Sample Plates 1 mm diameter Ability to load 1µl sample and matrix Application: Enhanced sensitivity by concentrating sample; useful in high throughput methods
Advanced Sample Preparation Voyager Training Class
Sample Dilution/Concentration Note: highly dilute samples can be concentrated by Speed- Vac or Solid Phase Extraction. Compound Concentration 0.1 to 10 pmol/µL 10 to 100 pmol/µL Peptides and proteins Oligonucleotides Polymers 100 pmol/µL Dilute samples to the concentrations shown in the table below. If the sample concentration is unknown a dilution series may be needed to produce a good spot on the MALDI plate.
Drop dialysis cleanup of Enolase Yeast Enolase (47 kDa) in 8 M urea was dialyzed for 1 hr on a Millipore membrane. After Before
ConditionCondition the ZipTip with 10 µl of acetonitrile (ACN), then 10 µl of 50% ACN/0.1% TFA, then 2 x 10 µl of 0.1% TFA. LoadLoad the sample onto the ZipTip by pipetting 5-10 µl sample up and down several times and discarding the liquid. WashWash C 18 tip with 3 x 10 µl of 0.1% TFA to remove salts. EluteElute the sample from the ZipTip with 30-70% ACN or elute directly into the matrix (e.g. CHCA in 50% ACN/0.1%TFA); minimal volume of ~3 µl can be used. Procedure for using C 18 ZipTips
Use of the C 18 ZipTip 1.Sample Concentration and Buffer Removal Dilute samples can be concentrated by adsorbing analyte from multiple 10 l aliquots into the ZipTip and eluting out into a small volume, effecting a 10- to 50-fold concentration. Mild conditions (e.g. 0.1% TFA) will retain peptides and proteins on a ZipTip but remove common buffers and salts such as: 2M NaCl, 100mM Phosphate, 8M Urea, 6M Guanidine or 50% Glycerol For more detailed information on ZipTips, click hereclick here
C 18 Efficiently Removes digestion Buffer Counts Mass (m/z) C18 Prep in PBS/Urea/NaCl Standard Prep in PBS/Urea/NaCl Analysis of a peptide map of IgG HC digest containing phosphate, NaCl, urea and DTT at 0.1 mg/ml digested with endo Lys C.
In-Gel Digest Fundamentals Handling the gel and slices Washing and destaining Enzymatic Digestion Peptide Extraction Concentration/Cleanup MALDI-TOF Analysis
In-Gel Digest Method MALDI-TOF Analysis Acquire a good spectrum in reflector mode with a method optimized for high resolution in Da range. Calibrate with internal Trypsin peaks T7 ( ) and T4 ( ) if present, otherwise use close external calibration. Alternatively, samples can be spiked with dilute Cal Mix 1 or 2 (approx. 1:500 in the matrix) for internal calibration. Finally, samples can be internally re-calibrated with known peak masses from a good Protein Prospector MS-Fit hit. If spectrum is poor due to contaminants or low peptide concentration try cleanup and/or concentration of the remaining sample with ZipTip C 18