米粉中氮含量检测方案(氮磷钙测定仪)

智能文字提取功能测试中

APPLICATION NOTEF&F-D-004-2014/A3 NITROGEN DETERMINATION IN RICE FLOURDUMAS COMBUSTION METHOD Nitrogen Determination in Rice Flouraccording to the Dumas method (He/Ar as Carrier) Reference： AOAC 992.23 Crude Protein in Cereal Grains and Oilseeds Tested with VELP Scientifica NDA 702 Dual Carrier Gas Dumas Nitrogen Analyzer (Code F30800080) Introduction Rice flour Certified Reference Material (CRM)， traceable to NIST standard (SRM)， is used to evaluate the reliability ofthe analytical method for the nitrogen and protein determination by using helium and argon as carrier gas with NDA 702. Nitrogen Determination in Rice Flour The Dumas method starts with a combustion furnace (CF) to burn thesample， obtaining elemental compounds. Water is removed by a first physical trap (WT1 - DriStepTM)， placed afterthe combustion， and a second chemical one (WT2). Between the two， theelemental substances passed through a reduction furnace (RF).The auto-regenerative CO2 adsorbers (CO2) let pass only the elementalnitrogen that is detected by the LoGas TM innovative Thermal ConductivityDetector (TCD) with no requirement for a reference gas.The NDA 702 is controlled through the intuitive DUMASoftTM. NDA 702 Preliminary Operations (daily) Follow the operating manual to start the NDA 702 and check that the following parameters are set： Temperature Combustion reactor (Code A00000158)：1030°C Temperature Reduction reactor (Code A00000226)： 650°C Flow rate MFC1 Carrier gas (He/Ar)： 190 ml/min Flow rate MFC2 Carrier gas (He/Ar)： 220 ml/min Condition the system by testing 2 EDTA standard (Code A00000149) and 3 to 5 empty tin foils (Code A00000153) asCheck up. Verify the calibration curve with one or more tests as Standard by testing the same standard used for the curve creation. Sample Preparation Using a spatula， put~ 150 mg rice flour Certified Reference Material (CRM) into the tin foil. Close the tin foil， obtaining a capsule and load the capsule into the autosampler. Analysis Procedure Fill the following fields in the database： Sample name， Weight， Method， Sample type，Calibration number The CEREAL MEAL 1 method shows the following parameters：Protein factor： 6.25O2 flow rate： 400 ml/minO2 factor： 1.6 ml/mg Press to start the analysis. Analysis time： from 3 minutes for one run. Typical Results on Rice Flour Results have been obtained with the following calibration curve： in a range of 0 - 5.9 mg N with 5 measurements ofEDTA standard (N%=9.57) (Code A00000149). The data obtained are included in the tolerance admitted by the EDTA certificate. HELIUM as Carrier Gas ARGON as Carrier Gas Sample quantity (mg) Nitrogen% Sample quantity (mg) Nitrogen % 150.98 1.329 150.24 1.376 150.14 1.348 150.29 1.365 150.51 1.349 150.58 1.335 150.78 1.353 150.67 1.367 150.50 1.389 151.27 1.337 151.25 1.345 150.63 1.316 150.69 1.339 150.58 1.366 152.24 1.348 149.98 1.371 150.44 1.339 151.00 1.357 151.12 1.348 150.99 1.331 Average ± SD 1.349±0.016 1.352±0.021 RSD%* 1.168 1.520 Nitrogen Certified Value (Nitrogen%)： 1.38±0.05 *RSD% = (Standard Deviation * 100)/ Average Conclusion The results show the reproducibility of 10 consecutive tests on rice flour Certified Reference Material (CRM)， traceableto NIST standard (SRM). Results are extremely reliable， as demonstrated by the RSD， both using helium and argon as carrier gas， with the sameconditions (method and sample weight) since the goal is to obtain < 2.0% relative standard deviation， as requested byofficial methods. The data obtained are included in the tolerance admitted by the rice flour certificate. Helium remains the best choice for premium accuracy but its shortages and interruptions are affecting any relatedproduct or instrument， including elemental analyzers. Argon， the best alternative available， has demonstrated to be avalid substitute， ensuring optimal results. VELP Scientifica NDA 702 Dual Carrier Gas Dumas Nitrogen Analyzer is theperfect response to simple， fast and precise nitrogen/protein determination， both with Helium and Argon as carrier gas. 摘要：利用可溯源至NIST标准(SRM)的米粉标准物质(CRM)，评价了NDA 702以氦、氩为载体 气体测定氮、蛋白的分析方法的可靠性。 实验样品：用抹刀将~ 150毫克的米粉标准物质(CRM)放入锡箔纸中。合上锡箔，获得一个胶囊，并将胶囊装入自动取样器。实验结果：在0-5.9 mg N的范围内5次测定EDTA标准(N% = 9.57)(代码A00000149)。获得的数据包含在EDTA证书允许的公差中。 结论：连续10次对米粉标准物质(CRM)的检测具有重复性，可追溯至NIST标准(SRM)。RSD证明，结果是非常可靠的，使用氦和氩作为载气，在相同的条件(方法和样品重量)，因为目标是获得< 2.0%的相对标准偏差，根据方法的要求。获得的数据包括在米粉证书所允许的公差内。氦仍然是高jing度的合适的选择，但它的短缺和中断影响了任何相关产品或仪器，包括元素分析仪。氩是现有的Z佳替代品，已被证明是一种有效的替代品，确保了Z佳的结果。VELP Scientifica NDA 702双载气Dumas氮分析仪以氦气和氩气为载气，对简单、快速和jing确的氮/蛋白质测定具有完美的反应。