坚果中N/蛋白质含量检测方案(定氮仪)

智能文字提取功能测试中

F&F-D-003-2016/A3 N/PROTEIN DETERMINATION IN NUTS APPLICATION NOTE N/Protein Determination in Nutsaccording to the Dumas method (He/Ar as Carrier) Reference： AOAC 992.23 Crude Protein in Cereal Grains and Oil seeds； ISO 16634-1：2008 Oilseeds and animal feed stuffs； AACC 46-30 Crude protein-Combustion method Tested with VELP Scientifica NDA 702 Dual Carrier Gas Dumas Nitrogen Analyzer (Code F30800080) DUMAS COMBUSTION METHOD Introduction Recently there was an archeological dig in Israel where researchers found evidence showing that nuts formed a majorpart of man's diet 780，000 years ago. Seven varieties of nuts along with stone tools to crack open the nuts were foundburied deep in a bog. Even then man was aware of the health benefits connected to the consumption of nuts. In fact nuts are an excellentsource of protein and healthy fats； the amounts vary depending on the type of nut. Protein Determination in Nuts 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 via PC 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 (He/Ar)： 190 ml/min Flow rate MFC2 (He/Ar)： 220 ml/min Condition the system by testing 2 EDTA standard (Code A00000149) and 3 to 5 empty tin foils (Code A00000153)as Check up. Verify the calibration curve with one or more tests as Standard by testing the same standard used for the curve creation. Sample Preparation Raw almonds Expected Protein range： 20-25 % Raw peanuts Expected Protein range： 20-25% Hazelnuts Expected Protein range： 12-15 % Samples have been freeze and quickly homogenized by grinding， in order to avoid loss of oil (particle size 0.5 mm).Using a spatula， put~ 100 mg of finely grinded sample directly 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 numberThe parameters recommended by VELP for the analysis of the different nuts are： Method name Almonds Peanuts Hazelnuts Protein factor 5.18 5.46 5.30 02 flow rate 400 ml/min 400 ml/min 400 ml/min O2 factor 1.4 ml/mg 1.4 ml/mg 1.6 ml/mg After settings the parameter press to start the analysis. Analysis time： from 3 minutes for one run. Typical Results on Raw almonds， peanuts and hazelnuts The obtained results are in accordance with the expected value. Results have been obtained with the followingcalibration curve： in a range of 2- 8 mg N with 8 measurements of EDTA standard (N%=9.59) (Code A00000149).The data obtained are included in the tolerance admitted by the EDTA certificate. The tables below show the results with Helium and Argon as carrier gases. The sample weight is always the same withboth carrier gases. HELIUM as ARGON ascarrier gas carrier gas Sample Sample quantity Nitrogen % Protein % Sample quantity Nitrogen %(mg) Protein% (mg) Rawalmonds 100，69 4，013 20，787 101，29 4，069 21，077 100，60 4，059 21，026 100，60 20，886 102，07 4，010 20，772 20，855 100，04 4，010 20，772 100，46 4，012 20，782 101，50 4，036 20，906 100，75 4，058 21，020 103，68 4，083 21，150 101，25 4，116 21，321 102，05 4，079 21，129 101，17 20，870 102，86 4，089 21，181 102，03 21，093 Average ± SD% 4，047±0，034 20，965±0，178 Average ± SD% 4，052±0，034 20，988±0，175 RSD%* 0，848 0，848 RSD%* 0，836 0，836 Raw 23，806 23，598 peanuts 100，33 4，361 23，811 100，11 4，339 23，691 103，15 4，326 23，620 100，29 4，306 23，511 100，46 4，286 23，402 101，25 4，387 23，953 103，05 4，311 23，538 101，82 4，323 23，604 103，67 4，273 23，331 101，80 4，316 23，565 103，40 4，270 23，314 101，36 4，298 23，467 100，65 4，300 23，478 100，77 4，300 23，478 Average±SD% 4，311±0，036 23，537±0，196 Average ± SD% 4，324±0，029 23，608±0，158 RSD%* 0，832 0，832 RSD%* 0，668 0，668 HELIUM as carrier gas ARGON ascarrier gas Sample Sample quantity Nitrogen% Protein %(mg) Sample quantity Nitrogen % Protein %(mg) Raw hazelnuts 100，532，612 13，844 102，40 2，632 13，950 102，96 2，619 13，881 100，81 2，599 13，775 101，96 2，612 13，844 102，16 2，606 13，812 100，91 2，616 13，865 100，60 2，619 13，881 102，65 2，582 13，685 102，10 2，634 13，960 102，58 2，611 13，838 101，41 2，633 13，955 Average±SD% 2，609±0，013 13，826±0，007 Average ± SD% 2，621±0，015 13，889±0，080 RSD% * 0，514 0，514 RSD%* 0.577 0.577 Protein Expected range： 12-15% Conclusion Results are extremely reliable and reproducible as demonstrated by the RSD， by using helium or argon as carrier gas，with the same conditions (method and sample weight) since the goal is to obtain < 2.0% relative standard deviation， asrequested by official methods. 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 excellent 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.       最近，在以色列进行的考古挖掘中，研究人员发现了证据，表明坚果是78万年前人类饮食的主要组成部分。在沼泽深处发现了七种坚果，还有用来砸开坚果的石器。即使在那时，人类已经意识到坚果的健康益处。事实上，坚果是蛋白质和健康脂肪的极好来源;含量因坚果的种类而异。实验样品：Raw almonds（生杏仁） Expected Protein range: 20-25 % Raw peanuts （生花生）Expected Protein range: 20-25 % Hazelnuts （榛子）         Expected Protein range: 12-15 % 样品被冷冻并通过研磨迅速均匀化，以避免油的损失(颗粒尺寸0.5 mm)。用抹刀直接将100毫克磨碎的样品放入锡箔纸中。合上锡箔，获得一个胶囊，并将胶囊装入自动取样器。检测仪器：意大利VELP  杜马斯定氮仪（NDA 702）实验结果：所得结果与期望值一致。结果已通过以下校准曲线获得:在2 - 8 mg N范围内，EDTA标准(N% = 9.59)的8次测量(代码A00000149)。获得的数据包含在EDTA证书允许的公差中。下表显示了氦和氩作为载气的结果。两种载气的样品重量总是相同的。结论：RSD证明，使用氦或氩作为载气，在相同的条件(方法和样品重量)下，结果是非常可靠和可重复的;2.0%相对标准偏差，按方法要求。氦仍然是较好的选择，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。氩是现有的较好替代品，已被证明是一种有效的替代品，确保了优异的效果。VELP Scientifica NDA 702双载气Dumas氮分析仪以氦气和氩气为载气，对简单、快速和准确的氮/蛋白质测定具有完美的反应。