Type Of Extraction Solvent Research Articles

Modified QuEChERS in combination with dispersive liquid-liquid microextraction based on solidification of the floating organic droplet method for the determination of organophosphorus pesticides in milk samples.

In this work, a rapid, environment friendly and sensitive method was established for the extraction and analysis of five organophosphorus pesticides (OPPs) (chlorpyrifos, chlorpyrifos-methyl, isocarbophos, malathion and phorate) in milk samples by means of gas chromatography-flame photometric detection. The pesticides were first extracted with acetonitrile from milk samples by using the modified "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method. No other clean-up was required after extraction. Then the above-mentioned acetonitrile extract was concentrated by using the dispersive liquid-liquid microextraction combined with solidification of floating organic droplets technique. Several factors that could influence the extraction efficiency, such as type of extraction solvent, disperser solvent, volume of extraction and disperser solvent, salt effect, sample pH, and extraction time, were investigated and optimized. As a result, 15 µL of 1-dodecanol were used as the extractant because of its lower toxicity, 300 µL methanol was chosen as dispersant and the extraction time was set to 1 min. Under the optimized conditions, good linearity was exhibited from 0.01 to 1.0 mg/L with the correlation coefficients higher than 0.9968. The limits of detection of the five OPPs were ranged in 0.1-0.3 μg/L, and the limits of quantification were at the range of 0.3-1.0 μg/L. Moreover, the recoveries of the target analytes from milk samples at spiking levels of 0.01, 0.05 and 0.1 mg/L were between 80.5 and 106.5% with the relative standard deviations varied from 3.6 to 6.3%. This method has been successfully applied to detect OPPs in real milk samples.

An integrated method for the simultaneous determination of alkylphenol ethoxylates and brominated flame retardants in sewage sludge samples by ultrasonic-assisted extraction, solid phase clean-up, and GC-MS analysis

Generally, a major route of alkylphenol ethoxylates (APEs) and brominated flame retardants (BFRs) to enter the environment is via the wastewater treatment works (WWTW) facilities. Consequently, the levels of APEs and BFRs in sewage sludges may give an indication of the general use and exposure of these compounds. The present study was aimed at an integrated method for the analysis and quantification of APEs and BFRs in sewage sludge from selected wastewater treatment plants. The optimization of the extraction procedure included variation of the amount of extracted biomass, the duration, temperature during sonication as well as type of extraction solvent. Chromatographic determinations of APEs and BFRs were carried out with gas chromatography equipped with mass spectrometry detector after derivatization with heptafluorobutyric anhydride (HFBA). The mean percentage recoveries ranged from 39% to 79% (n=3) for sewage sludge after extracting 5g biomass sludge with hexane: acetone (4:1) at 55°C for 45min in two cycles. The mean concentrations of APEs obtained ranged from<LOQ to 365ngg−1, <LOQ to 166ngg−1, <LOQ to 642ngg−1 while the concentration of BFRs obtained range from<LOQ- 17ngg−1, <LOQ to 163ngg−1, <LOQ to 14ngg−1 for sludge samples from Leeuwkuil, Rietspruit, and Sebokeng, respectively. All compounds, except for nonylphenol (NP), BDE47, and BDE154, were detected from the Rietspruit WWTW. The presence of these pollutants in Rietspruit WWTW may be attributed by the fact that this treatment plants treat wastewater from domestic as well industrial discharges from the surrounding area.

Determination of β-agonists in Porcine Meats by Ion-Pair Extraction and High Performance Liquid Chromatography

ABSTRACTIon-paired extraction was employed for the determination of salbutamol, clenbuterol, and ractopamine. Tetrabutylammonium bromide was used as the ion-pairing agent and water–acetonitrile was the extraction solvent. The concentration and pH of the buffer, salt addition, concentration of tetrabutylammonium bromide, and type and volume of extraction solvent were optimized. No centrifugation step was required. Matrix interferences from real samples were eliminated using matrix-matched calibration. Under the optimum conditions, a linear calibration relationship was present from 0.0025 to 3 µg mL−1 with an enrichment factor of more than 25. This method was combined with high-performance liquid chromatography for the determination of β-agonists in porcine meats with low limits of detection, high recovery, and rapid analysis.

Dynamic microwave-assisted extraction online coupled with single drop microextraction of organophosphorus pesticides in tea samples

A new method for the determination of seven organophosphorus pesticides was developed using dynamic microwave-assisted extraction online coupled with single drop microextraction prior to gas chromatographic mass spectrometry (GC–MS). The method combines the advantages of dynamic microwave-assisted extraction and single-drop microextraction, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, tea samples were extracted with 25% ethanol aqueous solution and purified with acidic alumina at the same time, and then the analytes were concentrated into microextraction solvent. When the extraction was completed, the solvent microdrop containing the enriched analytes was retracted into the microsyringe and directly analyzed by GC–MS without any filtration or cleanup step. The method makes extraction, cleanup, separation, and enrichment to be carried out in one step. Several experimental parameters, including type of extraction solvent, type and amount of dispersant, type and volume of microextraction solvent, microwave power, extraction time, and flow rate of extraction solvent were investigated and optimized. Under optimal experimental conditions, good linearity was observed in the range of 2.00–500.00μgkg−1. The limits of detection and quantification were in the range of 0.4–1.7μgkg−1 and 1.1–5.6μgkg−1, respectively. The present method was applied to the analysis of tea samples, and the recoveries of analytes were in the range of 84.9–106.4% with the relative standard deviations ranging from 1.0 to 6.1%. The results showed that the present method was a rapid and feasible method for the determination of organophosphorus pesticides in tea samples.

Optimized Dispersive Liquid-Liquid Microextraction Method and High Performance Liquid Chromatography with Ultraviolet Detection for Simultaneous Determination of Sorbic and Benzoic Acids and Evaluation of Contamination of These Preservatives in Iranian Foods.

A rapid, simple, and sensitive dispersive liquid-liquid microextraction procedure followed by HPLC-UV was applied to determine the benzoate and sorbate in foods. The method was optimized for some variables including extraction solvent type and volume, dispersing solvent type and volume, and the effects of salt and pH. Optimum conditions were determined as follows: sample volume, 5 mL; extraction solvent (chloroform) volume, 250 μL; disperser solvent (acetone) volume, 1.2 mL; NaCl amount, 0.75 g/5 mL at pH 4. Sixty samples were analyzed, including 15 doogh, 15 fruit juice, 15 cookie, and 15 tomato paste; benzoic acid was detected in 57 samples (95%) at levels up to 448.1 μg/mL and sorbic acid in 31 samples (51.6%) at levels up to 1369 μg/mL. Under the optimum experimental conditions, the LOD and LOQ were determined as 0.1 and 0.5 μg/mL for benzoate and 0.08 and 0.3 μg/mL for sorbate, respectively. The results showed that these preservatives are commonly used at high levels in yogurt drinks (dooghs) and cookies. Also, the concentration of benzoic acid that was detected in the tomato paste and fruit juice samples was low but may affect children and sensitive persons.

Dispersive liquid–liquid microextraction: An efficient approach for the extraction of Cd and Pb from honey and determination by flame atomic absorption spectrometry

In this work, the application of dispersive liquid–liquid microextraction (DLLME) for the extraction and preconcentration of Cd and Pb in honey and subsequent determination by flame atomic absorption spectrometry (FAAS) is proposed. Parameters such as type and volume of dispersive solvent (300μL of acetonitrile for Cd and 900μL of acetone for Pb), type and volume of extraction solvent (140μL of carbon tetrachloride), concentration of complexing agent (sodium diethyldithiocarbamate, 0.25gL−1 for Cd and 0.50gL−1 for Pb), pH (7.0), temperature (35°C), washing cycles of extract (2 times), centrifugation speed (840g for Cd and 4600g for Pb) and sample mass (500mg) were evaluated. The limits of detection (LODs) were 20 and 140ngg−1 for Cd and Pb, respectively. These limits are lower than those established by the Brazilian Ministry of Agriculture, Livestock and Supply (500ngg−1 for both elements) for honey and for food in European Community. Samples were also digested in a microwave-assisted digestion system followed by element determination by inductively coupled plasma mass spectrometry (ICP-MS). Therefore, the proposed method is promising for routine analysis and quality control of Cd and Pb in honey.

Multi-residue method for determination of 58 pesticides, pharmaceuticals and personal care products in water using solvent demulsification dispersive liquid–liquid microextraction combined with liquid chromatography-tandem mass spectrometry

A rapid and efficient sample pretreatment using solvent-based de-emulsification dispersive liquid–liquid microextraction (SD-DLLME) coupled with liquid chromatography-tandem mass spectrometry (LC–MS/MS) was studied for the extraction of 58 pharmaceuticals and personal care products (PPCPs) and pesticides from water samples. Type and volume of extraction and disperser solvents, pH, salt addition, amount of salt and type of demulsification solvent were evaluated. Limits of quantification (LOQ) in the range from 0.0125 to 1.25µgL−1 were reached, and linearity was in the range from the LOQ of each compound to 25μgL−1. Recoveries ranged from 60% to 120% for 84% of the compounds, with relative standard deviations lower than 29%. The proposed method demonstrated, for the first time, that sample preparation by SD-DLLME with determination by LC–MS/MS can be successfully used for the simultaneous extraction of 32 pesticides and 26 PPCPs from water samples. The entire procedure, including the extraction of 58 organic compounds from the aqueous sample solution and the breaking up of the emulsion after extraction with water, rather than with an organic solvent, was environmentally friendly. In addition, this technique was less expensive and faster than traditional techniques. Finally, the analytical method under study was successfully applied to the analysis of all 58 pesticides and PPCPs in surface water samples.

Liquid Chromatographic Determination of NSAIDs in Urine After Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Droplets

An environmentally benign method of sample preparation based on dispersive liquid–liquid microextraction and solidification of floating organic droplets (DLLME-SFO) coupled with high-performance liquid chromatography with ultraviolet detection has been developed for analysis of non-steroidal anti-inflammatory drugs (NSAIDs) in biological fluids. A low-toxicity solvent was used to replace the chlorinated solvents commonly used in conventional DLLME. Seven conditions were investigated and optimized: type and volume of extraction solvent and dispersive solvent, extraction time, effect of addition of salt, and sample pH. Under the optimum conditions, good linearity was obtained in the range 0.01–10 µg mL−1, with coefficients of determination (r2) >0.9949. Detection limits were in the range 0.0034–0.0052 µg mL−1 with good reproducibility (RSD) and satisfactory inter-day and intra-day recovery (95.7–115.6 %). The method was successfully used for analysis of diclofenac, mefenamic acid, and ketoprofen in human urine. Analysis of urine samples from a patient 2 and 4 h after administration of diclofenac revealed concentrations of 1.20 and 0.34 µg mL−1, respectively.

Development of a low-density-solvent dispersive liquid-liquid microextraction with gas chromatography and mass spectrometry method for the quantitation of tetrabromobisphenol-A from dust.

The development of an alternative dispersive liquid-liquid microextraction protocol utilizing a low-density extraction solvent, toluene, is described here for the extraction of the brominated flame retardant, tetrabromobisphenol-A, from dust prior to selected ion monitoring analysis by gas chromatography with mass spectrometry. Method parameters of dispersive solvent type and extraction solvent type were optimized. Excellent recovery (88.9%; n = 5 spike replicates) with good precision was achieved in a spike and recovery study. This developed method was utilized to survey tetrabromobisphenol-A concentrations in dust sampled from a local electronics recycling facility from the ambient environment and 20 computer towers undergoing recycling. Concentrations of tetrabromobisphenol-A from dust in computer towers ranged from not detected (n = 2) up to 64 μg/g with a mean value of 11 μg/g and median of 4.1 μg/g tetrabromobisphenol-A. A composite sample of dust collected from the ambient indoor environment was analyzed with a resulting concentration of 36 μg/g. This is the first application of this novel green method for pre-concentrating flame retardants from dust and the first report of tetrabromobisphenol-A concentrations at a U.S.-based electronics recycling facility.

Evaluation and application of microwave-assisted extraction and dispersive liquid–liquid microextraction followed by high-performance liquid chromatography for the determination of polar heterocyclic aromatic amines in hamburger patties

This study developed an analytical method based on microwave-assisted extraction and dispersive liquid–liquid microextraction followed by high-performance liquid chromatography for the determination of three polar heterocyclic aromatic amines from hamburger patties. Effective parameters controlling the performance of the microextraction process, such as the type and volume of extraction and disperser solvents, microwave time, nature of alkaline aqueous solution, pH and salt amount, were optimized. The calibration graphs were linear in the range of 1–200ngg−1, with a coefficient of determination (R2) better than 0.9993. The relative standard deviations (RSD) for seven analyses were between 3.2% and 6.5%. The recoveries of those compounds in hamburger patties were from 90% to 105%. Detection limits were between 0.06 and 0.21ngg−1. A comparison of the proposed method with the existing literature demonstrates that it is a simple, rapid, highly selective and sensitive, and it gives good enrichment factors and detection limits for determining HAAs in real hamburger patties samples.

Lead preconcentration as rac-(E,E)-N,N′-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine complexes from water and tobacco samples by dispersive liquid-liquid microextraction

A dispersive liquid-liquid microextraction (DLLME) procedure for determination of Pb(II) in water and tobacco samples has been developed using rac-(E,E)-N,N′-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine as a chelating agent. Factors influencing the efficiency of DLLME have been optimised, including metal solution pH, type and amount of dispersing solvent, type and amount of extraction solvent, amount of chelating agent and sample volume. The optimized conditions for maximum recovery were as follows: sample pH 6; dispersing solvent, 500 μL of ethanol; extraction solvent, 150 μL of chloroform; chelating agent, 150 μL of 0.01% rac-(E,E)-N,N′-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine; and sample volume, 15 mL. The method was validated using the certified reference material SPS-WW2 waste water. The method offered a limit of detection (LOD) of 2.6 μg/L, a limit of quantification (LOQ) of 8.5 μg/L, and a relative standard deviation (RSD) of 5.2%.

Dispersive liquid-liquid microextraction with solidification of floating organic droplets for simultaneous extraction of pesticides, pharmaceuticals and personal care products

Dispersive liquid-liquid microextraction based on solidification of floating organic droplets (DLLME-SFO) has been applied to the extraction of pharmaceutical and personal care products (PPCPs) and pesticides from water samples. The PPCPs included bisphenol A, sodium diclofenac, gemfibrozil, furosemide, glibenclamide, nifedipine, nimesulide, propylparaben and triclocarban. The pesticides included 2,4-D, atrazine, azoxystrobin, cyproconazole, clomazone, dichloran, difenoconazole, diuron, epoxiconazole, fenoxaprop-p-ethyl, fipronil, iprodione, irgarol, propanil, propiconazole, tebuconazole, and trifloxystrobin. The type and volume of extraction solvent, type and volume of disperser solvent, ionic strength and pH were optimized. All species were then quantified by liquid chromatography tandem mass spectrometry (LC-MS/MS). The limits of quantification (LOQs) ranged from 50 to 500 ng L−1, and the linearity ranged from the LOQ of each compound up to 10,000 ng L−1. Recoveries ranged from 63 to 120 %, with relative standard deviations lower than 14 %. It is making use of a low-toxicity and affordable extraction solvent (1-dodecanol) and was successfully applied to the analysis of surface water samples.

Surfactant-free Microemulsion Reinforced Hollow-Fiber Liquid-Phase Microextraction Combined with Micellar Electrokinetic Capillary Chromatography for Detection of Phthalic Acid Esters in Beverage and Urine

For the first time, the surfactant-free microemulsion reinforced hollow-fiber liquid-phase microextraction (SFME-HF-LPME) was developed for the determination of phthalic acid esters (PAEs) followed by field-enhanced sample injection with reverse migrating micelles (FESI-RMM) in capillary electrophoresis. An SFME composed of toluene, isopropanol, and water was used to reinforce HF. The prepared SFME-HF was applied to extract PAEs. After extraction, analytes were desorbed and analyzed by capillary electrophoresis. Several important parameters influencing the extraction efficiency of SFME-HF-LPME such as the type of extraction solvent, SFME component, extraction time, desorption condition, pH value, stirring rate, and salting-out effects were optimized. The proposed method provided a good linearity, low limits of detection, and good repeatability of the extractions. This method was then utilized to analyze trace PAEs in beverage and urine. The results indicated that the developed method is an excellent alternative for the PAEs routine analysis in the food and biological field.

Determination of Urinary PAH Metabolites Using DLLME Hyphenated to Injector Port Silylation and GC-MS-MS.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants and well-known carcinogens. Hydroxy derivatives of PAH are considered as biomarkers of PAH exposure, and there is a need to measure these metabolites at low concentrations. So, a precise and eco-friendly analytical method has been developed for rapid determination of PAH metabolites. For the first time, a new analytical method based on coupling of dispersive liquid-liquid microextraction (DLLME) with auto-injector port silylation (auto-IPS) followed by gas chromatography-tandem mass spectrometry (GC-MS-MS) analysis is reported for the analysis of seven urinary PAH metabolites. Factors affecting DLLME and IPS, such as type and volume of extraction and disperser solvent, pH, ionic strength, injector port temperature, volume of N,O-bis(trimethylsilyl)trifluoroacetamide and type of solvent were investigated. Under optimized conditions, the limit of detection and limit of quantification were found to be in the range of 1-9 and 3-29 ng/mL, respectively. Satisfactory recoveries of metabolites in urine samples in the range of 87-95% were found. The developed method has been successfully applied for the determination of PAH metabolites in urine samples of exposed workers. DLLME-auto-IPS-GC-MS-MS method is time, labor, solvent and reagent saving, which can be routinely used for the analysis of urinary PAH metabolites.

UV-vis spectrophotometric determination of trinitrotoluene (TNT) with trioctylmethylammonium chloride as ion pair assisted and disperser agent after dispersive liquid–liquid microextraction

In the present study, a simple, fast and inexpensive method based on dispersive liquid–liquid microextraction (DLLME) prior to microvolume UV-vis spectrophotometry was developed for the preconcentration and determination of trinitrotoluene (TNT). The procedure is based on the color reaction of TNT in alkaline medium and extraction into CCl4 as an ion pair assisted by trioctylmethylammonium chloride, which also acts as a disperser agent. Experimental parameters affecting the DLLME method such as pH, concentration of sodium hydroxide, amount of trioctylmethylammonium chloride, type and volume of extraction solvent were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 0.9ng/mL and the calibration curve was linear in the range of 3–200ng/mL. The relative standard deviation for 25 and 100ng/mL of TNT were 3.7% and 1.5% (n=6), respectively. The developed DLLME method was applied for the determination of TNT in different water and soil samples.

A simple dispersive liquid–liquid microextraction method for determination of Ag(I) by flame atomic absorption spectrometry

A simple and efficient dispersive liquid–liquid microextraction (DLLME) procedure was optimized for the determination of Ag(I) by flame atomic absorption spectrometry (FAAS). In this method, 8-hydroxyquinoline was used as a chelating reagent for Ag(I) and resulted complex was extracted in chloroform, while ethanol is used as disperser solvent. The effective parameters on the recovery of Ag(I), such as the pH of sample, the type and volume of extraction and disperser solvents, the amount of 8-hydroxyquinoline reagent, extraction time, the effect of temperature and interfering ions of sample solution were investigated. The calibration graph of this procedure was linear in the range of 0.02–0.4mgL−1 with detection limit of 2.0μgL−1 (n=21). The relative standard deviation (RSD) was 4% and the preconcentration factor was 65. Good recovery (%) values were obtained changing between 95 and 102%. The certified reference material (CWW-TM-D waste water) was used to verify the accuracy of the developed method (recovery, 96%). The proposed method was applied for determination of silver in different water samples, anode slime and cream samples.

Effects of various factors of ultrasonic treatment on the extraction recovery of drugs from fish tissues

In the present research, a combined extraction method of ultrasound-assisted extraction (UAE) in conjunction with solid phase extraction (SPE) was applied to isolation and enrichment of selected drugs (metoprolol, ticlopidine, propranolol, carbamazepine, naproxen, acenocumarol, diclofenac, ibuprofen) from fish tissues. The extracted analytes were separated and determined by ultra-high performance liquid chromatography with UV detection (UHPLC–UV) technique. The selectivity of the developed UHPLC–UV method was confirmed by comparison with ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) analysis.The important parameters, such as composition of type and pH of extraction solvent, solid/liquid rate volume of extraction solvent and number of extraction cycles were studied. The ultrasonic parameters, such as time, power and temperature of the process were optimized by using a half-fraction factorial central composite design (CCD). The mixture of 10mL of methanol and 7mL of water (pH 2.2) (three times) was chosen for the extraction of selected drug from fish tissues. The results showed that the highest recoveries of analytes were obtained with an extraction temperature of 40°C, ultrasonic power of 300W, extraction time of 30min.Under the optimal conditions, the linearity of method was 0.12–5.00μg/g. The determination coefficients (R2) were from 0.979 to 0.998. The limits of detection (LODs) and limits of quantification (LOQs) for the extracted compounds were 0.04–0.17μg/g and 0.12–0.50μg/g, respectively. The recoveries were between 85.5% and 115.8%.

Solid-Phase Extraction Followed by Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Drop for the Determination of Parabens.

A dispersive liquid-liquid microextraction based on solidification of floating organic drop method combined with solid-phase extraction (500-mg C18 sorbent) was developed for preconcentration and determination of some parabens. The experimental parameters influencing the extraction efficiency such as the type of extraction and disperser solvents, as well as their volumes, breakthrough volume, flow rate and salt addition were studied and optimized. The optimum experimental conditions found included: sample volume, 100 mL; KCl concentration, 1% (w/v); extraction solvent (1-undecanol) volume, 20 µL and disperser solvent (acetone) volume, 250 µL. Under the optimum experimental conditions, calibration graphs were linear in the range of 1-200 µg L(-1) with limits of detection ranged from 0.3 to 1.7 µg L(-1). The relative standard deviations were in the range of 1.2-3.1% (n = 5). The enrichment factors and absolute recoveries of parabens in different matrices were 245-1886 and 9.0-69.8%, respectively. The method was applied to the simultaneous determination of parabens in different matrices. The relative recoveries from water, shampoo and mouth rinse samples, which have been spiked at different levels of parabens, were 87.83-112.25%, 82.80-108.40% and 90.10-97.60%, respectively.

Application of In-Syringe Dispersive Liquid-Liquid Microextraction Coupled to GC/FID for Determination of Trace Contamination of Phthalate Esters in Water Samples.

In this work, a simple and easy to handle one-step in-syringe setup for the dispersive liquid-liquid microextraction method has been developed for preconcentration of trace quantities of four kinds of phthalate esters (PEs) in water samples as a prior step to its determination by gas chromatography/flame ionization detector. The environmental pollution at this method has been limited due to using a glass syringe as extraction unit and also a very small amount of n-hexane as a safe solvent. Some important parameters such as the type of extraction and disperser solvents, extraction and disperser solvents volume, sample volume and ionic strength were investigated and optimized. Validation experiments showed that the optimized method had precision (1.7-6.9%) and high recovery (94.32-104.7%), and the limits of detection were from 0.406 to 1.33 µg L(-1). At the end, the method was successfully applied for the determination of PEs in real water samples.

Determination of polycyclic aromatic hydrocarbons using lab on valve dispersive liquid–liquid microextraction coupled to high performance chromatography

In this work, dispersive liquid–liquid microextraction (DLLME) method was applied for high performance liquid chromatography (HPLC) determination of 15 PAHs in aqueous matrices.The extraction procedure was automated using a system of multisyringe flow injection analysis coupled to HPLC instrument with fluorescence detector. Factors affecting the extraction process, such as type and volume of extraction and dispersive solvent, extraction time and centrifugation step were investigated thoroughly and optimized utilizing factorial design. The best recovery was achieved using 100µL of trichloroethylene as the extraction solvent and 900µL of acetonitrile as the dispersive solvent.The results showed that extraction time has no effect on the recovery of PAHs. The enrichment factors of PAHs were in the range of 86–95 with limits of detection of 0.02–0.6µgL−1. The linearity was 0.2–600µgL−1 for different PAHs. The relative standard deviation (RSD) for intra- and inter-day of extraction of PAHs were in the range of 1.6–4.7 and 2.1–5.3, respectively, for five measurements.The developed method was used to assess the occurrence of 15 PAHs in tap water, rain waters and river surface waters samples.