Proteomic Target
High-resolution proteomic analysis relies on specific amino acid sequences within fiber proteins to identify true biological sources in blended textile products. In wool and hair identification, species marker peptides act as molecular fingerprints that distinguish costly cashmere or camel hair from domestic sheep wool and synthetic substitutes. These unique peptide fragments remain stable through commercial scouring, dyeing, and finishing operations.
Their analytical scope covers animal fiber identification in raw stock, yarns, or garments, but cannot differentiate fiber geographical origins.
Mass Spectrometry
Laboratory technicians digest extracted fiber keratin using trypsin enzymes, which cleave the protein chains at specific lysine and arginine sites. The resulting peptide mixture enters a liquid chromatography-mass spectrometry instrument, which measures the exact mass-to-charge ratio of individual fragments. Advanced software matches the detected ion spectra against reference databases containing known keratin sequences for goats, sheep, yaks, and camels.
Because specific peptide sequences exist exclusively in cashmere keratin, their presence confirms genuine goat hair content even in heavily processed or dyed fabrics. Quantitative algorithms calculate the relative signal intensity of these unique markers to determine exact blend percentages by weight.
Composition Verification
Commercial buyers rely on peptide identification to enforce labeling compliance under international textile labeling acts. The method exposes fraudulent substitution of sheep wool or yak fiber in premium cashmere knitwear.
Detection Floor
Chemical degradation from severe bleaching or strip-dyeing destroys peptide chains, limiting identification accuracy in recycled or damaged textiles. Laboratories report inconclusive results when thermal or chemical processing destroys the target amino acid sequences beyond recognition.
