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[Preprint]. 2024 Sep 2:rs.3.rs-4947448. [Version 1] doi: 10.21203/rs.3.rs-4947448/v1

Figure 2. Mass spectra representative of Aβ peptides over multiple reagents and blocking buffers.

Figure 2

(A) MALDI-TOF mass spectra of plasma Aβ peptides replicates utilizing the PAβ V1.0 assay procedure, comparing five different buffers or detergents using single IP procedure; 10% N4PE CSF diluent (PAβ V2.0 assay), 10% SuperBlock, 10μg/ml TruBlock, 0.5% Triton100, and 0.5% Tween20. Representative spectra from each experiment are presented. Interference peaks were consistently observed at 5771.1 m/z and 7746.8 m/z across all assays. Additionally, another interference peak at 6631.0 m/z was consistently noted in all assays except the PAβ V1.0 assay. (B) Upon magnification in the range of 4000–4850 m/z, the theoretical m/z values of peptides were as follows: 4132.6 m/z for Aβ1–38, 4144.7 m/z for Aβ3–40, 4231.8 m/z for Aβ1–39, 4330.9 m/z for Aβ1–40, 4515.1 m/z for Aβ1–42, and 4689.4 m/z for APP669–711. Aβ1–38 IS at 4160.7 m/z, Aβ1–40 IS at 4383.3 m/z, and Aβ1–42 IS at 4569.3 m/z were utilized as internal standards for the normalization of mass spectra. Notably, an interference peak was detected at 4153.4 m/z in samples processed using 10% SuperBlock, 10pg/ml TruBlock, 0.5% Triton100, and 0.5% Tween20.