CS255776B1 - Powdered reagent mixture for the quantitative determination of nitrates and nitrites in plants - Google Patents

Abstract

Powdered reagent mixture for the seven-quantitative determination of nitrates and nitrites in plants based on the principle of the reaction of nitrites with sulfanilic acid, or its derivatives, and subsequent coupling with •L-naphthylamine, or its derivatives, to form an azo dye, contains, in powder form, manganese salts in an amount of 2 to 7 parts by weight, zinc powder in an amount of 0.5 to 1.5 parts by weight, sulfonic acid or its derivatives in an amount of 1 to 3 parts by weight, r/·-naphthylamine or its derivatives in an amount of 0.5 to 1.5 parts by weight, organic solid acids in an amount of 30 to 50 parts by weight, for example citric acid, and fillers in an amount of 50 to 130 parts by weight.

Description

The invention relates to a reagent composition for the semi-quantitative determination of nitrates and nitrites in plants.

The methods used to date require laboratory and laboratory tests. instrumentation and / or orientation methods for field determination are based on reaction with diphenylamine (diphenylbenzidine), which are dissolved in concentrated sulfuric acid. Sulfuric acid is a strong caustic agent, when working in the field it is not possible to contaminate the worker, wear clothes, etc. Colored. the reaction is unstable. Calibrating and evaluating assay results is also difficult.

Various forms of indicator papers are also known, but these are difficult to access and also costly. The resolution is insufficient, the stability of the reagent mixture of the indicator paper is limited, the intensity of the surface coloring is uneven.

The above mentioned disadvantages are eliminated by the powdered reagent mixture for semi-quantitative determination of nitrates and nitrites in plants by reaction of nitrites with sulfanilic acid or their derivatives and subsequent coupling with N-naphthylamine or its derivatives to form an azo dye, which consists essentially of containing from 2 to 7 parts by weight of manganese salt, 0.5 to 1.5 parts by weight of zinc powder, 1 to 3 parts by weight of sulfanilic acid or its derivatives; 0.5 to 1.5 parts by weight of organic solid acid in an amount of 30 to 50 parts by weight; and fillers, for example, barium or calcium sulfate, or silica gel, in an amount of 50 to 130 parts by weight.

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The chemicals required to prepare the mixture are readily available and relatively inexpensive. The preparation of the reagent mixture is simple and quick. The reagent mixture should be stored in a dark container. Unlike the test papers, a DC area staining is achieved after homogenization of the reagent mixture with a sample of the squeezed liquid from the plant under investigation, thereby increasing the objectivity in assessing the staining.

By modeling the composition of the reagent mixture and its weight ratio to the test fluid, the color intensity and thus the resolution can be varied within the necessary range of nitrate and nitrite concentrations in the fluid.

By way of illustration, the following examples of reagent compositions are given.

Example 1

For the semi-quantitative determination of nitrogen in the form of nitrates and nitrites in silage oat, a reagent mixture of the following composition was used:

parts by weight manganese sulphate zinc powder parts mass. sulfanilic acid

0.8 parts by weight % of the naphthylamine; calcium sulfate parts mass. % silica gel with 10% gypsum parts by weight. citric acid

In three samples the values were compared with the laboratory method of Caialdo, D.A. - Haroon, M. - Schrader, L.E. - Youngs, U.L., Rapid Colorimetric Determination of Nitrate in Plant Tissue by Nitration of Salicylic Acid, Comm. Sbil. Sci. Plant Anal. Vol. 6, No. 1, 71, 1975.

sample semiquantitative method laboratory method 1 less than 0.04 wt. 0.035 wt. 2 less than 0.08 wt. 0.063 wt. 3 more than 0.21 wt. 0.264 wt.

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The color of the mixture, which rises from faint pink, pink, deep pink, red to reddish-violet according to the nitrate and nitrite concentration in the sample, is compared with the color intensity of the standards. For normal fresh forage, the signal of inappropriate forage is a dark red and mauve color.

Example 2

One drop of liquid pressed from the carrot was homogenized with 0.20 parts by weight. reagent mixtures containing 5 parts by weight of the composition; manganese sulfate, 1 part wt. zinc, 2 parts by weight. of sulfanilic acid, 1.2 parts-wt. -naphthylamine, 60 parts by weight. barium sulfate, 45 parts by weight. tartaric acid.

The nitrogen content, calculated as nitrate, ranged from 0.04 to 0.14% by weight in various types of carrots.

Example 3

One drop of molded liquid from the ryegrass was homogenized with 0.25 parts by weight. of the reagent mixture, which contained 5 parts by weight. manganese sulfate, 1 part wt. zinc powder, 2 parts by weight. of sulfanilic acid, 0.7 parts by weight. (naphthylamine, 50 parts by weight calcium sulfate and 45 parts by weight tartaric acid).

The nitrogen content calculated as nitrate ranged from 0.025 to 0.375% by weight for various samples.

Claims (1)

Powdered reagent mixture for semi-quantitative determination of nitrates and nitrites in plants based on the reaction of nitrites with sulfanilic acid or derivatives thereof and subsequent coupling with -naphthylamine or derivatives thereof to form an azo dye, characterized in that it contains manganese salts in an amount of 2 to 7 0.5 to 1.5 parts by weight, sulfanilic acid or derivatives thereof in an amount of 1 to 3 parts by weight, naphthylamine or derivatives thereof in an amount of 0.5 to 1.5 parts by weight, zinc powder in an amount of 0.5 to 1.5 parts by weight; % organic solid acids in an amount of 30 to 50 parts by weight, for example citric acid and fillers, for example barium or calcium sulphate or silica gel, in an amount of 50 to 130 parts by weight.