Determination of inorganic anions by ion chromatography using a graphitized carbon column dynamically coated with cetyltrimethylammonium ions.
The simultaneous determination of inorganic anions by ion chromatography using a dynamically coated graphitized carbon column with cetyltrimethylammonium (CTA) ions was investigated with suppressed conductivity detection. Column preparations with CTA and sodium carbonate-sodium hydrogencarbonate concentration in the eluent were examined to optimize the separation of seven common anions (F-, Cl-, NO2-, Br-, NO3-, HPO(4)2- and SO(4)2-). Calibration curves were linear from 0.5 to 5 micrograms/ml for F-, from 1.0 to 10 micrograms/ml for Cl-, from 1.5 to 15 micrograms/ml for NO2-, from 2.0 to 20 micrograms/ml for Br- and NO3-, from 5.0 to 50 micrograms/ml for HPO(4)2- and from 3.0 to 30 micrograms/ml for SO(4)2- with correlation coefficients (r) of 0.999 or better. The relative standard deviations of peak areas were between 0.3 and 0.9% for 10 repeated measurements. The application of this newly developed method was demonstrated by the determination of inorganic anions in the water for pharmaceutical purposes. Using CTA-Br as the coating agent, a permanently coated ion-exchange column was obtained, which allowed efficient separations of seven anions without adding any coating agent to the eluent.
Nagashima
H
H
Institute of Science and Technology, Inc., Tokyo, Japan.
Okamoto
T
T
D000838:Anions / Q000032:analysis*; D002138:Calibration; D002244:Carbon; D002593:Cetrimonium Compounds / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods*; D015203:Reproducibility of Results; D012997:Solvents; D013696:Temperature
D000838:Anions; D002593:Cetrimonium Compounds; D012997:Solvents; D002244:Carbon