摘要
本文进一步研究了DPD亚铁滴定法测定ClO_2+Cl_2总量及ClO_2%的适宜条件,指出必须加入足量的H_2PO_4^--HPO_4^(2-)缓冲液以维持滴定介质的pH值在6.2—6.5范围内;在测定ClO_2时,为了有效地掩蔽Cl_2,甘氨酸的加入量必须充分,且在较浓时反应片刻,然后稀释,才能得到准确的测定结果.还讨论了终点返红现象及其消除。
The appropriate conditions for determination of ClO2 + Cl2 sum and ClO2% by DPD (N, N-diethyl-p-phenylenediamine)-Ferrous titrimetric method have been studied further in this paper. The pH value of titrimetric medium must be maintained at 6.2 to 6.5 by adding enough amount phosphate buffer solution. Sufficient glycine is added for effective masking Cl2 when ClO2 is determined singly, and let the reaction proceeded moment at more concentrating solution before dilution, only in these cases, accurate determination can be obtained. The phenomenon of return-red at endpoint and their elimination has been discussed.
