This Small Business Innovation Research (SBIR) Phase I project is in the topical area of analytical and surface chemistry and in the subfield of process instrumentation. Research designed to establish the feasibility of an instrument capable of measuring multivariate (size and concentration) drop distribution data in heterogeneous liquid dispersions is the thrust of this activity. An instrument of this type can have significant value both as a research device and as a process monitoring tool. Such a device is needed to obtain fundamental knowledge and to improve the design of liquid-liquid contact equipment in various chemical, petrochemical, pharmaceutical, nuclear and metallurgical processes. Phaedron Technologies, Inc. intends to demonstrate during this Phase I activity that such a miniature probe can be developed for these applications and made available at modest costs. The likelihood of attaining this goal is supported by Phaedron's recent success in the development and utilization of a Laser Capillary Spectrophotometer (LCS) system to obtain bivariate drop distribution data. The planned research will be directed towards the design, fabrication and testing of a miniature LCS probe for direct introduction into process vessels to meet various process requirements. The LCS technique is based on the measurement of a pulse width and height of an electrical signal due to attenuated light as the dispersion is forced through a capillary across the path of two parallel laser beams. The probe will be connected to optical fiber bundles to transmit and receive light signals. In Phase I, a suitable photoelectric circuit for data acquisition and the necessary software for data analysis will be developed to implement the conceptual design, and the device will be fabricated and tested. Economic competitiveness would accrue from controlled production of specifically tailored specialty chemicals due to monitoring capabilities heretofore not possible.