连续流动分析仪与自动凯氏定氮仪测定土壤全氮含量比较
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摘要
凯氏蒸馏法是土壤氮含量测定的经典方法,但费时费力,随着技术的发展,连续流动分析仪自动分析技术开始应用于氮测定。选择50个农田土壤和2个国家土壤标准物质(河南黄潮土GBW07413a和江西红壤GBW07416a),利用硫酸+催化剂(K_2SO_4∶CuSO_4∶Se=100∶10∶1)进行消煮,将土壤全氮转化为铵态氮,消煮液中铵态氮分别用连续流动分析仪和自动凯氏定氮仪测定。结果表明,两种方法测定土壤全氮含量相比无明显差异,测定结果之间呈显著线性相关关系,回归直线方程为:Y(连续流动分析仪-N)=0.995 1X(自动凯氏定氮仪-N)+0.003 5,相关系数r=0.980(n=50,P<0.01)。对3个土壤样品和2个国家土壤标准物质采用连续流动分析仪分别重复测定7次,相对标准偏差均小于5%。国家土壤标准物质全氮测定值与标准确认值一致。连续流动分析仪测试速度快,试剂消耗量少,精密度和准确度满足要求,可用于大批量土壤全氮含量的分析测定。
Various methods for assessing soil total nitrogen(N)have been developed to manage N nutrient and to understand N cycle in soil.Kjeldahl distillation-titration(KDT)has been used widely as a reference method for N determination in soils,but it is time consuming method.The objective is aimed at establishing a time saving method for determining of soil total N by a continuous flow analyzer(CFA).Fifty soil samples and two standard samples were digested with H_2 SO_4 catalysts(K_2 SO_4∶Cu SO_4∶Se=100∶10∶1).N contents in the digests were determined by a CFA and an automated KDT instrument,respectively.The result of t test found that there was no any significant difference of the soil contents measured by the CFA and the KDT method.A significant linear correlation could best describe the measured N values measured by both methods:Y(CFA-N)=0.995 1 X(KDT-N)+0.003 5.The pearson's correlation coefficient was 0.980 with a significance level(n=50,P<0.01).The CFA method for soil N measurement had a high precision with relative standard deviation(RSD)less than 5%.It is suggested that the CFA based on colorimetric detection of the pure ammonium chloride distillate(Berthelot reaction)can be used to determinate N in the Kjeldahl digests of soil samples.The CFA method is labor saving and can handle large numbers of samples.
Various methods for assessing soil total nitrogen(N)have been developed to manage N nutrient and to understand N cycle in soil.Kjeldahl distillation-titration(KDT)has been used widely as a reference method for N determination in soils,but it is time consuming method.The objective is aimed at establishing a time saving method for determining of soil total N by a continuous flow analyzer(CFA).Fifty soil samples and two standard samples were digested with H_2 SO_4 catalysts(K_2 SO_4∶Cu SO_4∶Se=100∶10∶1).N contents in the digests were determined by a CFA and an automated KDT instrument,respectively.The result of t test found that there was no any significant difference of the soil contents measured by the CFA and the KDT method.A significant linear correlation could best describe the measured N values measured by both methods:Y(CFA-N)=0.995 1 X(KDT-N)+0.003 5.The pearson's correlation coefficient was 0.980 with a significance level(n=50,P<0.01).The CFA method for soil N measurement had a high precision with relative standard deviation(RSD)less than 5%.It is suggested that the CFA based on colorimetric detection of the pure ammonium chloride distillate(Berthelot reaction)can be used to determinate N in the Kjeldahl digests of soil samples.The CFA method is labor saving and can handle large numbers of samples.
引文
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[2] Sáez-Plaza P,Michalowski T,Wybraniec S.An overview of the Kjeldahl method of nitrogen determination[J].Part I.Early History,Chemistry of the Procedure,and Titrimetric Finish.Crit.Rev.Anal.Chem,2013,43(4):178-223
[3] Bremner J M,Sparks D L.Methods of soil analysis,prat3-chemical methods[M].Soil Science Society of American,American Society of Agronomy,Madison,WI,pp.1996,1085-1121.
[4]张英利，许安民，尚浩博，等．AA3型连续流动分析仪测定土壤和植物全氮的方法研究[J]．西北农林科技大学学报(自然科学版)，2006,34(10):128-132.
[5] Chemat Z,Hadj-Boussaad D E,Chemat F.Application of atmospheric pressure microwave digestion to total kjeldahl nitrogen determination in pharmaceutical[J].Agricultural and Food Products.Analysis 1998,26(5):205-209.
[6]贝美容，罗雪华，杨红竹．AA3型连续流动分析仪(CFA)同时测定橡胶叶全氮、全磷、全钾的方法研究[J]．热带作物学报，2011,32(7):1258-1264.
[7] Searle P L.The bertholet or indophenols reaction and its use in the analytical chemistry of nitrogen[J].Analyst,1984,109:549-568.
[8] Baethgen W E,Alley M M.A manual colorimetric procedure for measuring ammonium nitrogen in soil and plant Kjeldahl digests[J].Communications in Soil Science and Plant Analysis,1989,20:9-10,961-969.
[9]罗宏德，王沙毅．连续流动分析技术的发展与应用[J]．现代科学仪器，2010,(5):131-132.
[10] Mcleod S.Determination of total soil and plant nitrogen using a micro-distillation unit in a continuous flow analyzer[J].Anal.Chim.Acta.,1992,266:113-117.
[11]林樱楠，郭承芳，王暖春，等．连续流动分析仪在烟草分析领域的应用[J]．安徽农业科学，2012,40(3):1477-1478.
[12]夏倩，刘凌，王流通，等．连续流动分析仪在水质分析中的应用[J]．分析仪器，2012,(2):64-68.
[13]鲍士旦.土壤农化分析(3版)[M]．北京：中国农业出版社，2008.
[14]温云杰，李桂花，黄金莉，等.连续流动分析仪与自动凯氏定氮仪测定小麦秸秆全氮含量之比较[J]．中国土壤与肥料，2015,(6):146-151.
[15] GB/T 27411-2012.检测实验室中常用不确定度评定方法[S].
[16] JJF1059.1-2012.测量不确定度评定与表示[S].
[17] GB/T5009.1-2003.食品卫生检验方法，理化部分，总则[S].
[18]毛红祥，桂素萍，肖植特．AA3型连续流动分析仪测定有机肥料全氮含量[J]．中国土壤与肥料，2015,(3):116-119.
[19] Junsomboon J,Jakmunee J.Flow injection conductometric system with gas diffusion separation for the determination of Kjeldahl nitrogen in milk and chicken Meat[J].Analytica Chimica Acta,2008,627(2):232-238.
[2] Sáez-Plaza P,Michalowski T,Wybraniec S.An overview of the Kjeldahl method of nitrogen determination[J].Part I.Early History,Chemistry of the Procedure,and Titrimetric Finish.Crit.Rev.Anal.Chem,2013,43(4):178-223
[3] Bremner J M,Sparks D L.Methods of soil analysis,prat3-chemical methods[M].Soil Science Society of American,American Society of Agronomy,Madison,WI,pp.1996,1085-1121.
[4]张英利，许安民，尚浩博，等．AA3型连续流动分析仪测定土壤和植物全氮的方法研究[J]．西北农林科技大学学报(自然科学版)，2006,34(10):128-132.
[5] Chemat Z,Hadj-Boussaad D E,Chemat F.Application of atmospheric pressure microwave digestion to total kjeldahl nitrogen determination in pharmaceutical[J].Agricultural and Food Products.Analysis 1998,26(5):205-209.
[6]贝美容，罗雪华，杨红竹．AA3型连续流动分析仪(CFA)同时测定橡胶叶全氮、全磷、全钾的方法研究[J]．热带作物学报，2011,32(7):1258-1264.
[7] Searle P L.The bertholet or indophenols reaction and its use in the analytical chemistry of nitrogen[J].Analyst,1984,109:549-568.
[8] Baethgen W E,Alley M M.A manual colorimetric procedure for measuring ammonium nitrogen in soil and plant Kjeldahl digests[J].Communications in Soil Science and Plant Analysis,1989,20:9-10,961-969.
[9]罗宏德，王沙毅．连续流动分析技术的发展与应用[J]．现代科学仪器，2010,(5):131-132.
[10] Mcleod S.Determination of total soil and plant nitrogen using a micro-distillation unit in a continuous flow analyzer[J].Anal.Chim.Acta.,1992,266:113-117.
[11]林樱楠，郭承芳，王暖春，等．连续流动分析仪在烟草分析领域的应用[J]．安徽农业科学，2012,40(3):1477-1478.
[12]夏倩，刘凌，王流通，等．连续流动分析仪在水质分析中的应用[J]．分析仪器，2012,(2):64-68.
[13]鲍士旦.土壤农化分析(3版)[M]．北京：中国农业出版社，2008.
[14]温云杰，李桂花，黄金莉，等.连续流动分析仪与自动凯氏定氮仪测定小麦秸秆全氮含量之比较[J]．中国土壤与肥料，2015,(6):146-151.
[15] GB/T 27411-2012.检测实验室中常用不确定度评定方法[S].
[16] JJF1059.1-2012.测量不确定度评定与表示[S].
[17] GB/T5009.1-2003.食品卫生检验方法，理化部分，总则[S].
[18]毛红祥，桂素萍，肖植特．AA3型连续流动分析仪测定有机肥料全氮含量[J]．中国土壤与肥料，2015,(3):116-119.
[19] Junsomboon J,Jakmunee J.Flow injection conductometric system with gas diffusion separation for the determination of Kjeldahl nitrogen in milk and chicken Meat[J].Analytica Chimica Acta,2008,627(2):232-238.
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