| 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。 |
| 关键词: 连续流动分析仪 自动凯氏定氮仪 植物全氮 |
| DOI：10.11838/sfsc.20150624 |
| 分类号: |
| 基金项目: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) |
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| Determination nitrogen in the Kjeldahl digests of plant samples by continuous flow analyzer in comparison with automated distillation titration instrument |
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| Abstract: |
| 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 Pearsons 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)2SO4 was 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. |
| Key words: continuous flow analyzer automated Kjeldahl distillation titration plant nitrogen |
