Application of Headspace Solid-Phase Microextraction for Determination of Chloro-Organic Compounds in Sewage Samples

Solid phase microextraction (SPME) has been optimized and applied to the determination of the volatile halogenated compounds (VHCs) and semi-volatile halogenated compounds (SVHCs). Three types of SPME fiber coated with different stationary phases (PDMS–100 μm, CAR/PDMS-75 μm, PDMS/DVB–65 μm) were used to examine their extraction efficiencies for the compounds tested. Experimental parameters such as the selection of SPME coatings, extraction time, and addition of salts were studied. The carboxen-polydimethylsiloxane (CAR/PDMS) fiber appears to be the most suitable for the determination of VHCs. Analytical parameters such as linearity, limit of detection, and precision were also evaluated. Application of ECD detector for the determination of VHCs and SVHCs allows their determination on the low concentration level, ranging from 0.005 to 0.8 μg/L−1. The HS-SPME-GC/ECD procedure gave good analytical precision expressed as relative standard deviation (RSD) (ranged from 5.08% to 8.07%) for a concentration level of 5 μg/L−1 and good linearity (r2 > 0.98) in a wide calibration range. The applied HS-SPME-GC/ECD method was found to be a quick and effective technique for the determination of microtrace amounts of volatile and semi-volatile halogenated compounds in samples containing high amounts of various organic compounds

On the effectiveness and limits of fiscal stabilizers

The smoothing impact of fiscal stabilizers (proxied by government expenditures) on business cycle volatility is studied for a panel of European Union (EU) countries in the period 1970–1999. Special emphasis is put on the investigation of possible nonlinearities in the relationship between Gross Domestic Product (GDP) growth volatility and fiscal stabilizers. The results show that the business cycle volatility smoothing effect of fiscal stabilizers may revert at high levels. The results hold when using government revenues as a proxy for fiscal stabilizers.

Growth, convergence and EU membership

The effect of European integration on long-term growth of the EU-15 member states is studied by means of panel data methods. The length of EU membership is found to have a significant positive effect on economic growth, which is relatively higher for poorer countries. While previous empirical studies tend not to find positive growth effects of regional integration, the present study suggests an asymmetric, convergence-stimulating impact of EU membership on long-term growth.