A simple and low cost assay for total iron in various samples based on dispersive liquid-liquid microextraction (DLLME) coupled with digital scanning image analysis was proposed. Orthogonal experiment design was utilized to optimize the amount of extraction solvent and disperser solvent, O-phenanthroline concentration and buffer pH. Under the optimum conditions, the calibration curve was linear over the range of 0.047–1.0μgmL−1 (R2>0.99) of iron. The limit of detection (LOD) for iron was 14.1μgL−1 and limit of quantification (LOQ) was 46.5μgL−1. The relative standard deviations for seven replicate determinations of 0.5μgmL−1 of iron was 3.75%. The method was successfully applied for analysis of total iron in water and food samples without using any spectral instrument and it could have a potential industrial impact in developing fast and portable devices to analyze the iron content in water and certain foods.

In this work, an ecologically friendly, cheap, and highly efficient hydrophobic deep eutectic solvent based liquid phase microextraction procedure was developed and coupled with flame atomic absorption spectrometry for determination of cadmium. Hydrophobic deep eutectic solvent (HDES) was prepared by mixture of trihexyltetradecylphosphonium chloride and pivalic acid and used as extraction solvent. The formation of cadmium complex was achieved by sodium diethyldithiocarbamate trihydrate. Response Surface Methodology by Box–Behnken Design and three different models was used for optimizing experimental conditions and statistical analysis. Analytical parameters such as limit of detection, limit of quantification, relative standard deviation and enhancement factor were calculated as 1.6 µg L⁻¹, 5.0 µg L⁻¹, 3.3% and 43, respectively. Finally, the developed liquid phase microextraction method was applied to some food and water samples.

Polycyclic aromatic hydrocarbons are a class of highly toxic and unremitting organic pollutants that are widely distributed in the natural environment. In this work, a metal-organic framework (MOF) designated as HKUST-1 [Cu₃(BTC)₂] was synthesized, characterized, and applied as a solid-phase extraction sorbent for the determination of a trace polycyclic aromatic hydrocarbon, anthracene (Ant) as model compound, in various real samples by spectrofluorimetry. The synthesized MOF exhibited large surface areas and high extraction ability, making it excellent candidate as sorbent for enrichment of trace anthracene. The effects of influential parameters on the performance of the dispersive micro-solid-phase extraction (Dμ-SPE) process, such as the initial anthracene concentration, pH, sorbent dosage, and shaking time, were investigated and optimized by the experiment design method. Under the optimized experimental conditions, good linearity in the range of 3–85 ng mL⁻¹ with correlation coefficient 0.997 and good sensitivity with low detection limit 0.5 ng mL⁻¹ for Ant was achieved. The method has been validated in the analysis of real tap water, soft drink, and vegetable juice samples with recoveries in the range of 86.33–103.00% and relative standard deviations in the range of 1.94–3.77%. The as-prepared HKUST-1 was used for at least four times without any obvious decline of extraction capability. The results of this study show the great potential of MOFs as sorbents in Dμ-SPE procedures for the separation and determination of trace Ant in complicated matrices.

This study reports a simple, rapid and greener method based on ultrasound assisted-cloud point extraction coupled with inductively coupled plasma-optical emission spectroscopy (ICP-OES) for preconcentration and determination of antimony (Sb), tin (Sn) and thallium (Tl) in food and water samples. Factors affecting the preconcentration procedure were optimized using fractional factorial design and response surface methodology based on Box-Behnken design. Under optimum conditions, the calibration graphs were linear over the concentration range of 0.023–700 μg L−1 with correlation coefficients up to 0.9994, the limits of detection ranged from 0.007–0.010 μg L−1, the limits of quantification were from 0.023 to 0.033 μg L−1 and the relative standard deviations (n = 15) were between 1.3% and 4.1%. In addition, the preconcentration factors were found to be 150, 145 and 160 for Sb, Sn and Tl, respectively. Finally, the developed method was successfully applied in various food and water samples as well as certified reference materials for rapid determination of Sb, Sn and Tl.

A magnetic ionic based dispersive liquid liquid microextraction (MIL-DLLME) procedure was optimized for the analysis and extraction of cadmium in water and food samples by flame atomic absorption spectrophotometry (FAAS). Contribution of experimental variables were optimized through central composite design combined with response surface analysis. Under optimized conditions, the limit of detection was found 0.6 ng mL⁻¹ with the relative standard deviation of 1.7%. Dynamic range was obtained in the concentration range of 2–700 ng mL⁻¹ with correlation coefficient of 0.9983. Relative recoveries were ranged from 94% to 99% with enrichment factor of 172. The validation of the optimized method was successfully confirmed by reference material analysis. The optimized method allows the analysis of cadmium in water and food samples with good reliability of the determination. Compared with the conventional procedures, the method enabled a fast, green and simple determination of cadmium in the real sample with minimal solvent consumption and a higher extraction capability.

Heavy metals and arsenic (As) are hazardous to the environment and human health. In concert with the problem of metallic contaminants, certain macrophytes in wetlands are harmful invasive alien plants (IAP). Nevertheless, there exists a knowledge gap, that whether all IAP are nuisance or possess certain beneficial role as bioresource in environmental amelioration. Present study conducted microcosm experiments to investigate the heavy metals and As phytoremediation potential of IAP (Phragmites karka (Retz.) Trin. ex Steud. and Arundo donax L.). The results revealed the significant but differential heavy metals remediation (31.0 to 73.3%; p ≤ 0.01) and anti-oxidative defence potential (in terms of enzymatic activity) of IAP. Highest translocation factor (TF-0.89) was noted in case of P. karaka for Zn. Rhizofiltration (TF < 1) was observed as main phytoremediation mechanism. In the present experimental design, P. karka was noted as better phytoremediation tool than A. donax. In future studies, phytoremediation potential of these IAP can be tested at field scale, in conjunction with ‘Water-energy food (W-E-F) nexus’ and ‘biorefinery’ co-benefits.

In this work a novel magnetic metal–organic framework (MOF-199/dithiocarbamate modified magnetite nanoparticle composite) was synthesized and utilized for speciation analysis of As(iii) and As(v) via determination by electrothermal atomic absorption spectrometry. The synthesized sorbent represented selectivity toward As(iii) at pH = 3 while As(v) remained in the initial solution. Total amount of arsenic in the samples was determined after reduction of the As(v) species to As(iii) ions with the mixture of Na₂S₂O₃ and KI. A design of experiments approach was employed to find the best extraction conditions by evaluating the parameters affecting the preconcentration procedure. Under the optimal conditions the limit of detection, linearity and relative standard deviation of the method for As(iii) were 1.2 ng L⁻¹, 4–300 ng L⁻¹ and <8.4%, respectively. The developed method was validated by analyzing two certified reference materials. Finally, the outlined method was successfully employed to the rapid extraction and speciation analysis of As(iii) and As(v) in water samples and total arsenic in rice and canned tuna samples.

We applied novel vortex-assisted ionic liquid dispersive liquid-liquid microextraction (VA-IL-DLLME) method to preconcentration and extraction of Se(IV) ions from water, beverage and food samples. The method was optimized using central composite design combined with the response surface analysis. After extraction, inorganic selenium species (total Se, Se(IV) and Se(VI)) were determined by hydride generation atomic absorption spectrometry. 1-n-Octyl-3-methylimidazolium bis(trifluoromethane)-sulfonamide [C8mim NTf2] and tetrahydrofuran were used as the extraction and dispersive solvents, respectively. Applied vortex assisted the extractant dispersion and accelerated the mass transfer process. Obtained optimum conditions for microextraction procedure are as follows: mass of [C8mim NTf2], pH, extraction time and THF volume should be equal to 85 mg, 6.8, 15 min and 730 μL, respectively. Under these conditions, we observed linear range, limit of detection and enrichment factor equal to 5−500ng L⁻¹, 1.5 ng L⁻¹ and 120, respectively. We also fount linear regression coefficients in the dependence between Absorbance and Se(IV) concentration: Absorbance = 0.0652 CSₑ₍IV₎ + 0.0185. We added 200 μg kg⁻¹ of Se(IV) to selected food samples and 100 ng L⁻¹ of Se(IV) to selected waters and beverages. Relative standard deviations and recovery values were within the ranges of 2.4–3.5 % and 92.7÷103.4 %, respectively. The optimized VA-IL-DLLME method reported here provides high extraction efficiency, fast extraction and lower detection limit without a heating step than alternative microextraction methods. This method also requires environmental solvents for determination and preconcentration of trace Se species in the selected samples. In addition, the reported VA-IL-DLLME procedure is the first method which use [C8mim NTf2] as extraction solvent for the preconcentration and separation of Se(IV) ions.