The administrative order of the Ministry of Health, Labour and Welfare #261 (July 22, 2003) specifies the acceptable levels for F–, Cl–, NO2– and NO3–. Their concentrations are measured using ion chromatography. Here, anions in tap water were analyzed using IC NI-424 though NO2– could not be detected in tap water.
Sample : Tap water (Water), 100micro-L
Column : Shodex IC NI-424 (4.6mmID*100mm) Eluent : 8mM 4-Hydroxybenzoic acid + 2.8mM Bis-Tris + 2mM Phenylboronic acid + 0.005mM *CyDTA aq. Flow rate : 1.0mL/min Detector : Shodex CD Column temp. : 40°C
* CyDTA: trans-1,2-Diaminocyclohexane-N,N,N’,N’-tetraacetic acid