奶粉中N/蛋白质含量检测方案(定氮仪)

智能文字提取功能测试中

APPLICATIONNOTEF&F-D-002-2016/A3 NITROGEN DETERMINATION IN SPORT POWDERDUMAS COMBUSTION METHOD Nitrogen Determination in Sport Powderaccording to the Dumas method (He/Ar as Carrier) Reference： ISO 14891：2002 Milk and Milk Products Tested with VELP Scientifica NDA 702 Dual Carrier Gas Dumas Nitrogen Analyzer (Code F30800080) Introduction Bodybuilders may supplement their diets with protein for reasons of convenience， lower cost (relative to meat and fishproducts) and to avoid the concurrent consumption of carbohydrates and fats. Protein supplements are sold in ready-to-drink shakes， bars， meal replacement products， bites， oats， gels and powders. Protein powders are the most popularand may have flavoring added for palatability. The powder is usually mixed with water， milk or juice and is generallyconsumed immediately before and after exercising， or in place of a meal. Different sport powder products were chosen to demonstrate the suitability of the DUMAS method for Nitrogen/ Proteinanalysis by using Helium and Argon as carrier gas. Nitrogen Determination in Sport Powders 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 DUMASoft TM. 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~ 30-50 mg Sport Powder into the tin foil according to the nitrogen content. 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 ENERGY BAR method shows the following parameters： Protein factor： 6.25 O2 flow rate： 400 ml/min O2 factor：1.8 ml/mg Press to start the analysis. Analysis time： from 3 minutes for one run. Results on Sport Powder Results have been obtained with the following calibration curve： in a range of 0 -90 mg N with 8 measurements of EDTAstandard (N%=9.57) (Code A00000149) for both carrier gas. The data obtained are included in the tolerance admitted by the EDTA certificate. The table below shows the nitrogen/protein reproducibility of four sport powders analyzed for three consecutive timesusing Helium and Argon as carrier gas and a small sample weight (30-50 mg).The sample weight is always the same with Helium and Argon as carrier gas. HELIUM as Carrier Gas ARGON as Carrier Gas Sample Nitrogen% Protein % RSD% Nitrogen% Protein% RSD% Sport powder 1 13.10313.07213.127 81.89481.70082.221 0.21 13.02413.18813.127 81.40382.42682.046 0.63 Sport powder 2 11.62911.63011.479 72.67972.69071.742 0.75 11.62111.56911.597 72.63372.30572.478 0.22 Sport powder 3 12.002 12.040 12.024 75.011 75.247 75.149 0.15 12.01812.06112.020 75.11075.381 75.128 0.20 Sport powder 4 14.173 14.126 14.110 88.583 88.288 88.186 0.23 14.13614.165 14.073 88.35188.530 87.959 0.33 In order to prove the performance of two different NDA 702 Dumas Nitrogen Analyzer by using helium and argon carriergas， four sport powder samples were analyzed for three consecutive times. HELIUM as Carrier Gas ARGON as Carrier Gas Sample NDA 702_A NDA702_A NDA702_B NDA702_B NDA702_A NDA 702_A NDA 702_B NDA 702_B AverageN% RSD% AverageN% RSD% AverageN% RSD% AverageN% RSD% Sport powder 1 13.09 0.21 13.02 0.55 13.11 0.63 13. 13 0.42 Sport powder 2 11.57 0.75 11.54 0.21 11.59 0.22 11.54 0.88 Sportpowder 3 12.02 0.15 12.00 0.08 12.03 0.20 12.08 0.69 Sportpowder 4 14.14 0.23 14.04 0.08 14.12 0.33 14.01 0.38 Conclusion The determination of nitrogen and protein in sport powder using NDA 702 provides reliable and reproducible results byusing both Helium and Argon as carrier gas. The data confirm the complete combustion of the sample with no memory effect observed when changing sample.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. 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.            奶粉或乳粉是一种通过去除几乎所有的水而制成的乳制品。该产品比液态奶保质期长得多，水分含量低，不需要冷藏。它可以通过加水来重组，从而得到一种即食的液态牛奶:加水的多少取决于脂肪的含量，因此它的高营养品质，加上它的多功能特性，使它吸引了许多食品应用。奶粉被广泛用作食品配料，因为它适用于以下几个方面:糖果，如巧克力和焦糖，婴儿配方奶粉的制造和烘焙配方。检测样品：奶粉样品检测仪器：杜马斯定氮仪NDA701（意大利VELP）参照方法：UNI EN ISO 14891, FIL-IDF 185检测结果：所得结果可靠，符合期望值。用以下校准曲线获得了结果:在0 - 5 mg N范围内用5次EDTA标准测量(%N = 9.57)(代码A00000149)。NDA701的优点是:高效率,不间断性能节约时间，需要几分钟运行成本适中完全无监督，完全自动化的不包括苛刻和有毒的化学品环保,低残留量和废物