【作者】 李震；

【导师】 王金星； 李道亮；

【作者基本信息】 山东农业大学 ， 农业工程， 2017， 硕士

【摘要】 硝氮、亚硝氮和氨氮(三氮)是水产养殖水体中氮的三种存在形式。水产养殖水体中过量的三氮会引起养殖水体的富营养化,破坏水体生态平衡,造成鱼、虾和蟹等养殖水产品的死亡,严重影响水产养殖业的产量,造成巨大的经济损失。水产养殖水体中三氮传统的检测方法包括分光光度法、电化学方法和光谱法等,但是这些方法存在很多缺点:检测精度低,样品预处理麻烦,不适合样品的连续检测等。因此需要研究一种快速、准确的水产养殖水体中低浓度三氮的在线检测方法。拉曼光谱技术是一种简单快速的分析方法,已经越来越多的被应用于水质检测领域。论文以水产养殖水体中硝氮、亚硝氮和氨氮为研究对象,分别利用普通拉曼光谱技术、表面增强拉曼光谱技术对水溶液中三氮进行检测和分析研究,并对实际水产养殖水体中的三氮进行检测和分析,实现了对水产养殖水体中硝氮的定量检测。论文主要研究内容如下:(1)利用集成的拉曼光谱仪系统,采用普通拉曼光谱方法分别采集水溶液中硝酸根离子、亚硝酸根离子和铵根离子的拉曼光谱。对光谱数据进行分析,结果表明普通拉曼光谱方法可以检测到硝酸根离子(浓度≥1 mg/L)的拉曼特征峰信号,但特征峰强度较弱;低浓度亚硝酸根离子和铵根离子的拉曼特征峰信号检测不到,杂峰较多。(2)使用金溶胶表面增强基底对水溶液中三氮进行检测。实验结果表明,使用表面增强拉曼光谱(SERS)技术检测到的硝氮拉曼特征峰信号增强效果显著,并且能够看到NO3-的拉曼特征峰位于1045 cm-1附近;NO2-表面增强拉曼光谱信号强度弱,在浓度比较高时,能够看到NO2-的拉曼特征峰位于1335 cm-1附近;使用SERS方法无法检测到水溶液中低浓度铵根离子的拉曼散射信号。本方法实现了对水溶液中的低浓度硝酸根离子的定性检测。(3)采用表面增强拉曼光谱对不同浓度的NaNO3和NaNO2溶液检测,并对光谱数据进行预处理。同时采用一元线性回归法,建立基于表面增强拉曼光谱的NaNO3和NaNO2溶液的定量分析模型。研究结果表明,不同浓度硝酸钠溶液和其在1045 cm-1处拉曼特征峰强度的标准回归曲线为y=8.2333x+6772.1,相关系数平方R2=0.94279,线性拟合度较好,能够定量检测;亚硝酸钠溶液的浓度相对于拉曼信号强度所建立的标准回归曲线是y=0.9261x+1129.9,相关系数平方R2=0.84696,线性拟合度效果一般,灵敏度一般,只能定性检测;低浓度氨氮的拉曼信号检测不到,不能够进行浓度检测。在水产养殖水体中硝酸氮的检测中,该方法检测限约为1 mg/L,相对标准误差在4.0%-6.0%之间。在1 mg/L-5000 mg/L范围内,该方法检测精度可以满足检测要求,稳定性较好。本文实现了基于金溶胶基底的表面增强拉曼光谱的水产养殖水体中低浓度硝氮的定量检测。更多还原

【Abstract】 Nitrate,nitrite and ammonia nitrogen(3-Nitrogen)are three forms of nitrogen in aquaculture water.The overmuch 3-nitrogen in aquaculture water can cause eutrophication of water,and can also break the ecological balance of water,which can make the death of fish,shrimp,crab and so on.More seriously,it can affect the yield of aquaculture and cause huge economic loss.The traditional method to detect the 3-nitrogen in aquaculture water includes spectrophotometric,electrochemical method,spectral analysis method,etc.But those methods have a lot of disadvantages which includes: low detection precision,fussy process of sample treatment,not suitable for the continuous detection of sample,etc.Therefore,scientist needs to research a rapid and accurate method to detect the 3-nitrogen in aquaculture water.The Raman spectroscopy as an easy and rapidly analysis method has been used to detect water quality more and more widely.This thesis takes the 3-nitrogen in aquaculture water as the object of study and use the common Raman spectroscopy and surface-enhanced Raman spectroscopy respectively for the detection and analysis of 3-nitrogen in aqueous water,and then we detected 3-nitrogen in aquaculture water,and achieved the quantitative detection of nitrate.Mean contents of this paper are as follows:(1)Use the integrated Raman spectrometer and the common Raman spectroscopy to detect the spectrum of nitrate,nitrite and ammonium ion respectively.By analyzing the data of spectrum,we can see that common Raman spectroscopy can detect the Raman scattering signal of nitrate ion(concentration≥1mg/L),but the intensity of characteristic peak is weak.The Raman scattering signal of nitrite and ammonium ion at low concentration can’t be detected,because there’re so many impure peaks.(2)We use the gold sol SERS substrate to detect the 3-nitrogen in aqueous water.The results indicate that the SERS can detect the characteristic peak of nitrate better than the common Raman spectroscopy,and its intensity is several times than before.We can also see that the positon of NO3-’s Raman characteristic peak is near the 1045cm-1;the SERS signal of nitrite ion’s is very weak,but we can see that the position of NO2-’s Raman characteristic peak is near 1335cm-1when the concentration is high;SERS method can’t detect the Raman scattering signal of ammonium ion at low concentration in water.This method can be used for the qualitative detection of the low concentration of NO3-in aqueous water.(3)Use SERS to detect different concentration of nitrate and nitrite ion in water respectively,and the data is Processed.Then the quantitative analysis model of nitrate ion and nitrite ion in water was established with the employed of the unary linear regression method based on the SERS.The results indicate that the standard linear regression curve of different concentration of nitrate ion and its intensity of Raman characteristic peak which located in 1045 cm-1 is y=8.2333x+6772.1,R2=0.94279,and its linearity is well,and it can be used for quantitative detection;But the standard linear regression curve’s(y=0.9261x+1129.9,R2=0.84696)degree of fitting of nitrite ion in water is not good,meanwhile its sensitivity is low,and it can be used for qualitative detection;The Raman signals of low concentration ammonia nitrogen can not be detected.The limit of detection is 1mg/L,and the RSD range from 4.0%-6.0% in the detection of nitrate in aquaculture water.The precision can meet the requirement of detection,and the stability is well at the concentration ranged from 1 mg/L-10000 mg/L.The quantitative determination of nitrate ion in low concentration aquaculture water using the surface-enhanced Raman spectroscopy based on the gold sol substrate is performed in this paper.更多还原