凯氏定氮仪的发展史

2023/5/27凯氏定氮仪的发展史主题：蛋白的基本概念

凯氏定氮的方法方法的发展Büchi’s消化单元Büchi’s消化单元Kjeldahl法问题解决July05/KJ2China_KjeldahlSolutions蛋白的基本概念BasicsProteinJuly05/KJ3China_KjeldahlSolutions为什么要分析蛋白?蛋白质是：Basicnutrient－基本的营养Impactoncaloricvalue(17kJresp.4kcal)－热量来源Parameterforquality(e.g.meat)－品质参数Influenceonproductionprocess(e.ggelation,extrusion)－影响产品的中间处理（例，冻结，压榨）Influenceonflavourandcolouroffood(e.g.bakingprocessbread,roastingprocesscoffee)－影响食品的风味和颜色July05/KJ4China_KjeldahlSolutions蛋白的基本结构是氨基酸，分子式如下：Thereareabout200aminoacidsfoundinnature自然界已发现的大概有200种氨基酸Thereareabout20aminoacidsinaproteinhydrolysate蛋白水解后大概有20种氨基酸BasicsProteinJuly05/KJ5China_KjeldahlSolutions怎么测定蛋白质？－通过检测氮的含量计算蛋白含量Thenitrogencontentinproteinisinasmallrange(15%-18%,mean:16%)蛋白中氮的含量在15％－18％波动，平均16％Proteinisdeterminedbyanalysingthenitrogencontentandcalculatingtheprotein通过氮含量计算蛋白含量BasicsProteinJuly05/KJ6China_KjeldahlSolutions凯氏定氮概述July05/KJ7China_KjeldahlSolutions谁是凯氏?JohanKjeldahl1849–19001849 borninDenmark graduationfromuniversity ScientistatCarlsbergBreweries FermentationstudiesDevelopmentofamethodforexactdetermi-nationofnitrogeninanimalandvegetablematerialResearchoncarbohydratesinbarleyandmalt1883 PublicationoftheKjeldahlmethodJuly05/KJ8China_KjeldahlSolutions凯氏定氮的原理1.Digestion消化ConversionofProtein-NitrogentoNH4+将蛋白中氮转化为NH4+

2.Distillation蒸馏分离收集NH3SeparationofNH33.Titration滴定用酸中和滴定MeasureoftheAmountofAcidthatwasneutralisedbyNH3

July05/KJ9China_KjeldahlSolutionsDigestion消化(I)BlankSample1.0722tabsofCatalystSulphuricacidWeighsample称重

1gofdryorganicmaterial (homogeneous)1克干的有机物质（均质）SampleBlank空白addeverythingexcept sampleAddreagents加试剂

10gor2tabsofKjeldahl catalystmixture10g或2片凯氏消化片20ml硫酸

样品均质，称重后加入试剂July05/KJ10China_KjeldahlSolutionsDigestion消化(II)vapourstoScrubberDigestion

digestat370°Cfor90min oruntilthemixtureisclear (green/bluecolor)+30min

370℃90mins或消化澄清后30分钟

DigestionJuly05/KJ11China_KjeldahlSolutionsDistillation蒸馏(I)manually

orautomatedDilution

dilutethecooleddigestion solutionwith50mldeionised water加入50ml去离子水稀释

Dilution稀释July05/KJ12China_KjeldahlSolutionsDistillation蒸馏(II)Boricacidtitration硼酸滴定

add60mlofBoricacid4%加4％60ml的硼酸add2to3dropsofindicator accordingtoSher加两至3滴的指示剂Backtitration反滴定

add20.0mlofsulphuricacid standardsolution(0.5Nor equivalent)加20ml的硫酸标准液（0.5N)add2to3dropsofindicator accordingtoSher加2到3滴指示剂

PreparationofReceiver准备接受液July05/KJ13China_KjeldahlSolutionsDistillation蒸馏(III)Sodiumhydroxide

NaOH

add90mlofNaOH32%to thediluteddigestionsolution加90ml32％的NaOH到溶液中Distillation蒸馏

distillfor4min.蒸馏4分钟

NeutralisationandDistillationJuly05/KJ14China_KjeldahlSolutionsTitration滴定7.15Boricacidtitration

硼酸滴定

titratethecondensatewith sulphuricacidstandardsolution (0.5Norequivalent)totheend pointofpH4.65用0.5N的硫酸标准液中和滴定至终点PH4.65Backtitration反滴定

titratethecondensatewith sodiumhydroxidestandardsolution(0.5Norequivalent)用0.5N的NaOH标准液中和滴定

TitrationJuly05/KJ15China_KjeldahlSolutionsCalculation计算%P=(Consumption-Blank)x1.4007xNxPFx100SampleSize1.4007: 1ml0.1NVolumetricSolution1.4007mgNN: NormalityAcidPF: ProteinfactorNProteinJuly05/KJ16China_KjeldahlSolutionsProteinFactors蛋白转换因子Sampletype ProteinFactorGelatine 5.55Dairyproducts 6.38Meat 6.25Fish 6.25Nuts,oilseeds 5.4Cereals 6.25Fruit,Vegetable 6.25Corn 6.25Eggs 6.25July05/KJ17China_KjeldahlSolutions凯氏定氮法的发展July05/KJ18China_KjeldahlSolutions最早…July05/KJ19China_KjeldahlSolutionsBuchi公司开始凯氏分析于：1961开始生产上市凯氏定氮仪市场上第1个带有内置蒸汽发生器的蒸馏仪，大大提高蒸馏效率July05/KJ20China_KjeldahlSolutions定氮仪在Büchi的发展演变July05/KJ21China_KjeldahlSolutionsBüchi今日DigestionUnitsandScrubber消化单元和排废装置DistillationUnits蒸馏单元July05/KJ22China_KjeldahlSolutionsBüchi’sDigestionUnits消化单元July05/KJ23China_KjeldahlSolutions消化加热方式InfraredHeating红外加热BlockHeating整体铝块加热July05/KJ24China_KjeldahlSolutions红外消化炉特点

红外加热，通过辐射方式，非接触式加热升温速度快（10min预热）可以升温至650°C消化管排废和消化管紧密联接6管消化仪(K-424)或12管(K-435)

加热步骤可控，定时器

12管(K-435)K-424K-435July05/KJ25China_KjeldahlSolutions整体铝块加热消化炉的特点K-437K-438

铝块加热->接触式加热

可以升温到450°C

温度时间可控消化管排废和消化管紧密联接

酸气回收装置可控

20个消化位置

自动提升(K-438only)K-438:程序化(时间延迟,升温梯度,自动停止,…)July05/KJ26China_KjeldahlSolutionsDigestion红外和整体铝块消化炉的区别

Block铝块 IR红外

预热时间 60min 5min温控Temperature easy difficultcontrol

加热单元最大加热温度450°C 600°C

July05/KJ27China_KjeldahlSolutionsDigestion 铝块Block 红外IR

Watersamples +++ +++++upto100mlLiquidsamples +++++ +++++upto15mlDryorganicmaterial +++++ +++++0.2gto5gHumidorganicmaterial +++++ +++++0.2gto5g

Foamysamples ++ +++++Mineraloil +++++ +++++DifferencesIR–Block红外和整体铝块消化炉的区别July05/KJ28China_KjeldahlSolutions如何处理消化过程中的酸雾？Sulphuricacidvapoursarecorrosiveandvitriolic酸雾具有腐蚀性和毒性，解决方法：1)消化炉排废装置，标准配置2)中和酸雾的废气循环回收装置July05/KJ29China_KjeldahlSolutionsScrubberB-414模块化设计,可达4步高效能泵系统,34l/min大的回收试剂腔,3l大的气液接触面积,提高操作性能可加NaOHor碳酸钠(最高NaOH20%但推荐浓度NaOH10%)可以选择抗酸，提供特殊密封垫（抗酸）吸收步骤使用活性炭吸附July05/KJ30China_KjeldahlSolutionsStep1(optional)冷凝

Step2(standard)中和Step3(standard)吸收Step4(optional)反应ScrubberB-414July05/KJ31China_KjeldahlSolutions消化炉特殊附件Suctionmoduleforaqueoussamples水类样品吸收模块带有冷凝漕的吸收模块，专门处理水类样品，防止交叉污染用于H2O2消化的吸收模块(仅适用于K-424andK-435)用于连续添加H2O2的漏斗环保(不需要催化剂)更短的消化时间减少起沫July05/KJ32China_KjeldahlSolutionsRefluxmodule回流模块(仅适用于K-424andK-435)适用于必须在回流状况下才能进行的消化ModuleforDigestionswhichhavetobedoneunderrefluxconditionsDigestionUnits:SpecialAccessory消化炉特殊附件July05/KJ33China_KjeldahlSolutionsCOD-Accessory化学耗氧量附件(仅适用于K-437andK-438)DeterminationoftheChemicalOxygenDemandDigestionUnits:SpecialAccessory消化炉特殊附件July05/KJ34China_KjeldahlSolutionsBüchi’sDistillationUnits蒸馏单元July05/KJ35China_KjeldahlSolutionsSTEAM

最新的蒸馏单元K-350andK-355

July05/KJ36China_KjeldahlSolutions老型号–K-314BasicinstrumentforKjeldahlandNitrogendeterminationDisadvantagesK-314notimeroldtechnologyprice-performanceratioJuly05/KJ37China_KjeldahlSolutions蒸馏单元K-350andK-355

总介绍DistillationUnitK-350K-314替代产品DistillationUnitK-355凯氏定氮的延伸产品July05/KJ38China_KjeldahlSolutionsK-350的特点用于凯氏氮检测的基本型号定时器可存储一个方法:蒸馏时间和试剂量紧凑设计安全特点:消化管在位传感器,安全门以及维修门传感器July05/KJ39China_KjeldahlSolutionsK-355的特点

具有K-350全部功能，另加：蒸汽输出量可调(30–100%)额外配置抗强酸的泵(用于加强酸和水)冷凝水控制传感器可以储存9个程序:蒸馏时间,试剂量和蒸汽输出量不仅适用于凯氏定氮，还适用于更广泛的的应用July05/KJ40China_KjeldahlSolutions预算不高样品数量不多K-350:应用于KjeldahlandDevardaK-350/K-355的目标客户K-355:应用于Kjeldahl,Devarda和非凯氏应用－在样品准备中需要蒸溜应用的July05/KJ41China_KjeldahlSolutions我们的口号－“STEAM”S

安全操作T

节约时间和成本E

高效蒸馏A

官方认可的方法M

多用途设计July05/KJ42China_KjeldahlSolutions蒸馏单元B-324内置滴定仪连接装置

可以升级为全自动的蒸馏单元电子蒸汽调节内置泵系统用于NaOH,水和硼酸的添加消化管自动排空存储20种方法操作简单,LCD显示July05/KJ43China_KjeldahlSolutionsB-324的目标客户想要操作更舒适的想要连接滴定单元的客户应用于Kjeldahl,Devarda和steamdistillation蒸汽蒸馏的客户July05/KJ44China_KjeldahlSolutions蒸馏单元K-370蒸馏和滴定全部内置于一台仪器带有彩色显示屏的大控制面板最新的软件设计，带有-方便的数据输入输出功能-多任务处理-多语言-高存贮性能－10000数据-用户可以自定义方法紧密，功能型设计配备K-371自动进样器，可以实现自动进样July05/KJ45China_KjeldahlSolutions称量:自动样品量输入精确的液体加样器:用于反滴定自动型消化炉K-438:ControlandDocumentationofDigestionProcessPC:数据转移和备份自动进样器:多样品的自动处理打印机:外接A4Printer支持PCL3蒸馏单元K-370July05/KJ46China_KjeldahlSolutions自动进样器K-371K-437&K-438的20管架子可以适合自动进样器特殊架子:4管ExpressRack样品通过K-370控制利用蒸汽实现样品的转移－由样品架到蒸馏单元July05/KJ47China_KjeldahlSolutions自动进样器K-370/371自动进样器K-371蒸馏仪K-370样品转移原理July05/KJ48China_KjeldahlSolutions自动进样器K-370/371自动进样器K-371蒸馏仪K-370蒸馏过程中蒸汽的走向July05/KJ49China_KjeldahlSolutions自动进样系统K-370/371回收率(NH4)H2PO4July05/KJ50China_KjeldahlSolutionsCustomerswhowantmaximumcomfortCustomerswithhighsample通量(>15样品/天)需要标准化处理的客户需要广泛认证的客户K-370/371的目标客户July05/KJ51China_KjeldahlSolutionsLastbutnotleast…精确的接口制造用于和排废装置的紧密联接，有效防止烟雾泄漏专业的冷凝装置，避免飞溅和硫酸的过量消耗更宽的直径48mm=对起沫样品更有利300ml的大容量=可以消化大量的样品Ø48mmGlassblowing–oneofBüchi’sKeyCompetences玻璃吹制－Buchi公司核心竞争力之一July05/KJ52China_KjeldahlSolutionsDistillationUnits:SpecialAccessory蒸馏单元的专业附件Devarda防溅保护检测NO2-和NO3-必需的附件(例：肥料)July05/KJ53China_KjeldahlSolutionsTroubleShootingJuly05/KJ54China_KjeldahlSolutions仪器校验方法Distillation蒸馏标准物质－磷酸二氢氨(无水）(NH4)H2PO4(waterfree)理论含量:12.17%DigestionandDistillation消化和蒸馏标准物质:甘氨酸Glycin(99.7%)理论含量: