Analysis Of Carcinogenic Dyes In Textile And Clothing And Its Detection Methods

In twenty-first Century, with the increasing awareness of environmental protection and health, the impact of textiles on human health and environmental protection has attracted more and more attention, and the carcinogenicity of dyes used in textiles is the focus of attention.

The association between dyes and cancer was reported more than 100 years ago.

In 1895, German doctor Rehn reported that 4 of the 45 people working in Poinsettia factory had bladder cancer.

Since then, 5O has confirmed that bladder cancer is an occupational disease of dyestuff workers through animal tests and long-term clinical studies.

Therefore, when people wear and use textiles containing such dyes, they may pose potential health risks.

The carcinogenic dye discussed in this paper is a dye that causes cancer by itself without any reduction or other reactions, but it will directly lead to cancer or human body for a long time.

In view of the serious harm of carcinogenic dyes, many countries and world authoritative organizations have promulgated strict regulations and technical standards to limit them.

Direct blue 6, direct red 28, Direct Black 38, acid red 26, alkaline red 9, basic purple 14, disperse blue 1, disperse orange 11 and disperse yellow 3 are the European Commission's textile eco label (Eco-Label) (EU 2002 / 371 / EC directive) and the International Textile Association's textile ecological standard, which require that textiles can not use any of the ten kinds of dyes that have direct carcinogenic effect on human body. The latest recommended national standard GB/T18885-2009, "eco textile technical requirements" issued by the State General Administration of quality, technology, supervision and inspection and quarantine, also stipulates that no such dye should be used.

2 detection methods and standards of carcinogenic dyes abroad

The detection of carcinogenic dyes in textiles has always been a difficult problem. At present, there is no international standard for detecting carcinogenic dyes on textiles.

There are few reports on this field at home and abroad. The detection of carcinogenic dyes is described in the OeKo-Tex standard 200 (2010 Edition). Some dyes (azo dyes) can be detected by banned aromatic amines. Some dyestuffs (disperse dyes) can be detected by disperse dyes, while other dyes do not clearly indicate detection methods.

This brings great inconvenience to the implementation of relevant regulations, standards and conformity assessment procedures.

Germany, as a foreign country of related bills, proposed in 2000 a draft standard draft of the DINDMP512 draft on textile disperse dyes detection, namely, textile disperse dye detection. At present, some of the world's major testing institutions have basically checked the draft standard while testing the carcinogenic dyes on textiles, while others have made corresponding adjustments or improvements in technology according to their own experience and research results.

3 problems in the detection standard of carcinogenic dyes in China

At present, the detection methods and related standards of carcinogenic dyes in China are mainly GB/T20382-2006 "determination of carcinogenic dyes in textiles". This method uses methanol to extract samples and uses the high performance liquid chromatography two stage tube array detector (HPLC-DAD) to conduct qualitative and quantitative determination of the extraction solution.

Although this method is widely used in China, there are many problems.

1) ultrasonic assisted methanol extraction method can not completely extract dyes from fibers.

The 9 carcinogenic dyes belong to the direct, acidic, basic and disperse dyes. The chemical properties are quite different. It is simple and quick to use methanol to extract dyes from textiles.

However, the practice shows that the method can only extract some dyes on the fiber, and the recovery rate is low, which can not meet the requirements of Oeko-TexStandard100 quantitative detection.

In this way, the testing organization may be difficult to detect because of the low extraction volume, which may lead to misjudgment of the result, which will bring certain risks to the testing organization and related enterprises.

2) the sensitivity of HPLC-DAD is low, and false positive can not be accurately judged.

At present, the HPLC-DAD method is the most commonly used method to detect carcinogenic dyes. However, dyes often contain synthetic intermediates, isomers and dispersants. The composition is complex, and the selectivity and anti-interference ability of the detection methods are high. In the process of practical detection, when HPLC-DAD is used for qualitative detection, it is difficult to distinguish, and the sensitivity and selectivity of the method are low.

3) HPLC-DAD method was used to detect the test cycle.

According to the current GB/T20382-2006 method, the gradient elution process is too long, it takes 55 minutes. From one preparation to the completion of the test, it takes about 2 hours, and the detection efficiency is low.

4) the names of individual dyes in the standard, and the chemical abstracts are not updated in time.

The standard is alkaline red 9, chemical abstracts number (CASNO) is 25620-78-4, the author inquires the literature, at present, the basic red 9, chemical abstracts number (CASNO) has been changed to 569-61-9.

5) there are corrections in the standard.

The 4.4 part of the standard, the two part of the 0.0025mol/L phosphoric acid, the two hydrogen four butyl ammonium solution, is not properly configured. The standard is written as follows: "remove the phosphoric acid two hydrogen four butyl ammonium solution in the 4mL concentration of 1mol/L, dilute the water to the scale". If this is configured, the concentration is obviously 0.0020mol/L. Taking into account the use of the mobile phase in the back gradient leaching procedure is also 0.0025mol/L, it is necessary to remove two hydrogen four butylammonium phosphate from 5mL concentration of 1mol/L in 2000mL volumetric flask and dilute it to the scale with water.

4 recommendations

In view of the problems in the standard, it is suggested that two points should be noted in the test.

1) according to the dyeing mechanism of dyes on fibers, different dyes are used to extract dyes from textiles.

The 9 carcinogenic dyes belong to direct, acid, alkaline and disperse dyes. They are mainly used for dyeing cotton, wool, acrylic and polyester fibers.

The stripping agent should meet the following requirements: (1) only the fibers can be dissolved and dissolve and decompose; (2) the dyes can be dissolved, but they can not react with dyes (3) the solvent is stable, colorless and non flammable.

Ding you super [7] uses pyridine / water (4/3, V/V), pyridine / formic acid / water (20/5/75, V/V) and chlorobenzene to separate the direct dyes and acid dyes from natural fibers, the basic dyes on acrylic fibers and disperse dyes on polyester fibers, and two hydrogen and four butylammonium phosphate as cationic reagents, which can be completely separated from 9 dyes by means of acetonitrile. With diode array detector, the quantitation limit of 9 carcinogenic dyes is 1.0mg/kg~10.0mg/kg, the linear correlation coefficient is greater than 0.995, and the recovery rate is 92.3% to 106.8%, indicating that the extraction method is ideal. The author tried to add urea in the current extraction method and achieved good results.

2) establish a high performance liquid chromatography tandem mass spectrometry (HPLC-MSD) technology to detect carcinogenic dyes.

High performance liquid chromatography tandem mass spectrometry (HPLC / MS / MS) can greatly improve the analytical speed, separation efficiency and sensitivity of liquid chromatography, and give full play to the advantages of high selectivity and high sensitivity of mass spectrometry. It can provide reliable evidence for qualitative and quantitative analysis of target compounds by using the information of the characteristic parent ions and their daughter ions provided by the mass spectrometry, and can overcome the false positive phenomenon in HPLC detection.

Ding you and Ma Qiang et al have established a method for analyzing carcinogenic dyes by high performance liquid chromatography tandem mass spectrometry. The method is sensitive, concise and reliable.

5 Conclusion

There is a certain difference between the testing standards of related ecological textiles and the current Oeko-Tex Standard 100.

As the largest textile producer and exporter in the world, China's textile and garment exports are growing at a high speed every year, of which exports to the EU are growing most rapidly.

The necessary technical support can not keep up, and the lack of unified testing methods will not only bring difficulties to the implementation of relevant standards and regulations, but also bring obstacles to China's textile and clothing crossing the "green barrier".

Therefore, the relevant departments should speed up the revision and formulation of relevant standards, and establish a fast, scientific and accurate method for the detection of carcinogenic dyes, which not only guarantees the safety of our consumers, complies with the development trend of global green consumption trend, but also helps Chinese textile enterprises to participate in international competition at a higher level and promote the development of China's eco textiles.