SU1599726A1 - Method of qualitative determination of anion surfactants - Google Patents

Abstract

This invention relates to analytical chemistry, in particular to the quantitative determination of anionic surfactants. The goal is to increase the detection sensitivity and reduce the time spent on the method. The determination is carried out by treating an aqueous solution of the sample being analyzed with malachite green at PH 3.0-7.0 in the presence of synanol at a mass ratio of the color reagent and synanol 1: (5-10). The process is conducted with the subsequent measurement of the optical density of the resulting solution. 3 tab.

Description

The invention relates to the analytical chemistry of organic compounds, namely to methods for the determination of anionic surfactants (APAS), and can be used to quantify various alkyl sulfates, alkyl sulfonates and sodium alkyl aryl sulfonates used as the basis of synthetic detergents, emulsifiers, flotation agents.

The purpose of the invention is to increase the detection sensitivity and reduce the time spent on the method.

Example G. the Definition of anionic surfactants for the proposed method.

In a calibrated measuring flask of 25 ml is placed 2 ml of acetate buffer solution with a pH of 5.0; 4.0 ml

1-10% of an aqueous solution of malachite green (MOH), 1.0 ml of a 0.2% aqueous solution of synanol ACSE-12 and an aliquot portion of the analyzed solution containing 10-400 μg of antioxidant system, Bring the solution to the mark with distilled water and A spectrophotometer, for example, an SF-5, an SF-16, measures its optical density at 1 640-660 nm in a cuvette with 1-1 cm relative to a reference solution that does not contain ATIBo. The content of anionic surfactants in the analyzed solution is determined using a calibration curve. The construction of the calibration curve is carried out in a similar way using a standard solution determined by an anti-alkaline surfactant. The content of anionic surfactants when making a calibration curve should be 10, 50, 100, 200, 300, 400 µg.

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Table I shows the results of a quantitative determination of anionic surfactants such as alkyl sulfates, alkyl sulfonates, and alkylaryl sulfonates,

The data presented in TabLo 1 shows that the proposed method makes it possible to determine the AELS of the type of alkyl sulphates, alkyl sulphonates and alkylaryl sulphon-sodium and its content, 10-400 μg in 25 ml of the final volume | with a relative error of 1.5-12%. 1 At the same time, the total number of operations when performing a single determination is 1, 10, instead of 80 using a prototype, which results in at least five-: fold reduction in analysis time. ; Thus, the average time for performing a single determination of the anti-pavement agent on the prototype is 8-15 minutes, and according to the proposed method, 1.5-3 minutes

PRI and m. R 2. The rationale for the proposed pH range.

In tab. 1 shows the results of the determination of anionic surfactants by the proposed method at pH 5.0

In tab. Table 2 shows the results of the determination of anionic surfactants at other pH values of the proposed range, as well as at pH values that go beyond the suggested range. The determination is carried out in an example using buffer solutions with an appropriate pH value. Sodium dodecyl sulfate was used as an anionic surfactant.

The data presented in table. 2, it is shown that the determination of anionic surfactants according to the proposed method in the pH range 3.0-7.0 allows an increase in the sensitivity of the method. Thus, the relative error in the determination of sodium dodecyl sulfate in the proposed pH range is 1.1-8.3%. The implementation of the method at values of pI beyond the proposed interval does not lead to an increase in the sensitivity of the method. Thus, at pH 8.0, a rapid disappearance of the color of the solutions is observed due to the transition of the colored form of malachite green to the corresponding colorless base. This makes it possible in principle to determine AG1AB by the proposed method with a pH of more than 7.0,

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l The consequence of this is an increase in the relative error in the determination of aPAS with a deterioration in the accuracy of the analysis results.

P {) and measure 3. Justification of the proposed ratio of the concentrations of malachite green and syntanol ACTS-12.

The data presented in Tables 1 and 2. show the possibility of determining the anti-pavement effect of the proposed method with a molar ratio of MOH: CACSE-1 2: 1: 5 °.

In tab. Table 3 shows the results of the determination of the ASTR at other values of the ratio of concentrations of MH and CASSE-12 of the proposed interval (MH: CACSE-12 1: (5-10), as well as for other values of MH: CACSE-12 beyond the proposed interval.

The determination is carried out analogously to Example 1 using a constant concentration of MOH and a variable concentration of CASE-12.

The data presented in table. 3 shows that the implementation of the proposed method for determining the anti-pavement of anti-inflammatory substances using MOH and CASE-12, taken in a molar ratio of 1: (5-10), makes it possible to increase the detection sensitivity. Thus, with an increase in the relative content of SASSE-12 more than the MOH: SASSE-12 1:10, the sensitivity of the proposed method decreases. The consequence of this is an increase in the limit of the determination of the AAL, in particular PDSN, DDSN, and an increase in the relative error of determination. With a decrease in the relative content of TSTSSE-12 below the MOZ of GSANTSE- 2 1: 5, along with a decrease in the sensitivity of the method, in particular when determining the PDSN, the formation of insoluble precipitates is observed, which causes an increase in the relative error and, in a number of cases, the impossibility of implementing the method.

Claims (1)

Invention Formula Method for the qualitative determination of anionic surfactants. By treatment with an aqueous solution. When the pH of the solution is less than 3.0, the sample is analyzed using a color reagent. five 0 five 0 five 0 five 0 l The consequence of this is an increase in the relative error in the determination of aPAS with a deterioration in the accuracy of the analysis results. P {) and measure 3. Justification of the proposed ratio of the concentrations of malachite green and syntanol ACTS-12. The data presented in Tables 1 and 2. show the possibility of determining the anti-pavement effect of the proposed method with a molar ratio of MOH: CACSE-1 2: 1: 5 °. In tab. Figure 3 shows the results of the determination of the anti-pesticide active substances at other values of the ratio of concentrations of MH and CACSE-12 of the proposed interval (MH: CACSE-12 1: (5-10), as well as for other values of MH: CACSE-12 beyond the proposed interval . The determination is carried out analogously to Example 1 using a constant concentration of MOH and a variable concentration of CASE-12. The data presented in table. 3 shows that the implementation of the proposed method for determining the anti-pavement of anti-inflammatory substances using MOH and CASE-12, taken in a molar ratio of 1: (5-10), makes it possible to increase the detection sensitivity. Thus, with an increase in the relative content of SASSE-12 more than the MOH: SASSE-12 1:10, the sensitivity of the proposed method decreases. The consequence of this is an increase in the limit of the determination of the AAL, in particular PDSN, DDSN, and an increase in the relative error of determination. With a decrease in the relative content of TSTSSE-12 below the MOZ of GSANTSE- 2 1: 5, along with a decrease in the sensitivity of the method, in particular when determining the PDSN, the formation of insoluble precipitates is observed, which causes an increase in the relative error and, in a number of cases, the impossibility of implementing the method. Invention Formula Method for the qualitative determination of anionic surfactants by treating an aqueous solution of an analyzed sample with a color reagent protonation of malachite green, accompanied by a decrease in the concentration of the corresponding form, was dyed with the last measurement of the optical density of the cell solution, which is also different from that. In order to increase the sensitivity of the determination and reduce the time spent on the process, malachite zelaAPAV Introduced aPAV, µg () Sodium dodecletsulphate (SDS) C Sodium Pentadecipium Sulfate (PDSN) C.jHj. .Sodium sodium sulfate (TDSN) With „Ngt5S), Ka Sodium pentadecyl sulfonate C ,, Hj, ( Sodium alklaryl sulfonate (sulfonol) C "H5", C "H" 50 Ma p - 12-16 This and the treatment are carried out at a pH of 3.0-7.0 in the presence of synthanol at a mass ratio of the color reagent and .sintanol equal to 1: (5-10). t a b l i c i Relative error, Z J2 8.1 3.0 2.1 1.5 .eight 12 2; 8 2.1 1.1 1.5 P 6.3 6.2 23 1.6 1.7 12 9.2 3.7 2.0. 2.0 1.5 3.0 Glycine-HC1 4.0 Acetate 6.3 Acetate 7.0 Phosphate 8.0 Phosphate 2, About Glycine-NS table 2 ddsn 1: 7.5 1: 12,5 pdsn 1: 7.5 Table 3