Search results for "Mercury-vapor lamp"
showing 3 items of 3 documents
Photochemical-chemiliminometric determination of aldicarb in a fully automated multicommutation based flow-assembly
2004
[EN] A sensitive and fully automated method for determination of aldicarb in technical formulations (Temik) and mineral waters is proposed. The automation of the flow-assembly is based on the multicommutation approach, which uses a set of solenoid valves acting as independent switchers. The operating cycle for obtaining a typical analytical transient signal can be easily programmed by means of a home-made software running in the Windows environment. The manifold is provided with a photoreactor consisting of a 150 cm long x 0.8 mm i.d. piece of PTFE tubing coiled around a 20 W low-pressure mercury lamp. The determination of aldicarb is performed on the basis of the iron(III) catalytic minera…
A Fully Automated Assembly Using Solenoid Valves for the Photodegradation and Chemiluminometric Determination of the Herbicide Chlorsulfuron
2005
Abstract This paper presents a new photochemiluminescent system for the determination of chlorsulfuron in water samples. The light from a low‐pressure mercury lamp is used as a clean, reproducible, and inexpensive “reagent” for the derivation of the pesticide, performed in glycine buffer at pH 9.5. Then, the photo‐products from irradiation are oxidized by permanganate in sulfuric acid solution. The oxidation reaction was favored by using high temperatures. A comparative study and discussion about the use of polyphosphoric acid instead of sulfuric acid in the oxidation reaction is also presented. The use of solenoid valves allows for the easy, complete automation of the process with low samp…
‘In situ’ preparation of nitrous acid solutions by photoreduction in a flow assembly for analysis of pharmaceuticals
2003
The solutions of nitrite ion, or nitrous acid, are frequently used as reagent in different analytical procedures and in pharmaceutical analysis. The low stability of the aqueous solutions of this reagent implies the tedious work of freshly prepared solutions every day and being kept in the refrigerator. In this paper, a photoreactor formed by a low pressure mercury lamp and nesting in a continuous-flow manifold is studied, tested, and proposed for the in situ reduction of nitrate solution into nitrite. The conversion into nitrite is reproducible and it has been successfully applied to determination of different drugs, mostly from the sulphonamide family, in an FIA assembly.