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. 2024 Aug 28;9:155. doi: 10.1038/s41541-024-00946-5

Fig. 3. Schema showing samples and a pooled quality control (QC) sample being spotted onto a matrix-assisted laser desorption/ionisation (MALDI) target.

Fig. 3

A pooled QC sample was prepared from the vaccines and falsified samples. An Assist Plus robot was used to combine the matrix with each sample in a 1:1 (V/V) ratio and then spot onto the MALDI plate. Only the QC and first three samples are illustrated, but all four authentic vaccines and eight falsified constituent samples were prepared in the same way across multiple MALDI plates which were analysed in a random sequence within the MALDI instruments. CHCA: α-cyano-4-hydroxycinnamic acid; MALDI-MS: matrix-assisted laser desorption/ionisation-mass spectrometry. This figure was created using BioRender.com.