Fig. 3: Advantages of internal-standard quantification.
From: High-throughput glycosylation screening method for biologics development using MALDI-TOF-MS
a Relative-intensity profiles of the IgG N-glycans obtained after HILIC clean-up on hand-packed cotton micro-tips (blue) and on pre-packed Sepharose CL-4B plates (red). Error bars, mean ± SD (n = 3). b Calibration of the reduced internal standard. The signal ratio (S/I) plotted against the amount of G0F added gives a linear fit over 0.05–1.7 (R² = 0.9998). c Fold-change in glycan abundance after spiking the sample with G0F, calculated by the internal-standard workflow. Only the spiked G0F increases (left bar); all other glycans remain essentially unchanged. d The same dataset processed without internal standard. Although G0F still rises, every other glycan appears to fall, illustrating the systematic bias introduced when an internal standard is not used.
