CS257557B1 - A method for determining residual nonpolar lipids in crude ergot sums of alkaloids - Google Patents

Abstract

Refractometric determination of the content of residual nonpolar lipids in crude ergot alkaloid aggregates after quantitative lipid conversion by dissolving the sample in 25- to 35-fold amounts of anhydrous acetic acid with the addition of 4% vol. hexane and subsequent dilution with water to a concentration of 30-50% vol. into the hexane phase. The lipid content is then determined from the differences in the refractive index of the hexane phases of the sample and the blank using an experimentally obtained factor or from a calibration curve. The method of determination is used in quality control of intermediate products for the production of pure forms of ergot alkaloids.

Description

The invention relates to the determination of the residual nonpolar lipid content of crude ergot alkaloids.

When isolating alkaloids from ergot (Secale cornutum), lipids, which contain up to 35% by weight of ergot, are isolated together with ergot alkaloids. In ergot extracts, in so-called raw aggregates, lipids are up to 25% by weight. The high lipid content is unacceptable due to further processing and is reduced to less than 4% by weight in crude aggregates.

Extraction methods (Soxhlet, Grosfeld, etc.) are mostly used to determine the total lipid content using a variety of extender (petroleum ether, diethyl ether, ethanol, n-propanol, n-butanol, chloroform with methanol, etc.). The lipid content of the extracts is then determined gravimetrically, by refractometry, NMR, IR spectrophotometry, differential calorimetry, or differential thermal analysis. In addition to extraction methods, lipids are determined by the Gerber method, by dissolving the sample in sulfuric acid, and the released fat is determined by volume in an αd-butyrometer. Hydromatographic methods (gas, thin-film, paper, column and liquid) are used for separation of lipid components.

Extraction into <> etrolether in a Soxhlet apparatus is used to determine the lipid content of the crude summaries. The disadvantage of the assay is the very long extraction time (8 hours) and the error caused by the fact that, together with the lipids, water is extracted and must be determined separately (as loss on drying) and read.

Recently, a simple refractometric method was invented to determine the residual nonpolar lipid content of the ergot crude alkaloid totals by quantitatively transferring the lipids by dissolving a sample of crude ergot alkaloids in a 25- to 35-fold amount of anhydrous acetic acid with 4% v / v addition. hexane followed by dilution with water to a concentration of 30 to 50% v / v to the hexane phase, whereupon the lipid content is determined from the differences in refractive index values of the sample and the blank using an experimentally obtained factor or a calibration curve. For each 0.001 refractive index difference, 1 wt. lipid content.

A linear dependence of the refractive index on the lipid content of hexane was found in the range from 0 to 10 g of lipids per 100 ml of solution. The advantage of the assay according to the invention is the speed of the assay (shortening the analysis time from 12 hours to 20 minutes), sufficient sensitivity, compared to the petroleum ether extraction method used hitherto, and accuracy. The assay method of the invention is used to control the quality of intermediates in the manufacture of pure ergot alkaloids.

Further details follow from the following examples.

He did

Weigh approximately 1 g of the test sample accurately into a 50 ml graduated flask and dissolve in 30 ml of anhydrous acetic acid. After dissolution, pipette 2.00 ml of hexane and mix. Then make up to the mark with water. At the same time, carry out a blank test, ie mix 30 ml of anhydrous acetic acid with 2,00 ml of hexane in a 50 ml graduated flask and make up to the mark with water. After 15 minutes the refractive index of the separated hexane layers is measured and the lipid content is calculated according to the formula!

(n _vz - n _sl ). 1 000% lipids (mass) = g where n _vz = observed refractive index of the hexane layer with the sample, n _s3 = observed refractive index of the hexane layer of the blank, g = sample weight in grams,

000 = factor obtained experimentally (for each 0.001 refractive index difference, 10 mg of lipids are in 2 ml of the hexane layer, i.e. with a 1 g sample weighing 1% by weight each).

The measurement of the sample hexane layer and the blank test hexane layer shall be made at the same temperature of the refractometer measuring block.

Example 2

To a 50 ml volumetric flask was weighed 1.0020 g of a defatted crude ergotamine summary (ss GAL 40, production 10), dissolved in 30 ml of anhydrous acetic acid, pipetted with 2.00 ml of hexane and, after mixing the flask, made up to the mark with water. At the same time, a blank test was performed, i.e. in a 50 ml volumetric flask, 30 ml of anhydrous acetic acid was mixed with 2.00 ml of hexane and made up to the mark with water. After separation of the hexane layers, the refractive index was measured at the same refractometer measuring block temperature in the sample (n _vz ) and in the blank (n _gl ).

Results: n _yz = 1.3764 n. = 1.3743 ⁸¹ (1.3764 - 1.3743). 1 000

Calculation:% lipid (w / w) = - = 2.06% * 1.0020

For comparison, the result of the determination with the light petroleum extraction method in a Soxhlet apparatus:

2.1 wt.

Example 3

To a 50 ml volumetric flask was weighed 0.5557 g of a non-defatted crude ergotamine summary (ss GAL 40, production 10), dissolved in 30 ml anhydrous acetic acid, pipetted with 2.00 ml hexane and, after mixing the flask, made up to the mark with water. At the same time, a blank test was performed, i.e. in a 50 ml volumetric flask, 30 ml of anhydrous acetic acid was mixed with 2.00 ml of hexane and made up to the mark with water. After separation of the hexane layers, the refractive index, at the same temperature of the refractometer measuring block, was measured in the sample (n _vz > and in the blank test (n _g ^)).

Results: η _γζ = 1.3868 n, - 1.3743 ³¹ (1.3868 - 1.3743). 1,000 ,, _ς ,

Calculation:% of lipids (w / w) = - ~ '

0,5557 (Prp comparison result of determination by petroleum ether extraction method in a Soxhlet apparatus:

22.0% by weight).

Claims (1)

OBJECT OF THE INVENTION Method for determining residual nonpolar lipids in crude ergot alkaloids by refractometry, characterized in that the lipids are quantitatively converted by dissolving a sample of crude ergot alkaloids in a 25- to 35-fold amount of anhydrous acetic acid with 4% v / v hexane followed by dilution with water to to 30% to 50% v / v to the hexane phase, whereupon the lipid content is determined from the differences in refractive index values of the sample and the blank using an experimentally obtained factor or from a calibration curve.