摘要
凯氏定氮法是测定植株全氮含量的经典方法,但费时费力。选择24个小麦秸秆样品,用浓H2SO4-H2O2消煮,分别利用连续流动分析仪与全自动凯氏定氮仪测定消煮液中氮含量,比较了两种方法测定结果,探讨利用连续流动分析仪测定植株样品全氮含量的可行性。结果表明：两种仪器测定的小麦秸秆中全氮含量无明显差异,彼此间呈显著线性相关,回归直线方程为Y（连续流动分析仪-N）=0.892X（凯氏蒸馏滴定-N）＋0.753,相关系数r=0.942 1（n=24,P〈0.01）。连续流动分析仪测定的回收率在96.6%～102.3%之间,对5个样品消煮液中氮浓度分别重复测定5次,相对标准偏差在5%以下。连续流动分析仪分析速度快,消耗试剂少,可用于大批量H2SO4-H2O2消煮的植株样品中全氮含量分析。研究结果为采用连续流动分析仪测定植株全氮含量提供了技术依据。
Kjeldahl distillation-titration has been used as a reference method for N determination in plants,but it is time consuming. This article aimed at establishing a time saving method for determining of plant N concentrations by continuous flow analyzer（ CFA）. Twenty four of wheat plant samples were selected and digested with H2SO4-H2O2. N contents in the digests were determined by CFA and an automated Kjeldahl distillation-titration（ AKDT） instrument,respectively. The test showed that there was no any significant difference of the plant N contents measured by the CFA and the AKDT method. A linear relationship best described the measured N values generated by both methods： CFA-N = 0. 892 AKDT-N ＋ 0. 753. The Pearson＇s correlation coefficient was 0. 942 1 with a significance level（ n = 24,P〈 0. 01）. The CFA method for plant N measurement had a high precision with relative standard deviation less than 5%. The standard recovery rate of feed samples with addition of（ NH4）2SO4was 96. 6% ～ 102. 3%. It suggested that the CFA based on colorimetric detection of the pure ammonium chloride distillate（ Berthelot reaction） could be used to determinate N in the Kjeldahl digests of plant samples. The CFA method was labor saving and could handle large numbers of samples. The human error in mixing and other operations was reduced to a great extent.
出处
《中国土壤与肥料》
CAS
CSCD
北大核心
2015年第6期146-151,共6页
Soil and Fertilizer Sciences in China
基金
国家重点基础研究发展计划(973计划)项目(2013CB127402)
中央级公益性科研院所专项资金资助项目(IARRP-2014-39)
关键词
连续流动分析仪
自动凯氏定氮仪
植物全氮
continuous flow analyzer
automated Kjeldahl distillation-titration
plant nitrogen
