Proteomic Identification Basics for Animal Fiber Blends
Proteomic mass spectrometry isolates species-specific keratin peptides to quantify animal fiber blend ratios precisely despite chemical or physical scale damage.
Isotope Labeled Standards
Calibration Material
Synthetic peptides containing heavy stable isotopes of carbon or nitrogen are used to achieve absolute quantification in complex protein mixtures. Using isotope labeled standards allows the mass spectrometer to distinguish between the native peptides of the textile sample and the added internal control. These standards are identical in chemical behavior to the natural peptides but show a distinct mass shift during mass analysis.
This separation allows precise calculation of protein concentration based on the ratio of light to heavy signal intensities.
Laboratory Assay
Textile laboratories add known quantities of these synthetic molecules to the digested wool sample prior to chromatographic separation. The mass spectrometer monitors both the endogenous peptide and the corresponding isotope labeled standards simultaneously. By comparing the peak area ratios of the two signals, the absolute concentration of cashmere or sheep wool is determined.
Quality Control
Reagent purity represents the primary parameter for quantitative accuracy. Chemical synthesis must ensure that the heavy peptide contains at least ninety-nine percent of the heavy isotope. Poor isotope incorporation introduces measurement bias into the final composition calculation.
Standard Scope
Storage conditions must prevent hydrolytic degradation. Peptides are kept frozen in aliquots. Repeated freeze-thaw cycles must be avoided.