Application of extraction technology in the detection of harmful substances in textiles
In recent years, the ecological requirements of textiles have attracted much attention, the testing requirements have become more stringent, and the requirements for testing capabilities have also increased. Extraction is the main process in the detection process of harmful substances. Currently commonly used solvent extraction techniques include Soxhlet extraction, ultrasonic extraction, microwave extraction and accelerated solvent extraction, etc., and new extraction techniques include solid phase extraction, solid phase micro extraction and liquid phase micro extraction And the multi-component extraction technology based on various extraction technologies includes Soxhlet-solid phase extraction, accelerated solvent-solid phase extraction and ultrasonic-solid phase microextraction.
This article reviews the extraction techniques used in the analysis of hazardous substances in textiles, and looks forward to more environmentally friendly and ecological extraction techniques.
2 Application of extraction technology in the detection of harmful substances in textiles 2.1 Solvent extraction technology Solvent extraction techniques such as Soxhlet extraction, ultrasonic extraction, etc. occupy an important position in the detection of harmful substances in textiles.
Soxhlet extraction is a simple and practical classic extraction technique. Zhang Weiya and others use Soxhlet extraction to extract residual alkylphenols and alkylphenol polyoxyethylene ethers 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 using Soxhlet extraction.
Ultrasonic extraction is the most used extraction technology, and various harmful substances can be pretreated with 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 used ultrasonic extraction to separately extract organotin compounds, chlorophenols, o-phenylphenol, and perfluorinated compounds from textiles. The detection limits and recovery rates were all under standard requirements. The extraction of pesticides in textiles mainly uses ultrasonic extraction, and Zhang Xiang and Wang Mingtai use ultrasonic extraction to extract pesticide residues in textiles.
The microwave extraction method is a combination of microwave technology and extraction technology. It uses microwave to improve the extraction efficiency during the extraction process. Wang Chengyun et al. Used microwave-assisted extraction to extract residual octylphenol, nonylphenol, octylphenol polyoxyethylene ether, and nonylphenol polyoxyethylene ether in textiles with a high recovery rate. Shao Chaoying et al. Established a microwave-assisted extraction method for polybrominated diphenyl ether flame retardants. Through microwave-assisted extraction orthogonal experiment, the microwave extraction conditions were determined. The detection limit of the method is low, the standard addition recovery rate is high, and it is suitable for many traces in textiles.
Detection and analysis of brominated biphenyl (ether) flame retardants.
Accelerated solvent extraction technology is a brand-new extraction method proposed by Richter et al. In 1995, which uses a conventional solvent, a novel sample preparation method for extracting solid or semi-solid with a solvent at a higher temperature and pressure, using The increased temperature and pressure increase the solubility of substances and the diffusion efficiency of solutes, and improve the extraction efficiency. Yu Luoping et al. Adopted the accelerated solvent extraction method to extract PFOS and PFOS in textile samples in response to international limits on PFOS and PFOS in textiles. The minimum detection limit, linear range and method recovery rate of this method Can meet the requirements.
2.2 New extraction technology Solvent extraction technology requires the use of large amounts 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, low consumption of organic solvents is one of the requirements for the continuous development of extraction technology. In recent years, a variety of new sample extraction technologies have been developed, such as solid phase extraction, Solid phase microextraction, liquid phase microextraction, etc.
Solid phase extraction is a sample pretreatment technology based on liquid-solid separation and extraction. The process of solid phase extraction is essentially a column chromatography separation process, which uses a solid adsorbent to adsorb the target compound and the matrix and interfering compounds in the liquid sample. To separate and enrich target compounds. Ma Qiang et al. Established an analytical method for the migration of textile alkylphenols. Quantitative analysis of textile soaking solution after purification by solid phase extraction column. Niu Zengyuan and others studied the migration of phthalate ester environmental hormones in artificial sweat in textiles, and determined the best conditions for solid phase extraction to concentrate and enrich the phthalate compounds in the extract of artificial sweat.
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 sample injection. The theory of SPME is based on the different partition coefficient of the analyte between the sample matrix and the extraction medium (coating). The amount should remain unchanged. After the extraction layer is determined, the amount of analyte adsorbed by the coating is linear with the initial concentration of the substance in the sample. This is the theoretical basis for quantitative analysis using SPME. Among them, the headspace solid phase microextraction method is used to determine highly volatile substances; the direct solid phase microextraction method is suitable for determination of low volatile substances. Zhang Zhuoyu et al., Gao Lirong et al., Nie Fengming et al. Used headspace solid-phase microextraction to determine volatile organic compounds (VOCs) in textiles. The extraction conditions of SPME are optimized, including the selection of extraction head, equilibration time, extraction time, extraction temperature, headspace volume, ionic strength, stirring speed, desorption temperature and time, which meet the requirements for rapid analysis of trace VOCs in textiles. Liu Ying and others used solid-phase microextraction headspace sampling technology and gas chromatography to analyze abnormal odors in textiles. Wang Li et al. Used solid-phase microextraction to adsorb and enrich organophosphorus pesticides in textiles, and performed qualitative and quantitative detection after thermal desorption at the gas chromatography-mass spectrometry inlet. It can be used for rapid detection of substances in ecological textiles.
Liquid phase microextraction was first proposed by Jeannot in 1996 as 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 nano-upgraded organic solvents for extraction. It adapts to the requirements of the miniaturization of modern analytical science and is an environmentally friendly "green" analytical technology. The basic principle of the technology is based on the distribution balance between the sample and the extraction solvent of micro-upgrade or even nano-upgrade, that is, the micro-droplet solvent is placed in the stirred or flowing solution to achieve micro-extraction of solute. Liquid phase microextraction includes direct submerged liquid phase microextraction, headspace liquid phase microextraction, hollow fiber membrane liquid phase microextraction, and flowing liquid phase microextraction. Zhang Hui et al. Used liquid-phase microextraction using ionic liquid as the extractant to improve the textile sample preparation method in the national standard method for textile testing (GB / T 17592-2006), and established azo dyes derived from textile A new method of extracting aromatic amines. The extraction effects of direct immersion microextraction and solvent stick microextraction were compared, and it was determined that solvent stick microextraction was the microextraction mode. Compared with the national standard method of textile testing, the liquid-phase microextraction conditions are optimized. The method is simple and fast, and shows good enrichment effect and high recovery rate.
2.3 Multiple extraction techniques Various extraction techniques have their own advantages and disadvantages, and the combined use of different extraction techniques strengthens their respective advantages and improves extraction efficiency. Lv Chunhua et al. And Niu Zengyuan established the method of combining Soxhlet extraction and solid phase extraction to determine alkylphenol polyoxyethylene in textiles
It is suitable for allyl ether and phthalate esters. The combination of these two extraction methods can effectively extract textiles, enrich and concentrate, and purify impurities. This method has good reproducibility, accuracy and reliability. Ma Qiang et al. Used a combination of accelerated solvent extraction and solid phase extraction to determine the alkylphenol polyoxyethylene ether and flame retardant in textiles. Using these two extraction methods combined, the detection is accurate and fast, and the sensitivity is high. It can be used in textiles Actual inspection work. Chen Jun et al. Studied the method for extracting free formaldehyde and volatile organic compounds in textiles by combining ultrasound and solid-phase microextraction. The detection limit of this method is low. High recovery rate.
2.4 Looking forward At present, there are many kinds of extraction technologies applied to the detection and analysis of hazardous substances in textiles, but there are still many ecological and environmentally friendly extraction techniques that are not applied to the detection of hazardous substances in textiles, such as cloud point extraction. Cloud point extraction is an emerging liquid-liquid extraction technology that has emerged in recent years. It induces phase separation by changing the experimental parameters such as the pH value, ionic strength, and temperature of the solution to separate hydrophobic and hydrophilic substances. The main advantage is that it does not use toxic and harmful organic solvents, which meets the needs of the development of green analysis technology. It has been widely used in trace enrichment of metal ions. In the testing of heavy metals in textiles, the use of cloud point extraction to enrich to a certain concentration can increase the stability of the detection.
3 Conclusion Extraction technology is the key to the detection of hazardous substances in textiles. With the increasingly strict requirements for textile hazardous substances and the green and ecological detection, fast and efficient extraction techniques with low consumption of organic solvents will become the mainstream trend.
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