文档介绍：该【EPA3512 】是由【鼠标】上传分享，文档一共【3】页，该文档可以免费在线阅读，需要了解更多关于【EPA3512 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。METHOD?#:??Approval?for?NPDES?(Issued?1978)TITLE:Nitrogen,?Kjeldahl,?Total?(Colorimetric,Semi-Automated?Digester,?AAII)ANALYTE:CAS?#??N?Nitrogen???7727-37-9INSTRUMENTATION:AutoanalyzerSTORET??and??method?covers?the?determination?of?total?Kjeldahl?nitrogen?in?drinkingand?surface?waters,?domestic?and?industrial?wastes.?The?procedure?convertsponents?of?biological?origin?such?as?amino?acids,?proteins?andpeptides?to?ammonia,?but?may?not?convert?the?pounds?ofsome?industrial?wastes?such?as?amines,?pounds,?hydrazones,?oximes,semicarbazones?and?some?refractory?tertiary?amines.?The?applicable?range?ofthis?method?is??to?20?mg/L?TKN.?The?range?may?be?extended?with?sampledilution.??of??sample?is?heated?in?the?presence?of?sulfuric?acid,SOand?K?HgSO?for?two244and?one?half?hours.?The?residue?is?cooled,?diluted?to?25?mL?and?placed?on?theAutoAnalyzer?for?ammonia?determination.?This?digested?sample?may?also?beused?for?phosphorus?determination.??Kjeldahl?nitrogen?is?defined?as?the?sum?of?free-ammonia?anicpounds?which?are?converted?to?ammonium?sulfate)?SO(NH,424under?the?conditions?of?digestion?described?below.??Kjeldahl?nitrogen?is?defined?as?the?difference?obtained?by?subtractingthe?free-ammonia?value?(Method?,?Nitrogen,?Ammonia,?this?manual)?fromthe?total?Kjeldahl?nitrogen?value.??Handling?and??may?be?preserved?by?addition?of?2?mL?of?concSOper?H?liter?and24?stored?at?4°C.?Even?when?preserved?in?this?manner,?conversion?anicnitrogen?to?ammonia?may?occur.?Therefore,?samples?should?be?analyzed?assoon?as?possible.??Digester-?Manifold?for?Ammonia?(Figure?1)?TFE?(Teflon?boiling?stones),?Markson?Science,?Inc.,?Box?767,?Delmar,CA?92014)?Sulfate:?Dissolve?8?g?red?mercuric?oxide?(HgO)?in?50?mL?of?1:4sulfuric?acid?(10?mL?conc?SOH:?40?mL?distilled?water)?and?dilute?to?100?mL24with?distilled?water.??Solution:?(Sulfuric?acid-mercuric?sulfate?potassium?sulfate?solution):Dissolve?133?g?of?SOKin?700?mL?of?distilled?water?and?200?mL?of?concSO?.H2424Add?25?mL?of?mercuric?sulfate?solution?and?dilute?to?1?liter.??Acid?Solution?(4%):?Add?40?mL?of?conc.?sulfuric?acid?to?800?mL?ofammonia?free?distilled?water,?cool?and?dilute?to?1?liter.??Sodium?Hydroxide?(20%):?Dissolve?200?g?of?sodium?hydroxide?in?900?mLof?ammonia-free?distilled?water?and?dilute?to?1?liter.??Sodium?Potassium?Tartrate?Solution?(20%):?Dissolve?200?g?sodiumpotassium?-tartrate?in?about?800?mL?of?ammonia-free?distilled?water?and?diluteto?1?(NaStockHPO?Buffer)?in??Solution:about?800?Dissolv?mL?oef??g?o?ffr?sodiumee?water?phosphat.?Add?20e,?g??dibof?asicsodium24hydroxide?and?dilute?to?1?liter.??Buffer?Solution:?Combine?the?reagents?in?the?stated?order;?add?250mL?of?stock?sodium?potassium?tartrate?solution?()?to?200?mL?of?stock?buffersolution?()?and?mix.?Add?xx?mL?sodium?hydroxide?solution?()?and?diluteto?1?liter.?See?concentration?ranges,?Table?I,?position?of?working?buffer.??Salicylate/Sodium?Nitroprusside?Solution:?Dissolve?150?g?of?sodiumsalicylate?and??g?of?sodium?nitroprusside?in?about?600?mL?of?ammonia?freewater?and?dilute?to?1?liter.??Hypochlorite?Solution:?Dilute??mL?sodium?hypochlorite?solution(clorox)?to?100?mL?with?ammonia?free?distilled?water.??chloride,?stock?solution:?Dissolve??gCl?NH?in?distilled?water4and?bring?to?volume?in?a?1?liter?volumetric?flask.?1?ml=??-???20?or?25?mL?of?sample,?add?5?mL?of?digestion?solution?()?and?mix?(use?avortex?mixer).??(4-8)?Teflon?boiling?stones?().?Too?many?boiling?chips?will?cause?thesample?to?boil?over.??Block?Digester?in?manual?mode?set?low?and?high?temperature?at?160°Cand?preheat?unit?to?160°C.?Place?tubes?in?digester?and?switch?to?automaticmode.?Set?low?temperature?-?timer?for?1?hour.?Reset?high?temperature?to?380°Cand?set?timer?for?2?1/2?hours.??sample?and?dilute?to?25?mL?with?ammonia?free???the?level?of?all?reagent?containers?to?ensure?an?adequate??the?salicylate?line,?place?all?reagent?lines?in?their?respectivecontainers,?connect?the?sample?probe?to?the?Sampler?IV?and?start?theproportioning??the?Sampler?IV?wash?receptacle?with?about?25?mL?of?%?sulfuric?acid().??reagents?have?been?pumping?for?at?least?five?minutes,?place?thesalicylate?line?in?its?respective?container?and?allow?the?system?to?equilibrate.?Ifa?precipitate?forms?after?the?addition?of?salicylate,?the?pH?is?too??stop?the?proportioning?pump?and?flush?the?coils?with?water?usinga?syringe.?Before?restarting?the?system,?check?the?concentration?of?the?sulfuricacid?solutions?and/or?the?working?buffer??prevent?precipitation?of?sodium?salicylate?in?the?waste?tray,?which?can?clogthe?tray?outlet,?keep?the?nitrogen?flowcell?pump?tube?and?the?nitrogenColorimeter?"To?Waste"?tube?separate?from?all?other?lines?or?keep?tap?waterflowing?in?the?waste??a?stable?baseline?has?been?obtained?start?the?Sampler.??standard?curve?by?plotting?peak?heights?of?processed?standardsagainst?concentration?values.?Compute?concentrations?paring?samplepeak?heights?with?standard?curve.??and??a?single?laboratory?(EMSL),?using?sewage?samples?of?concentrations?of?,,?and??mg?N/L,?the?precision?was?+/-?,?+/-??and?+/-,respectively.??a?single?laboratory?(EMSL),?using?sewage?samples?of?concentrations?of???mg?N/L,?the?recoveries?were?99?and?99%,?respectively.?,?.,?Hemphill,?.?and?Donaldson,?.,?"Automatic?Determination?ofTotal?Kjeldahl?Nitrogen?in?Estuarine?Water",?Technicon?Symposia,?pp.?362-367,?Vol.?1,1967.?,?.,?and?Booth,?.,?"Evaluation?anic?Nitrogen?Methods",?EPA?Officeof?Research?and?Monitoring,?June,?1972.?,?.?and?Booth,?.,?"Simultaneous?and?Automated?Determination?of?TotalPhosphorus?and?Total?Kjeldahl?Nitrogen",?Methods?Development?and?QualityAssurance?Research?Laboratory,?May,?1974.??"Total?Kjeldahl?Nitrogen?and?Total?Phosphorus?BD-40?Digestion?Procedurefor?Water",?August,?1974.?,?.,?and?Booth,?.,?"Evaluation?of?the?Block?Digestion?System?for?theMeasurement?of?Total?Kjeldahl?Nitrogen?and?Total?Phosphorus",?EPA-600/4-78-015,Environmental?Monitoring?and?Support?Laboratory,?Cinncinnati,??1.?CONCENTRATION?RANGES?(NITROGEN)?????????????Dilution?loopsRangeml?stock?NaOH???????????Initial?sample??????????????????ResampleApprox.??Nper?liter??lineDiluent?lineResample?lineDiluent?linecal.?setting(±10%)buffer?solution??(RED/RED).80?(RED/RED).32?(BLK/BLK).80?(RED/RED)7000-??(RED/RED).80?(RED/RED).32?(BLK/BLK).80?(RED/RED)1000-??(ORN/YEL).80?(RED/RED).32?(BLK/BLK).80?(RED/RED)7000-1120??(ORN/YEL).80?(RED/RED).32?(BLK/BLK).80?(RED/RED)1000-5120??(ORN/YEL).80?(RED/RED).32?(ORN/YEL).80?(RED/RED)7000-280??(ORN/YEL).80?(RED/RED).32?(ORN/YEL).80?(RED/RED)1000-1080