Ionization Interference
Chemical interference alters the ionization efficiency of target analytes due to the presence of co-eluting compounds in the sample mixture. This matrix effect is a major concern when analyzing dye-treated or chemically processed wool fibers. It can suppress or enhance the signal of the peptide markers, leading to inaccurate fiber quantification.
Signal Suppression
When a mass spectrometer analyzes a garment digest, residual dyes and finishing agents can enter the ion source at the same time as the peptides. These impurities compete with the fiber proteins for ionization, reducing the peptide signal. This signal suppression makes it look like there is less of the target fiber than actually exists in the blend.
Textile Processing
Garment factories often apply synthetic softeners, water-repellent coatings, and chemical dyes that exacerbate the matrix effect. If the testing laboratory does not thoroughly clean the sample during preparation, these additives will distort the analysis. Removing these chemicals requires washing and clean-up steps before protein extraction.
Analytical Adjustment
Testing methods combat this problem by using standard addition techniques or isotopically labeled internal standards. These steps help correct for signal loss, ensuring that the measured fiber percentages remain accurate despite the presence of processing chemicals. This ensures that even heavily finished, retail-ready garments can be tested with high precision, giving the buying brand a final, reliable confirmation of fiber content before the product is distributed to retail stores.
