A rapid and high-throughput microplate spectrophotometric method for field measurement of nitrate in seawater and freshwater.
A rapid and high-throughput microplate spectrophotometric method for field measurement of nitrate in seawater and freshwater.
复制标题
一种快速、高通量微孔板分光光度法现场测量海水和淡水中的硝酸盐
DOI：
10.1038/srep20165
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发表时间：
2016-02-01
影响因子：
4.6
通讯作者：
Wen J
中科院分区：
文献类型：
--
作者：
Wu J;Hong Y;Guan F;Wang Y;Tan Y;Yue W;Wu M;Bin L;Wang J;Wen J
常用的锌镉还原法是测定硝酸盐的常用方法。但该方法耗时长、样品量大，在野外硝酸盐研究中应用较少。在这里，我们报告了一种改进的锌镉还原方法(MZCRM)，用于测量海水和淡水中自然丰度水平的硝酸盐。MZCRM的主要改进包括使用小体积的一次性管子进行反应，使用涡流振荡器来提高还原速度，以及使用微板读取器来进行高通量分光光度测量。考虑到盐度的影响，在低盐度和高盐度条件下，分别设置了5~10PSU和20~35PSU两个盐度区间，以更准确地测定硝酸盐。在优化的实验条件下，在盐度为5PSU和20PSU时，还原速率分别稳定在72%和63%。硝酸盐的最低检出限为0.5μM，线性范围为100μM(RSD为4.8%)。环境样品分析表明，MZCRM与传统的锌镉还原方法具有很好的一致性。总之，改进后的方法大大提高了操作的准确度和效率，实现了现场硝酸盐分析中硝酸盐的快速、高通量测定，且成本低廉。
The well-known zinc-cadmium reduction method is frequently used for determination of nitrate. However, this method is seldom to be applied on field research of nitrate due to the long time consuming and large sample volume demand. Here, we reported a modified zinc-cadmium reduction method (MZCRM) for measurement of nitrate at natural-abundance level in both seawater and freshwater. The main improvements of MZCRM include using small volume disposable tubes for reaction, a vortex apparatus for shaking to increase reduction rate and a microplate reader for high-throughput spectrophotometric measurements. Considering salt effect, two salinity sections (5~ 10 psu and 20~ 35 psu) were set up for more accurate determination of nitrate in low and high salinity condition respectively. Under optimized experimental conditions, the reduction rates were stabilized on 72% and 63% on the salinity of 5 and 20 psu respectively. The lowest detection limit for nitrate was 0.5 μM and was linear up to 100 μM (RSDs was 4.8%). Environmental samples assay demonstrated that MZCRM was well consistent with conventional zinc-cadmium reduction method. In total, this modified method improved accuracy and efficiency of operations greatly and would be realized a rapid and high-throughput determination of nitrate in field analysis of nitrate with low cost.