GB/T 41671-2022 in English

This standard specifies a system of detection methods for 9 types of organic/inorganic solvent residues in solution-spun chemical fibers, including:

• 4 types of chromatographic detection techniques: GC-MS, LC-MS/MS, headspace gas chromatography, spectrophotometry
• 2 types of titration methods: complexometric titration (sodium thiocyanate), acid-base titration (concentrated sulfuric acid)
• 7 key organic solvents: DMF, DMAC, DMSO, NMP, etc. (see Appendix A)

1. Sample pretreatment

Different methods use different extraction schemes:

• Organic solvent: 70℃ methanol ultrasonic extraction for 60min (GC-MS)
• NMMO system: room temperature water extraction (LC-MS/MS)
• Ultra-high molecular weight polyethylene fiber: n-hexane Soxhlet extraction (Appendix C)

2. Instrument parameter optimization

The standard provides key parameter reference:

• GC-MS: DB-WAX column, 50-250℃ programmed temperature
• LC-MS/MS: C18 column, acetonitrile-0.1% formic acid water gradient elution

1. Method selection: Prioritize the fiber-solvent correspondence table in Appendix D
2. Quality control: Each batch of samples needs to be subjected to a blank test and spike recovery
3. Data verification: When the difference between the spectrophotometric method and the GC-MS result is greater than 20%, the GC-MS shall prevail
4. Special treatment: The detection of decalin needs to distinguish between cis/trans isomers (see clause 5.5)

This standard integrates the original industry detection methods (such as FZ/T 50057-2016), major technological breakthroughs:

• New LC-MS/MS method for detecting NMMO decomposition products
• Specified for the first time a dedicated test scheme for ultra-high molecular weight polyethylene fibers (Appendix B/C)
• Unified calculation methods for residual solvent limits for various types of fibers