Eco-textile Testing

Ecological textile testing mainly conducts scientific testing and analysis on prohibited azo dyes testing, formaldehyde content testing, heavy metal content testing, pH value testing, pesticide residue testing and chlorinated phenols, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Prohibited azo dyes testing: Tests whether the textile contains azo dyes that may be reductively decomposed to release 24 carcinogenic aromatic amines. These amines are absorbed by the human body through skin contact, and are the core monitoring indicators of textile safety. Gas chromatography-mass spectrometry (GC-MS) is usually adopted for qualitative and quantitative analysis.

Formaldehyde content testing: Determines the amount of free and partially hydrolysed formaldehyde in the textile. Formaldehyde is commonly used for anti-wrinkle and anti-shrinkage finishing, but excessive residues will irritate the skin and mucous membranes, and may even induce cancer. The main test methods are the water extraction method or the steam absorption method, using a UV-visible spectrophotometer to measure the absorbance.

Heavy metal content testing: Tests the extractable heavy metals such as antimony, arsenic, lead, cadmium, chromium, cobalt, copper, nickel and mercury. These elements may come from dyes, catalysts or processing aids, and can cause cumulative toxicity to the human body through skin contact or saliva migration. Inductively coupled plasma optical emission spectrometry (ICP-OES) or mass spectrometry (ICP-MS) is mainly used for testing.

pH value testing: Measures the acidity and alkalinity of the aqueous extract of the textile. The surface of human skin is weakly acidic. If the pH value of the textile deviates from the neutral range (usually required to be 4.0-7.5 or 4.0-8.5), it may destroy the protective layer of the skin and cause allergies or infections. The testing is carried out in accordance with the standard ISO 3071, using a pH meter for determination.

Pesticide residue testing: Tests the residues of pesticides such as organochlorines and organophosphates that may be used during the planting of natural fibres such as cotton. These residues are toxic, bioaccumulative and environmentally persistent. The main test method is organic solvent extraction, combined with gas chromatography-mass spectrometry (GC-MS) for analysis.

Chlorinated phenols (PCP/TeCP) testing: Tests the residues of preservatives and mildew inhibitors such as pentachlorophenol (PCP) and tetrachlorophenol (TeCP). They were historically used for the antibacterial treatment of textiles and leather, but have been strictly restricted due to their high toxicity and environmental hazards. Gas chromatography-electron capture detector (GC-ECD) or gas chromatography-mass spectrometry is usually adopted for detection.

Phthalates (plasticizers) testing: Determines the phthalate plasticizers (such as DEHP, DBP and BBP) that may be added in the coatings, prints or synthetic leather of textiles. This type of substance is classified as an endocrine disruptor, and poses a particular risk to the health of children. The testing mostly adopts solvent extraction followed by analysis with gas chromatography-mass spectrometry (GC-MS).

Sensitizing disperse dyes testing: Screens 21 specific disperse dyes in the textile that may cause allergic contact dermatitis of the skin. These dyes are mainly used for dyeing synthetic fibres such as polyester, and migrate to the skin through perspiration. The test methods are usually liquid chromatography-mass spectrometry (LC-MS) or high-performance liquid chromatography (HPLC).

Testing Scope

Various fibres and yarns: Including natural fibres such as cotton, linen, wool and silk, synthetic fibres such as polyester, nylon and acrylic, and raw materials and semi-finished products of regenerated fibres such as viscose and lyocell. The pesticide residues, heavy metal background contents and hazardous chemical pollution of their raw materials need to be tested.

Various fabrics and materials: Covering woven fabrics, knitted fabrics, nonwovens and various composite fabrics. The testing focus is on the chemicals introduced in the finishing process such as formaldehyde, azo dyes, abnormal pH value, flame retardants and waterproofing agents, as well as the residues brought by the dyeing and printing processes.

Garments and apparel products: Including all garments that directly or indirectly contact the skin, such as underwear, outerwear, children's clothing and sportswear. This is the core field of ecological testing, and requires a comprehensive evaluation of the prohibited substances, colour fastness, odour and physical safety (such as the cords and small parts of children's clothing).

Home textiles: Involving bedding (sheets and quilt covers), towels, curtains, carpets and tablecloths. In addition to the chemical safety indicators, attention also needs to be paid to their colour fastness to perspiration and rubbing, and the safety of the fillings (such as the cleanliness and microbial indicators of down).

Special function textiles: Such as products claiming to have functions such as flame retardancy, waterproofness, oil repellency, stain resistance, antibacterial and UV resistance. Their functionality needs to be verified, and the key is to test whether the chemical auxiliaries used to realize these functions (such as PFAS perfluorinated compounds, halogenated flame retardants and triclosan) meet the ecological requirements.

Leather and fur products: Leather garments, leather shoes, leather bags and so on. In addition to covering the general indicators of textiles, the testing items particularly focus on hexavalent chromium, short-chain chlorinated paraffins (SCCPs), formaldehyde, and the hazardous substances in the dyes and tanning agents specific to leather processing.

Infant products and toy textiles: Including baby clothes, sleeping bags, diapers, comfort blankets and fabric toys. The ecological requirements for this type of product are the most stringent, the testing limits are lower, and mandatory testing of the colour fastness to saliva and perspiration, flammability and specific phthalates is added.

Testing Methods

Gas chromatography-mass spectrometry (GC-MS): Used to detect volatile and semi-volatile organic compounds. It is the core method for analysing the aromatic amines released by prohibited azo dyes, organochlorine pesticides, polychlorinated biphenyls (PCBs), some phthalates and chlorinated phenols. After the pretreatment of the sample, chromatographic separation is carried out, and mass spectrometry performs qualitative and quantitative analysis with high sensitivity and selectivity.

High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS/MS): Suitable for the analysis of organic compounds that are not easily volatile, thermally unstable or of large molecular weight. It is mainly used to detect sensitizing disperse dyes, some basic or acid dyes, perfluorinated compounds (PFCs), and certain pesticides and biocides.

Inductively coupled plasma mass spectrometry (ICP-MS): Used for the analysis of trace and ultra-trace heavy metal elements. It has the advantages of an extremely low detection limit, a wide linear range and the simultaneous analysis of multiple elements, and is one of the most advanced and sensitive technical means for detecting the extractable heavy metals (such as lead, cadmium, arsenic and mercury) in textiles.

UV-visible spectrophotometry (UV-Vis): A classic optical analysis method. In ecological textile testing, it is mainly used for the determination of the formaldehyde content (acetylacetone method) and the qualitative screening of some specific dyes. This method has popular equipment and simple operation, but relatively poor selectivity.

Atomic absorption spectrometry (AAS): Used to determine the content of specific metal elements. It includes the flame atomic absorption method (FAAS) and the graphite furnace atomic absorption method (GFAAS), and the latter has higher sensitivity. It can be used to detect the extractable heavy metals such as antimony, chromium and nickel in textiles, and is an important supplement to ICP-MS.

Ion chromatography (IC): Used to separate and determine the ionic substances in the sample. In ecological testing, it can be applied to the determination of the hexavalent chromium (Cr(VI)) content. After the extraction of the sample, the hexavalent chromium ions are separated in the chromatographic column and quantitatively analysed by the detector.

Biological test methods: Including in vitro biological methods such as cytotoxicity tests, skin irritation tests and sensitization tests. They are used to comprehensively evaluate the biocompatibility of textiles, assess the influence of their extracts on living cells or tissues, and serve as an important supplement to chemical testing, especially suitable for the evaluation of new materials and unknown risks.

Testing Standards

Domestic Standards:

1. GB 18401-2010, National general safety technical code for textile products

2. GB/T 18885-2009, Ecological textiles — Technical requirements

3. GB/T 3920-2024, Textiles — Tests for colour fastness — Colour fastness to rubbing

4. GB/T 3921-2008, Textiles — Tests for colour fastness — Colour fastness to washing with soap or soap and soda

5. GB/T 3922-2013, Textiles — Tests for colour fastness — Colour fastness to perspiration

International Standards:

1. ISO 3071, Textiles — Determination of pH of aqueous extract

2. ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method

3. ISO 105, Textiles — Tests for colour fastness

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Gas chromatography-mass spectrometer (GC-MS): Composed of a gas chromatography unit and a mass spectrometry detector, and is the "main force" equipment for the organic pollutant analysis of ecological textiles. Equipped with an automatic sampler, chromatographic columns of different types (such as weakly polar capillary columns) and a powerful spectral library, it can realize the precise screening and confirmation of multiple hazardous substances in complex matrices.

Inductively coupled plasma mass spectrometer (ICP-MS): High-end equipment for ultra-trace element analysis. The sample solution is nebulized and enters the high-temperature plasma to be ionized, and the ions are separated and detected by mass spectrometry. It has a detection capability at the ppt (parts per trillion) level, and is the key equipment for meeting the heavy metal limit requirements of strict standards such as Oeko-Tex Standard 100.

High-performance liquid chromatograph (HPLC) and liquid chromatography-tandem mass spectrometer (LC-MS/MS): The HPLC is equipped with UV, fluorescence or diode array detectors for the conventional analysis of dyes and additives. The LC-MS/MS adopts a triple quadrupole mass spectrometer, and through the multiple reaction monitoring (MRM) mode, quantitatively determines the target substances with high selectivity in complex backgrounds, with extremely high sensitivity and accuracy.

UV-visible spectrophotometer: An instrument for measuring the absorption of ultraviolet and visible light by substances. It is indispensable in standard methods such as the formaldehyde content determination. Modern models are usually equipped with a constant temperature cuvette holder, automatic scanning function and data processing software, ensuring a stable detection process and accurate results.

pH meter and conductivity meter: Used to detect the pH value and conductivity of the aqueous extract of textiles. The pH meter needs to be equipped with a composite electrode and regularly calibrated with standard buffer solutions. The conductivity meter is used to evaluate the total amount of soluble salts in the textile, and is an important indicator for evaluating whether the washing of the processing process is thorough.

Atomic absorption spectrometer (AAS): Including two atomization systems, flame and graphite furnace. The equipment is configured with corresponding hollow cathode lamps (each element corresponds to a specific lamp) for the determination of specific metal elements. The graphite furnace atomic absorption method has high sensitivity and can directly analyse trace elements, but the analysis speed is relatively slow.

Sample pretreatment equipment: This is the basis for ensuring the testing accuracy, including Soxhlet extractors, ultrasonic extraction instruments, microwave digestion/extraction instruments, solid-phase extraction (SPE) devices, nitrogen blowing concentrators and shaking water baths. Efficient sample pretreatment equipment can improve the extraction efficiency, reduce human errors and shorten the analysis time.

Colour fastness testers: A series of dedicated instruments, such as rubbing fastness testing machines, perspiration fastness testers, washing fastness testing machines and light fastness testers (xenon arc lamps). They are used to simulate and evaluate the ability of the textile colour to resist the action of various factors during use, and are an important part of the physical safety evaluation of ecological textiles.