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A method was developed for the determination of simple phenolic compounds (PCs) in waste waters from olive oil production plants by liquid chromatography (LC). The sample under examination was acidified to pH 2 to precipitate proteins, acetone was added to eliminate the colloidal fraction, and hexane was used for extraction to eliminate lipidic substances. The solution obtained was filtered and injected into the LC system; the wavelength selected for the spectrophotometric detection was specific for PCs, so that carbohydrates, organic acids, and short-chain free fatty acids did not interfere. Recoveries of 9 PCs spiked to a real sample were 90-100% for concentrations ranging from 20 to 2000 mg/L for each analyte.

From the leaves of aloe, a succulent plant, a dried exudate commonly called aloe can be obtained, which is used as a natural drug for its cathartic effect and is widely employed as a bittering agent in alcoholic beverages. This investigation provides a tentative characterization of several commercial aloe exudates carried out both by reversed phase HPLC and by headspace GC-MS analysis. By means of HPLC the derivatives were evaluated, and by GC-MS the volatile fraction was investigated. Qualitative and quantitative differences among the constituents in various samples of different origins were found. In particular, these were evident in the HPLC profile of Kenya aloe and an Aloe barbadensis sample, which exuded a high content of isoaloeresin D and aloins, whereas GC-MS analysis showed the presence of anisole exclusively in Kenya aloe samples. Moreover, the results obtained by means of the latter technique suggested a reason for the prevailing use of Mosselbay and Port Elizabeth aloes in bitter spirits formulation.