Chemical derivatization processes applied to amine determination in samples of different matrix composition

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Green Aspects of Techniques for the Determination of Currently Used Pesticides in Environmental Samples

Pesticides are among the most dangerous environmental pollutants because of their stability, mobility and long-term effects on living organisms. Their presence in the environment is a particular danger. It is therefore crucial to monitor pesticide residues using all available analytical methods. The analysis of environmental samples for the presence of pesticides is very difficult: the processes involved in sample preparation are labor-intensive and time-consuming. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solvent-less and solvent-minimized techniques are becoming popular. The application of Green Chemistry principles to sample preparation is primarily leading to the miniaturization of procedures and the use of solvent-less techniques, and these are discussed in the paper

Methods of isolation and determination of volatile organohalogen compounds in natural and treated waters

Volatile organohalogen environmental pollutants and their sources and the routes of entry into various elements of the environment are described. Comprehensive literature data on the concentrations of these pollutants in natural and treated waters and in wastewaters in various countries are tabulated and discussed. A wide selection of the techniques for the isolation and preconcentration of the above pollutants are presented and discussed. Direct aqueous injection into a capillary column, liquid-liquid extraction, solid-phase extraction and headspace analysis are emphasized

Application and optimization of headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–flame-ionization detector (GC–FID) to determine products of the petroleum industry in aqueous samples

A simple and solvent-free analytical method has been optimized for the determination of hydrocarbons (C6–C20) from products of the petroleum industry in aqueous samples. Extraction and analysis were carried out using headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled with flame-ionization detector (GC–FID). A ZB-5 capillary column (30 m × 0.25 mm inner diameter, 0.25 μm film thickness) was used for GC separation and a 100 μm polydimethylsiloxane (PDMS) fiber was used to isolate the analytes. Parameters of HS-SPME, analytes desorption and GC–FID were selected and an analytical procedure is proposed. Under the optimum conditions the limits of detection were in the range of 2.0–13 μg L− 1 and the relative standard deviations were between 2.6 and 14%. The developed analytical method was successfully applied to the analysis of water contaminated by unleaded petrol and unfiltered water used to extinguish a simulated fire

Multi-residue method for the determination of 16 recently used pesticides from various chemical groups in aqueous samples by using DI-SPME coupled with GC–MS

A simple and solvent-free multi-residue method has been optimized to determine 16 currently used pesticides from different chemical groups in aqueous samples. The extraction of analytes was carried out with direct immersion solid-phase microextraction (DI-SPME) and for the identification and quantitative determination gas chromatography coupled with mass spectrometry (GC–MS) was applied. Two commonly used adsorbent coatings have been applied and compared: 100 μm of polydimethylsiloxane (PDMS) and 85 μm of polyacrylate (PA). The method development parameters of DI-SPME, analyte desorption and GC–MS analysis have been outlined along with the final experimental conditions. When the optimum extraction conditions were applied (extraction time 60 min, 10% (w/v) NaCl solution, 45 °C) the limits of detection (LODs) were in the range of 0.015–0.13 μg L−1 and the relative standard deviations (RSDs) were between 1.9 and 9.6%. The developed analytical method was successfully applied to the analysis of natural water samples from the following sources: river, sea, canal and rain

Destruction of chlorinated pesticides in TiO2-enhanced photochemical process

Aqueous solutions containing 200mg/dm3 of lindane, p,p´-DDT and methoxychlor were photodegraded for 60 min in UV/TiO2/O2 system. Sparged air was introduced into the reactor environment. Titanium dioxide supported on glass, hollow microsphers served as the photocatalyst. Pesticides destruction ratio was evaluated and oxidation products were identificated by gas chromatography with thermionic specific detector (GC-TSD) and mass spectroscopy detector (GC-MS). The concentration of pesticides after reaction was determined in the liquid phase, in the solid phase (adsorbed on the photocatalyst) and in the gas phase. The experimental data indicates that pesticide removal with the gas phase was insignificant, therefore it was neglected in the assessment of the photodegradation efficiency. From 14% to 58% of investigated pesticides remained adsorbed on catalyst surface after photodegradation. High content of pesticides in the solid phase after reaction resulted from their low solubility in water and indicates significant adsorption ability of the pesticides by TiO2