Mass Spectrometry SRM Calibration Protocols for Cashmere Wool Blends
Selected reaction monitoring mass spectrometry quantifies cashmere wool blends down to one percent using species-specific tryptic keratin peptides.
Precursor Product Transition
Ion Selection
Triple quadrupole mass spectrometers utilize a sequence of ion selection and fragmentation to monitor specific target molecules with high selectivity. This process relies on a defined precursor product transition where a specific parent peptide ion is selected in the first analyzer, fragmented in the second, and its unique fragment ions are detected in the third. By focusing on these specific ion transformations, the spectrometer can filter out background interference.
Targeted Monitoring
Selecting a unique precursor product transition for each species-specific peptide ensures the accuracy of quantitative fiber tests. In cashmere and wool analysis, this transition must be highly specific to avoid false positives. This target setup allows the instrument to operate in multiple reaction monitoring mode for rapid sample screening.
Fiber Quantification
Integrating the peak area generated by the detected fragment ions yields a value proportional to the peptide concentration in the sample digest. If the precursor product transition is chosen correctly, the signal strength directly corresponds to the amount of goat or sheep fiber. This measurement provides the basis for calculating the total fiber ratio.
Quality Validation
Industrial testing laboratories depend on these transitions to produce clear, legally defensible certificates of fiber composition. The use of a robust precursor product transition ensures that the results are reproducible across different instruments and different laboratories. When the fiber ratios are confirmed, apparel brands can confidently release the tested batch of apparel for distribution.
This systematic verification ensures that premium textiles meet both regulatory standards and customer expectations.