Residual Water Determination
Due to their chemical properties lyophilized peptides may still contain traces of moisture. This is not considered an impurity, but reduces the actual peptide content by approximately 2 to 15%. In order to determine the exact composition of a lyophilized peptide probe the amount of residual water also needs to be analyzed.
Residual water in a peptide is determined by gas chromatography. The peptide sample is heated to desorb the water and then added into a column with a gas stream (carrier gas, mobile phase) which different chemical components pass at different rates depending on their various properties and their interaction with the column filling (stationary phase). As the water exits the column, it is detected and quantified.
Material requisition: 1.5 mg/sample
Time needed: 2 weeks