An instrumental method for the individual, sequential or collective measurement of the physical and chemical properties of liquids is presented. A prototype of the fibre drop analyser (FDA), working at only one wavelength in the infrared, has been constructed and tested. The instrument has been used to measure individually surface tension, viscosity, refractive index and the chemical composition of the test solution. The instrument has the capability of simultaneously measuring all of these quantities in one measurement cycle and this possibility is discussed on the basis of one set of results obtained from the sugar processing industry. The instrument is also potentially capable of measuring electrochemical properties of a liquid and some preliminary results are presented. The laboratory FDA has been used to test a series of samples from a large cane sugar manufacturer's process and these measurements demonstrate that the FDA technology has the potential to be used as a remote optrode industrial process monitor for sucrose manufacture, and possibly in other industrial applications.

A new instrumental method has been devised for the individual, sequential, or collective measurement of the physical and chemical properties of liquids. The instrumental theory for the fiber drop analyzer (FDA) has been developed for the measurement of surface tension, viscosity, refractive index, and chemical composition of a liquid. An empirical theory is suggested for the measurement of pH in a limited range. The analytical theory for the fiber drop analyzer has been established, a prototype constructed and tested for measuring individually surface tension, viscosity, refractive index, and the chemical composition on a restricted set of test solution. The instrument is shown to have the capability to simultaneously measure the above measurands, but in addition can in individual measurement procedures, measure all these quantities. The instrument perhaps is also potentially capable of measuring specific gravity and pH in its existing form, and other optical properties of liquids with some basic modification. The laboratory FDA has been used to test a series of samples from a large cane sugar manufacturer’s process and these measurements demonstrate that this technology has the potential to be used as a remote optrode industrial process monitor for sucrose manufacture and very possibly, elsewhere in other industrial applications.