JPS61210954A - Analysis of glycerol in soap - Google Patents

Abstract

PURPOSE:To analyze quickly the glycerol existing in soap with a simple operation and good accuracy by dissolving the soap into water then feeding the soln. through a glass insert into a gas chromatograph. CONSTITUTION:The soap is dissolved in the water and thereafter the soln. is fed into the gas chromatograph through the glass insert without subjecting the soln. to a pretreatment operation such as separation, concentration or the derivation of sample, by which the analysis is executed in gas chromatograph analysis. The glass insert passes only the low boiling component such as glycerol in the soap into the column and blocks the high boiling component so as to remain therein to prevent the contamination of the column. An internal standard method is easier as the method for quantitative analysis. A porous high-polymer type packing material is preferable as the packing material as the glycol such as glycerol or ethylene glycol is fed into the gas chromatograph without pretreatment.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for analyzing glycerin in soap, and more specifically, the present invention relates to a method for analyzing glycerin in soap. The present invention relates to a method for conducting accurate analysis in a short period of time.

[Conventional technology]

Tada Nada's cosmetic soaps, laundry soaps, powdered household and industrial soaps, and soap waste liquids (hereinafter referred to as soaps) that are made from oils and fats contain 1 to 2 grams of glycerin. In products made from fatty acids or fatty acid methyl esters, glycerin is added for the purpose of improving physical properties.

Therefore, analyzing glycerin present in soap is an important issue from the viewpoint of product process control, quality control, and research.

Conventionally, the following methods are known as methods for analyzing glycerin present in soap.

(1) Chemical analysis method Glycerin test method (JISK3350) A simple periodic acid titration method that is widely used as the only chemical quantitative method for glycerin.

[Problem that the invention seeks to solve]

However, the chemical analysis method has the disadvantage that when a compound having a hydroxyl group on an adjacent carbon atom, such as glycols such as ethylene glycol and propylene glycol, coexists in the sample, the glycerin content becomes excessive. Also,
There is a drawback that the analysis time is as long as about 2 hours. The gas chromatographic analysis method does not directly analyze soap, but performs pretreatment operations such as separation or concentration, and derivatization of the sample, so it has the disadvantage that it requires approximately one hour for analysis.

[Means for solving problems]

In order to solve these drawbacks, the inventors of the present invention have conducted extensive research and found that soap is dissolved in water for gas chromatography analysis, and separation and pretreatment operations such as concentration and sample derivatization are required. The present invention has been completed by discovering a method for analyzing glycerin present in soap with simple operations, in a short time, and with high precision, without having to carry out any additional steps.

That is, the present invention is a method for analyzing glycerin in soap, which is characterized in that, in gas chromatography analysis, soap is dissolved in water and then injected into a gas chromatograph through a glass insert.

In the present invention, since the soap aqueous solution is directly injected into the gas chromatograph, a glass insert is always inserted into the injection port. Glass inserts are used to pass only low-boiling components such as glycerin in soap into the column, while allowing high-boiling components to remain in the glass insert to prevent column contamination. The glass insert must be replaced with a new one after two or three analysis operations.O There are two methods for quantitative determination: the absolute calibration curve method and the internal standard method, but the absolute calibration curve method has problems such as the need for precision in diluting the sample. Therefore, the internal standard method is easier.

Glycols such as glycerin, ethylene glycol, propylene glycol, etc. are directly injected into the gas chromatograph without pretreatment such as separation or concentration, or derivatization of the sample, so use a suitable packing material. There is a need.

For example, TenanGC (AKZORagea/ah
Laboratory), Chromosorb
lol (JOHMSMANVILers As5o
Porous polymeric optical fibers such as those manufactured by Cation Co., Ltd.) are preferred.

As the detector, a hydrogen flame ionization detector with high detection sensitivity is suitable.

The carrier gas can be nitrogen or helium, but
Helium is preferred.

As the separation tube, a metal, synthetic resin or glass tube can be used, but a glass tube is preferable.

〔Effect of the invention〕

The method for analyzing glycerin in soap of the present invention is based on the conventional method for analyzing glycerin in soap.
Compared to the method of separating glycerin present in soap,
There is no need to perform pre-treatment operations such as separation or concentration, or sample derivatization; simply dissolve the soap in water, and it is easy to separate and quantify glycerin and other glycols, which are present in soap. Glycerin can be analyzed with high accuracy with simple operations.

Further, while conventional analysis methods require about 1 to 2 hours, the present invention allows analysis to be performed within 30 minutes.

〔Example〕

Next, the present invention will be explained with reference to Examples and Comparative Examples. The part in the example is heavy ts1 regret is tJt.

1° Gas chromatography analysis method The gas chromatography analysis method was performed according to the general rules for gas chromatography analysis methods (JISKO114) K.

1-L Gas chromatograph analysis conditions 1) Equipment ff1
T name: Hewlett Packard Card Co., Ltd. JL15712) Detector: Hydrogen flame ionization detector 3) Recording paper feeding speed: 5 m+/min 4) Flow rate of carrier gas: Helium...30a
j/min, hydrogen...25d/min, air...300m/min
/min5) Temperature: Sample vaporization chamber temperature...230℃, Separation tube temperature...175℃, Detector temperature...230℃6) Separation tube, filling material and filling method: TanaxGC approx. 123
No. 17 was filled in a tube having an inner diameter of 3 fi and a length of 1200 m, and helium (30 d/min) was passed through the tube, and air baking was performed at a separation tube temperature of 175° C. for 24 hours.

1-2 Reagents Reagents having a purity of 99 or higher were used for reagents such as G+)-N'), ethylene glycol, propylene glycol, and 1,4-butanediol.

1-λ Internal standard solution 1.4-butanediol approx. 0.5? To be exact, dissolve it in a volumetric flask of IQ Olj with pure water and make 10
0d and circle.

Table 1 - Preparation of Sample Approximately 0.5 f of soap was accurately weighed into a 10 jllj female 7 flask, 2 d of internal standard solution was added, and pure water was added to make a total of 10 wj. The sample was dissolved by heating.

1-5. The mixed sample, 1.4-butanediol manufactured by III and glycerin, was added to about 0.0% each.
1F was accurately weighed into a 10 d volumetric flask and dissolved in pure water to make 10 m.

1-a Calculation of correction coefficient Internal standard substance (1,4-butanediol) t1. .

Calculate the glycerin correction coefficient when O.

A 5 .mu.t sample of the mixture was injected into a gas chromatograph, and the chromatography of the mixture sample was recorded under the analysis conditions of the 1-1.degree. gas chromatograph described above, and the peak area was measured. Then, the correction coefficient was calculated using the following formula.

1-& Calculation of glycerin content in soap Inject a 5 μt sample into a gas chromatograph and perform the procedure described in 1-1 above. A cucomadogram of the sample was recorded under gas chromatograph analysis conditions, and the peak area was measured. Then, the glycerin content in the soap was calculated using the following formula.

sM2 Chemical Analysis The chemical analysis method was performed according to J I SK335G.

2-1. Reagent acid solution 100 agK! After M, pure water was poured.

2) N/2 hydrochloric acid solution Pure water was added to hydrochloric acid 1&3f to make toooy.

2-2. Sample Pretreatment (Soap Decomposition and Fatty Acid Removal) l) Sample 10F was accurately weighed into a 30011/mm beaker.

2) After dissolving the sample in 100mj of boiled pure water, 50Q
Transferred to a tri separatory funnel.

3) Approximately 25 ml of 10% sulfuric acid solution was added, mixed, and allowed to cool.

4) After cooling, approximately 100ffiZ of petroleum ether was added, mixed by shaking, and then left to separate into layers.

5) The aqueous layer was extracted into a 250 d volumetric flask.

6) Pure water 50ILt was added to the separatory funnel in 2) above, shaken, and then allowed to stand still to separate the layers, and the aqueous layer was drawn into the volumetric flask in 5) above. This operation was then repeated again.

7) Add pure water to make 2501!1j. This solution was used as the test solution.

2-3. Method 1) A 20+/ml test solution was placed in a 300 TR1 conjugated Erlenmeyer flask, 25ml+/ of potassium periodate solution was added and mixed, and the pupils were left in the dark for 40 minutes.

2) Take out the bottle from a dark place and add N/Q hydrochloric acid solution 5d110%.
Add 20 ml of potassium iodide solution and 50 ml of pure water and titrate with %N/10 sodium thiosulfate standard solution. When the solution turns slightly yellow, add 1 ml of 100% starch solution and perform the titration while shaking thoroughly. The end point was when the purple color caused by starch disappeared.

3) At the same time, a blank test was conducted in parallel with the main test.

2-4. Calculation
Shown in the table.

[Notes] 1) Cosmetic soap made by Nila Sun Rose Nissan Soap) 2) Cosmetic soap made by Nissan Opera Nissan Soap) 3) After preparing the sample, record the chromatogram and measure the peak area. 4) Time required to complete titration after sample pretreatment As is clear from the results, the glycerin content in the soaps of Examples 1 to 3 (average [1,68) was lower than that of the comparative example. 1 to 3 (average value L63), and also Example 4 to
6 (average value L38) is Comparative Examples 4 to 6 (average value L40)
is in good agreement with

The average analysis time for Examples 1 to 6 was 27 minutes, while the average analysis time for Comparative Examples 1 to 6 was 121 minutes.The method of the present invention can perform analysis in a short time.

Examples 7 to 9, Comparative Examples 7 to 9 Soaps containing no glycerin were prepared using fatty acids as raw materials, and samples to which known amounts of glycerin, ethylene glycol, and propylene glycol were added were analyzed.

4-13 Preparation of soap 1) Fatty acids with a saponification value of 260 and a molecular weight of 216 at 70℃
The mixture was heated to 1,000 f to dissolve it, and 1,000 f was poured into a kneader.

2) A 28% aqueous sodium hydroxide solution was heated to 50°C. The remaining #) 110F was added over 10 minutes.

3) The kneader was heated to 95°C and aged for 5 minutes.

4) After aging, the soap was extracted and soap was obtained. Table 2 shows the results of an analysis of a sample obtained by adding known amounts of glycerin, ethylene glycol, and propylene glycol to the obtained soap based on the above gas chromatographic analysis method and chemical analysis method.

As is clear from the above results, the content of glycol, ethylene glycol, and propylene glycol in the soaps according to Examples 7 to 9 corresponds well with the amount added and has good accuracy, whereas in Comparative Examples 7 to 9, The glycerin content in the soap is higher than the known amount, resulting in poor accuracy.

Claims (1)

[Claims] 1. A method for analyzing glycerin in soap, which comprises dissolving the soap in water and then injecting it into a gas chromatograph through a glass insert.