酚二磺酸光度法测定水中总氮郭姿珠

工作简报,,(,410083)　:在酚二磺酸光度法测定水中总氮量的方法中,用高压反应釜代替比色管,改进了样品的碱性过硫酸钾消解效果,避免了样品消解不彻底,氧化剂分解不完全及样品中铵氮以氨气形式逸出等。标准曲线的线性范围在0.02～1.90mg·L-1之间,检出限(3σ)为0.02mg·L-1。按此方法测定了6种水样中的总氮量,测定值的相对标准偏差(n=6)均小于3.5%。用标准加入法对方法的回收率作了试验,测得结果在98%～102%之间。:光度法;样品消解;总氮;酚二磺酸;水样:O657.31　　　:A　　　:1001-4020(2009)05-0592-02PhotometricDeterminationofTotalNitrogeninWaterwithPhenolDisulfonicAcidasColorReagentGUOZi-zhu,DENGFei-yue,YONGFu-zeng(CollegeofChem.andChem.Eng.,CentralSouthUniversity,Changsha410083,China)Abstract:Inthephotometricdeterminationoftotalnitrogeninwaterwithphenoldisulfonicacidascolorreagent,amodificationofthesampledigestionwithalkalinepotassiumpersulfatewasmadebycarryingoutthedigestioninapressurizedreactionkettleinsteadofinacolorimetrictube,toavoidincompletesampledigestion,incompletedecompositionoftheoxidantandlossofammoniabyevolution.Linearrelationshipwaskeptbetweenvaluesofabsorbanceandconcentrationoftotalnitrogenintherangeof0.02-1.90mg·L-1.Detectionlimit(3σ)ofthemethodfoundwas0.02mg·L-1.Sixwatersampleswereanalyzedbytheproposedmethod,valuesofRSD′s(n=6)foundwerelessthan3.5%.Testforrecoverywasmadebystandardadditionmethod,givingresultsintherangeof98%-102%.Keywords:Photometry;Sampledigestion;Totalnitrogen;Phenoldisulfonicacid;Watersample　　,、,。,-(GB11894-1989)。;,,;,、;,:2008-05-17:(1982-),,,,　。;,。-[1-4],,,。1　1.1　722。:16g6g400mL。:25g500mL,150mL,(·592·:13%)75mL,。,2h,,。:10.0mg·L-1;:10.0mg·L-1;:4.0g·L-1;:。1.2　,4.0g·L-10.2mL,5mL,25mL。,124℃,108.8～137.3kPa,0.5h。,10mL,。2mL,,,10min,10mL。(1+1)20mL,100mL,,。1cm,410nm,,。2　2.1　2.1.1　硫酸银的用量,,。30～40mg·L-1,5mL0.15～0.20mg。,0.2mL,。2.1.2　消解时间8,4.00mL,124℃,5,10,15,20,25,30,35,40min。:0.5h,,,。0.5h。2.1.3　消解容器的选择10.0mg·L-10.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0mL,,:,97%～100%,,,。2.2　,,0.02～1.90mg·L-1,,A=0.0011+0.3962ρ,0.9999,4.04×104L·mol-1·cm-1。20,3(3σ),0.02mg·L-1。2.3　61mL(、),0.5mL()1mL(、、),,6,,1。1,。1　(n=6)Tab.1　Resultsofrecoveryandprecisiontestρ/(mg·L-1)　　　　　　ρ/(mg·L-1)/%RSD/%12.965.007.8898.41.8323.055.008.07100.41.6119.1310.0029.28101.53.156.2410.0016.1699.21.2018.0210.0027.8498.22.765.3710.0015.42100.50.982.4　10,10.01mg·L-1,t,。:[1]　,.[M].4.:,2002.[2]　GB11894-1989　-[S].[3]　GB/T7480-1987　[S].[4]　,.[J].,2005,30(6):108-109.·593·