FIBER-OPTIC-BASED INTERFACE FOR ONLINE SELECTIVE PHOTOMETRIC DETERMINATIONS IN SOLID SAMPLES BY SUPERCRITICAL-FLUID EXTRACTION

A novel windowless fiber optic-based flow-cell constructed from a dril led stainless steel block was used to link a supercritical fluid extra ctor and a spectrophotometer in order to obtain qualitative and quanti tative information from the supercritical extract during the supercrit ical fluid extraction (SFE) process. The coupled system allows the pro cess to be optimized in terms of extraction rate and extraction yield from the shape of the extraction curve and the area under it, respecti vely. The SFE of ground coffee samples was monitored spectrophotometri cally and the suppression of the contribution of coextracted compounds to the analytical signal was demonstrated from derivative spectra.