Senar Ozcan

Determination of selected polychlorinated biphenyls in water samples by ultrasound-assisted emulsification-microextraction and gas chromatography-mass-selective detection

Ultrasound-assisted emulsification-microextraction (USAEME) procedure was developed for the determination of selected polychlorinated biphenyls (PCBs) in 10 mL of water samples by gas chromatography-mass-selective detection. After determination of the most suitable solvent and extraction time, several other parameters including solvent volume, centrifugation time and ionic strength of the sample were optimized using a 2(3) factorial experimental design. The optimized USAEME procedure used 200 microL of chloroform as extraction solvent, 10 min of extraction with no ionic strength adjustment at 25 degrees C and 5 min of centrifugation at 4000 rpm. The limits of detection ranged from 14 ngL(-1) (for PCB153) to 30 ngL(-1) (for PCB101). Recoveries of PCBs from fortified distilled water are over 80% for three different fortification levels between 0.1 and 5 microgL(-1) and relative standard deviations of the recoveries are below 10%. The performance of the proposed method was compared with those involving traditional liquid-liquid extraction (LLE) and solid phase extraction (SPE) on the real water samples (i.e., tap and well water as well as domestic and industrial wastewaters, etc.) and comparable efficiencies were obtained. The proposed USAEME procedure has been demonstrated to be viable, simple, rapid and easy to use for residue analysis of PCBs in water samples.

Application of ultrasound-assisted emulsification-micro-extraction for the analysis of organochlorine pesticides in waters

Ultrasound-assisted emulsification-micro-extraction (USAEME) procedure was developed for the determination of different organochlorine pesticides (OCPs) in water samples by gas chromatography with mu-electron capture detection (GC-microECD). After the determination of the most suitable extraction solvent and its volume, parameters such as extraction time, centrifugation time and ionic strength of the sample were optimized by using a 2(3) factorial experimental design. For 10 mL of water sample, the optimized USAEME procedure used 200 microL of chloroform as extraction solvent, 15 min of extraction without ionic strength adjustment at 25 degrees C and 5 min of centrifugation at 4000 rpm. Limits of detection ranged from 0.002 to 0.016 microg L(-1). Mean recoveries of OCPs from fortified water samples are over 96% for three different fortification levels between 0.5 and 5 microg L(-1) and relative standard deviations of the recoveries are below 9%. The developed procedure was successfully applied for real water samples (i.e., tap water, well water, surface (lake) water, domestic and industrial wastewater). Performance of the procedure was compared with those involving traditional liquid-liquid extraction and solid-phase extraction. The result demonstrates that the USAEME procedure is viable, rapid and easy to use for analysis of OCPs in water samples.

Determination of polycyclic aromatic hydrocarbons in waters by ultrasound-assisted emulsification-microextraction and gas chromatography–mass spectrometry

An ultrasound-assisted emulsification-microextraction (USAEME) procedure was developed for the extraction of US EPA 16 polycyclic aromatic hydrocarbons (PAHs) in 10 mL of water samples, with subsequent determination by gas chromatography-mass spectrometry (GC-MS). After determination of the most suitable solvent and solvent volume, several other parameters (i.e., extraction time, centrifugation time and ionic strength of the sample) were optimized using a 2(3) factorial experimental design. Limits of detection ranged from 0.001 to 0.036 microg L(-1). The developed procedure was applied to fortified distilled water with different fortification levels (0.5, 2 and 5 microg L(-1)). Recoveries were over 92% and relative standard deviations of the recoveries were below 8%. The efficiency of the USAEME was compared with traditional liquid-liquid extraction (LLE) and solid-phase extraction on real water samples (i.e., tap water, well water and surface (lake) water as well as domestic and industrial wastewaters). The USAEME showed comparable efficiencies especially with LLE. The developed USAEME was demonstrated to be robust, viable, simple, rapid and easy to use for the determination of PAHs in water samples by GC-MS.

Analyses of polychlorinated biphenyls in waters and wastewaters using vortex-assisted liquid-liquid microextraction and gas chromatography-mass spectrometry.

A method was developed for viable and rapid determination of seven polychlorinated biphenyls (PCBs) in water samples with vortex-assisted liquid-liquid microextraction (VALLME) using gas chromatography-mass spectrometry (GC-MS). At first, the most suitable extraction solvent and extraction solvent volume were determined. Later, the parameters affecting the extraction efficiency such as vortex extraction time, rotational speed of the vortex, and ionic strength of the sample were optimized by using a 2(3) factorial experimental design. The optimized extraction conditions for 5 mL water sample were as follows: extractant solvent 200 μL of chloroform; vortex extraction time of 2 min at 3000 rpm; centrifugation 5 min at 4000 rpm, and no ionic strength. Under the optimum condition, limits of detection (LOD) ranged from 0.36 to 0.73 ng/L. Mean recoveries of PCBs from fortified water samples are 96% for three different fortification levels and RSDs of the recoveries are below 5%. The developed procedure was successfully applied to the determination of PCBs in real water and wastewater samples such as tap, well, surface, bottled waters, and municipal, treated municipal, and industrial wastewaters. The performance of the proposed method was compared with traditional liquid-liquid extraction (LLE) of real water samples and the results show that efficiency of proposed method is comparable to the LLE. However, the proposed method offers several advantages, i.e. reducing sample requirement for measurement of target compounds, less solvent consumption, and reducing the costs associated with solvent purchase and waste disposal. It is also viable, rapid, and easy to use for the analyses of PCBs in water samples by using GC-MS.

Application of miniaturised ultrasonic extraction to the analysis of organochlorine pesticides in soil.

A miniaturised ultrasonic extraction procedure was developed for the determination of different organochlorine pesticides (OCPs) in soil by gas chromatography (GC/mu-ECD). For an acetone-petroleum ether (1/1, v/v) as the extractor and a 5-min sonication, parameters such as sample amount, solvent volume and number of extraction steps were optimized by using a 2(3) factorial experimental design. Limits of detection ranged from 0.02 to 1.34 microg kg(-1). The developed procedure was applied to three different real soil samples with different fortification levels (25, 50 and 100 microg kg(-1)) and recoveries were estimated in the 82-106% range with relative standard deviations lower than 15%. Performance of the procedure was compared with those involving traditional shaking flask, Soxhlet extraction and large-scale ultrasonic extraction. The proposed procedure requires small volumes of solvent and sample. It is viable, rapid and easy to use for analysis of OCPs in soils.

Levels of Organochlorine Pesticides and Heavy Metals in Surface Waters of Konya Closed Basin, Turkey

The concentrations of organochlorine pesticides (OCPs), including α-, β-, γ-, and δ-hexachlorocyclohexane (HCH), heptachlor, heptachlor epoxide, dieldrin, aldrin, endrin, endrin aldehyde, endrin ketone, endosulfan I, endosulfan II, endosulfan sulfate, p,p′-DDE, p,p′-DDD, p,p′-DDT, methoxychlor, chlordane I, chlordane II, and heavy metals, such as As, Cr, Cu, Fe, Mn, and Ni in surface water samples from the Konya closed basin were determined to evaluate the level of contamination. Among all HCH isomers, β-HCH is the main isomer with a concentration range of 0.015–0.065 μg/L. DDE, DDD, and DDT were almost determined in all samples, in which DDE isomer had the highest concentration ranged from not detected to 0.037 μg/L. In all studied OCPs, aldrin showed the highest concentration at 0.220 μg/L. The concentrations of heavy metals in water samples were observed with order: Mn < Cu < Ni < As < Cr < Fe. In some samples, As, Fe, and Cr concentrations exceeded the drinking water quality recommended by EU, US EPA, WHO, and Turkish Regulation, while Cu, Ni, and Mn concentrations are below the guideline values. The levels of both OCPs and heavy metals were also compared with other previously published data.

An investigation on the sorption behaviour of montmorillonite for selected organochlorine pesticides from water.

The sorption behaviour of montmorillonite towards organochlorine pesticides (OCPs) from aqueous solutions is reported. After preliminary investigation of the sorption capability of clay for selected OCPs, aldrin was used as a model compound for further experiments. The batch sorption experiments were carried out as functions of contact time, pH of the solution, initial aldrin concentration and dosage of the montmorillonite. After traditional liquid–liquid extraction, the determination of OCPs was carried out by gas chromatography coupled with a μ-electron capture detector (GC-μECD). The results indicated that sorption of aldrin followed the second-order kinetic model and that the equilibrium time depended on the initial aldrin concentration. The film diffusion was found to be a main sorption rate control mechanism. The removal was explained according to the electrostatic bonding mechanism. The Freundlich isotherm model better represented the sorption data than the Langmuir model. The montmorillonite was also used efficiently for the removal of OCPs from fortified tap and surface (lake) water samples.

Using n-Alkanes for Identification of Oils in Domestic Wastewaters

The aim of this work was to investigate whether linear aliphatic hydrocarbons had a usable potential for the determination of waste oil in wastewater. For that, n-alkanes analyses of wastewater samples from five sampling points (P1-P5) of the sewage system of Konya–Turkey were carried out by gas chromatographic technique and the parameters of carbon predominance index (ICP), n-C17/n-C18 and unresolved complex mixture (UCM)/n-alkanes ratios were determined. It was found that sampling points P1, P2 and P3, which had ICP values 1.52±0.04, 1.43±0.05 and 1.12±0.05, respectively, were polluted with petroleum hydrocarbons and the aliphatic hydrocarbons detected in the sampling points of P4 and P5, which had ICP values of 0.96±0.05 and 0.95±0.03, respectively, were from natural origin. These results were also supported by the parameters of n-C17/n-C18 and UCM/n-alkanes ratios and by the correlation between the parameters of ICP, n-C17/n-C18, UCM/n-alkanes and COD, Pb, Cr for all sampling points

Analytical Methods for Viable and Rapid Determination of Organochlorine Pesticides in Water and Soil Samples

Organochlorine pesticides (OCPs) are the potential group of chemicals used to improve agricultural productivity. The extensive use of pesticides to improve agricultural productivity played an important role in the last century. These compounds have been applied for decades in preventing, repelling or mitigating the effects of pests. OCPs are one of the most persistent organic pollutants present in the environment. Although most of OCPs have been banned in many countries because of mutagenic and carcinogenic effects, they and their metabolites are still present in the environment owing to their persistence and lipophilic properties. The toxicity, potential bioaccumulation and non-biodegradability of these compounds represent risks to the environment (FAO/WHO, 1989). Maximum admissible concentration (MAC) of pesticides and related products for drinking water is 0.1 μg L-1 for individual pesticides and 0.5 μg L-1 for total concentrations given by the European Union (EU) Drinking Water Directives (EEC, 1980). Additionally, pesticides residue in surface water must be less than 1–3 μg L-1. Moreover, because of their hydrophobicity and persistence, OCPs accumulate in soils where they are likely to be retained for many years (FAO/WHO, 1989). Therefore, determination and monitoring of OCPs in different environmental matrices are important for environment, especially for human health. Consequently, residue analyses of OCPs in waters and soils by developing analytical procedure continue to be an active area of research in recent years (Santos & Galceran, 2004). Trace analysis of OCPs in water is usually performed by gas chromatography (GC) combined with a previous an extraction or a pre-concentration step including traditional liquid–liquid extraction (LLE) (Barcelo , 1993, Fatoki & Awofolu, 2003; Tahboub et al., 2005), solid phase extraction (SPE) (Aguilar et al., 1996; 1997), solid phase microextraction (SPME) (Page & Lacroix, 1997; Aguilar et al., 1999; Tomkins & Barnard, 2002; Li et al., 2003; Dong et al., 2005) and the more recently developed liquid phase microextraction under different names, i.e., dispersive liquid–liquid microextraction (DLLME) (Cortada et al., 2009a; Leong & Huang, 2009; Tsai & Huang, 2009), liquid-phase microextraction (LPME) (Huang & Huang, 2007; Farahani et al., 2008), single-drop microextraction (SDME) (Cortada et al., 2009b), polymer-coated hollow fiber microextraction (PC-HFME) (Basheer et al., 2004), stir bar sorptive extraction (SBSE) (Leo n et al., 2003; Pe rez-Carrera et al., 2007), ultrasound

Acute Toxicity of Organophosphorus Pesticides and Their Degredation By-Products to Daphnia Magna, Lepidium Sativum and Vibrio Fischeri

Organophosphorus pesticides (OPPs) attained the growing importance in pests control because of their rapid decomposition and less likely accumulation in environment. They are still of great concern however, for water sources contamination because of their high solubility in water and excessive usage. Their usage amounts were elevated after they were introduced as replacements for the highly persistent organochlorine pesticides. They are classified into two main groups, organophosphates (P=O) and organothiophosphates (P=S) depending on whether oxygen or sulphur forms a double bond with the central phosphorous atom. They were found in environment with enough frequency (Ballesteros and Parrado, 2004) to constitute an ecotoxicological risk. Their concentration in water sources (Barcelo et al., 1990; Konstantinou et al., 2006), in air (Tuduri et al., 2006) and food (Bai et al., 2006; Darko and Akoto, 2008) can vary between a few ppb to ppm levels. The presence of these pesticides can directly affect the health of aquatic and terresterial organisms and may present a threat to humans through contamination of drinking water supplies. OPPs always pose acute toxicity but not chronic toxicity on organisms because of their quick degradation (Ye et al., 2010). OPPs are known to cause inhibition of acetylcholinesterase (AChE) in target tissues which leads to accumulation of acetylcholine. According to its key physiological role in nerve transmission, AChE is the target of various insecticides. AChE is an enzyme vital for normal nerve function and AChE inhibition leads to over stimulation of the central and peripheral nervous systems, resulting in neurotoxic effects in organisms. OPPs also produce oxidative stress in different tissues (Possamai et al., 2007) and shows genotoxic (Bolognesi, 2003; Cakir and Sarikaya, 2005, Arredondo et al., 2008) and immunotoxic (Yeh, et al., 2005; Day et al., 1995) effects. The majority of OPPs give rise to only slight inhibition of AChE by themselves, unless they undergo oxidative activation. This process involves the substitution of the sulfur atom in the P=S bond of the organophosphate pesticide with an oxygen atom resulting with formation of oxon derivatives (OPPs-oxons) (Fig. 1). This substitution is a result of advanced oxidation processes such as O3, O3/UV, H2O2/UV, fenton, photo-fenton, TiO2/UV, etc. in water treatment and natural oxidation processes such as UV radiation and microbial degradation. Combined oxidation systems decreases toxicity effects of by-products via enhancing mineralization. Kim et al. (2006) used Vibrio fischeri and