Accumlations of ammonium acetate on polar materials under HILIC condition and its relation to retention of analytes
(English)Manuscript (preprint) (Other academic)
Ammonium acetate is a buffer salt commonly added to mobile phase in HILIC to improve the reproducibility of the retention of analytes. Adding buffer salt would then result to the change in retention and selectivity. In this study, we have developed methods for determine ammonium acetate in form of its hydrolyzed products (ammonium ion and acetate ion) adsorption on twelve different HILIC stationary phases under various mobile phase condition. The effect of functional group and mobile phase compositions on salt adsorption was then discussed. We also tried to develop a method for characterization important retention mechanism of HILIC systems and interpreted them under the relationship with salt adsorption. Adsorption of salt was based on both portioning and electrostatic interaction. Ammonium was found to preferentially adsorb on HILIC stationary phases except Purospher Star NH2 phase. It is worth noting that adding salt to mobile phase can promote partitioning retention mechanism, possibly as a result of phase separation due to salt out effect.
HILIC, salt adsorption, retention mechanism
Research subject Analytical Chemistry
IdentifiersURN: urn:nbn:se:umu:diva-68070OAI: oai:DiVA.org:umu-68070DiVA: diva2:615726