CS255316B1 - Method for group determination of urea and triazoid herbicides - Google Patents

Abstract

The solution concerns a method for group determination of triazine and urea herbicides side by side by thin layer chromatography, suitable especially for water management, hygiene, soil and food purposes. After parallel application of samples containing triazine and urea herbicides and standards, the chromatographic plate is gradually developed in two mobile systems so that first the active part is developed in the acetone-carbon tetrachloride system and after free drying the entire plate is developed in an aqueous solution of acetic acid. The groups of triazine and urea herbicides separated by gradual development are subsequently determined in comparison with the standards by known procedures. The method is suitable for the determination of triazine and urea herbicides in water samples, soil, in food products, in plant and animal material, especially for water management, hygiene, soil and food purposes.

Description

The subject of the invention relates to the grouping, and the triazine and urea herbicides were carried out by thin-layer chromatography suitable for water, sanitary, pedological and food purposes.

In the detection of triazine and urea herbicides by thin-layer chromatography, the mobile systems recom- mended by the chromatograms developed only allow partial separation of these substances, and separation of triazines from urea derivatives is problematic in virtually all cases. To develop the chromatogram proceed! the individual herbicides of the two groups usually coincide, overlap with each other, or some substances coincide in the chromatogram, which makes it difficult to determine. In such cases, it is necessary to use a combination of several mobile systems, which ensure separation of detected substances, which is very labor and time consuming. It is particularly problematic if it is desired to decompose all the herbicides present in the sample to be analyzed, since none of the recommended systems in the literature provides for the determination of the two groups of herbicides side by side.

The following developing systems are most commonly used in the chromatographic determination of triazine and urea herbicides: toluene-acetone [85 + 15] [DELLEY, R. et al: Z. anal. Chem. 228, (1967), 23, dichloromethane, chloroform-acetone (9 + 1) or (7-3), hexane-acetone (9 + 1), or (7 + 3) ABBOT,

D. C. et al., J. Chromatogr. 30, (1967), 136, chloroform-, ethyl acetate (9 + 1) (WALIERE,

K. C., BEROZA, M: J. AOAC 46, (1963), 250. The effect of separating these herbicides by these systems is illustrated in Table 1.

Table no. 1

_Rf values of some of the triazine herbicide and the urea to divide TLC

herbicide Chloroformacetone (9 + 1) Chloroformoctan ethyl. (9 + 1) R _f toluene- acetone (85 + 14) . 100 dichloro methane 2-Chloro-4-ethylamine-6-isopropylamino-1,3,5-triazine (atrazine) 82 33 59 10 2-chloro-4,6-di [ethylamino] -1,3,5-triazine (simazine) 75 25 48 7 2,4-di [isopropylamino] -6-methylthio-1,3,5-triazine (methronine) 88 47 69 58 2-isopropylamino-4-metylamí- amino-6-methylthio-l, 3,5-triazine (desmetrýnj 76 20 45 31 2-chloro-4,6-di (isopropylamino) -1,3,5-triazine [propazine] 92 42 65 57 2-ethylamino-4-isopropylamino-6-methylthio-1,3,5-triazine (ametrin) 84 31 60 10 3- (3,4-Dichlorophenyl) -1-methoxy-1-methylurea (linuron) 90 63 62 71 3- (4-chlorophenyl) -1-methoxy-1-methylurea [monolmuron] 91 66 67 65 3- [4-chlorophenyl) -1,1-dimethylurea (monuron) 60 19 26 10 3- (3,4-Dichlorophenyl) -1,1-dimethylurea (diuron 65 24 32 ¹⁴

It has now been found that triazine and urea herbicides can be determined group-wise by the thin-layer chromatography method of the invention.

The principle of the invention is that after the parallel application of samples containing mixtures of the substances to be determined and standards, the chromatographic plate is gradually developed in two mobile systems. First, a portion of the plate is developed in an acetone-carbon tetrachloride system and, after free drying, the entire plate is developed in an aqueous acetic acid solution. By sequentially developing a separate group of triazine and urea herbicides, they are subsequently determined by known methods, for example thin layer chromatography or gas chromatography, compared to standards.

After developing in the acetone-carbon tetrachloride system, all the herbicides present will advance to the front of the mobile system. In developing the chromatographic solution in aqueous acetic acid solution, the triazines remain at the head of the first mobile system and the urea herbicides progress toward the head of the second mobile system.

According to the process of the invention, because of the simple and rapid distribution, groups of triazine and urea herbicides can be determined side by side with sufficient precision without much time and material requirements. The method according to the invention is particularly suitable, in particular, for service water, sanitation, pedological and food laboratories where it is desired to summarize the groups of these pesticides side by side or where it is not considered necessary to determine these substances individually. Its use can be predicted especially in the determination of triazine and urea herbicides in samples, water, bases, in food products as well as in plant and animal materials

The following examples illustrate but do not limit the invention.

Example 1

For silicone plates, which are first purified by developing in acetone, apply a mixed standard solution (5 μΐ) in the form of 1 point of triazine [2-chloro-4-ethylamino-6-isopropylainino-1,3,5-triazine,

2-chloro-4,6-di (ethylamino) -1,3,5 ^; triazine,

2,4-di (isopropylamino) -6-methylthio-1,3,5-triazine,

2-isopropylamino-4-methylamino-6-methylthio-l, 3,5-triazine,

2-chloro-4,6-di (isopropylamino) -1,3,5-triazine] and urea [3- (4-bromo-3-chlorophenyl) -1-methoxy-1-methyl-urea,

3- (3-chloro-p-tolyl) -1,1-dimethylurea,

3- [4- (4-chlorophenoxy) phenyl] -1,1-dimethylurea,

3- (3,4-dichlorophenyl) -1-methoxy-1-methylurea,

3- (4-chloro-phenyl} -l-methoxy-l-methylurea,

3- (3-chloro-4-methoxyphenyl) -1,1-dimethylurea,

3- (4-Bromophenyl) -1-methoxy-1-methylurea

Of 1,1-dimethyl-3- (3-trifluoromethylphenylurea) herbicides in the same concentration (1? 1 = 0.01 <Mg).

The plate develops first in the mobile acetone-carbon tetrachloride (1 + 4) system up to one third valid and, by free air drying, develops in the mobile system with a 2% aqueous acetic acid solution up to the upper edge of the plate. Detected by suitable chemical reagents (eg Mitchell reagent - a mixture of silver nitrate and 2-phenoxyethanol in acetone followed by irradiation of the chromatogram with UV-rays - 254 nm), or the separated herbicide groups after isolation are determined by gas chromatography (GC). the head of the first mobile system as a single, point of the _Rf. 100 value of 19 and a urea forward to the face of existing as two points of R _f. values 100 45 [3- (4-bromo-phenyl J-1-methoxy-l- methyl-urea,

3- (3-Chloro-p-tolyl) -1,1-dimethyl-urea

3- (3-chloro-4-methoxyphenyl) -1,1-dimethylurea,

3- (3,4-dichlorophenyl) -1-methoxy-1-methylureas], and 51 [3- (4-chlorophenyl) -1-methoxy-1-methylurea,

3- (3-chloro-4-methoxyphenyl) -1,1-dimethylurea,

3- (4-Bromophenyl) -1-methoxy-1-methylurea

1,1-dimethyl-3- (3-trifluoromethylphenyl) urea.

The sensitivity of the detection is 0.02-0.05 µg of the respective herbicides in the spot.

Example 2

To a sample of natural dots (usually one liter), an aqueous solution of ammonium hydroxide is gradually added to a pH of 8-9 and extracted with 25 ml of chloroform for 25 min. The organic layer was separated and the aqueous layer was extracted with an additional 25 mL portion of chloroform for 2 min. After phase separation, the organic portion is added to the first portion, the aqueous layer is removed and the funnel is shaken with 10 ml of chloroform which is attached to the organic extract. After removal of the residual water by addition of anhydrous sodium sulfate, the extract is concentrated to dryness in a vacuum evaporator. If the extract is to be purified on an alumina column, the extract is dissolved in 10 ml of carbon tetrachloride. For direct separation and detection of herbicides by thin-layer chromatography, the extract is dissolved in 1 ml of acetone, from which an aliquot (1 to 5 μΐ) is then applied to the canvas as a single point and concomitantly applied to the canvas concentration range. The procedure is as in Example 1.

Example 3

To 100 ml of fresh soil sample is added

250 ml of extra methanol-water mixture (80 + 20) and extracted on a shaker for 2 hours. After settling, the aqueous layer is carefully decanted into a graduated cylinder through a funnel in which a tuft of cotton is present. The volume of extract obtained should be 170-200 ml. If less extract is obtained, the residue is collected on a centrifuge at 2000 rpm. for 15 minutes. The extracts are blotted and the final volume is recorded. 200 ml of distilled water, 5 ml of saturated sodium chloride solution are added to the roethanolic extract and the procedure is followed as for water analysis (Example 2).

The invention is of importance and good application for the rapid grouping of triazine and urea herbicides side by side in water samples, under food products, as well as in plant and animal material.

Claims (1)

255316 is added to the first portion, the aqueous layer is removed and the funnel is shaken with 10 ml of chloroform which is attached to the organic extract. After removal of the residue by addition of anhydrous sodium sulfate, the extract was concentrated to dryness under vacuum. If the extract is to be purified on an alumina column, the extract is dissolved in 10 ml of carbon tetrachloride. The thin-layer chromatographic separation of herbicides is determined by dissolving the extract in 1 ml of acetone, from which an aliquot (1 to 5 μΐ) of a single point canvas is applied and the mixed herbicide mixture standard is applied to the canvas at the desired concentration. -track range. Next, proceed as described in Example 1. Example 3 250 ml of methanol-water extraction mixture (80 ++ 20) is added to 100 ml of a fresh sample of the flask and extracted in a shaker for 2 hours. a funnel in which the tufted cotton wool. The volume of the extract obtained should be 170-200 ml. If less extract is obtained, the residue is separated on a centrifuge at 2000 rpm. for 15 minutes. The saspofja extracts and the final volume were recorded. 200 ml of distilled water, 5 ml of a saturated solution of sodium chloride were added to the ethanolic extract, followed by water analysis (Example 2). The invention has the meaning and good application of the rapid group determination of triazine and urea herbicides has resulted in water samples, food products as well as in plant and animal materials. OBJECTIVE The method of group determination of triazine and urea herbicides resulted in thin-layer chromatography, water, sanitary, pedological and food applications, characterized in that after the application of the samples containing the mixtures of the compounds and standards the gradual development of the plate in two-cell systems, the acetone-carbon tetrachloride system first being developed, after drying freely, the whole plate is formed in an aqueous acetic acid solution and by progressively developing separate groups of triazine and urea herbicides and comparing them with the following standards, e.g. thin layer chromatography or gas chromatography. Severograíia, n. P. Plant 7, Most Price 2.40 Kčs