CN106501410A - The detection method of N nitrosodiethanolamines in a kind of cosmetics - Google Patents

Abstract

The present invention relates in a kind of cosmetics N nitrosodiethanolamines detection method, and in particular to a kind of gas-chromatography thermal energy analyzer method for combined use of the N nitrosodiethanolamines in cosmetics, step is：N nitrosodiethanolamines are extracted from sample under ultrasound condition by cosmetics using water and chloroform mixed solution, after high speed refrigerated centrifuge, silicagel column is purified, and is detected with the solution obtained after methyl alcohol dissolution filter gas-chromatography thermal energy analyzer combination method after acetone eluant；The present invention can the N nitrosodiethanolamines that go out in water-soluble or fat-soluble cosmetics of effective detection, impurity peaks are few, and matrix interference is little, accurately, sensitivity is high, disclosure satisfy that the detection of N nitrosodiethanolamines in the dissimilar cosmetics such as creams class, aqua class, shampoo class.

Description

A kind of detection method of N-nitrosodiethanolamine in cosmetics

technical field

The invention relates to a method for detecting N-nitrosodiethanolamine in cosmetics and raw materials.

Background technique

N-nitrosamine compounds are a class of strong chemical carcinogens that can induce malignant tumors in various animals. Cosmetics, as daily necessities, will stay on the skin, hair, nails, lips and other parts for a long time, and their safety has attracted much attention. N-nitrosamines in cosmetics are strictly monitored at home and abroad. Currently, the most concerned N-nitrosamine compound in cosmetics is N-nitrosodiethanolamine, as classified according to the International Agency for Research on Cancer (IARC), N-nitrosodiethanolamine is classified as possibly carcinogenic to humans. Because diethanolamine and triethanolamine are widely used in cosmetics as moisturizers, pH balancers or mixed with lauric acid as emulsifiers and dispersants in cosmetics, and diethanolamine and triethanolamine are usually used Substances are easy to generate N-nitrosodiethanolamine in the production, storage and circulation of cosmetics. Therefore, the detection and control of N-nitrosodiethanolamine in cosmetics has attracted widespread attention at home and abroad. N-nitrosamines have been clearly listed as prohibited components in cosmetics.

N-nitrosodiethanolamine is a yellow viscous oily liquid, which belongs to non-volatile nitrosamines. Due to the variety of substances contained in cosmetics, especially the content of many nitrogen-containing substances is much higher than that of N-nitrosodiethanolamine, it is difficult to detect N-nitrosodiethanolamine in cosmetics. At present, some detection methods for N-nitrosodiethanolamine in different cosmetics are carried out at home and abroad, such as gas chromatography, gas chromatography, liquid chromatography and liquid chromatography-mass spectrometry. Currently, the commonly used ISO/DIS15819-2013 method is liquid chromatography-mass spectrometry, but this method is easily interfered by other ingredients in cosmetics, and the detection limit is high.

Contents of the invention

In view of the above-mentioned status quo, the purpose of the present invention is to provide a pretreatment technology and analysis method for the detection of N-nitrosodiethanolamine in cosmetics, which has fewer impurity peaks, less matrix interference, accuracy and high sensitivity, and can meet the requirements of creams. Detection of N-nitrosodiethanolamine in different types of cosmetics such as cosmetics, lotions, and shampoos.

In order to achieve the above object, the technical scheme adopted in the present invention is:

(1) Take 3-5g of cosmetics into a 50mL standard stoppered volumetric flask, add 0.9-1.5g of a mixture of sulfamic acid ammonium and sodium chloride, add 5.4-9mL of water and chloroform mixed solution, and extract by ultrasonic to obtain Ultrasonic extraction solution;

(2) Take the above-mentioned ultrasonic extraction solution, after refrigerated centrifugation, take 3-5 mL of the supernatant and place it on a nitrogen blower to dry it with nitrogen gas, dissolve the residue with 3-5 mL of a mixed solution of chloroform and acetone, and pass it through a solid-phase extraction column , rinse with 6-10mL of chloroform and acetone mixed solution, elute with 6-10mL of acetone, collect the eluate in a test tube, dry it with nitrogen, dissolve 0.6-1mL of methanol and filter it with a 0.20μm microporous membrane. Obtain purified solution in a brown chromatographic bottle for use;

(3) Determination of N-nitrosodiethanolamine in the solution after the purification of step (2) gained by gas chromatography-thermal energy analyzer coupling method, gas chromatography condition is: gas chromatography column adopts medium polarity chromatography column, carrier gas It is helium; the temperature of the gas chromatographic column adopts temperature programming.

The mass ratio of the mixture amine sulfamate and sodium chloride added in the step (1) is 1:2.

The volume ratio of water and chloroform mixed solution in the step (1) is 5:4.

The water in the step (1) is ultrapure water with a resistivity greater than 18MΩ*cm.

The refrigerated centrifugation conditions of the step (2) are as follows: a refrigerated temperature of 4° C., a rotational speed of 12000 r/min, and a centrifugation time of 15 to 20 minutes.

The volume ratio of the mixed solution of chloroform and acetone used for dissolving the residue and washing in the step (2) is 5:1.

The solid phase extraction column in the step (2) is a glass packed column filled with 2-3 g of silica gel and 3-5 g of activated anhydrous sodium sulfate on the top.

The detection conditions in the step (3) are, gas chromatograph: inlet temperature 250°C, sample volume 2 μL, septum purge 15mL/min, chromatographic column adopts medium polar chromatographic column, carrier gas flow rate 2.1mL/min min, the temperature of the gas chromatographic column adopts a temperature program: the initial temperature is 150°C for 10 minutes, 10°C/min to 230°C for 2 minutes, and 250°C for 3 minutes; the conditions of the thermal energy analyzer detector are: interface temperature 250°C, cracker temperature 600°C, ozone flow rate 10mL/min, cooling temperature -20°C, voltage 760V.

Beneficial effects of the present invention: the present invention relates to N-nitrosodiethanolamine contained in cosmetics that are in direct contact with people, and a gas chromatography-thermal energy analyzer combined detection method is established. The detection limit of the N-nitrosodiethanolamine contained in the cosmetics is 20 μg/kg, the recovery rate of the method is 87-105%, and the relative standard deviation is less than 10%. The invention has low impurity interference, high recovery rate and stable method, which can provide technical method support for the detection of N-nitrosodiethanolamine in cosmetics and product quality control, and can meet different types of creams, waters, shampoos, etc. Determination of N-nitrosodiethanolamine in cosmetics.

Description of drawings

Fig. 1 is a sample processing flowchart of the present invention;

Figure 2 shows N-nitrosodiethanolamine in cosmetics, (a) before the silica gel chromatography column, (b) after the silica gel chromatography column.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. But the following embodiments are only limited to explain the present invention, and the protection scope of the present invention should include the entire content of the claims, not only limited to the present embodiment.

The steps of the embodiment of the present invention are as follows: extract N-nitrosodiethanolamine from the sample by using a mixed solution of water and chloroform under ultrasonic conditions, and after high-speed refrigerated centrifugation, purify the silica gel column and elute with acetone After the solution is dissolved in methanol and filtered, the solution obtained is detected by a gas chromatography-thermal energy analyzer method, which can effectively detect N-nitrosodiethanolamine in water-soluble or fat-soluble cosmetics. details as follows:

1. Reagents and materials

Unless otherwise stated, all reagents used were of analytical grade.

1.1 N-nitrosodiethanolamine (N-Nitrosodiethanolamine): the purity is greater than 97%;

1.2 Water: ultrapure water;

1.3 Dichloromethane: chromatographic grade;

1.4 Methanol;

1.5 Ammonium sulfamate;

1.6 Chloroform;

1.7 Helium: Concentration 99.999%

1.8 Oxygen: concentration 99.999%

1.9 acetone;

1.10 Anhydrous sodium sulfate;

1.11 silica gel;

1.12 N-nitrosodiethanolamine standard solution: Weigh 1mg (accurate to 0.0001g) standard substance of N-nitrosodiethanolamine, put it in a 10mL brown volumetric flask, add methanol to the mark, and ultrasonicate for 10min to help dissolve the solution. The concentration is: 100μg/mL, stored in the dark at -20°C, and the shelf life is 3 months;

2. Instruments and equipment

2.1 Gas chromatography: equipped with split/splitless inlet;

2.2 Balance: Sensitivity 0.0001g;

2.3 Refrigerated centrifuge: the speed is not lower than 12000r/min, and the freezing temperature is not lower than 0°C;

2.4 Ultrasonic water bath

2.5 Nitrogen blowing instrument

2.6 Amphoteric membrane

2.7 Thermal energy analyzer detector: equipped with a thermal cracker, the cracking temperature is not lower than 600°C;

3. Implementation steps, as shown in Figure 1.

3.1 Extraction

Take 5g (accurate to 0.0001g) sample in a 50mL conical flask with stopper, add 0.5g (accurate to 0.0001g) of sulfamic acid amine and 1g (accurate to 0.0001g) of sodium chloride, add 5mL ultrapure water and 4mL Chloroform, ultrasonically extract at room temperature for 30 minutes, transfer to a 15mL centrifuge tube, refrigerate and centrifuge at 12000r/min at 4°C for 15min, pipette 5mL supernatant into the test tube with a 5mL pipette, and place it on a nitrogen blower Blow dry, and dissolve the residue with 5 mL of a mixed solution of chloroform and acetone (volume ratio 5:1) to be purified.

3.2 Purification

Preparation of silica gel chromatography column: silica gel and anhydrous sodium sulfate were dried and activated at 110°C for 10 hours and then stored in a desiccator. When making a silica gel chromatography column, weigh 3 g of activated silica gel and dry-pack it into a glass chromatography column, tap it with a glass rod, add 5 g of activated anhydrous sodium sulfate to the top layer, and tap it.

Transfer the liquid to be purified in 3.1 to a silica gel chromatography column. Rinse with 10 mL of chloroform and acetone (volume ratio 5:1), elute with 10 mL of acetone, collect the eluate in a test tube, blow dry with nitrogen, pipette 1 mL of methanol-dissolved residue, and filter through a 0.20 μm microporous filter. Membrane filtration was placed in a 2mL brown chromatographic bottle, and stored at -20°C in the dark until injection.

Silica gel chromatography column purification can effectively eliminate the interference of impurities in cosmetics, see Figure 2, (a) is before the silica gel chromatography column, (b) is after the silica gel chromatography column, it can be seen that the chromatogram after silica gel chromatography column purification Only the N-nitrosodiethanolamine signal is present.

3.3 Determination

3.3.1 Gas chromatography conditions

Considering different types of gas chromatographs, the general technical conditions for gas chromatographic analysis are given below.

1) Chromatographic column: DB-624 quartz capillary column, 30m×0.32mm(i.d.)×1μm;

2) The column temperature adopts a temperature program: the initial temperature is 150°C for 10 minutes, 10°C/min to 230°C for 2 minutes, and 250°C for 3 minutes;

3) Carrier gas: helium

4) Carrier gas flow rate: 2.1mL/min;

5) Inlet temperature: 250°C;

6) Injection volume: 2 μL;

7) Septum purge 15mL/min.

3.3.2 Thermal energy analyzer analysis conditions

1) Interface temperature: 250°C;

2) Cracker temperature: 600°C;

3) Oxygen flow rate: 10mL/min;

4) Cooling temperature: -15°C;

5) Detector voltage: 760V.

3.3.3 N-nitrosodiethanolamine standard curve

Use accurate standard solution (100μg/mL) to prepare N-nitrosodiethanolamine solutions with concentrations of 50ng/mL, 100ng/mL, 200ng/mL, 500ng/mL, 1000ng/mL, and 10000ng/mL, and take 2μL in The determination was carried out under the above-mentioned instrument experimental conditions, and a standard curve was drawn with peak area versus concentration.

3.3.4 Calculation method of N-nitrosodiethanolamine content

The present invention adopts external standard method, and calculation formula is such as formula (1)

In the formula, W: the mass fraction of N-nitrosodiethanolamine in cosmetics (unit: milligram per kilogram; mg/kg);

c: the concentration of N-nitrosodiethanolamine in the sample obtained by the standard curve (unit: milligrams per liter; mg/L))

V: constant volume of the sample (unit: liter; L)

m: sample mass (unit: gram; g)

4. Linear equation and detection limit of the method

Use accurate standard solution (100μg/mL) to prepare N-nitrosodiethanolamine solutions with concentrations of 50ng/mL, 100ng/mL, 200ng/mL, 500ng/mL, 1000ng/mL, and 10000ng/mL, and take 2μL in Measured under the above-mentioned instrument experimental conditions, draw a standard curve with peak area (Y-axis) to concentration (X-axis), and draw a linear equation.

Table 1: N-nitrosodiethanolamine standard curve

5. Recovery and precision of the method

For the recovery rate test, three concentrations were set to be determined according to the above-mentioned sample pretreatment method and experimental conditions. Each concentration was tested 6 times, and the recovery rate and precision of the method were calculated. As a result, the recovery rate was 87-105%. , the calculation precision (relative standard deviation RSD) is less than 10%, and the results are shown in Table II.

Table 2: Recovery and precision of different spikes of N-nitrosodiethanolamine

6 Conclusion

Aiming at the N-nitrosodiethanolamine contained in the cosmetics that are in direct contact with people in the present invention, a gas chromatography-thermal energy analyzer combined detection method is established. Through the recovery rate and precision test of different samples, the detection limit of this method for N-nitrosodiethanolamine contained in cosmetics is 20 μg/kg, the recovery rate of the method is 87-105%, and the relative standard deviation is less than 10%. . The invention has little impurity interference, high recovery rate and stable method, and can provide technical method support for the detection of N-nitrosodiethanolamine in cosmetics and product quality control.

It should be noted that, according to the above-mentioned embodiments of the present invention, those skilled in the art can fully realize the full scope of the independent claims and dependent rights of the present invention, and the implementation process and method are the same as the above-mentioned embodiments. And the part not elaborated in the present invention belongs to the well-known technology in the art.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above examples, and various changes and improvements made to the present invention should all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. a detection method of N-nitrosodiethanolamine in cosmetics, is characterized in that comprising the following steps: (1) Take 3-5g of cosmetics into a 50mL standard stoppered volumetric flask, add 0.9-1.5g of a mixture of sulfamic acid ammonium and sodium chloride, add 5.4-9mL of water and chloroform mixed solution, and extract by ultrasonic to obtain Ultrasonic extraction solution; (2) Take the above-mentioned ultrasonic extraction solution, after refrigerated centrifugation, take 3-5 mL of the supernatant and place it on a nitrogen blower to dry it with nitrogen gas, dissolve the residue with 3-5 mL of a mixed solution of chloroform and acetone, and pass it through a solid-phase extraction column , rinse with 6-10mL of chloroform and acetone mixed solution, elute with 6-10mL of acetone, collect the eluate in a test tube, dry it with nitrogen, dissolve 0.6-1mL of methanol and filter it with a 0.20μm microporous membrane. Obtain purified solution in a brown chromatographic bottle for use; (3) Determination of N-nitrosodiethanolamine in the solution after the purification of step (2) gained by gas chromatography-thermal energy analyzer coupling method, gas chromatography condition is: gas chromatography column adopts medium polarity chromatography column, and carrier gas is Helium; the gas chromatographic column temperature is programmed. 2. detection method according to claim 1, is characterized in that: the mass ratio of the mixture sulfamic acid amine added in the described step (1) and sodium chloride is 1:2. 3. detection method according to claim 1, is characterized in that: the volume ratio of water and chloroform mixed solution is 5:4 in the described step (1). 4. The detection method according to claim 1 or 3, characterized in that: the water in the step (1) is ultrapure water with a resistivity greater than 18MΩ*cm. 5 . The detection method according to claim 1 , characterized in that: the refrigerated centrifugation conditions in the step (2) are: 4° C. refrigerating temperature, 12000 r/min rotating speed, and 15 to 20 minutes of centrifuging time. 6 . 6. detection method according to claim 1, is characterized in that: the volume ratio of the chloroform and acetone mixed solution that is used for dissolving residue and rinsing in described step (2) is 5:1. 7. The detection method according to claim 1, characterized in that: the solid phase extraction column in the step (2) is filled with 2 to 3 silica gels and top filled with 3 to 5 g of anhydrous sodium sulfate after activation. Glass packed column. 8. The detection method according to claim 1, characterized in that: the detection conditions in the step (3) are, gas chromatograph: inlet temperature 250° C., injection volume 2 μL, septum purging 15 mL/min , the chromatographic column adopts a medium-polarity chromatographic column, and the carrier gas flow rate is 2.1mL/min; the temperature of the gas chromatographic column is programmed to rise as follows: the initial temperature is 150°C for 10 minutes, 10°C/min to 230°C for 2 minutes, and 250°C for 3 minutes; The thermal energy analyzer conditions are: interface temperature 250°C, cracker temperature 600°C, ozone flow rate 10mL/min, cooling temperature -20°C, voltage 760V.