Abstract
In the course of analysis; sample storage, deproteinization and sample charging on a column, the concentration of hydrogen ion makes various effects on the observed value of free guanidino compounds in plasma. The pH of plasma increases by storage at room temperature and at-20°. And GAA and MG also increase remarkably by storage at room temperature, but do not increase at-20°. G and MG increase when the plasma is placed in acidic condition before deproteinization by ultrafiltration. Ghost peaks appeare on the chromatogram when the sample was charged on the column in the basic condition, and acidic guanidino compounds show lower value.
GAA and MG should be produced during storage at room temperature, and G and MG should be released from plasma protein in the acidic condition. Acidic guanidino compounds should slip down from the stational phase and make some ghost peaks when the sample was charged in the basic condition.
It is important to be careful of storage condition of plasma and to keep a check on the concentration of hydrogen ion in every step of the analysis.
