SIMULTANEOUS DETERMINATION OF ORGANIC AND INORGANIC ULTRAVIOLET-ABSORBING COMPOUNDS IN HUMAN SALIVA BY ELECTROSTATIC ION CHROMATOGRAPHY

Organic UV-absorbing compounds such as cr-amylase and tryptophan and i norganic UV-absorbing compounds such as nitrite, nitrate, iodide and t hiocyanate contained in human saliva were simultaneously determined by ion chromatography using a strong-strong positively-negatively charge d zwitterionic stationary phase. When both positive and negative charg es are close together in a single molecule of the stationary phase, th e positively-negatively charged zwitterionic stationary phase provides a specific retention behaviour for the separation of inorganic anions and organic zwitterions. It was demonstrated in previous experiments that the separation of inorganic anions and organic zwitterions is cau sed by simultaneous electrostatic repulsive and attractive interaction s between the same and opposite charges. Separation of inorganic anion s and organic zwitterions using ion chromatography based on simultaneo us electrostatic attraction-repulsion interactions between the same an d opposite charges has been termed ''electrostatic ion chromatography' '. This paper deals with a method for the improvement of the separatio n coefficient of electrostatic ion chromatography and a biological app lication.