Panayotis A. Siskos

Characterization of lead, cadmium, arsenic and nickel in PM2.5 particles in the Athens atmosphere, Greece

Concentrations of Pb, Cd, As and Ni in PM(2.5) particles were measured in samples collected, using low volume PM(2.5) samplers (Harvard Impactor system, HI) at two sites in Athens basin; Patission Street in Athens city center and Rentis, a semi-urban and industrial area, during March 1995-March 1996. Sample analysis for Pb, Cd, Ni and As was accomplished by electrothermal atomic absorption spectrometry after total digestion. Annual geometric mean values in 183 PM(2.5) particles samples were found to be: Pb: 143 nanogram(-3); Cd: 0.34 nanogram(-3); Ni: 4.55 nanogram(-3); As: 0.79 nanogram(-3). The geographical and temporal distribution patterns were investigated. Pb exhibited higher values during the winter period. For the other elements no significant seasonal variation was observed. Wind direction, air temperature and relative humidity affected element concentrations. Principal component analysis was applied on the data to enable source apportionment of toxic elements in PM(2.5) particles. It was found that Pb, As and Ni have common sources, which could be vehicles emissions/oil combustion and resuspended road dust. Cd and a portion of As originate from industrial activities.

Nitro-PAH in ambient particulate matter in the atmosphere of Athens.

Nitrated polynuclear aromatic hydrocarbons (NPAH) with a molecular mass of 247 Daltons were found in soot collected in downtown Athens during a campaign performed in 1996. In particular, 2-nitrofluoranthene (2-NFa) and 2-nitropyrene (2-NPy), which are mainly related to photo-induced chemical processes occurring in the atmosphere, were more abundant than 1-nitropyrene (1-NPy) usually associated to motor vehicle exhaust.

Carbonyl compounds in the urban environment of Athens, Greece

The concentration levels of 15 selected carbonyl compounds in 62 samples were determined at two sites in Athens basin from June to December 2000. Formaldehyde was the most abundant species (0.05-39 microg m(-3)), which comprised from 22% to 37% of the total measured compounds, followed by acetaldehyde (4.32-49 microg m(-3)), acetone/acrolein (0.64-198 microg m(-3)) and butanal (0.79-140 microg m(-3)). The mean formaldehyde/acetaldehyde and acetaldehyde/propanal molar ratios were calculated. No significant seasonal differences were observed for all the carbonyls. Photochemical production was found to weigh upon atmospheric levels for 83-93% in summer days, dropping below 33% in the winter. The importance of formaldehyde and acetaldehyde as a source of hydroxyl radicals in Athens was also assessed.

Rainwater composition in Athens, Greece

Wet precipitation-only samplers were used to collect wet deposition at two sites in the Athens basin, Greece for the period March 1986–February 1987. Concentrations of major cations (H+, NH+4, Na+, K+, Ca2+ and Mg2+) and major anions (Cl−, NO−3 and SO2−4) were determined for the first time in rainwater samples in Greece. Bicarbonate concentrations were calculated. The relative importance of natural and anthropogenic sources were estimated by a chemical balance. The majority of rain collected has a neutral or alkaline character. Acidity was due to the presence of H2SO4 and HNO3. The statistical analysis of the correlation between the concentration of chemical species confirm the influence of natural and anthropogenic sources. In all samples, SO2−4 concentrations exceed NO−3 concentrations despite the dominance of low S oil burning in the region. The wet flux of S was calculatd to be 0.34 gm−2a−1.

Comparative study of pretreatment methods for the determination of metals in atmospheric aerosol by electrothermal atomic absorption spectrometry.

A comparative study of pretreatment methods for the determination of 10 elements (As, Cd, Pb, V, Ni, Mn, Cr, Cu, Fe, Al) in atmospheric aerosols by electrothermal atomic absorption spectrometry (ETAAS) was conducted. For the digestion of the particulates collected in filters, six methods were compared using a mixture of HNO(3) and HF with or without the addition of various oxidative agents (HClO(4) or H(2)O(2)) or acids (HCl). The comparative study was performed using loaded cellulose filter samples, which were digested in Parr bombs and heated in a conventional oven at 170 degrees C for 5h. The extraction efficiency and blanks were compared and it was proved that the digestion method using only HNO(3)-HF extracted most of the metals and gave the lowest blanks. The HNO(3)-HF mixture was selected for the development of an improved microwave digestion method specific for aerosol-loaded filters. The operating parameters were optimized, so that quantitative recovery of the reference materials NIST 1649a urban dust and NIST 1648 urban particulate matter was achieved. The blank of cellulose and teflon filters were also determined and compared. Teflon filters present the lowest blanks for all the elements. The obtained limits of detection for each type of filters were adequate for environmental monitoring purposes. ETAAS instrumental operation was also optimized for the compensation and the elimination of interferences. The temperature optimization was performed for each metal in every type of filter and optimized parameters are proposed for 10 elements.

Determination of ephedrines in urine by gas chromatography-mass spectrometry.

A selective gas-liquid chromatographic method with mass spectrometry (GC-MS) for the simultaneous confirmation and quantification of ephedrine, pseudo-ephedrine, nor-ephedrine, nor-pseudoephedrine, which are pairs of diastereoisomeric sympathomimetic amines, and methyl-ephedrine was developed for doping control analysis in urine samples. O-Trimethylsilylated and N-mono-trifluoroacetylated derivatives of ephedrines--one derivative was formed for each ephedrine--were prepared and analyzed by GC-MS, after alkaline extraction of urine and evaporation of the organic phase, using d3-ephedrine as internal standard. Calibration curves, with r2>0.98, ranged from 3.0 to 50 microg/ml depending on the analyte. Validation data (specificity, % RSD, accuracy, and recovery) are also presented.

Chemical composition of wet and dust deposition in Athens, Greece

In the present study a wet/dry precipitation collector was used (Canadian MIC) to collect wet and dust deposition samples in one station in the center of the Athens basin, Greece, for the period September 1987–August 1988. Concentrations of the main cations (H+, NH4+, Na+, K+, Ca2+ and Mg2+) and main anions (Cl−, NO3− and SO42−) were determined. The analytical chemical methods were evaluated with NBS standard reference material and with rainwater samples from EMEP (European Monitoring Evaluation Programme). Statistical analyses of correlation between the concentration of chemical species and correlation diagrams between chemical species concentrations and wind directions were made in order to estimate the origin of the determined ions both in wet and dust deposition. In all samples non-marine molar sulfate concentrations exceed nitrate concentrations despite the dominance of low sulfur oil burning in the region (0.3% for domestic heating, 0.7% for industrial uses). For 37% of the samples the pH was lower than 4.5 and for 69% of samples was lower than 5.6. The wet flux of sulfur was calculated to be 0.67 gm−2yr−1. The results support the conclusion that chemical constituents in rain and dust deposition are a combination of emissions from natural and anthropogenic sources.

Evaluation of Anasorb CMS and comparison with Tenax TA for the sampling of volatile organic compounds in indoor and outdoor air by breakthrough measurements

The most widely used technique for the sampling of volatile organic compounds (VOCs) in indoor and outdoor air is preconcentration on a solid sorbent. The evaluation of the ability of a sorbent to trap specific VOCs is usually checked by measuring the breakthrough volume (BTV) of a compound on the sorbent. In this work, Anasorb CMS was evaluated and compared with Tenax TA for the sampling of VOCs commonly found in indoor and outdoor environments. The influence of parameters such as flow-rate, amount of the sorbent and vapour concentration on BTV was studied. The combination of Anasorb CMS and Tenax TA in a two-bed sorbent tube was also investigated for the sampling of complex mixtures of VOCs. The relative standard deviation for triplicate runs of the whole procedure for the evaluation of the sorbent was found to be approximately 3.5%.

Determination of sialic acids in biological fluids using reversed-phase ion-pair high-performance liquid chromatography

A simple, rapid and sensitive reversed-phase ion-pair high-performance liquid chromatographic method for the determination of N-acetylneuraminic acid and 2-deoxy-2,3-dehydro-N-acetylneuraminic acid in biological fluids is described. Determination of N-acetylneuraminic acid released by acidic hydrolysis, in serum, urine and saliva, and 2-deoxy-2,3-dehydro-N-acetylneuraminic acid in urine, without hydrolysis, was accomplished by injecting the sample without derivatization, into the chromatograph. Measurements were carried out isocratically within 6 min using a C18 column and a mobile phase of aqueous solution of triisopropanolamine, as ion-pair reagent, 60 mM, pH 3.5 at room temperature with UV absorbance detection. The present method is reported for the first time for the determination of sialic acids in biological fluids. Recoveries in serum, urine and saliva ranged from 90 to 102% and the limits of detection were 60 nM and 20 nM for the two sialic acids, respectively. The method has been applied to normal and pathological sera from patients with breast, stomach, colon, ovarian and cervix cancers, to normal urine and urine from patient with sialuria and to normal saliva.

An improved spectrophotometric method for the determination of free, bound and total N-acetylneuraminic acid in biological fluids

Abstract The spectrophotometric periodate-resorcinol method for the measurement of free, bound and total N-acetylneuraminic acid has been modified. The proposed method improves sensitivity by 27%, reduces the time of analysis by 33–52% and addresses interferences from biological substances. The improved procedure was applied to serum and urine samples for the determination of free, bound and total N-acetylneuraminic acid and compared successfully to the method reported by Jourdian et al. and to a commercially available enzymatic method. The results show that the proposed method is reliable, simple and convenient for routine use in clinical laboratory.