Cashmere Adulteration and the Test Methods That Survive a Dispute
Defending a cashmere claim demands LC-MS/MS proteomic proof tied to core samples that survive ISO 17025 cross-examination across two split lots.
Peptide Biomarkers
Chemical Tracer
Unique protein fragments provide a stable molecular signature for identifying the biological origin of natural animal fibers. These compounds, termed peptide biomarkers, are generated by enzymatically digesting the keratin extracted from the textile. They are highly resistant to degradation from heat, scouring and dyeing processes.
Extraction Process
Fibers are treated with reducing agents to dissolve the keratin and break the disulfide bonds. Trypsin enzymes are added to the solution to cleave the proteins at specific amino acid sites. This reaction produces a mixture of small peptides that can be analyzed by liquid chromatography mass spectrometry.
Fiber Authentication
Laboratories use these protein fragments to detect the presence of sheep wool in declared cashmere garments. Each animal species possesses a unique amino acid sequence that yields a distinct set of peaks on the chromatogram. This method eliminates the subjectivity associated with manual fiber identification by microscopic inspection.
Technical Integrity
Accuracy depends on using reference databases that represent the genetic profiles of different animal breeds. Processing damage, such as from strong acid treatments, can modify the peptides and affect the detection limit. It is important to compare the sample against known standards to ensure correct interpretation of the mass spectra.
This comparative analysis provides a secure audit trail that is accepted by customs authorities and retail inspection bodies.