Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10559701 | Talanta | 2011 | 6 Pages |
Abstract
Triethyloxonium tetrafluoroborate derivatization combined with direct headspace (HS) or SPME-gas chromatography-mass spectrometry (GC-MS) is proposed here for the simultaneous determination of nitrite and nitrate in seawater at micromolar level after conversion to their corresponding volatile ethyl-esters (EtO-NO and EtO-NO2). Isotopically enriched nitrite [15N] and nitrate [15N] are employed as internal standards and for quantification purposes. HS-GC-MS provided instrumental detection limits of 0.07 μM NO2â and 2 μM NO3â. Validation of the methodology was achieved by determination of nitrite and nitrate in MOOS-1 (Seawater Certified Reference Material for Nutrients, NRC Canada), yielding results in excellent agreement with certified values. All critical aspects connected with the potential inter-conversion between nitrite and nitrate (less than 10%) were evaluated and corrected for by the use of the isotopically enriched internal standard.
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Authors
E. Pagliano, M. Onor, E. Pitzalis, Z. Mester, R.E. Sturgeon, A. D'Ulivo,