COMPLEXOMETRIC DETERMINATION OF THORIUM, LANTHANUM, AND TRIVALENT CERIUM WITH THE USE OF CARMINIC ACID

Journal Article · Wed Jan 01 04:00:00 EST 1958 · Chemia Analityczna (Warsaw) (Poland)

OSTI ID:4152954

Dobrowolski, J

S>It was found that solutions of carminic acid, which are yellow at pH less than 7, acquire a violet coloration in the presence of La/sup 3/)+ and Ce/ sup 3+/; on addition of Th the solutions acquire a blue color. For a complexometric determination of Th, using carminic acid as an indicator, 0.05 to 1.00 ml of the solution being analyzed are added to a 3 ml buffer solution of pH 2 (mixture of 0.1 N HCl and 0.1 N glycol). The mixture is heated to boiling, several drops of 1% ethanol solution of carminic acid are added, and titration is carried out with 0.01 to 0.1 M solution of Complexon III until the blue color of the solution changes to yellow. In the titration of 0.3 mg Th the determination error is less than 11%; in the case of larger amounts (more than 6 mg Th) it drops to less than 2%. For determination of La or Ce (or of their sum) 0.05 to 1.00 ml of the solution being analyzed are added to a 3 ml buffer solution of pH 3.7, and titration with a solution of Complexon III is carried out until the violet color of the solution changes to yellow. Accuracy of the determination is the same as in the case of Th. If Th is being determined in solutions containing La and Ce in approximately the same araounts, titration is carried out without their separation (Th content in the sample must be at least 5 mg). The determination error is less than 3.5%. In the determination of La and Ce in the presence of Th, the Th is first precipitated with H/sub 2/O/sub 2/. In such a case the results of the determination of La and Ce are somewhat too low (up to 10%) which is attributed to possible losses during the separation of Th.

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-14-022867
• OSTI ID: 4152954
• Journal Information: Chemia Analityczna (Warsaw) (Poland), Journal Name: Chemia Analityczna (Warsaw) (Poland) Vol. Vol: 3; ISSN CANWA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACIDITY
CARMINIC ACID
CERIUM
CHEMICAL REACTIONS
CHEMICALS
CHEMISTRY
COLOR
COMPLEXES
EDTA
ERRORS
HYDROGEN PEROXIDES
LANTHANUM
PRECIPITATION
QUALITATIVE ANALYSIS
QUANTITATIVE ANALYSIS
SEPARATION PROCESSES
SOLUTIONS
THORIUM