George Pilidis

Enrichment of PAHs and heavy metals in soils in the vicinity of the lignite-fired power plants of West Macedonia (Greece)

Abstract The polycyclic aromatic hydrocarbon (PAH) content and selected metals were measured in surface soils in the vicinity of the lignite-fired power plants in the vulnerable region of West Macedonia (Greece). The spatial distribution was assessed by direct comparison and normalisation procedures. The data indicated a moderate enrichment for Cr and Ni and to a lesser extent for Mn and relatively high PAH pollution. The prime source of most of PAHs and trace elements measured is ascribed to lignite combustion and less to other anthropogenic activities or soil composition. PAHs with three and four rings which exist mostly in the vapour phase in the atmosphere, are dispersed over long distances. As for cultivation purposes, the critical metal concentrations for plants in the majority of soil samples are not exceeded except for Ni, while the concentration of PAHs in surveyed soils is considered to be low in all respects.

Multielement concentrations in vegetable species grown in two typical agricultural areas of Greece

The multielement (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, V, Zn) levels in various common vegetables and surface soils collected from two typical growing areas of north-western Greece are presented. The results are representative and indicate metal concentration levels in vegetables grown in Greek areas under similar conditions. The content of the metals is generally at the same levels or even lower than that reported for vegetables consumed in several countries and species grown in other agricultural and industrial Greek areas. Enhanced levels of metals observed in certain vegetable species could be related to their concentration in the corresponding soils. The results of the present study indicate that the mean intake of heavy metals (As, Cd, Pb and Se) by adults due to consumption of vegetables from the two sites, for an average consumption, pattern, generally is well below the allowable daily intakes. On the other hand, the contribution of the vegetables to the recommended amounts of the essential elements (Cu, Fe, Mn and Zn) is satisfactory and higher than previously reported.

4-Aminoantipyrine spectrophotometric method of phenol analysis: Study of the reaction products via liquid chromatography with diode-array and mass spectrometric detection

Abstract The synthesis of new pyrazolone molecules and their application as chromogenic agents in phenol analysis by the 4-aminoantipyrine method has been described by our group in previous published papers. A fully detailed mechanism is given therein based on experimental and theoretical data. In this paper, the study of the reaction products and by-products via liquid chromatography with diode array and mass spectrometric detection is presented, sorting out the spectrophotometric determination of phenols.

Development of a method for the simultaneous determination of phosphoric and amino acid group containing pesticides by gas chromatography with mass-selective detection: Optimization of the derivatization procedure using an experimental design approach

An integrated gas chromatographic-mass-selective detection method for the analysis of the phosphoric and amino acid group containing pesticides is presented. The analytes are derivatized using a single-step procedure for the simultaneous esterification and acetylation of the active groups of analytes (-OH, -COOH, -NH2) by means of acetic acid and trimethyl orthoacetate. An experimental design approach based on the central composite design is used to investigate the dependence of the derivatization variables with the total yield of derivatization of pesticides. The variables selected for study were: the amount of reagents, the temperature and the reaction time. When considering the total pesticide derivatization yield, the amount of acetic acid, the reaction temperature and the reaction time are found to be statistically significant. The electron impact ionization mass spectra of the resulting derivatives are acquired and properly interpreted. Under the chromatographic conditions employed, acceptable peak separation is attained. When the selective ion monitoring mode is used for quantitation purposes, low detection limits in the range 0.05 to 14 microg/l are achieved. Recoveries of spiked water samples range from 96 to 103% and the mean RSD of the method do not exceed 3.5%.

Phase-transfer catalytic determination of phenols as methylated derivatives by gas chromatography with flame ionization and mass-selective detection

A convenient method for the GC determination of phenols as methylated derivatives is proposed, taking advantage of the beneficial features of phase-transfer catalysis (PTC). The optimal experimental conditions of pH, temperature, organic solvent, time of extraction-derivatization and amounts of the participating reactants and catalysts, were properly established. Several catalysts in soluble or polymer-bound form were tested. Most of them demonstrated appreciably high-performance characteristics but the polymer-bound catalyst is most favourable due to its facile separation from the rest of the reaction system after the extraction-derivatization. Interferences with the extraction and derivatization yield were not noticed. The chromatographic separation of 11 methylated derivatives of phenols was complete within 23 min. The detection limits of the method, which range from 0.005 to 0.120 microg, are inadequate for drinking water analysis. However, the method was successfully applied to the analysis of fortified composite lake water samples using GC-flame ionization detection and GC-MS in the single ion monitoring mode with the most abundant characteristic ions. Spiked recoveries of phenolics were in the range 94-102%, on the basis of distilled water calibration graph, signifying that PTC determination of phenols is not affected by the composition of such matrices.

Use of a sequential extraction scheme with data normalisation to assess the metal distribution in agricultural soils irrigated by lake water

Abstract Multi-element analysis was performed in a sandy loam and a loam agricultural soil irrigated with water from a relatively polluted lake applying a sequential extraction procedure. Extracts were analyzed for: Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn. The concept of data normalisation is introduced, yielding interesting information on the relative intrinsic affinity of some of the metals for the separate phases of the soil system. The results indicated a low percentage of easily exchangeable and carbonate bound metals. For certain elements, the study revealed new information for the separate extracted phases as regards the relative retention behaviour of these metals. The majority of the metals extracted were found in the oxidizable (organically bound+sulphides) and reducible (Fe–Mn oxyhydroxides) fractions. These fractions are considered as the most efficient scavengers for the studied metals. Total metal analysis showed an enrichment of some elements in the surface soils as a result of agricultural and anthropogenic activities. The depth variation of heavy metals in the core soils in connection with extractability by EDTA suggests a relatively high mobility of Pb, Cu, Co and Mn. The results of this study present both an issue of local interest and the interpretation of the trend of the binding metals in the phases of soil systems using a simple normalization method.

An integrated gas chromatographic method towards the simultaneous determination of phosphoric and amino acid group containing pesticides

SummaryAmpropylfos, glyphosate, glufosinate and bialaphos are water soluble pesticides that contain phosphoric and amino acid groups in their molecules. Their polar nature and high water solubility make extraction difficult and limit the options for using the various derivatization techniques often employed for gas chromatographic analysis. A multiresidue method is proposed that allows the simultaneous determination of six analytes (pesticides and some of their metabolites) in environmental waters down to sub-μb L−1 levels. A mixture of trifluoroacetic anhydride and trifluoroethanol converts them in a single-step reaction to derivatives that are sufficiently volatile for gas chromatographic analysis. Electron capture and mass-selective detection are used for quantitation purposes, and their analytical characteristics are presented. Under the chromatographic conditions employed, acceptable separation is attained for the derivatized analytes, with both glufosinate and bialaphos emerging as double peaks. Recoveries of spiked environmental water samples range from 88 to 106%. The mean relative standard deviation of the method does not exceed 3.0%, whereas, depending on the detection system, the limits of detection for the analytes are in the range of 0.09–65 μg L−1, the upper value being the bialaphos detection limit.

Pyrazol-3-ones. Part III: Reactivity of the Ring Substituents

Publisher Summary All pyrazolones are named according to the International Union of Pure and Applied Chemistry (IUPAC) recommendations as pyrazol-3-ones and not as pyrazol-5-ones. The IUPAC nomenclature numbers the ring clockwise, whereas most organic chemists are used to an anti-clockwise numbering. Alkylation of pyrazol-3-ones usually occurs not only on side-chain substituents, such as primary amino groups, but also on the nitrogen atom of the unsubstituted lactam group. Alkylation can also occur on a stabilized carbanion generated from a methyl group by a strong base. Most of the acylation reactions are carried out with 4-amino-1,2-dihydro-1,5-dimethyl-2- phenyl-3H-pyrazol-3-one (4-aminoantipyrine). The acid chlorides are prepared separately or generated in situ from the corresponding carboxylic acid in the presence of the aminopyrazol-3-ones. The only halogenation reactions of the ring substituents of pyrazol-3-ones known are those with bromine, N-bromosuccinimide, and hydrogen bromide. Sulfonation of 5-aminopyrazol-3-ones is described. Coupling the diazonium salts with carbon nucleophiles is the most common reaction. Condensation reactions are discussed. One of the categories of reactions may involve nucleophilic addition either by or to the pyrazol-3-one side-group. A variety of nucleophilic substitution reactions are discussed. Pyrazol-3-ones are oxidized by a variety of oxidizing agents. The reduction of functional groups, such as aldehyde, nitro, nitroso, alkene, and imino as well as deamination of amines and cleavage of amides are accomplished by various reducing agents without affecting the pyrazol-3-one ring. Some miscellaneous reactions are discussed.

Pyrazol-3-ones. Part II: Reactions of the Ring Atoms

Publisher Summary This chapter examines the reactions of the ring atoms of pyrazol-3-ones, in particular 1,2-dihydro-3 H -pyrazol-3-one and 2,4-dihydro-3 H -pyrazol-3-one. The chapter describes reactions of pyrazol-3-ones with alkyl halides, esters of sulfonic and carbonic acids, trimethyloxonium tetrafluoroborate, diazo compounds, Mannich or Mitsunobu conditions or miscellaneous reagents. Pyrazol-3-ones are known to be ambient compounds and depending on the solvent in which they are dissolved can exist in several tautomeric forms. Usually in less polar solvents such as chloroform pyrazol-3-one tautomers are dominant, whereas in more polar solvents such as dimethylsulfoxide 3-hydroxypyrazole tautomers are dominant. It is noted that pyrazol-3-ones are weak acids and can be titrated with strong bases. 2,4-Dihydro-3H-pyrazol-3-ones are stronger acids than 1,2-dihydro-3H-pyrazol-3-ones, which are very weak. The outcome of acylation of the ring atoms of pyrazol-3-ones with acid chlorides depends on the type of substitution on the pyrazol-3-one ring. Both C- and N acylation are possible. With 2-aryl-4-(or 5)-substituted pyrazol-3-ones and reaction with acid chlorides occurs in 1,4-dioxane with calcium hydroxide.

Anaerobic Co-Digestion of table olive debittering & washing Effluent, cattle manure and pig manure in batch and high volume laboratory anaerobic digesters: Effect of temperature

The prospective of table olive debittering & washing Effluent (DWE) as feed stock wastewater for anaerobic digestion (AD) systems was investigated in batch and continuous systems together with cattle and pig manures. While DWE considered unsuitable for biological treatment methods due to its unbalanced nature, the co-digestion of the wastewaters resulted in a 50% increase in the methane production/gram volatile solids(added) (CH(4)/gVS(added)), accompanied by 30% phenol reduction and 80% total organic carbon removal (TOC). pH increase during the co-digestion period was not identified as an inhibitory factor and all reactors were able to withstand this operational condition change. Moreover, no volatile fatty acid (VFA) accumulation was observed, indicating that the reactors were not operating under stress-overloading state. Under thermophilic conditions a 7% increase on the TOC removal efficiency was achieved when compared to the mesophilic systems while, under mesophilic conditions phenolic compounds reduction was 10% higher compared to the thermophilic systems.