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Complexometric determination of barium with copper(II)-EDTA-PAR as indicator
| Content Provider | Semantic Scholar |
|---|---|
| Author | Nonova, D. Lihareva, Nadejda |
| Copyright Year | 1973 |
| Abstract | A sensi t ive m e t h o d for de tec t ing the end-po in t of the d i rec t E D T A t i t r a t i on of Ba has been deve loped using a m i x e d C u ( I I ) E D T A / P A R indica tor . The exchange equi l ib r ium be tween C u ( I I ) E D T A and Ba ions was u t i l ized to employ the well de tec tab le endpo in t of Cn(I I ) wi th P A R . The m e t h o d was app l i ed to the analys is of ba r i t e concent ra te a n d to the de t e rmina t i on of su lphate . 1 -100 mg of Ba were de t e rmined wi th errors of a b o u t ~ 0.5--3~ . Er ro r s in the su lpha te de t e rmina t i on were a b o u t 0 .1 -0 .5 ~ Procedures 1. Ba Titration. To 100 ml of the sample solution containing 1--100 mg of Ba add 10 ml of 6.5 N ammonia, 5--6 drops of 0.01 M solution of Cu(II)-disodinm complex of EDTA and 3--5 drops of 0.050/0 aqueous PAR [4-(2-pyridylazo-resorcinol)] solution. Titrate with 0.01--0.05 M EDTA solution until the red-violet colour fades and continue carefully to a distinct change to pure yellow with no dark shade. 2. Barite Analysis. Fuse 0.3 g of the sample in a platinum crucible with 8 time the weight of Na2CO a and K2CO~, treat the melt as usual, collect the slight hydrochloric acid solution in a 250 ml volumetric flask and proceed as above, only add 3 ml of aqueous triethanolamine solution (1:2) before the ammonia as masking agent for Fe and A1. A turbidity of the solution can be prevented by further addition of tartaric acid, yet results are about 20/0 higher in this case due to the Ca present as Ba is usually accompanied by Ca and the similarity in their analytical properties is most troublesome in their quantitative determination. A correction for Ca will be dealt with later. 3. Sulphate Determination. Precipitate the slightly acid solution containing 15--30 mg of sulphate with an exactly measured excess of BaCI~ solution, allow to digest and filter. Aliqnots of the filtrate are treated as under 1. |
| Starting Page | 31 |
| Ending Page | 31 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| DOI | 10.1007/BF00453183 |
| Volume Number | 265 |
| Alternate Webpage(s) | https://rd.springer.com/content/pdf/10.1007/BF00453183.pdf |
| Alternate Webpage(s) | https://doi.org/10.1007/BF00453183 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
