SU1317357A1 - Method of quantitative determining of residual solvents in extracted inorganic substances - Google Patents

Abstract

The invention relates to a quantitative analysis using the method of gas-liquid chromatography used for the extraction of inorganic and organic substances, in particular feed, solvents. The aim of the invention is to reduce time and increase accuracy. To the test sample, 50-1250% of water is added based on the weight of the sample, as well as a polar properties dissolving agent that absorbs water and the analyzed mixture of extracting agents without breaking the miscibility and does not disrupt the assessment of gas chromatography. An internal standard is then added, in which the retention time does not coincide with the retention times of the determined extracting agents, is fed to a measuring flask, to which a mixture of the dissolving agent and water is added, and after stirring, the upper light is chromatographed. . 3 hp f-ly. (L Co 4J with SP

Description

The invention relates to methods for the quantitative isolation and analytical gas chromatography determination used for the extraction of inorganic and organic substances, in particular feed, solvents or mixtures of solvents before and after drying.

From the description of the US patent. № 3715910 Cl. 73-23.1, pub. 1973, a method is known for gas chromatographic determination of solvents in biological material, which provides for the thickening of solvents from its mixture with biological material in the serum after the introduction of an appropriate amount of water, followed by analysis of the gas flow.

However, the known method does not provide complete extraction and quantitative determination of the extracting agent in cases of extra yeast feed, despite the preliminary re-treatment with water and the corresponding heating.

From the description of the C1M patent number 3779066 ,. cl. 73-23.1, pub. 1973, a gas-chromatographic method of determination is also known, in which the test material is heated in a preliminary evaporator of the construction and the residual solvent is sent directly to the gas chromatograph. In order to improve the evaporation process, the sample material is uniformly wetted with water, which significantly improves reproducibility.

The disadvantage of this method is that the quantitative determination of the extracting agent depends on the pretreatment and the properties of the test material, the implementation of the method requires special equipment, it is laborious, long and does not provide a differential determination of solvents.

The purpose of the invention is to reduce time and increase accuracy.

The goal is achieved by the fact that, in carrying out the method of quantifying residual solvents in extracted inorganic and organic substances, mainly in feed, providing for the sampling of these substances and the separation of residual solvents from them, followed by gas chromatographic analysis, a mixed sample

sew with 50-1250% of water relative to the amount of sample, preferably 400%, then the eluate is injected, after which the standard solution is added, and the mixture is adjusted to a predetermined volume with an eluate before performing gas chromatographic analysis.

An aqueous solvent solution with polar properties, mainly alkanols, alkanones, low fatty acid esters, preferably n-propanol, butanone, and acetic acid methyl ester is used as the eluate.

The standard solution is added to the sample to be analyzed in a ratio of 1

Chromatography is subjected to an upper bright solution, obtained immediately after stirring the mixture, prepared according to the indicated procedure.

The evaluation is carried out by determining the ratio of heights or areas of the extracting agent (standard and counting of the content in grams on a calibration curve showing the ratio of heights or areas of extracting agent) of the standard depending on the amount (g). The percentage is as follows:

one.

formula

BUT

-g -x

100,

(one)

where X is the percentage of extracting agent; And the number (in g) of the calibration curve; E - sample weight. Simplifying the assessment with the same accuracy contributes to the calculations using the factor of the reference solution:

F - -§- 1

(2)

F is the factor of the reference solution; B - the ratio of the heights or areas of the extracting agent / standard at the experimental point;

1 — Concentration of the extracting agent in an appropriate reference solution. The percentage is calculated by the formula

WITH

100,

(3)

31317357

de X is the percentage of extracting agent; C is the ratio of the heights or areas of the extracting agent / sample standard;

F is the factor of the reference solution; E - sample weight. A change in the parameters of the components used influences the increase in outflow a, a, la

in

dividing 50 ml of a solution of n-propanol, a firing agent (for example, benz mixture, 1 ml of gasoline (0.6 g) and

zine / ethanol). In the study of this factor, samples of fodder yeast with various contents were used.

1 ml of ethanol (0.76 g), the exact amount is determined by analytical weight ;, all this is added to the mark

1 ml of ethanol (0.76 g), the exact amount is determined by analytical weight ;, all this is added to the mark

gasoline (0.01-20%) and ethanol (0.05 - 15 solution of n-propanol (initial rast30%) before and after drying.

When using alkalis and kis-. lot, promoting hydrolysis and thereby the release of solvents, as with

thief 1).

When preparing the initial solution II, 5 ml of the initial solution G is pipetted, 5 ml of the initial solution G is pipetted in the preparation of the initial solution II, added at room temperature and at the same time a flask with a volume of 250 mp,

During the boiling time and exposure time from 15 minutes to 3 hours, it is impossible to obtain values similar to those in the implementation of the proposed method. Also, treatment with alkaline solutions of the substrate used initial solutions.

It was previously introduced 50 MP solution of n-propanol, and make up to the mark with a solution of n-propanol.

When preparing the reference plant

pressure in the refractory tube at 130 ° C and exposure time of up to 3 hours does not contribute to the achievement of other results.

The table shows the comparative 30 data when carrying out the method by heating with the addition of water and in the extraction process with n-propanol. To determine the 100% content of gasoline by the heating method in the preliminary 35 evaporator of the gas chromatograph, several determinations and summation of values are required, while gasoline, as well as ethanol, as determined by extraction method 40, are about 100% practically at the first extraction.

The data in percent refers to the volume. For example, from the original solution II, reference samples can be prepared using the following sample to contain residual extractants, for example, 0.005 g / kg to 0.1 g / kg gasoline or alcohol in the extracted material:

etalino

solution number

initial

solution

12345 678

II (ml)

1 2 3 5 7 10 15 20

Several MPs of n-propanol solution and an appropriate amount of the initial solution II are introduced into 25 ml volumetric flasks. Before topping up to the reference label with propanol solution, 50 ml of standard solution I are added to the reference solutions No. 1–4,

 The reference solutions are chromatographed in a sequence of increasing concentrations, and the reference curve is recorded as a height ratio:

The total content of solvents in the pro- gram 45a to the standard solutions No. 5-8 is the share of 1 ml of the standard solution II.

When preparing a standard acetone solution, about 50 mp of n-propanol was introduced into a 100 ml volumetric flask and 20 ml of acetone was added, all this was added to the mark with n-propanol (standard solution I).

Both for the reference solution and for the test solutions, 50 μl of this standard solution 55 (10 μl of acetone) per 0-2.5% of the extractant components (gasoline and ethanol) are used.

The sum of the peak surface of gasoline Enzy - Peak surface of acetone

HV gasoline

 The sum of the heights of the peaks - gasoline Peak height acetone

or as a superficial attitude:

For 2.5–50% of the components of the extra agent, both for standard solutions and for test solutions, 1 MP of a standard solution (150 µL of acetone) is used, which contains 15 ml of acetone in 100 MP of n-propano, la ( standard solution II).

When preparing reference solutions in a 100 ml volumetric flask

1 ml of ethanol (0.76 g), the exact amount is determined by analytical weight ;, all this is added to the mark

n-propanol solution (initial rast

thief 1).

When preparing the initial solution II, 5 ml of the initial solution D is pipetted, added to a 250-ml volumetric flask, in which

the thief use the original solutions.

It was previously introduced 50 MP solution of n-propanol, and make up to the mark with a solution of n-propanol.

When preparing the reference plant. For example, from the initial solution II, according to the following sample, reference solutions can be prepared for the content of residual extractants, for example, 0.005 g / kg to 0.1 g / kg gasoline or alcohol in the extracted material:

etalino

solution number

initial

solution

12345 678

II (ml)

1 2 3 5 7 10 15 20

Several MPs of an n-propanol solution and the corresponding amount of the initial solution II are introduced into 25 ml volumetric flasks. Before topping up to the reference label with propanol solution, 50 ml of standard solution I are added to the reference solutions No. 1–4,

 Standard solutions are chromatographed in a sequence of increasing concentrations, and the reference curve is recorded as a height ratio:

HV gasoline

 Sum of gasoline peak heights Acetone peak height

or as a superficial attitude:

For ethanol:

Ethanol peak height

HV-ethanol h

Acetone peak height

or as a superficial attitude:

RU-ethanol "2E25 5 2SH of ethanol Peak surface of acetone

depending on the concentration.

The gasoline components contained in the sample are the heights and surfaces folded in a manner similar to the reference curve and are divided by the height and surface of the internal standard. With this value of the height and surface ratio, the reference curve gives the amount A (g) for gasoline and, similarly, the amount of ethanol (g). The percentage is obtained by the formula (1).

The method is carried out as follows.

Example 1. About 3.5 g of extractable gasoline-ethanol mixture of fodder yeast extractant (with moisture content of decanter) is extracted into a measuring flask (25 ml) containing n-propanol as eluate in an amount of about 10 ml and 4 ml of water and accurately weighed. Immediately close the measuring flask and shake on the pumper for 15 minutes. Then a standard solution, in this case acetone, is fed into the measuring flask in an amount corresponding to the amount of the standard solution and the mixture of n-propanol and water is added to the mark. After repeated agitation and precipitation of the yeast, the upper bright liquid is immediately fed to the gas chromatograph for analysis.

Example 2. About 2 g of fodder yeast extracted with a mixture of extracting agents, gasoline-ethanol, are fed to a measuring flask (25 ml) containing n-propanol as eluate in an amount of about 10 ml and 8 ml of water and weighed to the nearest 1 mg. The measuring flask is immediately closed and shaken on a rocking chair for 15 minutes, then a standard solution (acetone) is fed into the measuring flask in an amount corresponding to the amount of the reference solution and the n-propanol-water mixture is added to the mark. After repeated agitation and precipitation of the yeast, the upper bright solution is immediately fed to the analysis in a gas chromatograph.

PRI me R 3. About 1 g of the extracted mixture of extracting agents, gasoline-ethanol, bacterial biomass is fed to a measuring flask (25 ml) containing about 10 ml and 8 ml of water as eluate and weighed to the exact 1 mg. The measuring flask is immediately closed and shaken on a rocking chair for 15 minutes, then a standard solution (acetone) is fed into the measuring flask in an amount corresponding to the amount of the reference solution and the n-propanol-water mixture is added to the mark. After repeated agitation and precipitation of bacterial biomass, the upper light

the solution is fed to a gas chromatograph.

PRI me R 4. About 3.5 g of a sample of oilseeds extracted by gasoline extracting agent

load-in measuring flask

(25 ml), containing 10 ml of n-propanol, and weighed to the nearest 1 mg. Close the measuring flask and shake for 5 minutes. Then

5 ml of water are added and shaken again for 10 minutes. After that, a standard solution (acetone) is fed into the measuring flask in an amount corresponding to the amount of the reference

solution and add n-propanol to the mark. After repeated agitation, the solution is subjected to chromatography.

Example 5. 1 g of feed yeast (dry product) extracted with gasoline / ethanol extractant (dry product) is precisely weighed into a volumetric flask (25 ml) containing 10 ml of a mixture of n-propanol (98%) and water (2%) for 15 Shake for a minute, add the appropriate amount of standard (acetone). And add to the mark with a mixture of 2% water and 98% n-propanol. After shaking and precipitating the yeast

the clean solution is fed to a gas chromatograph.

The amount of the internal standard depends on the expected amount of components of the extractants gasoline and ethanol and in the range of 0-2.5% of the components of the extractants gasoline and ethanol with a test sample of 10 µl of the internal standard (acetone) and in the limit

2.5-50% of the components of extractants (gasoline and ethanol) with a weight of 150 microns internal standard (acetone).

The evaluation is carried out as follows.

There are two calibration curves (one for gasoline, the other for ethanol), corresponding to the expected content of gasoline and ethanol. To determine the Bezin content, all heights or peak areas of the gasoline components are summed up, the ratio to acetone used as a standard solution is determined, and heights or areas ratios are plotted depending on the amount (in g). Similarly, a calibration curve for determining the content of ethanol is compiled. The gasoline components contained in the sample are summed up taking into account the heights or areas by analogy with the calibration curve and the ratio is determined by the height or area of acetone.

The content of the components is determined by formulas (1) or (3).

The determination of ethanol is carried out in the same way.

Chromatography was carried out in an apparatus with column loading with porolite of 0.2–0.3 mm f 10% polyglycol 3000, at a column temperature of 90 ° C, an evaporator temperature of 150 ° C, column output, carrier gas — nitrogen 3 l / h; combustible gases: hydrogen - 1.5 l / h, air - 25 l / h, the amount supplied is 2-5 ml.

Claims (3)

1. Method for quantitative determination of residual solvents in extracted inorganic and organic substances, mainly in feed, involving the sampling of these substances and the removal of residual solvents from them with the editor A. Revin  Compiled by N.Artsybashev Tehred M. Khodanich Proofreader G. Reshetnik Order 2417/40 Edition 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 the following gas chromatographic analysis, characterized by that, in order to reduce time and increase accuracy, the sample is mixed with 50-1250% water relative to the amount of sample, which is respectfully 400%, then the eluate is injected, after which the standard solution is added, and before the gas chromatographic analysis of the mixture obtained is adjusted to a predetermined volume with a zljuat. 2. The POP.1 method, characterized in that the quality of the eluate uses an aqueous solvent solution with polar properties, preferably alkanols, alkanones, esters of low fatty acids, preferably n-propanol, butanol, methyl ester of acetic acid. 3. A method according to Claims 1 and 2, characterized in that the standard solution is added to the sample to be analyzed in a 1: 1 ratio. 60-70% gasoline-ethanol 15-20% gasoline-ethanol 99.5% gasoline, 99.7% ethanol 0.49% gasoline, 0.3% ethanol 6% gasoline-ethanol 3% gasoline-ethanol 1% gasoline-ethanol 0.0 0.0