AN INVESTIGATION OF THE APPLICABILITY OF ATTENUATED TOTAL-REFLECTION INFRARED-SPECTROSCOPY FOR MEASUREMENT OF SOLUBILITY AND SUPERSATURATION OF AQUEOUS CITRIC-ACID SOLUTIONS

Currently applied methods for measurement of solubility and supersatur ation based on viscometry, refractometry, interferometry and density r equire the separation of phases prior to measurement. ATR (attenuated total reflection) infrared spectroscopy provides a unique configuratio n in which the infrared spectrum of a liquid phase can be obtained in a slurry without phase separation. The applicability of the technique was investigated using a micro Circle(R) open boat cell equipped with a ZnSe (zinc selenide) ATR rod. Experiments conducted with aqueous cit ric acid proved that ATR infrared spectroscopy can be successfully emp loyed to determine solubility and supersaturation.