MALDI-TOF-MS spectra of spiked and nonspiked urine samples after PEP extraction, elution, and combination with CCA matrix. Assignment of peaks: 1, thiamine; 2, TD3; 3, O-octanolycarnitine; 4, OCD3; 5, nonanoylcarnitine; 6, decatrienoylcarnitine; 7, 9-decenolycarnitine; 8, decanolycarnitine. A. Spectrum from a urine that was spiked with 400 nmol each of TD3, OCD3, and reserpine. B. Similar spectrum where a second spike of 140 fmol per spot of thiamine, OCD3 and reserpine was done just prior to MALDI-TOF-MS analysis. Inset: spectrum from a blank urine, lacking peaks for TD3 and OCD3. (Note: data for reserpine is shown in Figure 11.)