Fig. 4.

ESI Q-TOF-MS¹ spectra of immunodetected neutral GSLs with short-chain fatty acids from human plasma. The spectra were acquired from silica gel extracts of antibody-stained GSLs being equivalent to 104.1 mg of human plasma protein, respectively, and recorded in the positive ion mode. The immunostained chromatograms shown in the insets correspond to 17.4 mg of human plasma protein, respectively (see Fig. 1). The dotted frames indicate the lower bands of the respective antibody-detected double bands from which the silica gel extracts were prepared. A: Lc2Cer; B: Gb3Cer; C: Gb4Cer; D: nLc4Cer. ESI Q-TOF-MS¹ spectra of immunodetected neutral GSLs with long-chain fatty acids of the upper bands of the respective antibody-detected double bands are shown in supplementary Fig. I. The major [M+Na]⁺ ions of the detected neutral GSLs and their proposed structures are listed in Table 3. Unknown ions, which appeared in the spectrum of minor nLc4Cer (D) and originated most likely from the silica gel extraction procedure, are marked with asterisks and were not further analyzed.