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Quantitative Determination of Crystalline Na 5 P 3 O 10 –I (Form‐I) in Commercial Tripolyphosphate using X‐ray Diffraction Patterns
Author(s) -
Kijkowska R.,
Kowalski Z.,
PawlowskaKozinska D.,
Wzorek Z.
Publication year - 2002
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/1521-4079(200210)37:10<1121::aid-crat1121>3.0.co;2-o
Subject(s) - pyrophosphate , diffraction , x ray , powder diffraction , x ray crystallography , chemistry , analytical chemistry (journal) , sodium , calibration , crystallography , materials science , chromatography , optics , mathematics , physics , enzyme , statistics , biochemistry , organic chemistry
Abstract An x‐ray diffraction method (XRD) for quantitative determination of the crystalline Na 5 P 3 O 10 ‐I (Form‐I) in a mixture of Form‐I/Form‐II was applied for commercial pentasodium tripolyphosphate analysis. The XRD pattern of the Form‐I shows the unique non‐overlapping 2θ peak at a position of ≈ 21.8 deg. and also at ≈ 29.0 deg. (Cu radiation). The area (integral of the intensity) under the peaks is proportional to the amount of the Form‐I in the mixture covering the range up to 100 wt.%. That enables one to obtain a calibration line and to determine the amount of Form‐I in the mixture of Form‐I/Form‐II and also in commercial pentasodium tripolyphosphate. Commercial samples with high Form‐I concentration, in case they are contaminated with sodium pyrophosphate (Na 4 P 2 O 7 ), should be diluted with Form‐II to bring the concentration of the Form‐I below 50 wt.% in the analysed sample.