Fourier transform infrared determination of CO2 evolved from carbonate in carbonated apatites.
A quantitative method based on FTIR has been developed to determine carbonate in synthetic apatites. The method measures the evolved CO2 after reaction of 50 mg apatite with 2 mL of hydrochloric acid (0.5 M) in a reaction vessel, heated to 40 degrees C. The CO2 evolved was swept by a carrier of nitrogen to a laboratory-made infrared gas cell of 39 mm pathlength and 490 microL volume. The signals were recorded as a function of time and the areas of the chemigram peaks obtained from the measurements in the wavenumber range of 2,500-2,150 cm(-1), were interpolated using a calibration curve. The method can be used to study apatites with carbonate contents below 0.2% with a sampling frequency of 8 h(-1).
Cassella
A R
AR
Department of Analytical Chemistry, Pontificia Universidade Catolica do Rio de Janeiro, Brazil.
de Campos
R C
RC
Garrigues
S
S
de la Guardia
M
M
Rossi
A
A
D001031:Apatites / Q000737:chemistry*; D002245:Carbon Dioxide / Q000032:analysis*; D002254:Carbonates / Q000737:chemistry*; D004867:Equipment Design; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation / Q000379:methods
D001031:Apatites; D002254:Carbonates; D002245:Carbon Dioxide