Measurement of diffusive flux of ammonia from water.
Measurement of diffusive flux of ammonia from water.
复制标题
测量水中氨的扩散通量。
DOI：
10.1021/ac980144k
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发表时间：
1998
影响因子：
7.4
通讯作者：
W. Winiwarter
中科院分区：
文献类型：
--
作者：
Z. Genfa;T. Uehara;P. Dasgupta;A. Clarke;W. Winiwarter
开发了一种仪器用于测量与地表水（特别是海水）平衡的气态氨浓度 NH(3(sw,eq))。该仪器可测量指定条件下流动水面的氨通量，并可根据 Fickian 扩散原理计算 NH(3(sw,eq))。通量收集器类似于先前为空气采样而开发的湿式平行板剥离器。所研究的样品在设备的一块板上运行；从样品中释放的氨通过另一块板上的受体液体的缓慢流动来收集。流出接受液中的NH(3)+NH(4)(+)(以下称为N(T))在硅胶柱上预浓缩，随后通过荧光流动注射分析(FIA)系统进行测量。通过 6 分钟的循环（4 分钟加载，2 分钟进样），分析系统可以测量受体液体中低至 0.3 nM N(T) 的浓度。与通量收集器相结合，它足够灵敏，可以测量海水中的氨通量。仪器的设计使其几乎不受环境氨的影响。在实验室（N(T) 0.2-50 μM）和现场调查（N(T) 0.18-1.7 μM）中，观察到氨通量与海水（加标、合成、天然）中的 N(T) 浓度之间存在良好的线性关系，尽管 N(T) 含量耗尽的老化海水在添加 N(T) 后表现出不寻常的行为，表明存在“氨需求”。夏威夷州椰岛实验室测得的海水中 NH(3(sw,eq)) 水平为 6.6 至 33 nmol/m(3)，平均值为 17.4 ± 6.9 nmol/m(3)，而之前报告的中太平洋 NH(3(sw,eq)) 值为 2.8-21 nmol/m(3)（平均值为 10 ± 7 nmol/m(3)）海洋（Quinn, P. K.；等人 J. Geophys. Res. 1990, 95, 16405-16416）。
An instrument was developed for the measurement of gaseous ammonia concentration, NH(3(sw,eq)), in equilibrium with surface waters, notably ocean water. The instrument measures the ammonia flux from a flowing water surface under defined conditions and allows the calculation of NH(3(sw,eq)) from the principles of Fickian diffusion. The flux collector resembles a wetted parallel plate denuder previously developed for air sampling. The sample under study runs on one plate of the device; the ammonia released from the sample is collected by a slow flow of a receptor liquid on the other plate. The NH(3) + NH(4)(+) (hereinafter called N(T)) in the effluent receptor liquid is preconcentrated on a silica gel column and subsequently measured by a fluorometric flow injection analysis (FIA) system. With a 6-min cycle (4-min load, 2-min inject), the analytical system can measure down to 0.3 nM N(T) in the receptor liquid. Coupled with the flux collector, it is sufficiently sensitive to measure the ammonia flux from seawater. The instrument design is such that it is little affected by ambient ammonia. In both laboratory (N(T) 0.2-50 μM), and field investigations (N(T) 0.18-1.7 μM) good linearity between the ammonia flux and the N(T) concentration in seawater (spiked, synthetic, natural) was observed, although aged seawater, with depleted N(T) content, behaves in an unusual fashion upon N(T) addition, showing the existence of an "ammonia demand". NH(3(sw,eq)) levels from ocean water measured in the Coconut Island Laboratory, HI, ranged from 6.6 to 33 nmol/m(3) with an average of 17.4 ± 6.9 nmol/m(3), in comparison to 2.8-21 nmol/m(3) (average 10 ± 7 nmol/m(3)) NH(3(sw,eq)) values previously reported for the Central Pacific Ocean (Quinn, P. K.; et al. J. Geophys. Res. 1990, 95, 16405-16416).