Fig. 2From: The rapid detection of procalcitonin in septic serum using immunoaffinity MALDI chipsA MALDI-TOF MS spectra of in-situ enriched recombinant PCT (140Â ng/mL) concentrated by acetonitrile (solid line) and without concentration treatment (dashed line). B Relative intensities of singly and doubly charged ions at different concentrations of recombinant PCT. The PCT concentrations are 5; 10; 50; 100; 500; 1000Â ng/mL The numbers represent S/N ratios for singly (black) and doubly (red) charged ionsBack to article page