Automatically On-line Nutrients Analyzer For Ocean Based On Intermittent Chemical Analysis

The concentration measurement usually uses method called laboratory detection in marine environmental monitoring,which tests the sample with the color reaction by adding quantitative reagents to the sample.However,it is easy to cause manual error.Furthermore,improper storage also affects the sample's quality,which couldn't guarantee the real-time validity of the results.In this paper,a nutrient analyzer based on discontinuous chemical analysis is developed,under the project "Automatically on-line nutrients analyzer for ocean based on intermittent chemical analysis",which is developed by Shenzhen Science and Technology Innovation Committee.The main research results are as follows.(1)This paper describes a hardware system of the nutrient analyzer,which is divided into control module and photometer module.The photometer module includes light driving,optical signal detection,low-pass filter,analog to digital conversion and power supply.(2)This paper designs a software system of the nutrient analyzer,including system process,communication protocol,secure digital memory,serial communication,clock management,temperature detection and concentration measurement.(3)This paper describes elaborates the system principle,flowing system and optical system of the nutrient analyzer,which realizes quantitative injection to samples and reagents.Based on the flow injection analysis,the automatic nutrient analyzer can measure concentration of ammonium,nitrite,nitrate,phosphate and silicate,and it's performance parameters are showed by the percentage of full concentration range,with 5% in system detection limit,2% in system repeatability error,1% in system zero drift,3% in system range drift and 2% in system linearity,which meet the instrument standards well.The system has a high degree of automation,and sets seawater sampling,reagent extraction,chemical reaction,absorbance measurement and pipeline cleaning as a whole.It has many advantages,such as low consumption,small error,high precision and small size.It can be used to monitor the concentration of the marine nutrients continuously in real time,meeting the requirements of the on-site monitoring system.