of the State Committee for Inventions and Discoveries at the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Plant Patent, Uzhgorod, st. Gagarina, 101