Direct monitoring of soil and water nitrate by FTIR based FEWS or membrane systems
Direct monitoring of soil and water nitrate by FTIR based FEWS or membrane systems
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DOI：
10.1021/es020885
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发表时间：
2003-06-15
影响因子：
11.4
通讯作者：
Katzir, A
中科院分区：
文献类型：
--
作者：
Shaviv, A;Kenny, A;Katzir, A
银光纤的发展，以最小的损失传输到中红外（MIR）铺平了道路，成功地利用其作为有效的ATR（衰减全反射）元件，促进光纤倏逝波光谱（FEWS）的实施，直接监测环境系统中的硝酸盐。水，土壤提取物和糊状物中含有硝酸盐的样品用于测定硝酸盐浓度与一个共同的ATR ZnSe晶体和银卤化物纤维（FEWS）。收集了土壤糊和悬浮液以及磷酸盐、碳酸盐、硫酸盐、铵和土壤有机成分的光谱，以研究可能对硝酸盐测定的干扰。估计的标准误差（SEE）和R-2值与扁平的纤维，使用简单的单点相关法，优于圆柱形FEWS和ZnSe ATR晶体在纯水中获得的。在大多数土膏中，通过应用简单的互相关方法模式，实现了SEE和R2的显着改善。通过离子交换膜，部分装载硝酸盐或碳酸盐，直接传输的MIR辐射，被发现这些离子的MIR-FTIR测定的有效替代方案。FEWS设备的进一步开发和修改应允许在土壤和环境系统中的硝酸盐的原位和在线测定。
The development of silver halide fibers that transmit with minimal loss into the mid-IR (MIR) paved the way to their successful utilization as effective ATR (Attenuated Total Reflectance) elements, promoting the implementation of Fiberoptic Evanescent Wave Spectroscopy (FEWS) for direct monitoring of nitrate in environmental systems. Samples containing nitrate in water, soil extracts, and pastes were used for the determination of nitrate concentration with a common ATR ZnSe crystal and with silver halide fibers (FEWS). Spectra of soil pastes and suspensions and those of phosphate, carbonate, sulfate, ammonium, and soil organic constituents were collected to study possible interference with nitrate determination. The standard error of estimate (SEE) and R-2 values obtained with flat fibers, using the simple single-point correlation method, were superior to those obtained for cylindrical FEWS and ZnSe ATR crystals in pure water. A significant improvement in the SEE and R2 was achieved in most soil pastes by applying the simple mode of the Cross Correlation method. Direct transmission of MIR radiation through ion-exchange membranes, partially loaded with nitrate or carbonate, was found an effective alternative for MIR-FTIR determination of these ions. Further development and modification of the FEWS devices should allow in-situ and online determination of nitrate in soil and environmental systems.