过硫酸钾氧化-紫外光度法测定总氮方法的改进

过硫酸钾氧化紫外光度法测定总氮的空白吸光度高的主要原因是:K2S2O8在220nm波长上有特征吸收,适当降低K2S2O8、NaOH的用量,延长消解时间,使用二次蒸馏水,用低浓度亚砷酸钠溶液,还原消解后剩余的极少量的K2S2O8,可以降低空白吸光度.K2S2O8-NaOH碱溶液不稳定,使用期短,三天后氧化能力迅速降低,原因是:K2S2O8溶液中,加入NaOH,加速了K2S2O8的分解.K2S2O8和NaOH分别配制,并在K2S2O8溶液中,加入少量HCl,抑制其水解.两种溶液可使用丰年以上时间.

Use the Measurement of Same Water Kind NO3-N and TN

Over the high and main reason of intensity of light of blank absorb oxidizing the measurement of purple and outside intensity of light method the total nitrogen of sulfuric acid potassium is.The K_2 S2_2 O_8 there is characteristic absorption,adequacy on 220 nm wave- lengths to lower the using of K_2 S2_2 O_8,NaOH to measure,extension clear up solution time,use distilled water two times,and use the sour aqua of second arsenic of low and thick degree,and restore clear up solution empress surplus of minimum amount the deal's K_2 S2_2 O_8,can lower the blank absorb the intensity of light.K_2 S2_2 O_8-NaOH alkali the aqua is unsteady to settle,use a short,three divas oxidize soon the ability lower,reason is:K_2 S2_2 O_8 aqua inside,affiliation NaOH,accelerated the K_2 S2_2 O_8 decomposition.The K_2 S2_2 O_8 prepare,combine with NaOH respectively in the K_2 S2_2O_8 aqua,a little amount HCl fo affiliation,repress the solution of its water.Like this,two kinds of aquas can use above time of half a year.