Degradation products of profenofos as identified by high-field FTICR mass spectrometry: Isotopic fine structure approach.

This study was performed to identify the degradation products of profenofos "a phenyl organothiophosphate insecticide" in raw water (RW) collected from the entry point of Metropolitan Water Works Authority "Bangkaen, Thailand" and ultrapure water (UPW) with and without TiO under simulated sunlight irradiation. Degradation of profenofos was followed with ultrahigh performance liquid chromatography (UHPLC) and follows pseudo first-order kinetic. Accordingly, high-field FTICR mass spectrometry coupled to an electrospray ionization source was used to reveal the degradation routes of profenofos and the isotopic fine structures (IFS) elucidations to approve the chemical structures of its degradation products.

Ozone photolysis of paracetamol in aqueous solution.

The degradation of a paracetamol (N-acetil-para-aminofenol) aqueous solution (C (0) P = 5 mmol L(-1)) is studied in a bench-scale setup by means of simple ozonation (O3) and ozonation catalyzed with UV light (O3/UV) in order to quantify the influence of UV light on the degradation process. The results have shown that under the adopted experimental conditions (25°C, applied ozone dose = 9.8 mg L(-1) and gas flow rate of 20 L h(-1)) both oxidative systems are capable of removing the substrate with mineralization degrees up to 51% for ozonation and 53% for O3/UV.

Photolysis pathway of imazapic in aqueous solution: ultrahigh resolution mass spectrometry analysis of intermediates.

Direct degradation of imazapic, an herbicide of the imidazoline family, has been investigated in aqueous solution at different concentrations, pH values, and temperatures. The efficiency of the photodegradation process has been evaluated through degradation rate constants that could be fitted best with pseudo-first-order kinetics ( Ct = C0 e(- kt )). Ultrahigh resolution mass spectrometry (FTICR/MS) was used in electrospray ionization mode as a tool to study the photolysis process on a molecular level, whereas UV-vis and high-performance liquid chromatography/mass spectrometry analysis were used to follow, by time, the evolution of the intermediates.

Ecotoxicity of biocomposites based on renewable feedstock - preliminary studies.

The aim of the work was to study the biodegradation process of biocomposites prepared from renewable resources and the ecotoxicological assessment of their biodegradation products. Biocomposites from modified starch reinforced with various cellulose fibers were prepared by the extrusion process. Biodegradation studies were carried out according to the ISO respirometic method.

Triclosan determination in water related to wastewater treatment.

Triclosan in the waste, river and sea water samples collected in Hong Kong was analyzed by using gas chromatography-ion trap mass spectrometry method. (13)C(12)-triclosan was used as internal standard for the quantitative analysis. Water samples were prepared and cleaned-up by using a C(18) solid-phase extraction cartridge.