Development of a new type of nitrate analyzer
Date Issued
2007
Date
2007
Author(s)
Hsieh, Chih-Chiang
DOI
zh-TW
Abstract
Abstract
This research combined the flow injection analysis and gas segmented continuous flow analysis to develop a new type of nitrate analyzer. Steps to build the device are as following. First, an autosampler or injection valve is replaced by a pump to continuously inject the sample. Second, a debubbler is added in front of the cadmium reductor to prevent air interference and to maintain stable reduction efficiency of the reductor. Last, flow rates and detection time is adjusted to optimize the analyzer. Continuous and stable signals can be produced and consequently a spectrophotometer without the time scan function can still be used as the recorder. There is no significant difference between measurements of natural waters made by this new method and by traditional flow injection method. Moreover, the operation precision is lower than 1%, and the detection time is about 2 minutes. For the analysis of fresh water samples, the detection range is from 0 to 100uM, the detection limit ca. 0.159uM, and the resolution 0.053uM. For seawater analysis, the detection range is from 0 to 50uM, the detection limit is ca. 0.204uM, and the resolution is 0.068uM. The efficiency of cadmium reductor drops 2% every 10 samples while seawater or polluted fresh water is measured. Therefore, this thesis suggests that measuring a reference material every 3 to 5 samples in order to monitor the decay rate so that the accuracy of the measurements can be improved.
Subjects
硝酸鹽,自動分析,氣泡去除裝置
natrate,automation,debubbler
Type
thesis
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