Identification of calcium palmitate in gallstones by infra-red spectroscopy

Crystallographic studies have shown that calcium palmitate was the fourth most frequent crystalline constituent of gallstones, but it has never been detected using an infra-red technique. This report demonstrates that IR spectroscopy represents an accurate and easy method for detection of this compound in gallstones. First, palmitic acid has been unequivocally identified from gallstones after chloroformic extraction in an acidic medium, on the basis of 1H NMR and mass spectra. Secondly, the characteristic bonds of pure calcium palmitate have been well established (2920, 2850, 1575, 1540, 1470, 1430, 1412, 1110, 710 cm-1) enabling the identification of this compound isolated or in association with other components of calculi.