Determining Raw Cashmere Fiber Diameter and Composition Tolerances
Raw cashmere verification requires coupling OFDA diameter distribution limits with MALDI-TOF mass spectrometry to prevent low-micron wool substitution.
Quantitative PCR
Genomic Quantification
Molecular amplification techniques based on real-time tracking of fluorescent reporter dyes measure target deoxyribonucleic acid sequences throughout exponential reaction phases. In commercial fibre authenticity testing, quantitative PCR identifies and quantifies species-specific genomic fragments within raw animal hair, processed yarns, and finished fabrics. The method isolates target DNA strands, amplifying sequence copies to verify true biological origin against declared textile compositions.
The scope spans natural protein and plant fibres containing intact cellular debris, ceasing to function when processing chemicals, intense bleaching, or high thermal history completely destroy residual genetic chains.
Amplification Dynamics
DNA extraction protocols break down protein cuticles and nuclear envelopes to liberate residual cellular material from raw fleece or textile fragments. Primers bind specifically to designated species sequences, such as specific mitochondrial or nuclear DNA segments differentiating sheep wool from cashmere goat hair. Polymerase enzymes replicate target fragments through thermal cycling between denaturation, annealing, and extension stages.
Intercalating fluorescent dyes or sequence-specific probes emit luminescence directly proportional to accumulated DNA copy volume. Optical sensors capture this fluorescence at the end of each cycle, establishing a cycle threshold value where signal lifts clearly above baseline noise.
Quantification Validation
Technicians generate standard calibration curves using reference DNA extracts prepared from authentic, certified single-source animal hair standards. Cycle threshold values from commercial test specimens are plotted against these curves to determine the precise initial template mass of each targeted fibre species. Negative controls containing no template run alongside active samples to confirm that reagent sets remain free of cross-contamination.
Extremely high cycle threshold values indicate extensive thermal or chemical DNA degradation, rendering quantitative conclusions unreliable.
Market Enforcement
Customs authorities and luxury brand verification desks deploy quantitative PCR to detect cashmere adulteration by cheaper sheep wool or yak fibres. Conventional optical microscopy often fails to distinguish damaged or chemically altered wool cuticles from genuine cashmere scales, making molecular verification necessary. Test certificates documenting species DNA ratios expose blended fraud in premium worsted suiting fabrics and knitwear lots.
Mills that treat blended fibres with heavy oxidizing agents face test invalidation, leading buyers to reject shipments where DNA damage prevents clear species confirmation.