In recent years, the ecological requirements of textiles have received much attention, testing requirements have become more stringent, and the requirements for testing capabilities have also increased. Extraction is the main process in the detection of harmful substances. Currently, solvent extraction techniques commonly used include Soxhlet extraction, ultrasonic extraction, microwave extraction and accelerated solvent extraction. The new extraction techniques include solid phase extraction, solid phase microextraction and liquid phase microextraction. The multi-component extraction techniques based on various extraction techniques include Soxhlet-solid phase extraction, accelerated solvent-solid phase extraction, and ultrasonic-solid phase microextraction.
In this paper, the extraction techniques applied in the analysis of harmful substances in textiles are reviewed, and the more environmentally friendly extraction techniques are prospected.
2 Application of extraction technology in the detection of harmful substances in textiles 2.1 Solvent extraction technology Solvent extraction technologies such as Soxhlet extraction and ultrasonic extraction play an important role in the detection of harmful substances in textiles.
Soxhlet extraction is a simple and practical classic extraction technology. Zhang Weiya and other methods use Soxhlet extraction to extract residual alkylphenols and alkylphenol ethoxylates in textiles. The recovery rate meets the requirements. Hu Yongjie et al. established a method for determining the content of chlorine-containing organic carriers in ecological textiles by Soxhlet extraction.
Ultrasonic extraction is the most widely used extraction technique, and a variety of harmful substances can be pretreated by ultrasonic extraction. Ultrasonic extraction technology is an extraction technology formed by the combination of solvent extraction technology and ultrasonic technology. The presence of ultrasonic field improves the efficiency of solvent extraction. Cheng Lijun, Fan Yuanmu, and Liu Huiting extracted the organotin compounds, chlorophenols, o-phenylphenol and perfluorinated compounds in textiles by ultrasonic extraction. The detection limits and recovery rates were all under standard requirements. The extraction of pesticides in textiles mainly uses ultrasonic extraction. Zhang Xiang and Wang Mingtai use ultrasonic extraction to extract pesticide residues in textiles.
Microwave extraction is a combination of microwave technology and extraction technology. Microwave is used to improve extraction efficiency during the extraction process. Wang Chengyun et al used microwave-assisted extraction to extract octylphenol, nonylphenol, octylphenol ethoxylate, and nonylphenol ethoxylate in textiles with high recovery. Shao Chaoying et al. established a microwave-assisted extraction method for polybrominated diphenyl ether flame retardants. The microwave extraction conditions were determined by microwave-assisted extraction orthogonal experiment. The detection limit of the method was low, the standard addition rate was high, and it was suitable for trace amounts in textiles.
Detection and analysis of brominated biphenyl (ether) flame retardants.
Accelerated Solvent Extraction Technology A new extraction method proposed by Richter et al. in 1995, using conventional solvents to extract solid or semi-solid novel sample preparation methods with solvents at higher temperatures and higher pressures. Increased temperature and pressure increase material solubility and solute diffusion efficiency and improve extraction efficiency. Yu Yuping et al. used the accelerated solvent extraction method to extract perfluorooctane sulfonic acid and perfluorooctanoic acid from the international requirements for perfluorooctane sulfonic acid and perfluorooctanoic acid in textiles. The minimum detection limit, linear range and method recovery rate of this method were obtained. Can meet the requirements.
2.2 New extraction technology Solvent extraction technology requires the use of a large number of organic solvents that are toxic and harmful to humans and the environment. Although solvent extraction technology still plays an important role, the development of time-saving and efficient organic solvent consumption is one of the requirements for the continuous development of extraction technology. In recent years, a variety of new sample extraction technologies, such as solid phase extraction, have been developed. Solid phase microextraction, liquid phase microextraction, etc.
Solid phase extraction is a sample pretreatment technology based on liquid-solid separation extraction. The solid phase extraction process is essentially a column chromatography separation process. It is a solid adsorbent capable of adsorbing target compounds with matrix and interference compounds in liquid samples. The difference is to separate and enrich the target compound. Ma Qiang et al. established an analytical method for the migration of textile alkylphenols. The textile soaking liquid is purified by solid phase extraction column and quantitatively analyzed. Niu Zengyuan et al. studied the migration of phthalate environmental hormones in artificial sweat in textiles, and determined the optimal conditions for enrichment of phthalate esters in artificial sweat extracts by solid phase extraction.
Solid phase microextraction was initiated by Pawliszy of Warterlee University in Canada in 1990. It is a sample pretreatment method that integrates extraction, concentration, desorption and injection. The theory of SPME is based on the difference in the partition coefficient between the sample matrix and the extraction medium (coating) of the analyte, when extracting using a liquid polymer coating, in the extraction equilibrium state and before the extraction. The amount should remain unchanged. When the extraction layer is determined, the amount of analyte to be adsorbed is linear with the initial concentration of the substance in the sample. This is the theoretical basis for quantitative analysis using SPME. Among them, headspace solid phase microextraction is used to determine high volatile matter; direct solid phase microextraction is suitable for the determination of low volatile matter. Zhang Zhuoyu et al., Gao Lirong et al., Nie Fengming et al. Analytical methods for the determination of volatile organic compounds (VOCs) in textiles by headspace solid phase microextraction. The extraction conditions of SPME, including extraction head selection, equilibration time, extraction time, extraction temperature, headspace volume, ionic strength, stirring speed, desorption temperature and time, were optimized to meet the rapid analytical requirements for trace VOCs in textiles. Liu Wei et al. used solid phase micro-extraction headspace sampling technology and gas chromatography to analyze the abnormal odor in textiles. Wang Li et al. used solid phase microextraction to adsorb and accumulate organophosphorus pesticides in textiles, and then qualitatively and quantitatively detected them by gas chromatography-mass spectrometry. It can be applied to the rapid detection of substances in ecological textiles.
Liquid phase microextraction was first proposed by Jeannot et al. in 1996 to propose a new type of water sample pretreatment technology. This technology combines the advantages of liquid phase extraction and solid phase extraction, and uses only micro-upgraded or even upgraded organic solvents for extraction, adapting to the requirements of modern analytical science miniaturization, and is an environmentally friendly "green" analysis technology. The basic principle of the technology is based on the distribution balance between the sample and the micro-upgraded or even upgraded extraction solvent, that is, the micro-drop solvent is placed in the stirred or flowing solution to achieve micro-extraction of the solute. Liquid phase microextraction includes direct immersion liquid phase microextraction, headspace liquid phase microextraction hollow fiber membrane liquid phase microextraction and flow liquid phase microextraction. Zhang Hui et al. used liquid phase microextraction with ionic liquid as extractant to improve the textile sample pretreatment method in the national standard method for textile testing (GB/T 17592-2006), and established the azo dye from textiles. A new method for the extraction of aromatic amines. The extraction effects of direct immersion microextraction and solvent rod microextraction mode were compared, and the solvent extraction microextraction was determined as the micro extraction mode. The liquid phase micro-extraction conditions are optimized compared with the national standard method for textile testing. The method is simple and rapid, and shows good enrichment effect and high recovery rate.
2.3 Multi-extraction technology Various extraction techniques have their own advantages and disadvantages, and different extraction techniques are used in combination to enhance their respective advantages and improve extraction efficiency. Lu Chunhua et al. and Niu Zengyuan established a method for the determination of alkylphenol polyoxyethylene in textiles by Soxhlet extraction and solid phase extraction.
It is suitable for alkenyl ether and phthalate esters. The combination of these two extraction methods can effectively extract textiles, enrich and concentrate, and purify impurities. The method is reproducible, accurate and reliable. Ma Qiang et al. determined the combination of solvent extraction and solid phase extraction in the determination of alkylphenol ethoxylates and flame retardants in textiles. The combination of these two extraction methods is accurate, rapid and sensitive, and can be used in textiles. The actual inspection work. Chen Jun et al. studied the combination of ultrasonic and solid phase microextraction to extract free formaldehyde and volatile organic compounds in textiles. The method has a low detection limit. High recovery rate.
2.4 Outlook At present, many kinds of extraction techniques have been applied to the detection and analysis of harmful substances in textiles, but many eco-friendly extraction techniques have not been applied to the detection of harmful substances in textiles, such as cloud point extraction. Cloud point extraction is a new liquid-liquid extraction technique that has emerged in recent years. Separation of hydrophobic substances from hydrophilic substances by changing experimental parameters such as pH, ionic strength, temperature, etc. of the solution. The main advantage is that it does not use toxic and harmful organic solvents and adapts to the needs of the development of green analytical technology. It has been widely used for trace enrichment of metal ions. In the heavy metal test of textiles, the concentration of the cloud point extraction is concentrated to increase the stability of the test.
3 Conclusion Extraction technology is the key to the detection of harmful substances in textiles. With the increasingly strict requirements for harmful substances in textiles and the green and ecological detection, the new extraction technology with low efficiency and low consumption of organic solvents will become the mainstream. trend.
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