Ion chromatography for determination of nitrite and nitrate in seawater using monolithic ODS columns

摘要

A fast and highly sensitive ion chromatographic method using monolithic ODS columns was developed for the determination of nitrite (NO2-) and nitrate (NO3-) in seawater. Two monolithic ODS columns (50 mm x 4.6 mm i.d. + 100 mm x 4.6 mm i.d.) connected in series were coated and equilibrated with 5 mM cetyltrimethyl ammonium chloride (CTAC) aqueous solution. The column efficiency with 0.5 M NaCl as the mobile phase did not decrease in spite of the increase in flow rate of the mobile phase. Thus, good chromatograms were obtained within 3 minutes for NO2- and NO3- in artificial seawater without interferences by coexisting ions. The detection limit (S/N = 3) with UV detection at 225 nm was 0.8 and 1.6 mu g/L for NO2- and NO3-, respectively. The characteristics of the monolithic CTA'-coated ODS columns were discussed. The present method was successfully applied to the fast and sensitive determination of NO2- and NO3-, in real seawater samples. (c) 2005 Elsevier B.V. All rights reserved.