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In recent years, the consumption rate of herbal teas has increased rapidly. In this study, 28 different plants (fennel, linden, roots, chamomile, green tea, thyme, sage, rosemary, rosehip, ginger, balm, echinacea, blue tea etc.) used as herbal tea bags and leaves/flowers. Different types of herbal tea were prepared keeping boiling water in contact for ten min with herbal teas and were digested with HNO3 and H2O2 in a microwave oven. In these samples, trace element concentrations (As, Ba, Cd, Co, Cu, Cr, Ni, Pb, Se, V, Zn) were determined by Inductively Coupled Plasma Mass Spectrometry. The analytical performances were assessed as linearity, the limit of detection, limit of quantification, specificity/selectivity and recovery (%). The recovery values changed between 88 and 112%.

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Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20mgg(-1)) is sufficient for the rapid removal of high amount of MG dye in short time (3.99min).

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A simple and rapid ultrasonic assisted-ionic liquid based-liquid-liquid microextraction (UA-IL-DLLME) method has been developed for the enrichment and separation of Cu(II), Ni(II) and Pb(II). A two level factorial design was used to determine the effect of key factors such as pH, volume of ionic liquid (IL), carbon tetra chloride (CCl4) and sonication time (St). 1-Butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) and CCl4 were used as an extractant and dispersant solvent, respectively. The accuracy of the proposed method was evaluated by analysing of SRM Apple Leaves 1515 certified reference material. The limits of detections (LODs) were 0.17 µg/L, 0.49 µg/L and 0.95 µg/L for Cu, Ni and Pb, respectively. The enrichment factor (EF) was 100. The method has been successfully applied for the analysis of the content of Cu, Ni and Pb in spice, vegetable and fruit samples by flame atomic absorption spectrometry (FAAS).

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In the present study, a microextraction technique combining Fe3O4 nano-particle with surfactant mediated solid phase extraction ((SM-SPE)) was successfully developed for the preconcentration/separation of Cd(II) and Pb(II) in water and soil samples. The analytes were determined by flame atomic absorption spectrometry (FAAS). The effective variables such as the amount of adsorbent (NPs), the pH, concentration of non-ionic (TX-114) and centrifugation time (min) were investigated by Plackett-Burman (PBD) design. The important variables were further optimized by central composite design (CCD). Under the optimized conditions, the detection limits (LODs) of Cd(II) and Pb(II) were 0.15 and 0.74 µg/L, respectively. The validation of the proposed procedure was checked by the analysis of certified reference materials of TMDA 53.3 fortified water and GBW07425 soil. The method was successfully applied for the determination of Cd(II) and Pb(II) in water and soil samples.

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A solid phase extraction method for enrichment-separation and the determination of cobalt (Co(2+)), copper (Cu(2+)), nickel (Ni(2+)), zinc (Zn(2+)) and lead (Pb(2+)) ions in real samples has been proposed. The influences of some analytical parameters like pH, flow rate, eluent type and interference of matrix ions on recoveries of analytes were optimized. The limits of detection were found in the range of 1.6-3.9 µg L(-1), while preconcentration factor for all understudy metal ions were found to be 166 with loading half time (t 1/2) less than 10 min. The procedure was applied for the enrichment-separation of analyte ions in environmental samples with recoveries higher than 94.8% and relative SD <4.9% (N = 5).

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The present study involves the development of solid-phase extraction (SPE) procedure for the preconcentration of trace amounts of copper (Cu(2+)), iron (Fe(3+)) and zinc (Zn(2+)) ions on duolite XAD 761 modified by bis(2-hydroxyacetophenone)-2,2-dimethyl-1,3-propanediimine(BHAPDMPDI). The complexation between the metal ions and the proposed ligand was investigated potentiometrically. The metal ions retained on the sorbent were quantitatively determined via complexation with BHAPDMPDI. The complexed metal ions were efficiently eluted using 6 mL of 4 mol L(-1) nitric acid in acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ions were optimized. Using the optimized parameters, the linear response of the SPE method for Cu(2+), Zn(2+) and Fe(3+) ions were in the ranges of 0.01-0.34, 0.01-0.28 and 0.02-0.31 µg mL(-1), respectively, and the detection limits for Cu(2+), Zn(2+) and Fe(3+) ions were 1.8, 1.6 and 2.4 µg mL(-1), respectively. The proposed method exhibits a preconcentration factor of 208 for all of the ions studied and an enhancement factor for Cu(2+), Fe(3+) and Zn(2+) ions of 34, 28 and 38, respectively. The presented results demonstrate the successful application of the proposed method for the determination of these metal ions in some real samples with high recoveries (> 95%) and reasonable relative standard deviation (RDS <5%).

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In this research at first palladium nanoparticle attached to a new chemically bonded silica gel has been synthesized and has been characterized with different techniques such as X-ray diffraction (XRD), fourier transform infrared (FT-IR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Then, this new sorbent (chemically modified silica gel with N-propylmorpholine (PNP-SBNPM)) was efficiently used for preconcentration of some metal ions in various food samples. The influence of effective variables including mass of sorbent, flow rate, pH of sample solutions and condition of eluent such as volume, type and concentration on the recoveries of understudy metal ions were investigated. Following the optimization of variables, the interfering effects of some foreign ions on the preconcentration and determination of the investigated metal ions described. At optimum values of variables, all investigated metal ions were efficiently recovered with efficiency more than 95%, relative standard deviation (RSD) between 2.4 and 2.8, and detection limit in the range of 1.4-2.7 ng mL⁻¹. The present method is simple and rapidly applicable for the determination of the understudied metal ions (ng mL⁻¹) in different natural food samples.

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In this study, a solid-phase extraction method combined with atomic absorption spectrometry for extraction, preconcentration, and determination of iron (Fe(3+)), copper (Cu(2+)), and lead (Pb(2+)) ions at trace levels in water samples has been reported. The influences of effective parameters such as flow rate, pH, eluent conditions (type, volume, and concentration), sample volumes, and interference of matrix ions on metal ions recoveries were studied. Under optimized conditions, the limits of detection were found in the range of 0.7-2.2 µg L(-1), while preconcentration factors for Fe(3+), Cu(2+), and Pb(2+) ions were found to be 166, 200, and 250, respectively, and loading half time (t (1/2)) values were less than 2 min for all analyte ions. The proposed procedure was applied for the determination of metal ions in different water samples with recovery of >94.4% and relative standard deviation less than 4.4% for N = 5.

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Selective, sensitive and efficient methods for preconcentration of trace amounts of metal ions including Cr(3+), Cu(2+), Zn(2+) and Ni(2+) ions by incorporation of 2-hydroxy-(3-((1-H-indol 3-yle)phenyl) methyl) 1-H-indol (2-HIYPMI) on SDS-A has been reported. The proposed methods are based on the uptake of chelate of under study metal ions with these new ligands loaded on SDS-A. The influences of the analytical parameters including pH, ligand and SDS amount, eluting solution (type and concentrations) and sample volume on metal ions recoveries were investigated. The extraction efficiency was >95% with relative standard deviation lower than 5%. The method has been successfully applied for the extraction and determination of these ions content in some real samples.

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A method for preconcentration of trace heavy metal ions in environmental samples has been reported. The presented method is based on the sorption of Cr(3+), Co(2+), Cu(2+), Fe(3+), Ni(2+), and Zn(2+) ions with 2-(2,4-dichlorobenzylideneamino) benzenethiol as respective chelate on modified Duolite XAD 761. The metals content of the sorbed complexes are eluted using 6 ml of 4M nitric acid. The influences of the analytical parameters including pH, amount of ligand and solid phase and condition of eluting solution, the effects of matrix ions on the retentions of the analytes were examined. The recoveries of analytes are generally higher than 94% and the RSD is between 1.5% and 2.2%. The method has been successfully applied for the evaluation of understudy metals content in some food samples.

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A sensitive and simple method based on modification of Sepabeads SP70 by 4-((E)-3-phenylallylidene) amino) benzenethiol for the simultaneous preconcentration of trace amounts of copper (Cu), nickel (Ni), chromium (Cr), and zinc (Zn) ions in some real samples has been reported. The metal ions which are retained as respective complexes on solid phase were eluted with 8 ml of 4 M nitric acid. The influences of different analytical parameters including pH, ligand amount and Sepabeads SP70 and SDS amount, eluting solutions, and sample volume on metal ions recoveries were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally >95% with RSD between 0.74 and 0.88. The proposed method has been successfully applied for the determination of these metals in some real samples with complex matrices.

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A simple and selective method for the determination of Cu(2+), Zn(2+) and Mn(2+) ions in real samples by FAAS after solid-phase extraction was developed. The method is based on the sorption of metal ions on Amberlite XAD-16 modified by 3-((2,6-dichlorophenyl)(1H-indol-3-yl)methyl)-1H-indole (DCPIMI) at a pH of 5.0. The metal ions retained on solid phase by complexation with ligand were then eluted with 6 mL of 4 mol L(-1) nitric acid in acetone. In order to obtain a reversible uptake and elution of metal ions, the influence of flow rates of eluent and sample solution, ligand concentration and amount of surfactant and condition of elution solution was also investigated. A preconcentration factor of 225 was achieved by passing 1350 mL of sample through the solid phase, while the limit of detection (LOD) of Cu(2+), Zn(2+) and Mn(2+) ions were found to be 1.9, 1.5 and 2.6 ng mL(-1), respectively, and the corresponding precision at 20 microg L(-1) was 2.1%, 2.3%, 3.0%.

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A sensitive and simple method for the simultaneous preconcentration of trace amount of Cu2+, Ni2+ and Cr3+ ions in some real samples has been reported. In this method these elements are adsorbed as respective complex with Bis(2-hydroxyacetophenone)-1,2-propanediimine (BHAPPDI) on Diaion SP-850 and the retained metal ions are eluted using 8 ml of 4 M nitric acid. The influences of the analytical parameters including pH, solid phase ingredients amount and condition of eluting solution and sample volume were investigated. The effects of matrix ions on retentions of the analytes were also examined. The recoveries of analytes were generally higher than 90% with a relatively low RSD. The method has been successfully applied for these metal ions contents evaluation in some food and environmental samples.

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A new method is described for the simultaneous preconcentration of trace metal ions. The method is based on the adsorption of Co(2+), Ni(2+), Cu(2+) and Cd(2+) ions on 2,4,6,8-tetra(2-hydroxyphenyl)-1,3,5,7(1,3)tetrabenzenzcyclooctaphane-14,16,34,36,54, 56,74,76-octol (salicylaldehyde calix[4] resorcinarenes) (new resorcinarenes derivative) modified on Amberlite XAD-16. The adsorbed analyte ions were eluted with 6 mL 3M HCl in acetone solution, which then were determined by atomic absorption spectroscopy. The influences of the analytical parameters including pH, ligand amount and solid phase ingredient, eluting solution conditions and sample volume were investigated. Common coexisting ions did not interfere with the separation and determination. The preconcentration factor is 208. The sorbent exhibited excellent stability and its sorption capacity under optimum conditions has been found to be more than 60 microg of ions per gram of sorbent. The relative standard deviation under optimum conditions is lower than 4.10%. The accuracy of the method was estimated by using different real samples.

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A sensitive and simple method for the preconcentration of copper (II) ions has been reported. The method is based on the adsorption of copper ion N(1), N(2)-bis(4-fluorobenzylidene)ethane-1,2-diamine loaded on Sepabeads. The sorpted copper content was eluted by 8 ml of 4M nitric acid in acetone. The influences of the analytical parameters including pH and sample volume were investigated. The interference effects of matrix ions on the retentions of the copper (II) ions were also examined. The recovery of understudy analyte was generally higher than 95%. The method has been successfully applied to the evaluation of copper contents in some real samples including water samples, vegetable samples and milk samples.

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A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in food samples has been reported. The method is based on the adsorption of zinc, nickel, iron and lead on sodium dodecyl sulfate (SDS)-coated alumina, which is also chelated with bis (2-hydroxyacetophenone)-1, 3-propanediimine (BHAPN). The retained analyte ions on modified solid phase were eluted using 8 mL of 4 mol L(-1) HNO(3). The analyte determinations were carried out by flame atomic absorption spectrometry. The influences of some metal ions and anions on the recoveries of understudy analyte ions were investigated. The proposed method has been successfully applied for the evaluation of these trace and toxic metals in some traditional food samples from Iran.

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A sensitive and simple method for simultaneous preconcentration of trace heavy metal ions in some food samples has been reported. The method is based on the adsorption of Cr(3+), Fe(3+), Cu(2+), Ni(2+), Co(2+) and Zn(2+) on bis(2-hydroxy acetophenone)ethylendiimine (BHAPED) loaded on activated carbon (AC). The adsorbed metals on activated carbon were eluted using 2 mol L(-1) nitric acid in acetone. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the recoveries of analyte ions were also investigated. The recoveries of analytes were generally higher than 94%. The method has been successfully applied for analysis of the metal contents in real samples including natural water samples.

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Rhododendron and multi-flower honeys obtained from Black Sea Region of Turkey (12 Rhododendron and 8 multi-flower honeys) were studied to determine the presence of the 14 trace elements such as Cu, Cd, Pb, Co, Cr, Ni, Al, Se, Zn, Mn, Fe, K, Ca and Mg. Trace element determination was performed by atomic absorption spectrometry (AAS) after microwave digestion. The results revealed that Rhododendron honeys exhibited higher concentrations of Cu, Co, Cr, Ni, Se, Zn, Ca and Mg but lower concentrations of Al, Mn, Fe and K than in the multi-flower honeys. Trace element levels in analyzed honey samples were generally lower than literature values.

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The utility of Nordmann fir (Abies nordmanniana (Stev.) Spach. Subsp. nordmanniana) leaves from Eastern Black Sea region for the removal (sorption) of metal ions from aqueous solutions was investigated. For this, the optimum values of pH, time, metal concentration, leaf concentration, leaf particle size and adsorption capacity were determined. Also the recovery conditions of the metals from leaves were studied. Cd metal was selected because of its toxic properties. Freundlich isotherm model was used to describe the adsorption behaviour and the experimental results obtained for Cd(2+) adsorption, followed this model well. The utility of Nordmann fir leaves to remove toxic metals from aqueous solutions was proved. Hence, this study showed that the leaves of Nordmann fir can provide cheap source as biosorbents for toxic metal removal from natural or wastewaters.

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A simple, selective and rapid flotation method for the separation-preconcentration of trace amounts of cobalt, nickel, iron and copper ions using phenyl 2-pyridyl ketone oxime (PPKO) has been developed prior to their flame atomic absorption spectrometric determinations. The influence of pH, amount of PPKO as collector, type and amount of eluting agent, type and amount of surfactant as floating agent and ionic strength was evaluated on the recoveries of analytes. The influences of the concomitant ions on the recoveries of the analyte ions were also examined. The enrichment factor was 93. The detection limits based on 3 sigma for Cu, Ni, Co and Fe were 0.7, 0.7, 0.8, and 0.7 ng mL(-1), respectively. The method has been successfully applied for determination of trace amounts of ions in various real samples.

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