Determination of carbonate in marine solid samples by FTIR-ATRspectroscopy

Abstract

A method for detecting carbonate in marine solid samples (sediments, corals) by Fourier transform infrared spectroscopy (FTIR) coupled to the total attenuated reflectance (ATR) technique is described. Compared to other techniques, the proposed method is not based on the measurement of CO₂ evolved by combustion or acidification of the sample, but on the direct measurement of carbonate present in the sample. For this reason, the method by FTIR-ATR spectroscopy does not require any chemical pre-treatment. The proposed method allows determination of carbonate in the range 6–100% (w/w) as Na₂CO₃ and gives comparable results with the determination of inorganic carbon by elemental analysis.