应用MultiNC3000型总有机碳总氮分析仪测定水中的总氮

应用MultiNC3000型总有机碳总氮分析仪测定水中的总氮IntroductionTotal nitrogen is one of the most important parameters in

MultiNC3000 应用型总有机碳总氮分析仪测定水中 的总氮 Introduction Totalnitrogenisoneofthemostimportantparametersin environmentalmonitoring,asitisanindicatorofwaterquality andthepresenceofpollutants.Thestandardmethodfor measuringtotalnitrogeninwateristheKjeldahlmethod,which involvesdigestingthesamplewithsulfuricacidandheatingitto convertorganicnitrogentoammoniumions.However,this methodistime-consumingandrequiresskilledoperators,and therearealsoissueswithinterferencesfrominorganicnitrogen compounds.TheMultiNC3000analyzerisamoderninstrument thatuseschemiluminescencedetectiontodeterminetotal nitrogenandtotalorganiccarboninasinglemeasurement.This paperwilldescribetheprinciplesandoperationofthe MultiNC3000analyzer,aswellasitsadvantagesandlimitationsfor themeasurementoftotalnitrogeninwater. PrinciplesofTotalNitrogenAnalysis TheMultiNC3000analyzerusesthechemiluminescence detectionmethodtomeasuretotalnitrogen.Inthismethod,the sampleisoxidizedtoconvertallnitrogencompoundstonitric oxide(NO),whichreactswithozone(O3)toformexcited-state nitrogendioxide(NO2*).Whenthisexcited-statemoleculereturns toitsgroundstate,itemitsaphotonoflight,whichisdetectedby aphotomultipliertube.Theintensityofthelightemissionis proportionaltotheamountofnitricoxideinthesample,whichis inturnproportionaltotheamountoftotalnitrogen. TheMultiNC3000analyzerachieveshighsensitivityand selectivitybyusingacatalysttoimprovetheefficiencyofthe oxidationreaction,andbyremovingpotentialinterferencesfrom nitratesandnitriteswithareductionstep.Theinstrumentalsohas abuilt-incarbonremovalsteptomeasuretotalorganiccarbonin thesample. AdvantagesoftheMultiNC3000Analyzer OneofthemainadvantagesoftheMultiNC3000analyzeris itsspeedandaccuracy.Theinstrumentcananalyzeupto300