Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56126, Pisa, Italy.
Talanta. 2011 Oct 15;85(5):2511-6. doi: 10.1016/j.talanta.2011.07.098. Epub 2011 Aug 5.
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-NO(2)). Isotopically enriched nitrite [(15)N] and nitrate [(15)N] are employed as internal standards and for quantification purposes. HS-GC-MS provided instrumental detection limits of 0.07 μM NO(2)(-) and 2 μM NO(3)(-). 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.
三乙氧氧𬭩四氟硼酸盐衍生化结合直接顶空（HS）或 SPME-气相色谱-质谱联用（GC-MS）用于在海水中痕量水平下同时测定亚硝酸盐和硝酸盐，在衍生转化为其相应的挥发性乙酯（EtO-NO 和 EtO-NO₂）后进行测定。同位素富集的亚硝酸盐 [(15)N] 和硝酸盐 [(15)N] 被用作内标和定量目的。HS-GC-MS 提供了 0.07 μM NO₂(-) 和 2 μM NO₃(-) 的仪器检测限。通过测定 MOOS-1（加拿大 NRC 的海水营养物质标准参考物质）中的亚硝酸盐和硝酸盐，对该方法进行了验证，结果与认证值非常吻合。通过使用同位素富集的内标，评估并纠正了亚硝酸盐和硝酸盐之间潜在的相互转化（小于 10%）的所有关键方面。
