Detection method of brilliant blue colorant intermediate

Abstract

The invention discloses a method for detecting a brilliant blue colorant intermediate. In particular to three main impurities of N-ethyl-N-(3 '-sulfonic acid benzyl) aniline (CAS: 101-11-1), sodium 2-formyl benzene sulfonate (CAS: 1008-72-6) and a leuco body, analysis and detection of brilliant blue and the impurities are realized by utilizing high performance liquid chromatography, the method is good in repeatability and high in sensitivity, the content of the impurities in the brilliant blue can be simultaneously detected, and the use safety of the coloring agent is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of colorant detection, and particularly relates to a method for detecting a brilliant blue colorant intermediate. Background Art

[0002] Brilliant blue is widely used in the food, pharmaceutical, cosmetic and other industries. In the food industry, it is suitable for coloring cakes, candies, beverages, etc. It can give food a bright blue color, increase the attractiveness of food and consumers' desire to buy. In addition, Brilliant blue can also be used for coloring medicines and cosmetics, as well as coloring feed, tobacco, toys, food packaging materials, etc.

[0003] The main impurities in the brilliant blue product are N-ethyl-N-(3'-sulfonylbenzyl)aniline (CAS: 101-11-1), sodium 2-formylbenzenesulfonate (CAS: 1008-72-6) and leuco form. Currently, there is no literature report on the simultaneous analysis of these impurities.

[0004] Therefore, how to use a reasonable method to effectively separate is the current technical difficulty. Summary of the invention

[0005] However, when developing chromatographic analysis technology, the similarity between Brilliant Blue and its leucochromatin structure also caused difficulties in separation and analysis.

[0006] To this end, the present invention aims to develop a chromatographic analysis technology for the three impurities in brilliant blue. By improving the composition and pH value of the mobile phase, the chromatographic separation of the above substances is achieved and baseline separation is achieved, and it can be applied to the quantitative analysis of the three impurities in brilliant blue products.

[0007] A method for detecting a brilliant blue colorant intermediate, specifically comprising:

[0008] High performance liquid chromatography was used to determine three main impurities of brilliant blue colorant N-ethyl-N-(3'-sulfonylbenzyl)aniline (CAS: 101-11-1), sodium 2-formylbenzenesulfonate (CAS: 1008-72-6) and leuco form. The chromatographic conditions of the high performance liquid chromatography were as follows:

[0009] Chromatographic column: Octadecylsilane bonded silica gel is used as filler;

[0010] Mobile phase A: 0.05-0.2 mol / L ammonium acetate solution with pH adjusted to 7-10 with triethylamine;

[0011] Mobile phase B: pure acetonitrile;

[0012] Elution mode: gradient elution.

[0013] The chromatographic column is C18 (Supersil ODS 5 μm, 4.6 mm×150 mm).

[0014] The gradient elution method is: 0-5 min, 10%-40% B; 5-15 min, 40-90% B; 15-20 min, 90% B; 20-40 min, 10% B.

[0015] The mobile phase A is a 0.1M NH4Ac solution, the pH value of which is adjusted to 7-8 with triethylamine, and the flow rate of the mobile phase is 1.0-1.5 mL / min. Preferably, the flow rate of the mobile phase is 1.0 mL / min.

[0016] The peak area of ​​the sodium 2-formylbenzenesulfonate and N-ethyl-N-(3'-sulfonic acid benzyl)aniline is linearly related to the concentration within the concentration range of 5×10-4 to 2.5×10-2 mg / mL, and the detection limit is 1×10-4 mg / mL.

[0017] The peak area of ​​the leucoform is linearly related to the concentration within the concentration range of 1.1×10-5 to 5.6×10-4 mg / mL, and the detection limit is 5.0×10-6 mg / mL.

[0018] The detector is an ultraviolet detector with a detection wavelength of 250-260 nm, preferably 254 nm.

[0019] The beneficial effects of the present invention are:

[0020] By adjusting the composition and pH of the mobile phase, good separation and detection of the brilliant blue colorant and three main intermediate impurities in high performance liquid chromatography were achieved, which simplified the originally complex detection method and improved the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The spectrum is bright blue.

[0022] Figure 2 This is the chromatogram of sodium 2-formylbenzenesulfonate.

[0023] Figure 3 This is the chromatogram of N-ethyl-N-(3'-sulfonylbenzyl)aniline.

[0024] Figure 4 This is the chromatogram of the leucochrome (v:v 1:500).

[0025] Figure 5 The chromatograms of four mixed samples are shown below. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with embodiments:

[0027] 1. Single component detection of three main intermediate impurities of brilliant blue

[0028] Sample preparation:

[0029] Weigh 5 mg of sodium 2-formylbenzenesulfonate and dissolve it in mobile phase A (ammonium acetate solution) to prepare a 0.5 mg / mL standard solution. Weigh 5 mg of N-ethyl-N-(3'-sulfonic acid benzyl)aniline and dissolve it in a small amount of acetonitrile, then dilute it with ddH2O to prepare a 0.5 mg / mL standard solution.

[0030] Take 1 μL of leucosome and dissolve it in 1 mL of ddH2O to prepare leucosome (v / v 1:1000).

[0031] Testing conditions:

[0032] Chromatographic column: C18 (Supersil ODS 5μm, 4.6mm×150mm); mobile phase: A is 0.1M NH4Ac solution, adjusted to pH 8 with triethylamine; B is pure acetonitrile; elution gradient: 0-5min, 10%-40% B; 5-15min, 40-90% B; 15-20min, 90% B; 20-40min, 10% B. Flow rate is 1.0mL / min; detection wavelength is 254nm; injection volume is 20μL.

[0033] The chromatogram of 0.5 mg / mL brilliant blue is as follows Figure 1 As shown, the retention time is 8.3min; Figure 2 It is shown that the retention time of 0.1 mg / mL sodium 2-formylbenzenesulfonate is 5.4 min; Figure 3 It is 0.1 mg / mL N-ethyl-N-(3'-sulfonic acid benzyl)aniline, with a retention time of 10.2 min; Figure 4 This is a chromatogram of a leuco form with a retention time of 8.8 min. In the figure, the concentrations of brilliant blue, sodium 2-formylbenzenesulfonate and N-ethyl-N-(3'-sulfonylbenzyl)aniline are 0.1 mg / mL, and the dilution ratio of the leuco form is 1:1000 (v:v).

[0034] The chromatogram of the mixed sample of these four substances is shown in Figure 5 , indicating that the chromatographic conditions can achieve baseline separation of the above four substances and can be applied to the analysis and determination of relevant samples.

[0035] 2. Detection of mixed components of three main intermediate impurities of brilliant blue

[0036] Sample preparation: Take 200 μL of brilliant blue, 200 μL of sodium 2-formylbenzenesulfonate, 200 μL of N-ethyl-N-(3'-sulfonate benzyl)aniline and 1 μL of leuco body stock solution respectively, dilute with 400 μL of dd H2O to prepare a mixed solution containing 0.1 mg / mL brilliant blue, 0.1 mg / mL sodium 2-formylbenzenesulfonate, 0.1 mg / mL N-ethyl-N-(3'-sulfonate benzyl)aniline solution and leuco body (v / v 1:1000).

[0037] Testing conditions:

[0038] Chromatographic column: C18 (Supersil ODS 5μm, 4.6mm×150mm); mobile phase: A is 0.1M NH4Ac solution, adjusted to pH 8 with triethylamine; B is pure acetonitrile; elution gradient: 0-5min, 10%-40% B; 5-15min, 40-90% B; 15-20min, 90% B; 20-40min, 10% B. Flow rate is 1.0mL / min; detection wavelength is 254nm; injection volume is 20μL.

[0039] 3. Linear relationship analysis test:

[0040] Sodium 2-formylbenzenesulfonate, N-ethyl-N-(3'-sulfonylbenzyl)aniline and leuco form in brilliant blue products were analyzed and determined. Mixed samples of different concentrations were analyzed by HPLC. The results showed that the peak areas were linearly related to their concentrations.

[0041] This analytical method can be used to analyze and determine the above three impurities in brilliant blue products. The regression data results are shown in Table 1.

[0042] 0.005 mg / mL sodium 2-formylbenzenesulfonate, 0.005 mg / mL N-ethyl-N-(3'-sulfonic acid benzyl)aniline and 0.000113 mg / mL leuco form were added to 0.0025 mg / mL brilliant blue solution, and the spike recoveries were 92%, 94% and 110%, respectively.

[0043] Table 1 shows the analytical data of by-products in Brilliant Blue.

[0044] Table 1

[0045]

[0046] In Table 1, the concentration of the leucochrome with a dilution of 1:1000 (v:v) was calculated to be 2.25 μg / mL, and the purity of the sample brilliant blue solution was calculated to be 100%.

[0047] The characteristics of the present invention are mainly aimed at the chromatographic analysis of sodium 2-formylbenzenesulfonate, N-ethyl-N-(3'-sulfonylbenzyl)aniline and leuco form in brilliant blue. With the separation effect of these impurities as the goal, the composition and pH value of the mobile phase are optimized, and better separation conditions as shown in the spectrum are obtained. The peaks of the detection target are well separated without tailing or ghost peaks, and a good quantitative detection effect is achieved.

Claims

1. A method for detecting a brilliant blue colorant intermediate, characterized in that: Specifically: High performance liquid chromatography was used to determine three main impurities of brilliant blue colorant N-ethyl-N-(3'-sulfonylbenzyl)aniline (CAS: 101-11-1), sodium 2-formylbenzenesulfonate (CAS: 1008-72-6) and leuco form. The chromatographic conditions of the high performance liquid chromatography were as follows: Chromatographic column: Octadecylsilane bonded silica gel is used as filler; Mobile phase A: 0.05-0.2 mol / L ammonium acetate solution with pH adjusted to 7-10 with triethylamine; Mobile phase B: pure acetonitrile; Elution mode: gradient elution.

2. The method for detecting a brilliant blue colorant intermediate according to claim 1, characterized in that: The chromatographic column is a C18 column.

3. The method for detecting a brilliant blue colorant intermediate according to claim 1, characterized in that: The gradient elution method is: 0-5 min, 10%-40% B; 5-15 min, 40-90% B; 15-20 min, 90% B; 20-40 min, 10% B.

4. The method for detecting a brilliant blue colorant intermediate according to claim 1, wherein: The mobile phase A is a 0.1M NH4Ac solution, the pH value of which is adjusted to 7-8 with triethylamine, and the flow rate of the mobile phase is 1.0-1.5 mL / min.

5. The method for detecting a brilliant blue colorant intermediate according to claim 1, characterized in that: The peak area of ​​the sodium 2-formylbenzenesulfonate and N-ethyl-N-(3'-sulfonic acid benzyl)aniline is linearly related to the concentration within the concentration range of 5×10-4 to 2.5×10-2 mg / mL, and the detection limit is 1×10-4 mg / mL.

6. The method for detecting a brilliant blue colorant intermediate according to claim 1, characterized in that: The peak area of ​​the leucoform is linearly related to the concentration within the concentration range of 1.1×10-5 to 5.6×10-4 mg / mL, and the detection limit is 5.0×10-6 mg / mL.

7. The method for detecting a brilliant blue colorant intermediate according to claim 1, characterized in that: The detector is an ultraviolet detector with a detection wavelength of 250-260nm.

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