Fig. 4
From: Development of a rapid and specific MALDI-TOF mass spectrometric assay for SARS-CoV-2 detection
Discrimination of SARS-CoV-2 “Delta Variant” from other Viral Strains. (A) MRM chromatogram of a SARS-CoV-2-positive patient sample with selected transitions for peptide B (NPANNAAIVLQLPQGTTLPK), peptide C (AYNVTQAFGR, and peptide D (ADETQALPQR). (B) MRM chromatogram of a SARS-CoV-2-positive sample with selected transitions for peptides B and C. (C) MALDI-TOF mass spectra of SARS-CoV-2 strain B.1.1.529 “omicron variant” (black) and SARS-CoV-2 strain B.1.617.2 “delta variant” (blue) from nasopharyngeal samples. Peptide D (ADETQALPQR), peptide Dext(KADETQALPQR), peptide D(D377Y) (AYETQALPQR), and peptide D(D377Y)ext(KAYETQALPQR) are highlighted. Peptides A (GQGVPINTNSSPDDQIGYYR), Aext(GQGVPINTNSSPDDQIGYYRR), and isotope-labeled peptide SIL-A (GQGVPINTNSSPDDQIGYYR*) are visible in both samples