JPH0943218A - Analyzing method for non-ion surfactant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To analyze the alkyl chain length of nonionic surfactant by analyzing the nonionic surfactant with reversed-phase based high speed liquid chromatography gradient-eluting by using water-methanol based elution liquid. SOLUTION: For nonionic surfactant polyoxyethylenealkylether, etc., is used, a reversed-phase based high speed liquid chromatography device can be a conventional device capable of performing gradient, and for the detector, an evaporation light scattering detector suitable for analyzing nonionic surfactant is favorably used. For the analysis method, nonionic surfactant to be analyzed is injected in a separation column and gradient elution using water-methanol based elution liquid is conducted. At this moment, the content of methanol in the initial elution liquid of 30 to 95vol.% is favoured and the composition of elution liquid is continuously changed so that the content of methanol is the final elution liquid of 80 to 100vol.%. By this the alkyl chain length of the nonionic surfactant becomes capable of easily analyzing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for analyzing a nonionic surfactant, and more specifically, to the distribution of the alkyl chain length of the nonionic surfactant and the number of bonds of alkyl groups in one molecule (esterification degree and The present invention relates to a method for analyzing a nonionic surfactant, which can analyze the distribution of the degree of etherification) in detail.

[0002]

BACKGROUND OF THE INVENTION Nonionic surfactants are widely used in industrial products because of their excellent cleaning, emulsifying and wetting effects. For example, it is suitable as a cleaning agent in the deinking process in the pulp and paper industry, in the cleaning process for metal surfaces, in the scouring process in the textile industry, as an emulsifier for food, cosmetics and agricultural chemicals, as an antifog agent for vinyl and glass, and as a spreading agent for agricultural chemicals. They are used in large amounts and the performance of these products is greatly influenced by the composition of the nonionic surfactant.

Therefore, establishment of a method for analyzing the composition of a nonionic surfactant is important both in terms of analytical chemistry and in developing excellent products. However, nonionic surfactants have a distribution of alkyl chain length distribution and oxyalkylene polymerization degree (AO
Since it is a very multi-component mixture having a distribution) and a distribution in the number of alkyl groups in one molecule (etherification degree or esterification degree), composition analysis is very difficult.

Conventionally, as a method for measuring the alkyl chain length distribution of these nonionic surfactants, for example, higher alcohol ether type nonionic surfactants (polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, etc.) have been used. The alkyl chain length distribution is determined by decomposing with hydroiodic acid or hydrobromic acid, and then analyzing the obtained volatile products (alkyl iodide, alkyl bromide, etc.) by gas chromatography, fatty acids. Ester type nonionic surfactant (fatty acid polyoxyethylene ester, fatty acid sorbitan ester, fatty acid polyoxyethylene sorbitan ester, fatty acid glycerin ester, fatty acid polyoxyethylene glycerin ester, etc.)
The alkyl chain length distribution of is known to be a method of converting to fatty acid by saponification decomposition, then converting to a methyl ester, and analyzing by gas chromatography, but in both cases, decomposition and derivatization must be performed, The operation is complicated, and the alkyl chain length distribution cannot be obtained for a mixture of several kinds of nonionic surfactants.

Further, the degree of esterification and the degree of etherification of nonionic surfactants are known by analogy with the molecular weight distribution obtained by gel filtration chromatography, or by gas chromatography after trimethylsilyl etherification. However, in the former case, the separation ability is not good, so that an accurate distribution cannot be obtained, and in the latter case, there is a problem that it is difficult to analyze a trialkyl compound or a tetraalkyl compound having a large molecular weight.

As described above, each method for obtaining the alkyl chain length distribution and the degree of ether / esterification of the nonionic surfactant has not only a problem, but also both the alkyl chain length distribution and the degree of ether / esterification have a problem. Since there is no method to obtain one of the three analysis methods, there is a drawback that these analyzes take time.

[0007]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned problems, the present inventor has found that a non-ionic surfactant is reversed phase high-speed by gradient elution using a water-methanol eluent. It was found that, when analyzed by liquid chromatography, the separation based on the effect of the oxyalkylene moiety can be suppressed as much as possible, and the alkyl chain length of the nonionic surfactant can be easily analyzed. It was also found that it is possible to analyze the distribution of the degree of etherification and the degree of esterification by carrying out a two-step gradient elution using a solvent having low polarity, and has completed the present invention. is there.

That is, the present invention provides a method for analyzing a nonionic surfactant, which is shown in the following (1) and (2). (1) A method for analyzing a nonionic surfactant, which comprises analyzing the nonionic surfactant by reverse phase high performance liquid chromatography by gradient elution using a water-methanol system eluent. (2) After the first-step gradient elution using a water-methanol eluent, the final eluent of the first step was acetone, tetrahydrofuran, isopropyl alcohol,
Add one or more solvents selected from n-propyl alcohol, ethanol and acetonitrile, and add
Characterized by performing a stepwise gradient elution,
The method for analyzing a nonionic surfactant according to (1).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. As the nonionic surfactant analyzed by the method of the present invention, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, fatty acid polyoxyethylene ester, fatty acid sorbitan ester, fatty acid polyoxyethylene sorbitan ester, fatty acid glycerin ester, Examples thereof include fatty acid polyoxyethylene glycerin ester.

The reversed-phase high performance liquid chromatography (HPLC) apparatus used in the present invention is a commonly used general-purpose HPLC apparatus and is not particularly limited as long as it can perform a gradient. The separation column used in the present invention is not particularly limited, and a commercially available reversed phase column can be used, but an ODS-based reversed phase column obtained by octadecylsilylating silica gel is preferable. Further, as the detector used in the present invention,
Evapolative Light Scattering Det
ecter, hereinafter abbreviated as ELSD) is preferably used. In this ELSD, the mobile phase is atomized with a nebulizer gas, then heated to evaporate the eluent, and a laser beam is applied to the substance remaining as a powder to detect the scattered light. This ELSD can detect all substances above a certain boiling point and is stable to any eluent if it is volatile, so it is very suitable for the analysis of nonionic surfactants such as the present invention. It is suitable.

In the analysis method of the present invention, first, a nonionic surfactant to be analyzed is injected into the separation column.
Nonionic surfactant is 0.1 to 0.1% of organic solvent such as methanol.
It is preferably injected as a dilute solution of about 5% by weight.
Next, gradient elution is carried out using a water-methanol system eluent, and the methanol content in the first eluent of this water-methanol system eluent is 30%.
˜95% by volume is preferable, and 50 to 90% by volume is more preferable.
In the gradient elution using this water-methanol system eluent, the methanol content in the final eluent was 80-100
It is preferable to continuously change the composition of the eluent so that the volume of the eluent is 100% by volume. The water-methanol eluent may contain up to 50% by volume of a third component other than water and methanol, but preferably does not contain the third component.

Gradient elution using such a water-methanol eluent makes it possible to easily analyze the alkyl chain length of the nonionic surfactant. The final eluent of the gradient elution (first step) was one or more solvents selected from acetone, tetrahydrofuran, isopropyl alcohol, n-propyl alcohol, ethanol and acetonitrile, preferably acetone, tetrahydrofuran, ethanol. By adding and performing the second stage gradient elution, the distribution of the degree of etherification and the degree of esterification of the nonionic surfactant can also be analyzed.
In the second-stage gradient elution, the content of one or more solvents selected from acetone, tetrahydrofuran, isopropyl alcohol, n-propyl alcohol, ethanol and acetonitrile in the final eluent is 20-100 volumes. %, Preferably 100% by volume, it is preferable to continuously change the composition of the eluent.

In the present invention, the temperature and the flow rate of the eluent during gradient elution are not particularly limited, and the temperature is preferably room temperature to about 50 ° C., and the flow rate of the eluent is about 0.1 to 2 ml / min.

[0014]

EXAMPLES In order to explain the analysis method of the nonionic surfactant of the present invention in more detail, the following examples will be given. Incidentally,% in the examples is% by volume unless otherwise specified.

Example 1 ODS column (Wakosil-5C18HG, manufactured by Wako Pure Chemical Industries, Ltd.)
After stabilizing a gradient-capable high performance liquid chromatography device equipped with 4.6 mm I.D. × 150 mm) and ELSD in the initial state of the gradient eluent shown in Table 1, polyoxyethylene lauryl ether (trade name) Emulgen 10
8, Kao Corporation and polyoxyethylene cetyl ether (trade name Emulgen 210, Kao Corporation) and polyoxyethylene stearyl ether (trade name Emulgen 3)
06, manufactured by Kao Co., Ltd.) (2 wt% methanol solution) was injected, column temperature 40 ° C., eluent flow rate 1.0 ml
The elution was carried out under the gradient conditions shown in Table 1 at a flow rate of / min.

[0016]

[Table 1]

The obtained elution results are shown in FIG. As is clear from FIG. 1, in this example, the alkyl chain length could be quickly determined.

Example 2 Example 1 was repeated except that a 2 wt% methanol / tetrahydrofuran = 50/50 (volume ratio) solution of sorbitan monostearate (trade name SPAN60, manufactured by Kanto Chemical Co., Inc.) was injected.
Elution was carried out under the same analytical conditions as. The obtained elution result is shown in FIG. As is clear from FIG. 2, in this example, the degree of esterification could be promptly determined.

Comparative Example 1 Elution was carried out under the same analytical conditions as in Example 1 except that the gradient conditions were changed as shown in Table 2.

[0020]

[Table 2]

The elution results obtained are shown in FIG. As is clear from FIG. 3, in this comparative example, the separation due to the polyoxyethylene group appeared remarkably, and it was difficult to determine the alkyl chain length.

Example 3 Gradient conditions were changed as shown in Table 3, and polyoxyethylene octyl phenyl ether (trade name Emulgen 810, manufactured by Kao Corporation) and polyoxyethylene nonyl phenyl ether (trade name Emulgen 920, Kao Corporation) were used. (stock)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected.

[0023]

[Table 3]

The elution results obtained are shown in FIG. As is clear from FIG. 4, in this example, the alkyl chain length could be quickly determined.

Example 4 Polyoxyethylene lauryl ether (trade name: Emulgen 108, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name: Emulgen 210, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was performed under the same analytical conditions as in Example 3, except that a mixed solution (2 wt% methanol solution) of Emulgen 306, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG. As is clear from FIG. 5, in this example, the alkyl chain length could be quickly determined.

Example 5 Example 3 except that a 2 wt% methanol / tetrahydrofuran = 50/50 (volume ratio) solution of sorbitan monostearate (trade name SPAN60, manufactured by Kanto Chemical Co., Inc.) was injected.
Elution was carried out under the same analytical conditions as. The obtained elution result is shown in FIG. As is clear from FIG. 6, in this example, the degree of esterification could be promptly determined.

Example 6 Polyoxyethylene glycerin monostearate (trade name NIKKOL TMGS-5, Nikko Chemicals Co., Ltd.)
Elution was carried out under the same analytical conditions as in Example 3 except that a 2% by weight methanol solution (produced by K.K.) was injected. The obtained elution result is shown in FIG. As is clear from FIG. 7, in the present embodiment,
It was possible to quickly determine the degree of esterification.

Example 7 Polyoxyethylene octyl phenyl ether (trade name Emulgen 840, manufactured by Kao Corporation) and polyoxyethylene nonyl phenyl ether (trade name Emulgen 950, Kao Corporation) were used, except that the gradient conditions were changed as shown in Table 4. (stock)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected.

[0029]

[Table 4]

The obtained elution results are shown in FIG. As is clear from FIG. 8, in this example, the alkyl chain length could be quickly determined.

Example 8 Polyoxyethylene lauryl ether (trade name: Emulgen 120, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name: Emulgen 220, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was performed under the same analytical conditions as in Example 7, except that a mixed solution (2 wt% methanol solution) of Emulgen 320, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG. As is clear from FIG. 9, in this example, the alkyl chain length could be quickly determined.

Example 9 Example 7 was repeated except that a 2 wt% methanol / tetrahydrofuran = 50/50 (volume ratio) solution of sorbitan monostearate (trade name: SPAN60, manufactured by Kanto Chemical Co., Inc.) was injected.
Elution was carried out under the same analytical conditions as. The obtained elution result is shown in FIG. As is clear from FIG. 10, in this example, the degree of esterification could be promptly determined.

Example 10 Elution was carried out under the same analytical conditions as in Example 7 except that a 2% by weight methanol solution of polyoxyethylene glycerin monostearate (trade name NIKKOL TMGS-15, manufactured by Nikko Chemicals Co., Ltd.) was injected. It was The obtained elution result is shown in FIG. As is clear from FIG. 11, in this example, the degree of esterification could be promptly determined.

Example 11 The gradient conditions were changed as shown in Table 5, and polyoxyethylene octyl phenyl ether (trade name: Emulgen 810, manufactured by Kao Corporation) and polyoxyethylene nonyl phenyl ether (trade name: Emulgen 920, Kao Corporation) were used. (stock)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected.

[0035]

[Table 5]

The elution results obtained are shown in FIG. FIG.
As is clear from this, in this example, the alkyl chain length could be quickly determined.

Example 12 Polyoxyethylene lauryl ether (trade name: Emulgen 120, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name: Emulgen 220, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was carried out under the same analytical conditions as in Example 11 except that a mixed solution (2 wt% methanol solution) of Emulgen 320, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG. As is clear from FIG. 13, in this example, the alkyl chain length could be quickly determined.

Example 13 Polyoxyethylene glycerin monostearate (trade name NIKKOL TMGS-5, Nikko Chemicals Co., Ltd.)
Elution was carried out under the same analytical conditions as in Example 11 except that a 2% by weight methanol solution (produced by K.K.) was injected. The obtained elution result is shown in FIG. As is clear from FIG. 14, in this example, the degree of esterification could be promptly determined.

Comparative Example 2 Using 100% methanol as an eluent, polyoxyethylene octyl phenyl ether (trade name: Emulgen 8) was used.
10, manufactured by Kao Corporation and polyoxyethylene nonylphenyl ether (trade name: Emulgen 920, Kao Corporation)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected. The obtained elution result is shown in FIG. As is clear from FIG. 15, it was difficult to determine the alkyl chain length in this comparative example.

Comparative Example 3 Polyoxyethylene lauryl ether (trade name Emulgen 120, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name Emulgen 220, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was performed under the same analytical conditions as in Comparative Example 2 except that a mixed solution (2 wt% methanol solution) of Emulgen 320, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG.
As is clear from FIG. 16, in this comparative example, the alkyl chain length could not be completely separated.

Comparative Example 4 Comparative Example 2 except that a 2 wt% methanol / tetrahydrofuran = 50/50 (volume ratio) solution of sorbitan monostearate (trade name SPAN60, manufactured by Kanto Chemical Co., Inc.) was injected.
Elution was carried out under the same analytical conditions as. The obtained elution result is shown in FIG. As is clear from FIG. 17, in this comparative example, it was difficult to determine the degree of esterification.

Comparative Example 5 Polyoxyethylene glycerin monostearate (trade name NIKKOL TMGS-5, Nikko Chemicals Co., Ltd.)
Elution was carried out under the same analytical conditions as in Comparative Example 2 except that a 2% by weight methanol solution (produced by K.K.) was injected. The obtained elution result is shown in FIG. As is clear from FIG. 18, it was difficult to determine the degree of esterification in this comparative example.

Comparative Example 6 Polyoxyethylene octyl phenyl ether (trade name Emulgen 840, manufactured by Kao Corporation) and polyoxyethylene nonyl phenyl ether (trade name Emulgen 950, Kao Corporation) were used by changing the gradient conditions as shown in Table 6. (stock)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected.

[0044]

[Table 6]

The elution results obtained are shown in FIG. FIG.
As is clear from this, it was difficult to determine the alkyl chain length in this comparative example.

Comparative Example 7 Polyoxyethylene lauryl ether (trade name: Emulgen 120, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name: Emulgen 220, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was performed under the same analytical conditions as in Comparative Example 6 except that a mixed solution (2 wt% methanol solution) of Emulgen 320, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG.
As is clear from FIG. 20, in this comparative example, the alkyl chain length could not be completely separated.

Comparative Example 8 Polyoxyethylene octyl phenyl ether (trade name Emulgen 810, manufactured by Kao Corporation) and polyoxyethylene nonyl phenyl ether (trade name Emulgen 920, Kao Corporation) were used by changing the gradient conditions as shown in Table 7. (stock)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected.

[0048]

[Table 7]

The elution results obtained are shown in FIG. FIG.
As is clear from this, it was difficult to determine the alkyl chain length in this comparative example.

Comparative Example 9 Polyoxyethylene lauryl ether (trade name: Emulgen 108, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name: Emulgen 210, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was performed under the same analytical conditions as in Comparative Example 8 except that a mixed solution (2 wt% methanol solution) of Emulgen 306, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG.
As is clear from FIG. 22, it was difficult to determine the alkyl chain length in this comparative example.

Comparative Example 10 Polyoxyethylene octyl phenyl ether (trade name Emulgen 840, manufactured by Kao Corporation) and polyoxyethylene nonyl phenyl ether (trade name Emulgen 950, Kao Corporation) were used by changing the gradient conditions as shown in Table 8. (stock)
Elution was performed under the same analysis conditions as in Example 1 except that a mixed solution (2% by weight methanol solution) prepared in (1) was injected.

[0052]

[Table 8]

The obtained elution results are shown in FIG. FIG.
As is clear from this, it was difficult to determine the alkyl chain length in this comparative example.

Comparative Example 11 Polyoxyethylene lauryl ether (trade name: Emulgen 120, manufactured by Kao Corporation), polyoxyethylene cetyl ether (trade name: Emulgen 220, manufactured by Kao Corporation), and polyoxyethylene stearyl ether (trade name) Elution was carried out under the same analysis conditions as in Comparative Example 10 except that a mixed solution (2 wt% methanol solution) of Emulgen 320, manufactured by Kao Corporation was injected. The obtained elution result is shown in FIG. As is clear from FIG. 24, in this comparative example, the alkyl chain length could not be completely separated.

[Brief description of drawings]

1 is a diagram showing the elution results obtained in Example 1. FIG.

FIG. 2 is a diagram showing elution results obtained in Example 2.

FIG. 3 is a diagram showing elution results obtained in Comparative Example 1.

FIG. 4 is a diagram showing elution results obtained in Example 3.

FIG. 5 is a diagram showing the elution results obtained in Example 4.

FIG. 6 shows the elution results obtained in Example 5.

FIG. 7 is a diagram showing elution results obtained in Example 6.

8 is a diagram showing the elution results obtained in Example 7. FIG.

9 is a diagram showing the elution results obtained in Example 8. FIG.

FIG. 10 is a diagram showing the elution results obtained in Example 9.

FIG. 11 is a diagram showing the elution results obtained in Example 10.

FIG. 12 is a diagram showing the elution results obtained in Example 11.

13 is a diagram showing the elution results obtained in Example 12. FIG.

FIG. 14 shows the elution results obtained in Example 13.

FIG. 15 is a diagram showing elution results obtained in Comparative Example 2.

16 is a diagram showing the elution results obtained in Comparative Example 3. FIG.

FIG. 17 is a diagram showing elution results obtained in Comparative Example 4.

FIG. 18 is a diagram showing elution results obtained in Comparative Example 5.

FIG. 19 is a diagram showing the elution results obtained in Comparative Example 6.

FIG. 20 is a diagram showing the elution results obtained in Comparative Example 7.

FIG. 21 is a diagram showing the elution results obtained in Comparative Example 8.

22 is a diagram showing the elution results obtained in Comparative Example 9. FIG.

FIG. 23 is a diagram showing the elution results obtained in Comparative Example 10.

FIG. 24 is a diagram showing the elution results obtained in Comparative Example 11.

Claims (6)

[Claims] 1. A method for analyzing a nonionic surfactant, which comprises analyzing the nonionic surfactant by reverse phase high performance liquid chromatography by gradient elution using a water-methanol system eluent. 2. The nonionic surfactant according to claim 1, wherein the first eluent of the gradient elution has a methanol content of 30 to 95% by volume and the final eluent has a methanol content of 80 to 100% by volume. Analysis method. 3. A first using an eluent of water-methanol system
After performing the gradient elution of the first step, one or more solvents selected from acetone, tetrahydrofuran, isopropyl alcohol, n-propyl alcohol, ethanol and acetonitrile are added to the final eluent of the first step, The method for analyzing a nonionic surfactant according to claim 1, wherein two-step gradient elution is performed. 4. The first eluent of the gradient elution of the first stage has a methanol content of 30 to 95% by volume, and the final eluent has a methanol content of 80 to 100% by volume, and the second stage of the gradient elution has a methanol content of 80 to 100% by volume. The content of one or more solvents selected from acetone, tetrahydrofuran, isopropyl alcohol, n-propyl alcohol, ethanol and acetonitrile in the final eluent of gentle elution is 20 to 100% by volume. Method for the analysis of nonionic surfactants of. 5. An evaporative light scattering detector (Evap) as a detector.
olative Light Scattering Detector) is used.
5. The method for analyzing a nonionic surfactant according to any one of items 4 to 4. 6. The nonionic surfactant is polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, fatty acid polyoxyethylene ester,
The method for analyzing a nonionic surfactant according to any one of claims 1 to 5, which is a fatty acid sorbitan ester, a fatty acid polyoxyethylene sorbitan ester, a fatty acid glycerin ester, or a fatty acid polyoxyethylene glycerin ester.