RU2412436C1 - Method of determining amount of choline chloride in premixes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of determining amount of choline chloride in premixes involves collecting samples, grinding and establishing content of choline chloride in the premix. The novelty lies in designing a "piezoelectric pump" type detector based on 6 piezoelectric quartz crystal resonators with fundamental oscillation frequency of 10 mHz, whose electrodes are modified by applying onto their surface films of the following standard chromatographic sorbents and indicators weighing 15-17 mcg: dinonyl phthalate, 4-aminoantipyrene, polyethylene glycol phthalate, dicyclohexane-18-crown-6, polyethylene glycol sebacate, methyl red. A sample weighing 2 g is then collected from mass heated to temperature 30±2°C, put into a 20 cm weighing bottle with a polyurethane membrane on the cap and held for 30 minutes. 1 cm³ of an equilibrium phase under the premix is collected using a syringe through the polyurethane membrane and then quickly injected into the static "piezoelectric pump" cell. The oscillation frequency of the piezoelectric quartz crystal resonators (with films) is simultaneously recorded with a 5 second interval for 35 seconds and a composite signal is generated in form of a kinetic "visual imprint". The area of the said imprint is calculated and content of choline chloride is determined from a calibration curve plotted in coordinates of the area of the "visual imprint" versus its content in the premix.

EFFECT: high accuracy of detecting choline chloride in premixes.

1 dwg, 1 tbl, 2 ex

Description

The invention relates to techniques for the quantitative determination of choline chloride in premixes and can be widely used in product quality control in the feed industry.

The closest in technical essence and the achieved effect is the photometric method [(GOST R 50929-96), Premixes. Methods for the determination of B vitamins].

The disadvantages of the existing method are the duration of the analysis, the presence of special measuring and other utensils, insufficient sensitivity of the reagent, a high detection limit when determining low concentrations of choline chloride, the need for preliminary sample preparation, high errors, the method for determining choline chloride does not have high expressivity and selectivity, the use of reagents hazardous to health, such as esters and acetone.

An object of the invention is to develop a method for determining the amount of choline chloride in premixes, which allows for high sensitivity, low detection limits, accuracy, ease of detection, rapid analysis and objectivity, the use of safe reagents in the determination of choline chloride.

The technical task of the invention is achieved by the fact that in the method for determining the amount of choline chloride in premixes, including sampling, grinding, determination of the content of choline chloride in the premix, it is new that a “piezoelectronic nose” based on 6 piezoelectric crystals is used to determine the content of choline chloride in premixes with a base oscillation frequency of 10 MHz, the electrodes of which are modified by applying the following standard chromatographic sorbents and indicators weighing 15-17 μg to their surface: d nonilftalat, 4-aminoantipyrine, polyethylene phthalate, dicyclohexano-18-crown-6, polietilenglikolsebatsinat, methyl red, are then selected preheated to a temperature of 30 ± 2 ° C a sample of 2 g is placed in a weighing bottle of 20 cm ³ of a polyurethane membrane on the lid, stand for 30 minutes, then through a polyurethane membrane 1 cm ^{3 of the} equilibrium gas phase is taken over the premix with a syringe, which is quickly injected into the body of the static "piezoelectronic nose", the oscillation frequency of the piezoelectric crystals is fixed simultaneously with an interval of 5 s for 35 s and form the total signal in the form of a kinetic “visual imprint”, calculate its area and determine the content of choline chloride according to the calibration graph constructed in the coordinates of the area of the “visual imprint” (S _v.o. units ² ) from its content in the premix (C _{choline chloride} , g / kg), see drawing.

The technical result of the invention is to increase the sensitivity, expressness, intensification of the process of determining the amount of choline chloride in premixes, reduce the limits of determination and relative error, significantly increase the accuracy, reproducibility and objectivity of measurements and decision making, increase the expressivity of measurements through the use of a "piezoelectronic nose" with a personally selected an array of sensors for determining choline chloride in premixes and an algorithm for processing their signals.

The drawing shows the kinetic visual prints.

The method for determining choline chloride in premixes is as follows:

- prepare a detection device of the "piezoelectronic nose" type on the basis of 6 piezoelectric quartz resonators with a basic oscillation frequency of 10 MHz, the electrodes of which are modified by coating the following standard chromatographic sorbents with a mass of 15-17 μg on their surface: dinonyl phthalate, 4-aminoantipyrine, polyethylene glycol phthalate , dicyclohexano-18-crown-6, polyethylene glycolsebacinate, methyl red;

- a sample weighing 2 g, heated to a temperature of 30 ± 2 ° C, is taken, placed in a 20 cm ³ bottle with a polyurethane membrane on the lid, incubated for 30 minutes, then a 1 cm ³ equilibrium gas phase is taken through a polyurethane membrane with a syringe above the premix, which is injected into a cell of a static “piezoelectronic nose”, then the oscillation frequency of the piezoelectric quartz resonators is fixed with an interval of 5 s for 35 s and a total signal is generated in the form of a kinetic “visual imprint”;

- calculate its area and determine the content of choline chloride according to the calibration graph constructed in the coordinates of the area of the "visual imprint" (S _VO , unit ² ) from its content in the premix (C _{choline chloride} , g / kg).

The method is illustrated by the following examples.

Example 1 (prototype).

A weighed portion of premix 2 g is introduced into a volumetric flask with a capacity of 100 cm ³ , 50 cm ^{3 of} distilled water are added. Heated to 80 ° C and shaken for 15 minutes The flask was cooled, the volume was adjusted to the mark with distilled water and filtered through a dehydrated folded filter into a beaker. Select 15 cm ^{3 of the} filtrate in a flask with a ground stopper, pour 10 cm ^{3 of a} solution of sodium phosphate and 5 cm ^{3 of a} solution of ammonium rheinxate. The flask with the contents is shaken and left for 2 hours at a temperature of 4 ° C. After crystals of choline chloride precipitated, the solution was filtered on a No. 2 Schott funnel with an asbestos layer, using a vacuum pump. The crystals remaining on the filter are washed with 4-5 portions (5 cm ³ each) of chilled isopropyl alcohol. Change the flask and dissolve carefully by stirring the upper asbestos layer with sediment.

The contents of the flask are filtered into a volumetric flask with a capacity of 25 cm ³ . The volume was adjusted in the flask with acetone to the mark. The intensity of the colored solutions is measured on a photoelectrocolorimeter with a green filter or spectrophotometer at a wavelength of 526 nm in a cell with an absorbing layer thickness of 10 mm relative to acetone.

Preliminary build a calibration graph in the coordinates D = f (C),

D is the optical density;

C is the content of choline chloride.

The content of choline chloride in the premix, kg / t (g / kg), is calculated by the formula:

where K is the mass of choline chloride, found according to the calibration graph, mg;

V is the total volume of the extract, cm;

m is the mass of the sample, g;

V ₁ - the volume of the solution taken for analysis, cm ³ .

The analysis data are given in the table.

Example 2

A method for determining the amount of choline chloride in premixes, including sampling, grinding, establishing the content of choline chloride in the premix, characterized in that:

- prepare a detection device of the "piezoelectronic nose" type on the basis of 6 piezoelectric quartz resonators with a base frequency of 10 MHz, the electrodes of which are modified by coating the following standard dinonyl phthalate, 4-aminoantipyrine, polyethylene glycol phthalate, dicyclohexano-18-crown-6 films on their surface , polyethylene glycolsebacinate, methyl red;

- a sample weighing 2 g, heated to a temperature of 30 ± 2 ° C, is taken, placed in a 20 cm ³ bottle with a polyurethane membrane on the lid, incubated for 30 minutes, then a 1 cm ³ equilibrium gas phase is taken through a polyurethane membrane with a syringe above the premix, which is injected into the body of the static “piezoelectronic nose”, then the oscillation frequency of the piezoelectric quartz resonators is fixed with an interval of 5 s for 35 s and a total signal is generated in the form of a kinetic “visual imprint”;

- calculate its area and determine the content of choline chloride according to the calibration graph constructed in the coordinates of the area of the "visual imprints" (S _VO , unit ² ) of its content in the premix (C _{choline chloride} , g / kg).

The analysis data are presented in the table.

Criteria Way Prototype The claimed Range of determined concentrations, g / t 50-100 5-100 The subjectivity of determining concentration + - Reproducibility - + Analysis time with sample preparation, min 330 35 Measurement time, min 60 one Analysis error,% 10 2-3 The cost of one determination (excluding the cost of auxiliary equipment), rub. 600 250

As can be seen from the table, the proposed method for determining the amount of choline chloride in premixes has a wide range of determination of concentrations, reasonable price, high accuracy, reproducibility, expressity, determination is carried out for a short period of time within 1 min.

Analysis of experimental data shows that the content of choline chloride in the premixes, determined by the proposed method, with the introduction of vitamin in the amount of 5 g / t; 20 g / t; g / t amounted to 5.02 ± 0.04, respectively; 20.16 ± 0.3; 49.88 ± 0.6. When determined in a known manner, respectively, 4.56 ± 0.13; 19.00 ± 1.1; 45.98 ± 1.6. According to the known method less choline chloride is determined at its various concentrations, respectively, by 8.8%, 14%, 11%. The root-mean-square error of the arithmetic mean value when determined by the proposed method is significantly lower than when determined by the known method, when the known method does not exceed 0.6%.

The method for determining the amount of choline chloride in premixes allows you to:

- ensure high accuracy of determination;

- ease of detection;

- expressness of the analysis (reduction of the total analysis time by 9.5 times)

- objectivity;

- security;

- reduce the cost.

Claims (1)

A method for determining the amount of choline chloride in premixes, including sampling, grinding, determining the content of choline chloride in the premix, characterized in that a detection device of the piezoelectronic nose type is prepared on the basis of 6 piezoelectric crystals with a fundamental oscillation frequency of 10 MHz, the electrodes of which are modified by application on their surface films of the following standard chromatographic sorbents weighing 15-17 μg: dinonyl phthalate, 4-aminoantipyrine, polyethylene glycol phthalate, dicyclohexano-18-crown-6, polyethylene ikolsebacinat, methyl red, a sample weighing 2 g is taken, heated to a temperature of 30 ± 2 ° C, placed in a 20 cm ³ bottle with a polyurethane membrane on the lid, incubated for 30 minutes, then a 1 cm ³ equilibrium gas phase is taken through a polyurethane membrane with a syringe above the premix , which is quickly injected into the cell of the static “piezoelectronic nose”, the oscillation frequency of the piezoelectric crystal resonators (with films) is fixed simultaneously with an interval of 5 s for 35 s and a total signal is generated in the form of a kinetic “visual imprint”, p calculate its area and determine the content of choline chloride according to the calibration graph constructed in the coordinates of the area of the "visual imprints" (S _VO units ² ) from its content in the premix (C _{choline chloride} , g / kg).