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. Author manuscript; available in PMC: 2022 Mar 1.
Published in final edited form as: Analyst. 2021 Nov 8;146(22):6780–6787. doi: 10.1039/d1an01132d

Figure 5.

Figure 5.

Stability of cocaine in (A) dried plasma, (B) dried serum, and (C) dried blood spheroid on hydrophilic paper and hydrophobic paper substrates. Cocaine-d3 was used as internal standard (IS). The ratio of analyte (A) signal (transition, m/z 304 → 182) to IS (transition, m/z 307 → 185) signal (A/IS) was monitored for 15 days and was normalized to A/IS derived from day zero (0). The inset depicts dried plasma, serum, and whole blood 3D morphologies (top-down) on hydrophobic paper substrate.