INTEGRATED PERVAPORATION DETECTION - CONTINUOUS AND DISCONTINUOUS APPROACHES FOR TREATMENT DETERMINATION OF FLUORIDE IN LIQUID AND SOLID SAMPLES

Methods based on integration of pervaporation and potentiometric detection in a laboratory-made module are proposed for the determination of fluoride in liquid and solid samples by formation of a volatile product with hexamethyldisiloxane. The method for liquid samples is developed in a continuous system either by injection or by aspiration of the in-line-formed derivative and features linear determination between 2.5 and 500 mu g/mL (detection limit of 1.5 mu g/mL) with good precision and a sample throughput of 20 samples/h, It has been validated and applied to tap water, ceramic industry wastewater, and dissolved fertilizers, The method for solid samples integrates leaching of the target analyte, formation of the volatile derivative, separation, and detection in the laboratory-made module and shows figures of merit similar to those of the method for liquid samples, but the sample throughput is 2 samples/h, It has been successfully applied to the determination of fluoride in orange tree leaves.