Mass spectrometry of synthetic CXCL11. NH₂-terminally truncated CXCL11 proteins were chemically synthesized, purified, and folded. The folded CXCL11(1-73), CXCL11(3-73), CXCL11(5-73), and CXCL11(7-73) proteins were repurified by RP-HPLC and the M_r was verified by ion-trap mass spectrometry. Spectra are averaged deconvolution spectra of the RP-HPLC fractions that were pooled for use in biochemical and biologic assays.