The instrumental engineering of a polymer fibre drop analyser for both quantitative and qualitative analysis with special reference to fingerprinting liquids

Abstract

Details of a fibre drop analyser (FDA) designed for industrial application are presented along with the specifications of the mechanical, electrical and optical design features necessary for the production of a commercial instrument. Details are given of experimental studies of the design of cylindrical drop heads. The measurement procedure for this instrument is described and the results are presented of a series of development measurements that have been obtained using a constant-volume-delivery single-wavelength (850 nm) FDA for a range of two-fibre test head designs. Brief details are given of the overall software package for the instrument. The method of obtaining both fibre drop traces (FDTs) and vibration drop traces (VDTs), using an environmental chamber necessary for measurements on volatile samples such as alcohol, is described. Details of newly developed integrated hardware and software approaches to the capture of FDTs and VDTs are described. The development of algorithms for the automatic fitting of these vibration data is briefly described, and experimental problems involved in obtaining reproducible vibration traces are discussed. An approach to the computer analysis of the vibration results is sketched, giving an empirical fit of preliminary experimental results which suggest that it might be possible to obtain viscosity measurements from single-drop VDTs. An approach to the FDT fingerprinting of liquid products is described using specially developed fingerprinting software. Finally, some preliminary discussions are presented as to the possibilities offered by the fingerprinting product differentiation capability of this technique.