Analytical control of active substances of the class of imidazolinones in herbicide formulations

Goal. The choice of a chromatographic method and the development of a method for the analytical determination of imazethapyr, imazamox, imazapyr in herbicide preparative forms in the joint presence. Methods. Active substances were analyzed by thin layer chromatography. The linear range of the dependence of the area of chromatographic zones on the amount of active substance was assessed by a mathematical-statistical method. Results. Determination of pesticides by thin-layer chromatography includes the main stages: classification of pesticides by polarity; extraction of active substances from the analyzed sample; chromatographic separation, detection and quantification. The decisive factor in the analysis stages is the dipole moment (μ, D), which characterizes the polarity of the compounds. Imazethapyr, imazamox and imazapir are polar compounds (μ≥6, D) with the corresponding values: 6.1; 6.4 and 6.8 D. Extraction of active substances is carried out with ethanol. Qualitative determination — in a thin layer of adsorbent silica gel in the mobile phase: a mixture of ethanol with acetic acid in a ratio of 4 : 1.5. Identify compounds at the wavelength of the spectrum λ 254 nm and using the developing reagent silver ammonia. The calibration dependence of the area of the chromatographic zone of the compound on its amount is linear in the detection range of 0.30—1.30 μg and is described by the regression equations for: imazethapyr S = 12.345 C + 0.7778, R2 = 0.99; imazapyr S = 9.3671 C + 1.081, R2 = 0.99; imazamox S = 7.6234 C + 1.4462, R2 = 0.98. The equation is used to quantify the active ingredients in the chromatogram. Conclusions. The use of the method of thin layer chromatography makes it possible to select selective conditions for the analysis of imazethapyr, imazamox, and imazapyr in the presence of herbicides in preparative forms. The developed technique is an express method of control and provides determination of active substances in the course of one analysis with high accuracy (relative error is less than 5% at n = 5, P = 0.95). The analytical support of the developed and patented method allows for analytical control of active substances of the imidazolinone class in the formulation of pesticides by analytical and toxicological laboratories, testing services without the use of expensive devices.

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Algorithm for assessing the completeness of seed treatment of wheat and barley

Interdepartmental Thematic Scientific Collection of Plant Protection and Quarantine ◽

10.36495/1606-9773.2019.65.212-224 ◽

2019 ◽

pp. 212-224

Author(s):

L. Chervyakova ◽

T. Panchenko ◽

O. Tsurkan ◽

N. Adamenko

Keyword(s):

Thin Layer ◽

Thin Layer Chromatography ◽

Control Method ◽

Bromphenol Blue ◽

Chromatography Method ◽

Agno3 Solution ◽

Stage Characteristic ◽

Layer Chromatography ◽

Active Substances

Goal. To develop a method for the determination of imidacloprid, clothianidin, prothioconazole and tebuconazole in the treatment seeds of wheat and barley. Methods. Active substances were determined by thin layer chromatography (TLC). Mathematical-statistical method for evaluate the linear range of the dependence of the area of the chromatographic zone on the amount of active substance was used. Results. The determination of pesticides includes a number of basic stage: characteristic the matrix by the ratio of the content of coextracting substances, that interfere with the determination, and the content of pesticides; classification of pesticides by polarity in according to the dipole moment (µ, D); extraction from the analyzed sample by organic solvent with corresponding of the dielectric constant, ε; purification; qualitative and quantitative determination. In the case of the analysis of treatment seeds, in which the amount of pesticides is much greater than coextracting compounds, the stages of classification and purification are excluded from the analysis. The extraction is carried out with ethanol. Qualitative determination of pesticides is carried out on plates with a thin layer of adsorbent (silicagel) in the mobile phase (mixture of hexane and ethanol, ε = 7.49) with using corresponding reagents. Silver ammonia (AgNO3) solution and followed by UV irradiation of the chromatogram is used for identification halogen-containing pesticides (zones of localization of compounds are formed dark spots of reduced silver). Pesticides containing donor atoms of sulfur, nitrogen, oxygen, identify by bromphenol blue (BPB) and subsequent bleaching of the background with an solution of citric acid (zones of localization of compounds are formed blue spots form on a light background). The active substances are identified with the corresponding Rf of the zones localization. Quantitatively of active substances is determined by the calibration dependence of the area of compound’ chromatographic zone on its quantity. For all four compounds, this dependence is linear in the concentration range of 0.20 — 0.80 µg and is described by the regression equation for: imidacloprid y = 6.25x + 5.45; for clothianidine y = 11.65x + 6.70; for prothioconazole y = 28.7x + 2.05; for tebuconazole y = 13.00x + 7.00. In all cases, the correlation between the indicators is estimated as strong (r = 0.99). Conclusions The algorithm for assessing the completeness of the treatment of wheat and barley seeds is an express control method and using the thin layer chromatography method allows to determine four active substances in one sample during one analysis with high accuracy (relative error of less than 5% at n = 5, P = 0.95) excluding laborious experiment.

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BACTERIA ENTEROBACTER NIMIPRESSURALIS 32-3 – THE PRODUCER OF PHYTOHORMONES

Agriciltural microbiology ◽

10.35868/1997-3004.9.68-75 ◽

2009 ◽

Vol 9 ◽

pp. 68-75

Author(s):

L.A. Chaykovska ◽

M.I. Baranska

Keyword(s):

Thin Layer ◽

Thin Layer Chromatography ◽

Physiologically Active Substances ◽

Layer Chromatography ◽

Active Substances

Qualitative (bioassays) and quantitative (thin-layer chromatography) determination of phytohormones produced by the bacterium Enterobacter nimipressuralis 32-3 were carried out. It was established, that cultural liquid of strаin contains physiologically active substances of three classes of phytohormones: auxin, gibberellin and citokinin.

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