b'Figure 11. Pierce FlexMix Calibration Solution chromatograms. Shown are sample chromatograms in positive and negative modes.100NL: 2.62E780Relative abundance Relative abundance604020010 20 30 40 50 60 70 80 90 100 110 120Time (min)100 NL: 6.19E7 72 9 1280 5 68 1160 1 3 10 13 1440 41520010 20 30 40 50 60 70 80 90 100 110 120Time (min)Figure 12. Example chromatograms of standard and calibration solutions. Base peak chromatogram of 200 ng Thermo Scientific Pierce HeLa Protein Digest Standard separated using a Thermo Scientific Acclaim PepMap 100 3 m x 75 m x 15 cm column with a 235% gradient (buffer A: 0.1% formic acid in LCMS-grade water, buffer B: 0.1% formic acid in 100% LCM-grade acetonitrile) at 300 nL/min for 120 minutes and detected on a Thermo Scientific LTQ Orbitrap XLMass Spectrometer (top). Thermo Scientific Pierce Peptide Retention Time Calibration Mixture (10 L at 5 pmol/L, before dilution to 0.5 pmol/L) was analyzed on a Thermo Scientific Velos Pro Mass Spectrometer System using a Thermo Scientific PepMap C18 column (75 m x 15 cm) with a 230% gradient of buffer B using buffer A (0.1% formic acid) and buffer B (0.1% formic acid, 99.9% acetonitrile) at 0.3 L/min (bottom). Learn more at thermofisher.com/mscalibrationTest your protein research knowledge Question: The protease of choice for mass spec sample preparation is: A. ChymotrypsinB. Lys-CC. TrypsinD. PepsinAnswer: C98 Mass spectrometry thermofisher.com/proteinbiology'