Cassella A R, de Campos R C, Garrigues S, de la Guardia M, Rossi A
Department of Analytical Chemistry, Pontificia Universidade Catolica do Rio de Janeiro, Brazil.
Fresenius J Anal Chem. 2000 Jul;367(6):556-61. doi: 10.1007/s002160000368.
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).
