DETERMINATION OF PHOSPHORUS AND FLUORINE IN POLYMERS AND ORGANIC COMPOUNDS WITH Nd~(3+)

Procedures are developed for the determination of fluorine and phosphorus in polymers and organic compounds by titration with Nd(NO3)3-EDTA after decomposing the sample by O-flask. An amount of sample corresponding to approximately 1 mg of fluorine is decolmposed and absorbed in an O-flask containing an excess of 0.01 M Nd3+ (NO3)3. The absorbing liquid is boiled for 3 minutes. After being allowed to cool, a pH= 5.5 buffer is added. In the presence of xylenol orange, the mixture is titrated with 0.01 M EDTA. The procedure for determining phosphorus is the same as described above, but precipitation reaction of NdPO4 is carried out in pH 5.5 after eliminating CO2. If sample contains F and P, PO43- in the solution containing F- can be determined after eliminating F - by adding HNO3 and concentrating solution to dryness, and the percentage of F can be found after determining the total content of F and P. Determination procedure of total content is the same as F-, but buffer is added while the mixture is hot. The maximum error of determing P is ±0.20% and F is ±0.30% except high fluorine or fully flucrinated compounds which give values approximately 0.50% lower than calculation.