Since the mid-1990's, custom peptides have routinely come with several forms of quality control data: mass determination, to insure that the mass of the peptide manufactured is correct, and an HPLC purity check. Many of these same companies guarantee that your peptide was made correctly, but they have no direct sequencing evidence to back this up. Researchers starting expensive or time-sensitive experiments were therefore at the mercy of their custom peptide and antibody supplier: their guarantee would require that you either take their word for it or pay for sequencing to be performed. Although most peptides are properly made, human error can occur at many steps: preparing the amino acids, entering the sequence, placing the amino acids in the proper location, to name just a few. Our goal is to eliminate this error and provide you with all of the QC data required to demonstrate that the mass, purity, and sequence are correct.
21st Century Biochemicals is proud to now offer MS CheckT, peptide sequence confirmation, for our custom peptide and antibody customers. We have invested in state of the art mass spectrometers, including the QSTART XL Pro, that allows us to perform peptide sequencing via CID MS/MS accurate to 10 ppm! This service is provided free of charge for all peptides that are ordered at the 10+mg size, 90% purity or higher and is provided free of charge for all custom antibodies. An example of the data provided by MS CheckT is shown below.
Computerized analysis matches the peaks shown to specific b and y ions, that in turn correspond to each amino acid residue. This data provides an exact map of the peptide's primary sequence, thus confirming that your peptide was manufactured not just with the right amino acids, but with the proper amino acid sequence. Take the guesswork out of your custom peptides and antibodies - choose 21st Century Biochemicals!