ABSTRACT
A flow-injection method for determination of xanthate with amperometric detection is presented. A composite carbon electrode modified with silica gel is used for detection. Very good reproducibility (1.5% r.s.d.) results from renovation of the electrode surface by three potential scans between measurements. In the analysis of flotation liquor, the interfering effect of metal complexes, formed by leaching of the ore in water, is eliminated by addition of EDTA. The method can be used to determine ethyl xanthate in the concentration range 0.10-10.0 mg/1, with a detection limit of 0.04 mg/1.
ABSTRACT
A polarographic thin-layer detector for high-performance liquid chromatography, was devised. The detector has a sandwich structure with a working surface area of the mercury electrode of 0.25 mm2. The detector was applied to the direct amperometric detection and for detection with reactivation of the electrode surface by voltage pulses. It is shown that the latter detection mode is suitable for the determination of compounds that form insoluble or complex mercury salts, e.g., thiourea. Thiourea and its derivatives can be separated and determined in a wide concentration range and the detection limit for thiourea corresponds to 2 ng injected. Thiourea can be determined directly in urine.
