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 inorganic UV-absorbing compounds such as nitrite, nitrate, iodide and thiocyanate contained in human saliva were simultaneously determined by ion chromatography using a strong-strong positively-negatively charged zwitterionic stationary phase. When both positive and negative charges are close together in a single molecule of the stationary phase, the 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 caused by simultaneous electrostatic repulsive and attractive interactions between the same and opposite charges. Separation of inorganic anions and organic zwitterions using ion chromatography based on simultaneous electrostatic attraction-repulsion interactions between the same and opposite charges has been termed ''electrostatic ion chromatography''. This paper deals with a method for the improvement of the separation coefficient of electrostatic ion chromatography and a biological application.