Abstract
Ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS) enables simultaneous identification and quantification of beta-casomorphine 5 (β-CM5) and beta-casomorphin 7 (β-CM7) at the level of ng/mL in milk. This analytical technique uses stable isotope-labeled beta-casomorphin 5 (β-CM5-d10) and beta-casomorphin 7 (β-CM7-d10) to achieve accurate quantitation of target peptides. In addition, solid-phase extraction (SPE) can be used for concentration and purification of milk extracts to improve the limits of detection and quantitation of the method.