Standardizing Trypsin Digestion Parameters for Cashmere Identification
Standardized trypsin digestion at pH 8.2 and thirty-seven degrees for sixteen hours yields diagnostic peptides separating cashmere from wool by liquid chromatography.
Proteomic Screening
Analytical Test
Protein analysis of animal fibers provides a highly accurate method for identifying the specific species of animal from which the fiber was harvested. Utilizing proteomic screening allows testing laboratories to detect cashmere blended with cheaper sheep’s wool or yak hair. This method ensures the authenticity of luxury textiles and protects the integrity of the supply chain.
Methodology Step
Extraction of proteins from the fiber sample involves chemical dissolution followed by enzymatic digestion to break the proteins into peptides. In proteomic screening, mass spectrometry then analyzes the peptide mixture to create a unique fingerprint of the fiber. This fingerprint is compared to a database of known animal proteins to identify the source.
The process is highly automated.
Commercial Verification
Retailers and brands use these laboratory results to verify fiber content declarations before accepting shipments of high-value soft goods. Because proteomic screening can distinguish closely related species, it is a preferred method for auditing cashmere and mohair claims. Independent testing laboratories execute these screens on representative samples taken from bulk shipments.
These audits protect the brand.
Scientific Constraint
Chemically damaged fibers or those subjected to intense bleaching and dyeing can have degraded proteins, which reduces the accuracy of the mass spectrometry results. When proteomic screening is applied to highly processed or recycled fibers, the damaged proteins may fail to yield a clear peptide map. In such instances, the test results may be inconclusive, requiring supplementary microscopic evaluation to confirm the fiber blend.
Despite these limitations, the method remains the most reliable defense against fraud in the luxury fiber market. Brands rely on it to ensure quality.