Ling Zhen,Ding Susu,Liu Hui,Yao Jingjing,Zhu Qingli,Wang Wei

Yangzhou Center for Food and Drug Control,China

Abstract

According to Hygienic Standard for Cosmetics (2007 Edition) and Safety and Technical Standards for Cosmetics (2015 Edition),Oxidative Hair Dyes were supervised and inspected in Yangzhou from 2013 to 2018.P-Phenylenediamine and other 6 kinds of components from 85 batches of samples were determined and analyzed by HPLC.Only one batch of samples had not passed test,o-Phenylenediamine was detected that should be prohibited in hair dyes.The results of supervision and inspection for oxidative hair dyes were good in Yangzhou from 2013 to 2018.

Key words

oxidative hair dyes;cosmetics;p-Phenylenediamine;supervision and inspection

Phenylenediamine are widely used as raw materials of oxidative hair dyes,[1]which are oxidized into dye intermediates under the action of oxidants,and the intermediates produce kinds of colors after the coupling reaction under the action of coupling agents (phenylenediphenols).[2]Phenylenediamine are strictly prohibited and restricted in cosmetics,and the incidence of lymphoma,leukemia,bladder cancer and breast cancer increased in people who have a long-term use of hair dyes or who have occupational exposure to hair dyes.[3-6]In view of the various safety problems and the large number of contacts and users,it is essential to strengthen the health administration and daily supervision for hair dyes.

In order to ensure the safety of hair dyes within the jurisdiction,Yangzhou Food and Drug Administration has carried out special supervision and sampling inspection for four times in the past five years.As a legal inspection institution,Yangzhou Center for Food and Drug Control has tested 85 batches of oxidative hair dyes,and the inspection items are p-Phenylenediamine and other 6 kinds of components.

The results of the test of the samples would provide technical support for the market supervision of oxidative hair dyes in Yangzhou,and guarantee the health and safety of consumers.

Experimental

Samples,reagents and apparatus

The samples were purchased from shopping malls,barber shops and beauty salons.

Dyes standards: p-Phenylenediamine,Hydrochinone,m-Aminophenol,o-Phenylenediamine,p-Aminophenol,2,5-Diaminotoluene sulfate and Resorcinol were purchased from Dr.E GmbH (Dr.Ehrenstorfer GmbH Trading Company,Germany).The specifications are 0.1 g ～ 0.5 g.

Triethanolamine (HPLC grade) was purchased from Shanghai Aladdin Biochemical Technology Co.,LTD.Acetonitrile (HPLC grade) was purchased from Beijing Dikma Technology Inc..Ethanol,phosphoric acid and sodium sulfite (GR) was purchased from sinopharm group chemical reagent co.LTD.

PHS-3C Meter (Thunder Magnetic Instrument Factory,Shanghai);Kh-400kdb high power CNC ultrasonic cleaner (HeChuang Ultrasonic Instrument Co.,LTD,Kunshan).

Methods

Inspection standards and limits

The samples produced before October 1,2015 were tested according to the detection method in “Hygienic Standard for Cosmetics” (2007 Edition) (hereinafter referred to “Standard 2007”),[7]while the samples subsequent produced were tested according to the method in “Safety and Technical Standards for Cosmetics” (2015 Edition) (hereinafter referred to “Standard 2015”),[8]The limits of seven kinds of components in two editions of standard for dyes were shown in Table1.

Table 1.Limits of dyes in two standards for dyes

HPLC separation

The system consisted of an Agilent 1260 HPLC system equipped with Agilent G1315C DAD detector (Agilent,U.S.A).Separation was achieved with a CAPCELL PAK C18column (250 mm × 4.6 mm,5 µm,Shiseido,Japan) heated to 25℃,and an isocratic mobile phase of phosphate buffer solution of triethanolamine (pH 7.7) -acetonitrile (95:5) (v/v),delivered at a flow rate of 1 mL·min-1.The monitoring wavelength was set at 280 nm.The sample injection volume was 5 µL.

Sample preparation

The sample (0.5 g) was placed in a 25 mL colorimetric tube with plug containing 1.0 mL 1% sodium sulfite solution,and 50% ethanol solution was added to 25 mL.The sample was shaked up and ultrasonic extracted for 15 min,centrifuged at 8000 ×gfor 10 min,and filtered by 0.45 µm filter membrane.The filtrate was injected quickly into the HPLC system.

Sample determination

The seven standards were accurately weighed and diluted with 95% ethanol solution into mixed standards solution,and then gradually diluted into a series of reference working solutions.The reference working solutions were injected into the HPLC to record the chromatographic peak area,calibration curves for standards were constructed by linear regression analysis.The analytical method was applied to the quantitation of the seven components in samples.The representative chromatogram was shown in Figure 1.

Results and discussion

Notes of sample test

Sampling

Oxidative hair dyes mostly composed of two agents,one (Agent A) is the dye and the other (Agent B) is the oxidant.According to the product manual,dyes were not be added into Agent B as usual,so dyes would be determined just in Agent A of the samples.While for the reported and high-risk samples,it is essential to test the dye components both in Agent A and B.

After samples were unsealed,part of the front contents should be discarded,and then contents should be quickly weighed and placed in the tube to slow down the oxidation of dyes with anti-oxidant (sodium sulfite) pre-added.

Preparation of standards and samples

Temperature,operating time and light affect the accuracy of testing commonly.

Both the standard solution and the sample solution should be newly prepared,because the dyes degrade quickly in the solution,and when the environmental temperature rises,it would accelerate the degradation,which would have a very serious impact on the calibration curve and the accuracy.Therefore,ice water should be added into the ultrasonic instrument to prevent the samples from overheating and degradation,and the environment temperature should also be strictly controlled.Standard solution should be prepared with brown volumetric flasks.

Figure 1.The HPLC chromatogram of dyes

Table 2.Results of tests of oxidative hair dyes from 2013 to 2018

Components confirmation

The components of hair dyes are complicated,which often mixed with impurities during industrial production.When the samples were tested,some degradation of dyes and phenylenediamine should be confirmed by ultraviolet spectrum,which have similar structure and retention time to the dye components but not being recorded in Standards.

Product packaging

Many samples are not uniform in color and physical form,and some of them are even oil-water separated.It was considered that is caused by the packaging bad-sealed,which was resulted that the components in hair dyes are easy to be oxidized.Therefore,it is also an important means to improve the quality of hair dyes by improving the quality of product packaging.

Sample determination

A total of 85 batches of samples were tested for the seven dye components,as shown in Table 2.One batch of samples had not passed the test in 2013-2014,the test value of “o-Phenylenediamine” was 0.43%,while it should not be detected according to the Standards.

Conclusion

From 2013 to 2018,the supervision and inspection results of oxidative hair dyes in the market of Yangzhou are good.However,in view of the high risk of oxidative hair dyes,it is still essential to strengthen the management and daily supervision for the health and safety of people.