A Solid Film Electrode of Intermetallic Ag2Hg3.02 for the Direct Determination of Folic Acid in Fresh and Processed Fruit Juices

AgSIE was used for the direct analysis of folic acid (FA), with a detection limit and lower level of quantitation of 6.8×10^?10 mol L^?1 and 2.3×10^?8 mol L^?1. The analysis in fresh and processed fruits was done without any sample pretreatment. In strawberry and acerola juices, FA concentration level values were below the method detection limit. FA was detectable in peach (77.7±0.4 µg L^?1 and 64.4±0.5 µg L^?1), Persian lime (45.4±0.7 µg L^?1), pineapple Hawaii (66.2±0.4 µg L^?1), pear pineapple (35.3±0.6 µg L^?1), cashew (54.4±0.5 µg L^?1), passion fruit (73.2±0.3 µg L^?1), and apple (84.4±0.5 µg L^?1).     

Determination of phosphate in freshwater samples by flow-injection with lucigenin chemiluminescence

Lucigenin chemiluminescence (CL) in conjunction with flow-injection analysis (FIA) is used for the determination of phosphate in freshwater samples. The procedure is based on the formation of molybdophosphoric heteropoly acid (MoP–HPA) by the reaction of phosphate and ammonium molybdate under acidic conditions. CL emission was observed as a result of oxidation of lucigenin in aqueous sodium hydroxide solution in the presence of MoP–HPA. Calibration was linear up to 500?µg?L^?1 (r ^2?=?0.9998; n?=?8), with a detection limit (S/N?=?3) of 0.95?µg?L^?1. An injection throughput of 120 h^?1, and relative standard deviation (RSD; n?=?4) of 1.3–3.2% were achieved in the concentration range studied. An on-line chelating column was used to remove interfering cations. The method was applied to freshwater samples, and the results (51?±?1.0 – 107?±?2.0?µg?L^?1) did not differ significantly from results obtained using a spectrophotometric method (52.5?±?1.0 – 102?±?2.0?µg?L^?1) at 95% confidence level (t-test).     

Trace determination of malachite green in water samples using dispersive liquid–liquid microextraction coupled with high-performance liquid chromatography-diode array detection

A simple and reliable method has been developed for the rapid analysis of trace levels of malachite green from water samples using dispersive liquid–liquid microextraction and high-performance liquid chromatography-diode array detection. Factors relevant to the microextraction efficiency, such as the type and volume of extraction solvent, nature and volume of the disperser solvent, the effect of salt, sample solution temperature and the extraction time were investigated and optimised. Under the optimal conditions the linear dynamic range of malachite green was from 0.2 to 100.0?µg?L^?1 with a correlation coefficient of 0.9962. The detection limit and limit of quantification were 0.1?µg?L^?1 and 0.3?µg?L^?1, respectively. The relative standard deviation (RSD) was less than 2.6% (n?=?5) and the recoveries of malachite green (5.0?µg?L^?1) from water samples were in the range of 99.2?±?1.7%. Finally the proposed method was successfully applied for the analysis of malachite green from fish farming water samples.     

Sensitive voltammetric determination of gallium in aluminium materials using renewable mercury film silver based electrode

Simple cyclic renewable silver amalgam film electrode (Hg(Ag)FE), applied for the determination of gallium(III) using differential pulse anodic stripping voltammetry (DP ASV), is presented. The effects of various factors such as: preconcentration potential and time, pulse height, step potential and supporting electrolyte composition are optimised. The calibration graph is linear from 5?nM (0.35?µg?L^?1) to 80?nM (5.6?µg?L^?1) for a preconcentration time of 60?s, with correlation coefficient of 0.995. For a Hg(Ag)FE with a surface area of 9.9?mm² the detection limit for a preconcentration time of 120?s is as low as 0.1?µg?L^?1. The repeatability of the method at a concentration level of the analyte as low as 3.5?µg?L^?1, expressed as RSD is 3.2% (n?=?5). The proposed method was successfully applied by studying the synthetic samples and simultaneously recovery of Ga(III) from spiked aluminium samples.     

Observations on toxicologically relevant arsenic in urine in adult offspring of families with Balkan Endemic Nephropathy and controls by batch hydride generation atomic absorption spectrometry

The aim of this study was to develop a method for the characterization of internal exposure to arsenic, which is thought to play a role in the development of a kidney disease, known as Balkan Endemic Nephropathy, typical for a district in Bulgaria, and to investigate whether the As body burden differs in the offspring versus control individuals. For this case study, an analytical procedure for the determination of toxicologically relevant arsenic (the sum of arsenite, arsenate, monomethylarsonate, and dimethylarsinate) in urine by batch-type hydride generation atomic absorption spectrometry was developed. Optimization experiments for levelling off the sensitivity of inorganic arsenic and its mono- and dimethylated species in dilute HCl–L-cysteine medium were performed. The limit of detection for hydride forming arsenic fraction was 0.5?ng As, i.e. 0.25?µg?L^?1 in 10?mL of 1?+?4 v/v diluted urine. The relative standard deviation was typically 1.5–1.8% for aqueous solution and 2–6% for urine samples at 1.0?µg?L^?1 As. The sample throughput rate was 15?h^?1. No statistical correlation and cross-correlation between individuals case-control and sex at 95% confidence were found: controls (n?=?99), mean 3.5?±?2.1 (SD), range 0.9–10.4, median 3.0?µg?L^?1 As and cases (n?=?102), mean 3.6?±?2.2 (SD), range 0.5–11.0, median 3.2?µg?L^?1 As. On the basis of this study, arsenic can be excluded as a factor involved in BEN development.     

Determination of Selenium by Single-Drop Microextraction and Diffuse Reflectance Infrared Spectroscopy

A simple and convenient assay based on single-drop microextraction with infrared spectroscopy is reported for the determination of selenium. The extraction conditions were carefully optimized and selenium was preconcentrated through single-drop microextraction in 1,2-dichloroethane containing N-hydroxy-N-phenyl-N′-(o-tolyl) benzimidamide. The method is selective and almost all common ions including molybdenum(VI), chromium(VI), and tungsten(VI) did not interfere with the isolation protocol. The selenite band at 875?±?2?cm^?1, which is assigned to the asymmetric vibrational stretch (υ₃), was used for the quantification of selenium. Low limits of detection and quantification of 2.0 and 6.6?µg?L^?1 demonstrate the sensitivity of the method. Good precision was evaluated by the standard deviation (2.0?µg?L^?1) and relative standard deviation (0.5%) for 8?µg?L^?1 was achieved for 10 measurements. The method was used to analyze human blood, urine, and water for selenium.     

Enhanced Specificity and Sensitivity for the Determination of Nickel(II) by Square-wave Adsorptive Cathodic Stripping Voltammetry at Disposable Graphene-modified Pencil Graphite Electrodes

Chemical sensors relying on graphene-based materials have been widely used for electrochemical determination of metal ions and have demonstrated excellent signal amplification. This study reports an electrochemically reduced graphene oxide (ERGO)/mercury film (HgF) nanocomposite-modified pencil graphite electrode (PGE) prepared through successive electrochemical reduction of graphene oxide (GO) sheets and an in situ plated HgF. The ERGO-PG-HgFE, in combination with dimethylglyoxime (DMG) and square-wave adsorptive cathodic stripping voltammetry (SW-AdCSV), was evaluated for the determination of Ni²⁺ in tap and natural river water samples. A single-step electrode pre-concentration approach was employed for the in situ Hg-film electroplating, metal-chelate complex formation, and non-electrolytic adsorption at –0.7 V. The current response due to nickel-dimethylglyoxime [Ni(II)-DMG₂] complex reduction was studied as a function of experimental paratmeters including the accumulation potential, accumulation time, rotation speed, frequency and amplitude, and carefully optimized for the determination of Ni²⁺ at low concentration levels (μg?L^?1) in pH 9.4 of 0.1 M NH₃–NH₄Cl buffer. The reduction peak currents were linear with the Ni²⁺ concentration between 2 and 16?μg?L^?1. The limits of detection and quantitation were 0.120?±?0.002?µg?L^?1 and 0.401?±?0.007?µg?L^?1 respectively, for the determination of Ni²⁺ at an accumulation time of 120?s. The ERGO-PG-HgFE further demonstrated a highly selective stripping response toward Ni²⁺ determination compared to Co²⁺. The electrode was found to be sufficiently sensitive to determine metal ions in water samples at 0.1?µg?L^?1, well below the World Health Organization standards.     

Determination of total antimony(III,V) by square-wave anodic stripping voltammetry with in situ plated bismuth-film electrode

A sensitive and reliable method is described for the determination of total Sb(III,?V) at traces levels by Osteryoung square-wave anodic stripping voltammery (OSWASV). This method is based on the co-deposition of Sb(III,?V) with Bi(III) onto an edge-plane pyrolytic graphite substrate at an accumulation step. OSWASV studies indicated that the co-deposited antimony was oxidised with anodic scans to give an enhanced anodic peak at about 450?mV vs. Ag/AgCl (sat. KCl). The anodic stripping peak current was directly proportional to the total concentration of antimony in the ranges of 0.01–0.10?µg?L^?1, 0.10–1.0?µg?L^?1 and 1.0–18.0?µg?L^?1 with correlation coefficient higher than 0.995 when 2.0?mol?L^?1 hydrochloric acid was used. The detection limits calculated as S/N?=?3 was 5.0?ng?L^?1 in 2.0?mol?L^?1 hydrochloric acid at 180?s deposition time. The relative standard deviation was 5% (n?=?6) at 0.10?µg?L^?1 level of antimony. The analytical results demonstrate that the proposed method is applicable to analyses of real water samples.     

Response surface optimisation applied to a headspace-solid phase microextraction-gas chromatography-mass spectrometry method for the analysis of volatile organic compounds in water matrices

A new method for the simultaneous determination of 12 volatile organic compounds (trans-1,2-dichloroethene, 1,1,1-trichloroethane, benzene, 1,2-dichloroethane, trichloroethene, toluene, 1,1,2-trichloroethane, tetrachloroethene, ethylbenzene, m-, p-, o-xylene) in water samples by headspace solid phase microextraction (HS–SPME)–gas chromatography mass spectrometry (GC–MS) was described, using a 100?µm PDMS (polydimethylsiloxane) coated fibre. The response surface methodology was used to optimise the effect of the extraction time and temperature, as well as the influence of the salt addition in the extraction process. Optimal conditions were extraction time and temperature of 30?min and ?20°C, respectively, and NaCl concentration of 4?mol?L^?1. The detection limits were in the range of 1.1?×?10^?3–2.3?µg?L^?1 for the 12 volatile organic compounds (VOCs). Global uncertainties were in the range of 4–68%, when concentrations decrease from 250?µg?L^?1 down to the limits of quantification. The method proved adequate to detect VOCs in six river samples.     

Rapid and sensitive determination of biphenyl and biphenyl oxide in water samples using dispersive liquid–liquid microextraction followed by gas chromatography

A rapid and sensitive method has been developed for the determination of biphenyl and biphenyl oxide in water samples using dispersive liquid–liquid microextraction followed by gas chromatography. This method involves the use of an appropriate mixture of extraction solvent (8.0?µL tetrachloroethylene) and disperser solvent (1.0?mL acetonitrile) for the formation of cloudy solution in 5.0?mL aqueous sample containing biphenyl and biphenyl oxide. After extraction, phase separation was performed by centrifugation and biphenyl and biphenyl oxide in sedimented phase (5.0?±?0.3?µL) were determined by gas chromatography-flame ionisation (GC-FID) system. Type of extraction and disperser solvents and their volumes, salt effect on the extraction recovery of biphenyl and biphenyl oxide from aqueous solution have been investigated. Under the optimum conditions and without salt addition, the enrichment factors for biphenyl and biphenyl oxide were 819 and 785, while the extraction recovery were 81.9% and 78.5%, respectively. The linear range was (0.125–100?µg L^?1) and limit of detection was (0.015?µg?L^?1) for both analytes. The relative standard deviation (RSD, n?=?4) for 5.0?µg?L^?1 of analytes were 8.4% and 6.7% for biphenyl and biphenyl oxide, respectively. The relative recoveries of biphenyl and biphenyl oxide from sea, river water and refined water (Paksan company) samples at spiking level of 5.0?µg?L^?1 were between 85.0% and 100 %.     

Cloud point extraction for the determination of cadmium and lead employing sequential multi-element flame atomic absorption spectrometry

A cloud point extraction procedure for pre-concentration and determination of cadmium and lead in drinking water using sequential multi-element flame atomic absorption spectrometry is described. 4-(2-thiazolylazo)-orcinol (TAO) has been used as complexing agent and the micellar phase was obtained using the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) and centrifugation. The conditions for reaction and extraction (surfactant concentration, reagent concentration, effect of incubation time, etc) were studied and the analytical characteristics of the method were determined. The method allows the determination of cadmium and lead with quantification limits of 0.30?µg?L^?1 and 2.6?µg?L^?1, respectively. A precision expressed as relative standard deviation (RSD, n?=?10) of 2.3% and 2.6% has been obtained for cadmium concentrations of 10?µg?L^?1 and 30?µg?L^?1, respectively, and RSD of 1.3% and 1.7% for lead concentrations of 10?µg?L^?1 and 30?µg?L^?1, respectively. The accuracy was confirmed by analysis of a natural water certified reference material. The method has been applied for the determination of cadmium and lead in drinking water samples collected in the cities of Ilhéus and Itabuna, Brazil. Recovery tests have also been performed for some samples, and results varied from 96 to 105% for cadmium and 97 to 106% for lead. The cadmium and lead concentrations found in these samples were always lower than the permissible maximum levels stipulated by World Health Organization and the Brazilian Government.     

Miniaturized flow-injection-analysis (μFIA) system with on-line chemiluminescence detection based on the luminol-hypochlorite reaction for the determination of ammonium in river water

A miniaturized flow-injection-analysis system constructed from glass and polydimethylsiloxane was employed for the determination of ammonium in river water. The sample was filtered and delivered to the reactor chip electro-osmotically using a disposable fritted capillary, while reagents were delivered to the system by gravity. Ammonia was mixed with the hypochlorite, to form a monochloramine. Once the alkaline luminol (3-aminophthalhydrazide) was delivered to the system, it was oxidized by the unconsumed hypochlorite emitting a bright blue light (λ _max?～?440?nm) that was detected using a miniaturized photomultiplier tube (PMT) located directly under the chip. The calibration model for ammonium standards was linear up to 0.1?µg?mL^?1 (y?=??8.96x?+?1.02; correlation coefficient, r ²?=?0.9715) over a working range of 0.0–0.5?µg?mL^?1. A detection limit of 10?±?6?µg?mL^?1 was achieved with a precision value of (RSD ≤ 6.4%), for n?=?5. A direct and standard addition method were used to determine the concentration of ammonium in a river-water sample (from the Humber Estuary, UK) which was found to be 0.075?±?0.005?µg?mL^?1, with a precision value of (RSD?≤?3.7%), for n?=?9. The results obtained showed good agreement with the average concentration 0.065?µg?mL^?1 (provided by the local environmental agency), for the analysis of ammonia at different sample points on the estuary.     

Voltammetry of Dissolved Iron(III)–Nitrilotriacetate–Hydroxide System in Water Solution

The investigation of the dissolved iron(III)–nitrilotriacetate–hydroxide system in the water solution (I=0.1 mol L^?1 in NaClO₄; pH 8.0±0.1) using differential pulse cathodic voltammetry, cyclic voltammetry, and sampled direct current (DC) polarography, was carried out on a static mercury drop electrode (SMDE). The dissolved iron(III) ion concentrations varied from 2.68×10^?6 to 6×10^?4 mol L^?1 and nitrilotriacetate concentrations were 1×10^?4 and 5×10^?4 mol L^?1. By deconvoluting of the overlapped reduction voltammetric peaks using Fourier transformation, four relatively stable, dissolved iron(III) complex species were characterized, as follows: [Fe(NTA)₂]^3?, mixed ligand complexes [FeOHNTA]^? and [Fe(OH)₂NTA]^2?, showing a one‐electron quasireversible reduction, and binuclear diiron(III) complex [NTAFeOFeNTA]^2?, detected above 4×10^?4 mol L^?1 of the added iron(III) ions, showing a one‐electron irreversible reduction character. The calculations with the constants from the literature were done and compared with the potential shifts of the voltammetric peaks. Fitting was obtained by changing the following literature constants: log β₂([Fe(NTA)₂]^3?) from 24 to 27.2, log β₁([FeNTA]^?) from 8.9 to 9.2, log β₂([Fe(NTA)₂]^4?) from 11.89 to 15.7 and log β₂([Fe(OH)₂NTA]^3?) from 15.63 to 19. The determination of the electrochemical parameters of the mixed ligand complex [FeOHNTA]^?, such as: transfer coefficient (α), rate constant (k_s) and formal potential (E°') was done using a sampled DC polarography, and found to be 0.46±0.05, 1.0±0.3×10^?3 cm s^?1, and ?0.154±0.010 V, respectively. Although known previously in the literature, these four species have now for the first time been recorded simultaneously, i.e. proved to exist simultaneously under the given conditions.     

1-Butyl-3-methylimidazolium hexafluorophosphate ionic liquid-based liquid–liquid microextraction for the determination of 4-nonylphenol and 4- tert -octylphenol in environmental waters

In the present study, room-temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate was used as extraction solvent in a liquid–liquid microextraction (LLME) procedure followed by liquid chromatography for determining 4-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP) in environmental water samples. RTIL-based LLME was a simple, inexpensive, and fast sample preparation method, and its parameters such as extraction time, addition of salt, selection of phase ratio, and pH value were optimized. The optimized method had acceptable limits of detection (LOD) and a precision of 2?µg?L^?1 and 8.1% for 4-NP and 0.6?µg?L^?1 and 3.7% for 4-t-OP, respectively. The proposed method was successfully applied in river water and effluent from a sewage-treatment plant, and the recoveries spiked at 6?µg?L^?1 and 25?µg?L^?1 levels were in the range of 82–113%.     

Sensitive Simultaneous Determination of o-Nitrophenol and p-Nitrophenol in Water by Surfactant-Mediated Differential Pulse Voltammetry

A simple, low-cost and sensitive electroanalytical method was developed for the simultaneous determination of p-nitrophenol and o-nitrophenol isomers in water samples at a glassy carbon electrode (CGE) in the presence of cationic surfactant. The electrochemical behavior of p-nitrophenol and o-nitrophenol was studied by cyclic voltammetry (CV) in 0.1?mol L^?1 acetate/acetic acid buffer (pH 3.70) in the presence and absence of cetylpyridinium bromide. The resolution of overlapped cathodic peaks potentials (E_pc) of isomers was successfully improved in the presence of 100.0?µmol L^?1 cetylpyridinium bromide, thus making this approach ideal for the simultaneous determination of isomers. Under the optimized conditions in 0.05?mol L^?1 HEPES buffer at pH 7.0 using differential pulse voltammetry (DPV) at a scan rate of 45?mV s^?1, pulse amplitude of 220?mV and modulation time of 10?ms, limits of detection 0.59?µmol L^?1 for p-nitrophenol and 1.14?µmol L^?1 for o-nitrophenol were obtained with linear ranges from 2.0 to 60.0?µmol L^?1 and 3.0 to 60.0?µmol L^?1, respectively. The intraday precision was assessed as relative standard deviation (%) for 20.0 and 40.0?µmol L^?1 concentrations were 4.30% and 2.41% for p-nitrophenol and 4.87% and 2.20% for o-nitrophenol, respectively. The developed method was applied for the determination of the isomers in lake water samples. The accuracy was attested by comparison with high-performance liquid chromatography with diode array detection (HPLC-DAD) as a reference analytical technique. Recovery values ranging from 90.3% to 111.8% also attested to the accuracy of method for analysis of real samples.     

Quantitative determination of toluene,ethylbenzene, and xylene degradation products in contaminated groundwater by solid-phase extraction and in-vial derivatization

Benzylsuccinic acid (BSA) and methylbenzylsuccinic acids (mBSAs) are unambiguous indicators of anaerobic toluene and ethylbenzene/xylene degradation, and so the determination of these compounds in landfill leachates and contaminated groundwater is highly relevant. Samples were diluted to <0.8?mS?cm^?1 in order to reduce their ionic strength, and subsequently extracted through strong anion exchange disks, followed by simultaneous in-vial elution and methylation. A detection limit of 0.1?µg?L^?1 was obtained for 100?mL samples. Using this method, 19.3?µg?L^?1 of BSA was measured in a landfill leachate, and low µg?L^?1 levels of all of the mBSAs were measured in gasoline-contaminated groundwater. The results were compared with the findings of BSAs at 16 other contaminated sites, and BSAs as indicators of biodegradation were evaluated. The estimation of biodegradation rates based on parent hydrocarbons and BSA concentrations or ratios is questionable. However, the degradation products serve as good qualitative in situ indicators for anaerobic biodegradation in contaminated groundwater.     

Determination of chlorophenols in environmental water samples using directly suspended droplet liquid-liquid-liquid phase microextraction prior to high-performance liquid chromatography

A new sample preparation method named directly suspended droplet liquid-liquid-liquid phase microextraction was used in this research for determination of three chlorophenols in environmental water samples. The analytes (2-chlorophenol, 3-chlorophenol and 4-chlorophenol) were extracted from 4.5?mL acidic donor phase, (pH 2, P1) into an organic phase, 350?µL?of benzene/1-octanol (90?:?10 v/v, P2) and then were back-extracted into a 7?µL droplet of an basic (pH 13) aqueous solution (acceptor phase, P3). In this method, contrary to the ordinary single drop liquid-phase microextraction technique, an aqueous large droplet is freely suspended on the surface of the organic solvent, without using a microsyringe as supporting device. This aqueous microdroplet is delivered at the top-centre position of an immiscible organic solvent which is laid over the aqueous donor sample solution while the solution is being agitated. Then, the acceptor phase containing chlorophenols was withdrawn back into a HPLC microsyringe and neutralised by adding of 7?µL HCl 0.1?M. The total amount was eventually injected into the HPLC system with UV detection at 225?nm for further analysis. Parameters such as the organic solvent, phases volumes, extraction and back-extraction times, stirring rate and pH values were optimised. The calibration graphs are linear in the range of 10–2000?µg?L^?1 with r?≥?0.9973. The enrichment factors were ranged from 115 to 170, and the limit of detection (LOD, n?=?7) varied from 5 to 10?µg?L^?1. The relative standard deviations (RSDs, n?=?5) were found 6.8 to 7.4 at S/N?=?3. All experiments were carried out at room temperature, (22?±?0.5°C).     

Amoxicillin removal from aqueous matrices by sorption with almond shell ashes

The adsorption of the antibiotic amoxicillin at low concentration levels (µg?L^?1 order) from aqueous solution on almond shell ashes has been investigated, either by kinetic or equilibrium assays. The effect of the adsorbent amount, initial concentration of the antibiotic, particle diameter (d_p) and temperature were considered to evaluate the adsorption capacity of the adsorbent. The results showed that amoxicillin sorption is dependent on these four factors. The adsorption process was relatively fast and equilibrium was established in about 12 hours. The optimum parameters for an initial concentration of 450?µg?L^?1 were 50?mg of adsorbent, 303?K and d_p?<?600?µm. A comparison of kinetic models showed that pseudo-second order kinetics provides the best correlation of the experimental data. Isotherm data adjusted better to Langmuir equation, with an adsorption capacity of 2.5?±?0.1?mg?g^?1 at 303?K. The desorption process was also evaluated (maximum efficiency of 5%). Thermodynamic parameters were calculated and the negative value of ΔH⁰ and ΔG⁰ showed that adsorption was exothermic and a spontaneous process.     

Ultrasound-assisted emulsification microextraction using low density solvent for analysis of toxic nitrophenols in natural waters

An ultrasound-assisted emulsification microextraction (USAEME) based on low-density solvents was successfully applied for the extraction and pre-concentration of four toxic nitrophenols in water samples. The extracted analytes were analyzed by high-performance liquid chromatography-UV detection. The important parameters influencing the extraction efficiency were studied and optimized utilizing two different optimization methods: one variable at a time (OVAT) and central composite design (CCD). The results showed that the emulsification process can be completed in a few seconds using low-density solvents, but almost 10–20?min is necessary for high-density solvents. Under the optimum conditions (extraction solvent, 1-octanol; extraction solvent volume, 40?µL; sample pH, 3.0; salt concentration, 20% (w/v) NaCl; extraction temperature, 40 (±3)°C), limits of detection of the method were in the range of 0.25 to 1?µg?L^?1 and the repeatability and reproducibility of the proposed method, expressed as relative deviation, varied in the range of 2.2–4.2% and 4.7–6.9%, respectively. Linearity was found to be in the range of 1 to 200?µg?L^?1 and the preconcentration factors (PFs) were between 77 and 175. The relative recoveries of the four nitrophenols from water samples at spiking level of 10.0?µg?L^?1 were in the range of 92.0 to 115.0%.     

Polycyclic aromatic hydrocarbon and ionic compositions of atmospheric bulk deposition samples at a national park under the influence of intense barbecue smoke

The main aim of this study was to present the effects of barbecue smoke on a small-scale environment, a national park under the influence of intense barbecue smoke, and to scientifically support the sustainable usage of the park. Twelve-weekly bulk deposition samples were collected directly at the barbecuing area, and the samples were analysed for 16 US EPA’s priority PAH compounds and major ions. The mean concentrations of the individual PAHs in the bulk deposition samples ranged from 11.8 ng L^?1 (Ane) to 1085 ± 581 ng L^?1 (IcdP). The most frequently observed PAH compounds in the bulk deposition samples were Np, Anp, Flr, Phe, An, Flu, BkF, BaP and IcdP. The mean total PAH deposition fluxes were determined as 3.6 ± 5.6 µg m^?2 day^?1. The chloride, potassium and the sulphate fluxes were determined as 145.2 ± 267.8 µg m^?2 day^?1, 182.9 ± 291.9 µg m^?2 day^?1, and 111.9 ± 65.9 µg m^?2 day^?1, respectively. Dominant ions in the bulk deposition samples were potassium ion, chloride and sulphate which addressed as the fingerprint of barbecue grilling.