Determination of Trace Levels of Nickel and Manganese in Soil,Vegetable, and Water

A simple and reliable method for rapid and selective extraction and determination of trace levels of Ni²⁺ and Mn²⁺ was developed by ionic liquid (IL) based dispersive liquid–liquid microextraction coupled to flame atomic absorption spectrometry (FAAS) detection. The proposed method was successfully applied to the preconcentration and determination of nickel and manganese in soil, vegetable, and water samples. After preconcentration, the settled IL‐phase was dissolved in 100 µL of ethanol and aspirated into the FAAS using a home‐made microsample introduction system. Injection of 50 µL of each analyte into an air–acetylene flame provided very sensitive spike‐like and reproducible signals. Effective parameters such as pH, amount of IL, volume of the disperser solvent, concentration of the chelating agent, and effect of salt concentration were inspected by a (2^5‐1) fractional factorial design to identify the most important parameters and their interactions. Under optimum conditions, preconcentration of 10 mL sample solution permitted the detection of 0.93 µg L^?1 Ni²⁺ and 0.52 µg L^?1 Mn²⁺ with enrichment factors 77.2 and 82.6 for Ni²⁺ and Mn²⁺, respectively. The accuracy of the procedure was evaluated by analysis of a certified reference material (CRM TMDW‐500, drinking water).     

On‐line Solid Phase Extraction of Copper in Water Samples with Flow Injection Flame Atomic Absorption Spectrometry

An on‐line solid phase extraction method for the preconcentration and determination of Cu(II) by flame atomic absorption spectrometry has been described. The procedure is based on the retention of Cu(II) ions at pH 6.0 on a minicolumn packed with Amberlite XAD‐1180 resin impregnated with chrome azurol S. After preconcentration, Cu(II) ions adsorbed on the impregnated resin were eluted by 1 mol L^?1 HNO₃ solution. Several parameters, such as pH, type of eluent, flow rates of sample and eluent solutions, amount of resin were evaluated. At optimized conditions, for 3.5 min of preconcentration time, the system achieved a detection limit of 1.0 µg L^?1, and a relative standard deviation of 1.2% at 0.2 µg mL^?1 copper. An enrichment factor of 56‐fold was obtained with respect to the copper determination. The proposed method was successfully validated by the analysis of standard reference material (TMDA 54.4 lake water) and recovery studies. The method was applied to the preconcentration of Cu(II) in natural water samples.     

Coprecipitation with Cu(II)‐4‐(2‐Pyridylazo)‐resorcinol for Separation and Preconcentration of Fe(III) and Ni(II) in Water and Food Samples

The coprecipitation method is widely used for the preconcentration of trace metal ions prior to their determination by flame atomic absorption spectrometry (FAAS). A simple and sensitive method based on coprecipitation of Fe(III) and Ni(II) ions with Cu(II)‐4‐(2‐pyridylazo)‐resorcinol was developed. The analytical parameters including pH, amount of copper (II), amount of reagent, sample volume, etc., were examined. It was found that the metal ions studied were quantitatively coprecipitated in the pH range of 5.0–6.5. The detection limits (DL) (n = 10, 3s/b) were found to be 0.68 µg L^?1 for Fe(III) and 0.43 µg L^?1 for Ni(II) and the relative standard deviations (RSD) were ≤4.0%. The proposed method was validated by the analysis of three certified reference materials (TMDA 54.4 fortified lake water, SRM 1568a rice flour, and GBW07605 tea) and recovery tests. The method was successfully applied to sea water, lake water, and various food samples.     

Ultrasound‐Assisted Emulsification–Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry for the Determination of Trace Lead in Water

The ultrasound‐assisted emulsification–microextraction (USAEME) method was combined with graphite furnace atomic absorption spectrometry (GFAAS) for the determination of trace Pb using dithizone (H²DZ) as chelating reagent. Some effective parameters influenced the detection and microextraction, such as ashing temperature and atomization temperature, pH, extraction solvent, sample volume, extraction time, and extraction temperature were selected and optimized. After extraction, the calibration curves for Pb was in the concentration range of 0.1–10 ng mL^?1, and the linear equation was y = 0.097 x + 0.023 (R = 0.99). Under the optimized conditions, the detection limit of the method was 20 pg mL^?1 with an enrichment factor of 70 and the relative standards deviation (RSD) for seven determinations of 1 ng mL^?1 Pb was 11%. The proposed method was successfully applied to determine trace Pb in Yueya Lake water, pond water, and spiked samples. Furthermore, a certified reference material of Environment Water (GBW08607) was analyzed and the determined value was in good agreement with the certified value, which showed the accuracy, recovery, and applicability of the reported method.     

Surfactant Enhance DLLME/FO‐LADS: Assay of Malachite Green Level in Aquatic Environment of Trout Fish

Malachite green (MG), a traditional agent used in aquaculture although is not approved; its low cost and high efficacy make illicit use likely. We developed a small‐scale, simple, and sensitive dispersive liquid–liquid microextraction procedure for the assay of trace amounts of MG in aquatic environment of Trout fish. Fiber optic‐linear array detection spectrophotometry with charge‐coupled device detector benefiting from a microcell was used for this purpose. The method is based on enhancement effect of an anionic surfactant on the extraction of MG in to very fine multidroplets of microextraction solvent which made assisted by disperser solvent. Under the optimum conditions, the enrichment factor 77.5 was obtained from a 5‐mL water sample. The calibration graph was linear up to 5 × 10^?7 mol L^?1 with detection limit of 1 × 10^?8 mol L^?1. The relative standard deviation for seven replicate measurements of 4 × 10^?7 and 5 × 10^?8 mol L^?1 of MG were 3.3 and 4.5%, respectively.     

Distribution Study of U,V, Mo,and Zr in Different Sites of Lakes Van and Hazar,River and Seawater Samples by ICP‐MS

The aim of this study is to investigate the concentrations of U, Th, V, Mo, and Zr in natural waters taken from Turkey. Among these water species, Lake Van is the largest soda lake and the fourth largest closed basin on Earth. The water samples were collected from 51 locations between 2008 and 2009. The inductively coupled plasma‐MS was used for determinations. The obtained U and Zr concentrations are in the range of 37–110 µg L^?1 and 17–78 µg L^?1 in Lake Van and 0.53–0.81 µg L^?1 and 0.15–0.19 µg L^?1 in Lake Hazar, respectively. The concentration of uranium in other studied waters varies from the lowest 0.09 µg L^?1 in Tigris (Dicle) river to the highest 4.0 µg L^?1 in Mediterranean Sea water. Mean Mo and V concentrations in the studied water samples were found to be in ranges of 0.1–17 and 2.7–113 µg L^?1, respectively. The obtained highest U concentration in Lake Van correlates with the highest Mo and Zr levels compared to the Lake Hazar and river waters. These results imply that there is a young occurrence of uranium minerals around Lake Van. It is concluded that there is about 50.000 ton of uranium in Lake Van water.     

Extraction of Phenol and Chlorophenols Using Ionic Liquid [Bmim]+[BF4]− Dissolved in Tributyl Phosphate

In the present work, experiments have been carried out with a focus to reduce the volume requirement of solvent by mixing with imidazolium based ionic liquids (ILs) for the solvent extraction of phenol, p‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, and pentachlorophenol from aqueous solutions. The effect of aqueous phase pH (2–12), agitation speed (100–450 rpm), solute concentration in feed (2–50 mg/L), temperature (303–333 K), treat ratio (1–11), and 1‐butyl‐3‐methyl imidazolium tetrafluoroborate [Bmim]⁺[BF₄]^? volume in tributyl phosphate (TBP; 0–0.7% v/v) on extraction of phenols has been studied and optimized. Parameters like strip phase pH (3–13) and stripping agent concentration (0.001–0.009 N) have also been studied for stripping of phenols from solvent phase. It has been found that 0.5% v/v of ionic liquid [Bmim]⁺[BF₄]^? in solvent TBP extracts more than 97.5% of phenol and chlorophenols from aqueous solutions with a treat ratio (aqueous to solvent phase ratio) of 5. Transport mechanism for extraction and stripping of phenol and chlorophenols using ionic liquid [Bmim]⁺[BF₄]^? has been discussed. The results show that by appropriate selection of extraction and stripping conditions, it is possible to remove nearly all phenols with a treat ratio of 5.     

Simultaneous Analysis of Natural Free Estrogens and Their Conjugates in Wastewater by GC‐MS

A solid‐phase extraction (SPE)‐gas chromatography (GC)‐mass spectrometry (MS) analytical method was developed for the simultaneous analysis of natural free estrogens and their conjugates in wastewater samples. Natural free estrogens and their conjugates in wastewater were successfully separated by the oasis hydrophilic‐lipophilic balance solid phase extraction (Oasis HLB SPE) method, and the conjugates were initially enzyme hydrolyzed by β‐glucuronidase or arylsulfatase from Helix pomatia prior to derivatization. N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA) plus 1% tert‐butyldimetheylchlorosilane (TBDMCS) was chosen as the derivatization reagent, and the most appropriate conditions of derivatization were determined to be at 95°C for 90 min. The recovery ratios of nine target chemicals were determined by spiking them in 1 L of ultra‐purified water or the influent of a wastewater treatment plant (WWTP). The recovery ratios of six out of nine for the analytes ranged from 73.3–114.9% with relative standard deviations (RSD) from 1.6–19.9%. The established method was successfully applied to environmental wastewater samples which were collected from one municipal wastewater treatment plant (WWTP) in Osaka, Japan, for the determination of natural free estrogens and their conjugates. In the influent sample, E1, E2, E1‐3S, E3‐3S, and E1‐3G were detected at concentrations of 16.6, 9.6, 8.2, 21.9, and 3.2 ng L^–1, respectively. However, only E1 was detected at a high concentration of 44 ng L^–1 in the effluent sample, suggesting that it is the dominant natural free estrogen in the effluent.     

A Novel Method for Dye Removal: Ionic Liquid‐Based Dispersive Liquid–Liquid Extraction (IL‐DLLE)

A novel, simple, fast, and efficient ionic liquid‐based dispersive liquid–liquid extraction (IL‐DLLE) has been applied to extract and remove Congo Red (CR; a carcinogenic textile dye) from aqueous solutions. In this methodology a binary solution, containing the extraction solvent (1‐hexyl‐3‐methylimmidazolium bis(trifluormethylsulfonyl) imid) and a suitable disperser solvent, was rapidly injected into the water sample containing CR dye. Therewith, a cloudy solution was formed, and most of the dye molecules were extracted into fine IL droplets and removed from aqueous phase. The effects of pH, type, and amount of IL, initial concentration of the dye, type and volume of the dispersant, and concentrations of salt on the extraction of the dye were studied. Experimental surveys were also accomplished for recovery of the IL by applying a reverse dispersive liquid–liquid extraction using acidic stripping solutions.     

Development of Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Drop for the Determination of Trace Lead in Water

A new method for determining lead (Pb) content was developed by dispersive liquid–liquid microextraction based on the solidification of floating organic droplets followed by flame atomic absorption spectrometry. Under optimum conditions, the calibration graph was linear within the Pb content range of 8.43–400 µg L^?1 with a detection limit of 2.53 µg L^?1. The relative standard deviation for 10 replicate measurements of 20 and 400 µg L^?1 of Pb were 3.41 and 2.78%, respectively. The proposed method was assessed through the analysis of certified reference water and recovery experiments.     

Selective Separation/Preconcentration of Silver Ion in Water by Multiwalled Carbon Nanotubes Microcolumn as a Sorbent

The present paper proposes the application of multiwalled carbon nanotubes (MWCNTs) as a solid adsorbent for selective separation/preconcentration of silver(I) in water samples prior to flame atomic absorption spectrometry. The procedure is based on the solid phase extraction of Ag(I)–2‐mercaptobenzothiazole chelate on MWCNTs. The elution step is carried out with 5 mL of 2 mol L^?1 HNO₃ in acetone solution at a flow rate of 1.0 mL min^?1. The influences of the various analytical parameters including pH of the solution, eluent type, sample volume, flow rates of eluent, matrix ions were investigated for optimization of the presented procedure. Tests of addition/recovery for analyte ion in real samples were performed with satisfactory results. Preconcentration factor and limit of detection for Ag(I) were 160 and 0.21 µg L^?1, respectively. The synthesized MWCNT exhibited excellent stability in eluent solution and its adsorption capacity was 5.4 mg of silver per gram of sorbent. The proposed method was successfully applied to trace silver determination in a variety of environmental water samples.     

Dispersive Liquid–Liquid Microextraction for Preconcentration and Determination of Nickel in Water

A method for the determination of nickel in water was developed. The procedure involves preconcentration of nickel by using dispersive liquid–liquid microextraction. The Ni(II) ions were extracted in chloroform in the form of complex with the reagent 2‐(2′‐benzothiazolylazo)‐p‐cresol. Ethanol was used as the disperser solvent. After injection of the extracting mixture in a solution of nickel, a cloudy mixture was observed. A quick centrifugation induces phase separation and thus the settling of rich phase. The nickel content in the rich phase is measured by flame atomic absorption spectrometry. Under optimal conditions, the limit of detection and quantification obtained were 1.4 and 4.7 µg L^?1, respectively. Some parameters used to characterize preconcentration systems, such as enrichment factor and consumption index were calculated and resulted in 29 and 0.34 mL, respectively. After optimization of variables and determination of analytical characteristics, the method was used for the analysis of certified reference materials (BCR‐713: wastewater, effluent and BCR‐414: plankton) and real water samples.     

Determination of Sulfamethoxazole and Trimethoprim and Their Metabolites in Hospital Effluent

In this work, an analytical methodological study was carried out to determine the antimicrobials sulfamethoxazole and trimethoprim, as well as their metabolites, in hospital effluent. The determinations were conducted by liquid chromatography tandem mass spectrometry using a hybrid triple quadrupole‐linear ion trap mass spectrometer (LC‐QqLIT‐MS). The data acquisition was made in selected reaction monitoring (SRM) mode, in which two SRM transitions were monitored to ensure that the target compounds were accurately identified by the information dependent acquisition (IDA) function. The limits of detection (LOD) and quantification (LOQ) were 0.25 and 0.80 µg L^?1 for sulfamethoxazole and 0.15 and 0.50 µg L^?1 for trimethoprim. The linear range for the SMX was 0.8–100.0 µg L^?1 and TMP was 0.5–100.0 µg L^?1 on the basis of six‐point calibration curves generated by means of linear regression analysis. The coefficients of the correlation were higher than 0.999, which ensured the linearity of the method. The average concentration of sulfamethoxazole and trimethoprim found in hospital effluent was 27.8 and 6.65 µg L^?1, respectively. The analytical methodology employed allowed two metabolites to be identified, N4‐acetyl‐sulfamethoxazole and α‐hydroxy‐trimethoprim. Fragmentation pathways were proposed.     

Removal of Heavy Metals from Synthetic Mixture as well as Pharmaceutical Sample Via Cation Exchange Resin Modified with Rhodamine B: Its Thermodynamic and Kinetic Studies

A new sorbent was prepared by loading rhodamine B on Amberlite IR‐120. Various physico‐chemical parameters such as effects of adsorbate concentration, contact time, pH, and temperature on the sorption of the dye have been studied. Thermodynamic parameters (ΔH° and ΔS°) were also evaluated for the sorption of dye. Kinetic studies revealed that the sorption of the dye was best fit for pseudo‐second‐order kinetic. The metal ion uptake in different solvent systems has been explored through column studies. On the basis of distribution coefficient (K_d), some heavy metal ions of analytical interest from binary mixtures have been separated. The limit of detection (LOD) for the Ni²⁺ and Fe³⁺ metal ions was 0.81 and 0.60 µg L^?1, and the limit of quantification (LOQ) was found to be 2.72 and 2.0 µg L^?1. This sorbent has also been successfully applied in the analysis of multivitamin formulation. The applicability of the modified resin in the separation of heavy metals constituting real and synthetic samples has been explored.     

Determination of Copper in Water Samples after Solid‐phase Extraction Using Dimethylglyoxime‐modified Silica

This work describes the modification of silica gel with dimethylglyoxime, in order to prepare an effective sorbent for the preconcentration and determination of copper. The sorption capacity of dimethylglyoxime‐modified silica‐gel (DMGMS) was 71.37 mg g^–1 and the optimum pH for the quantitative recovery of copper was found to be 5.0. The optimum flow rate, sorbent amount, and sample volume were 1 mL min^–1, 300 mg, and 50 mL, respectively. 10 mL of 0.1 mol L^–1 HCl was the most suitable eluent. The detection limit of copper was 6.0 ng mL^–1. The recommended method, for the determination of copper, is simple and reliable, without any notable matrix effect and can be successfully applied to environmental water samples. Copper recovery in the range from 99–100% was obtained from seawater and thermal spring water using this method. The method was applied to standard reference materials, NIST‐1515 (apple leaves) and NIST‐1643e (simulated fresh water), for the determination of copper and the results were in good agreement with certified values.     

Experimental Designs Applied to Desorption of Dichromate Ions after Separation and Preconcentration from Natural and Industrial Water by Modified Nano‐Alumina

Nano‐alumina modified by 9‐aminoacridine was used as a sorbent for separation and determination of dichromate ions from water. Statistical method, based on surface response design, has been used for the optimization of dichromate ions elution from 9‐aminoacridine nano‐alumina. The adsorbed dichromate ions were found to be eluted quantitatively with 0.8 mol L^?1 KCl in 1.6 mol L^?1 NaOH which optimized by response surface design. Under optimum conditions, the accuracy, precision (relative standard deviation, RSD%) and R‐square of the method were calculated as >98, <3, and >94%, respectively. Remarkable agreement between experimental and theoretical data was confirmed the predicted assumption. The method was applied to the simultaneous determination of dichromate in natural and industrial water samples. We also examined the retention of dichromate anions in the presence of Cl^?, , and anions at pH 3.     

The effect of drawdown on suspended solids and phosphorus export from Columbia Lake,Waterloo, Canada

This study examines the effect of drawdown on the timing and magnitude of suspended solids and associated phosphorus export from a 12 ha reservoir located in an urbanized watershed in southern Ontario, Canada. Water level in Columbia Lake was lowered by 1·15 m over a 2‐week period in November 2001. The total phosphorus (TP) concentrations ranged from 63 to 486 µg L^?1 in Columbia Lake and 71 to 373 µg L^?1 at its outflow. All samples exceeded the Provincial Water Quality Objective of 30 µg TP L^?1. Outflow concentrations of suspended solids and TP increased significantly with decreasing lake level and were attributed to the resuspension of cohesive bottom sediments that occurred at a critical threshold lake level (0·65 m below summer level). Suspended solids at the outflow consisted of flocculated cohesive materials with a median diameter (D₅₀) of c. 5 µm. Particulate organic carbon accounted for 8·5% of the suspended solids export by mass. A total mass of 18·5 t of suspended solids and 62·6 kg TP was exported from Columbia Lake, which represents a significant pulse of sediment‐associated P to downstream environments each autumn during drawdown. The downstream impacts of this release can be minimized if the water level in Columbia Lake is lowered no more than 0·5 m below summer levels. Copyright © 2004 John Wiley & Sons, Ltd.     

Occurrence of phthalate esters in the Seine River estuary (France)

The rigin and fate of six phthalate esters (dimethyl phthalate (DMP), diethyl phthalate (DEP), di‐n‐butyl phthalate (DnBP), butyl benzyl phthalate (BBP), di (2‐ethylhexyl) phthalate (DEHP) and di‐n‐octyl phthalate (DnOP)), were investigated during 2005 and 2006 in the densely populated Seine river estuary. Four compounds, DMP, DEP, DnBP and DEHP were detected at all the stations with DEHP (160–314 ng L^?1), followed by DEP (71–181 ng L^?1) and next DnBP (67–319 ng L^?1), except at la Bouille, where DnBP was the second most important compound. BBP and DnOP concentrations remained low and were not found at all the stations. Considering all six phthalates, Caudebec‐en‐Caux (beginning of the salinity gradient) was the least polluted station (464 ng L^?1), whereas Honfleur (771 ng L^?1) and La Bouille (716 ng L^?1) displayed the highest contamination levels, probably related to important industrial plants. From Caudebec‐en‐Caux to Honfleur (maximum turbidity), variation of DEHP concentration was related to that of suspended matter. In addition, the salinity rise in that area might have facilitated DEHP sorption upon particles. A significant correlation between flow magnitude and DEHP concentration was found (P < 0·01, n = 12), supporting the influence of the hydrological cycle upon contamination. Runoff contribution (56·9 kg d^?1) to river contamination was confirmed by the annual evolution of phthalate concentrations in the Seine river at Poses. Concentrations of DEHP in the tributaries were in the same range as those of the Seine River (100–350 ng L^?1), except for two in densely populated and industrialized areas: Robec (800 ng L^?1) and Cailly (970 ng L^?1). The treatment plant discharge fluxes were in the same range as those of tributaries (30·4–250 g d^?1). During high flow periods, the influence of tributaries and of treatment plants seemed to play a minor part in the contamination level of the Seine river estuary. Copyright © 2009 John Wiley & Sons, Ltd.     

A Multi‐Element Ion‐Pair Extraction for Trace Metals Determination in Environmental Samples

A multi‐element ion‐pair extraction method was described for the preconcentration of Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II), Pb(II), and Zn(II) ions in environmental samples prior to their determinations by flame atomic absorption spectrometry (FAAS). As an ion‐pair ligand 2‐(4‐methoxybenzoyl)‐N′‐benzylidene‐3‐(4‐methoxyphenyl)‐3‐oxo‐N‐phenyl‐propono hydrazide (MBMP) was used. Some analytical parameters such as pH of sample solution, amount of MBMP, shaking time, sample volume, and type of counter ion were investigated to establish optimum experimental conditions. No interferences due to major components and some metal ions of the samples were observed. The detection limits of the proposed method were found in the range of 0.33–0.9 µg L^?1 for the analyte ions. Recoveries were found to be higher than 95% and the relative standard deviation (RSD) was less than 4%. The accuracy of the procedure was estimated by analyzing the two certified reference materials, LGC6019 river water and RTC‐CRM044 soil. The developed method was applied to several matrices such as water, hair, and food samples.     

Occurrence of the Antimicrobials Sulfamethoxazole and Trimethoprim in Hospital Effluent and Study of Their Degradation Products after Electrocoagulation

In this study, an investigation was carried out into the occurrence of sulfamethoxazole (SMX) and trimethoprim (TMP) in the effluent of the university hospital (HUSM) of the UFSM. The degradation of these antimicrobials by the electrocoagulation (EC) process was also examined, in both the aqueous solution and hospital effluent, and a study was conducted in order to identify the subproducts formed. The experiments were optimized through factorial planning and, also, checked by response surface methodology. The best conditions for EC (achieving 58.0% of chemical oxygen demand (COD) reduction) were obtained by using 13 mA cm^?2, 500 mg L^?1 of NaCl, and 30 mm of interelectrode distance. The quantification of SMX (27.8 µg L^?1) and TMP (6.65 µg L^?1) in the hospital effluent, and the identification of the degradation products were carried out through liquid chromatography‐mass spectrometry quadrupole linear and ion trapping with electrospray ionization (LC‐ESI‐MS/MS_QTrap). Removals of 88.0% (degradation only) and 33.0% (adsorption only) were achieved for aqueous solutions of SMX and TMP, respectively, under optimized conditions. In hospital effluent samples, fortified with additions of SMX and TMP, corresponding removals of 16.0% (degradation) and 28.0% (adsorption) were achieved. This suggests that the EC process is efficient in degrading SMX in aqueous solution, although the same was not the case with TMP. The degradation products of SMX were identified (m/z 256.0 and 288.5); however, only the latter is mentioned in the literature. Toxicological aspects were not considered in this study.