Hisako Ogura

Separation and determination of quaternary ammonium compounds by high-performance liquid chromatography with a hydrophilic polymer column and conductometric detection

Abstract An HPLC method has been developed for separation and determination of long alkyl chain quaternary ammonium compounds. A column packed with a hydrophilic polymer packing, Shodex Asahipak GF-310 HQ, and a water–acetonitrile mixture containing 4,4′-bipyridyl and hydrochloric acid were used to depress hydrophobic adsorption of the quaternary ammonium compounds and increase the sensitivity of the conductometric detection with a micromembrane suppressor. Dodecyltrimethylammonium, cetyltrimethylammonium, tetradecyldimethylbenzylammonium and stearyltrimethylammonium ions can be completely separated from one another and quantified at 0.1 nmol level.

EFFECTS OF RAINWATER INFILTRATION INLET ON WATER BALANCE IN AN URBAN CATCHMENT AREA

In order to improve the hydrologic cycle in urban catchment with impervious area, we examine the infiltration capacity of two types of rainwater-infiltration inlet (RII) under actual rainfall conditions, and furthermore clarify the effects of the RIIs on increase of spring yield in urban catchment area. We measured water balance in a single RII and urban catchment area in which a small spring, named Kaga-Simizu Spring, is located and a lot of RIIs were installed. The results indicate that parts of RIIs may maintain large infiltration capacity even under heavy rainfall intensity. Ratio of infiltration to inflow in RIIs is evaluated to be 77.791.3 %, showing high performance of RIIs as an infiltration measure. Yields in Kaga-Simizu Spring increase recently mainly due to installation of RIIs with higher infiltration capacity.