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The accurate determination of thorium (Th4+) in the presence of uranyl ions (UO22+) is a challenge facing analytical chemists. In this article, a solidified floating organic drop microextraction procedure (SFODME) combined with inductively coupled plasma-optical emission spectrometry (ICP-OES) is presented for the separation of Th4+ from UO22+. Morin (2′,3,4′,5,7-pentahydroxyflavone) selectively forms a stable complex with Th4+ in an acidic medium (pH 2.5), while UO22+ does not. The formed complex can be separated into an organic drop of 1-undecanol in the presence of ethanol as a dispersive solvent. The major factors influencing the achievement of SFODME, that is, pH, morin concentration, the type and volume of the extracting and dispersive solvents, the sonication conditions, the ionic strength, and the presence of foreign ions, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.3–400.0 μg L−1. The detection limit and enrichment factor values were 0.12 μg L−1 and 31.1, respectively. The relative standard deviation for 12 replicates was 1.5%. No significant effects from potentially interfering species, including f-block elements, were observed. The procedure was effectively applied for the determination of Th4+ in phosphate rock and ceramic tile samples.

In this study, nano-sized cellulose modified with lactic acid (MW-Ce-LA) was prepared with the assistant of microwave then used for the adsorption of Cu2+ from real samples. This modified cellulose was characterized by means of FTIR, TEM, XRD, and elemental analysis. ICP-OES was used for determination of Cu2+. The effect of pH, adsorption times, temperature, sorbent dose, and initial adsorbate concentration were studied to detect the ideal adsorption condition. Langmuir model proved to be the best to fit the adsorption isotherm experiments with maximum adsorption capacity of 90.3 mg g−1 Cu2+. Calculated thermodynamic parameters (ΔG° and ΔH°) for adsorption of Cu2+ on MW-Ce-LA suggested exothermic and nonspontaneous character of the adsorption process. The reusability tests indicated regeneration of the prepared adsorbent simply using 1 mol L−1 of HCl. The examined method was used effectively to preconcentrate Cu2+ from water, blood, and food samples.

In this work, mesoporous strontium titanate nanoparticles (SrTiO3 NPs) were synthesized through a single-step combustion process and were characterized by FT-IR, XRD, SEM-EDX, and TEM. The effects of main parameters that may influence the extraction process (i.e., pH, sorbent amount, time of extraction, eluting agent, and the presence concomitant ions) were investigated. The optimum extraction was achieved at pH 6, 50 mg of sorbent, 20-min shaking time, and 4.0 mL of 0.1 mol L−1 thiourea as desorption agent. Under these conditions, the maximum adsorption capacity was 155.6 mg g−1 with a preconcentration factor of 250 (for a 1000 mL sample solution). The calibration graph was linear up to 1000 μg L−1 and the limit of detection was 1.75 μg L−1. The precision (as relative standard deviation) was 2.53% (n = 10). The procedure was employed for the preconcentration of Pb2+ from blood and urine samples of bladder cancer patients before its determination by FAAS.

A cloud point extraction (CPE) process was described for the separation and spectrophotometric analysis of Fe(III) in different water samples and blood as chelating agent. The complexation reaction between Fe(III) and Zincon was elaborated at pH 5.0 using acetate buffer and the complex was quantitatively recovered in a mixed micelle system composed of cethyltri methyl ammonium bromide (CTAB) and Triton X-114. This reaction was carried out at room temperature in the presence of 0.05 mol L-1 Na2SO4 as salting-out electrolyte. The linearity was up to 1000 µg L-1. The preconcentration factor was 50. The precision (as relative standard deviation) and the limit of detection were 2.5% and 3.1 µg L-1, respectively. The proposed procedure was used for the spectrophotometric detection of Fe(III) in water and blood samples and the data were statistically comparable to those achieved using ICP-OES technique.

A micelle-mediated procedure was presented for enrichment of Cu2+ using 4-(2-chloroacetamido)-salicylic acid and Triton X-114 as complexing and extracting agents, respectively. The experimental parameters that affect the extraction were investigated and optimized. Good analytical features were achieved including limit of detection (0.25 µg L-1), limit of quantification (0.83 µg L-1), linearity (1.0-500 µg L-1) and reproducibility (2.2%). For 50.0 mL sample, the enrichment factor was 49.5. Most concomitant ions not interfere with Cu2+ determination. The procedure was employed for preconcentration and determination of Cu2+ in different samples (water, blood and urine) by flame atomic absorption spectrometry with satisfying results.

Herein, we report the organized investigation on adsorption of Cd(II) and Hg(II) by thioglycolic acid modified mesoporous silica nanoparticles prepared by the sol-gel procedure. The modification process is enhanced by microwave irradiation. The morphological behavior of the prepared sorbent (MCM-41-TgA) was identified by SEM and TEM imaging as well as BET surface area analysis. The proposed chemical properties were confirmed by elemental analysis, FT-IR, XRD, and zeta potential. EDX and FT-IR spectra were used to confirm the adsorption process. Both ions could be quantitatively recovered from aqueous samples at pH 6 after shaking for 30 min at room temperature. The solid phase has relatively high adsorption capacity 91.3 and 42.8 mg g−1 for Cd(II) and Hg(II), respectively. Langmuir isotherm model fitted well with the experimental data confirming the formation of a mono layer with homogeneous adsorption sites. The thermodynamic studies concluded spontaneity and exothermic behavior of the adsorption process. MCM-41-TgA could be regenerated using 0.5 mol L-11 thiourea or EDTA for at least 10 adsorption/desorption cycles, and it was applied to preconcentrate Cd(II) and Hg(II) from real samples before their determination using ICP-OES.

2-(3-Ethylthioureido)benzoic acid was prepared and characterized by electronic spectrum, elemental analysis, Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectrum and mass spectrum. The produced ligand was applied for the preconcentrative of Fe3+, Co2+, Cu2+ and Zn2+ in aqueous samples by cloud point extraction methodology. Triton X-114 was used as extractant. Experimental parameters that may affect the extraction process were examined and optimized; such as pH, ligand and triton concentrations, type of diluting solvent, extraction temperature and ionic strength. The calibration curves were linear upto 500 μg L−1 for Fe3+, Cu2+ and Zn2+ and upto 200 μg L−1 for Co2+. The achieved detection limits were 1.5, 0.23, 0.71 and 0.35 μg L−1 for Fe3+, Co2+, Cu2+ and Zn2+ respectively. The accuracy was established by analysis of certified reference materials (Seronorm whole blood L2 and ZCS ZC85006 Tomato). The proposed procedure was used for preconcentration of these metal ions in water, biological and food samples prior to their determination by flame atomic absorption spectrometry.

Microwave assisted preparation of cellulose modified with gallic acid (MA-Cell-GA) was developed for high efficient adsorption of Al3+. The as-prepared modified cellulose has been characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and zeta potential measurements. Energy dispersive X-ray (EDX) spectrum was utilized to proof the adsorption of Al3+. The effect of various experimental factors, as pH, amount of adsorbent, shaking time, initial metal ion concentration, temperature, concomitant ions and desorption conditions on the extraction efficiency was investigated and optimized in batch mode experiments. The adsorption capacity and the surface area of MA-Cell-GA were 59.6mgg-1 and 160m2g-1, respectively which were significantly higher than those of the sorbent obtained via traditional reflux procedure. The thermodynamic factors (ΔH° and ΔG°) values for adsorption of Al3+ on MW-Cell-GA confirmed the non-spontaneousity and exothermic character of the adsorption process. It was indicated that the prepared adsorbent can be regenerated easily using EDTA. The procedure was successfully applied for the preconcentration of Al3+ in water, rocks, blood and soil samples prior to the determination using inductively coupled plasma optical emission spectrometry (ICP-OES).

A micro-cloud point extraction method was discussed for preconcentration and spectrophotometric quantification of U(VI). The method depends on complex formation between U(VI) and 2-(4-sulphophenyloazo)-1,8-dihydroxy-3,6-naphtalenedisulphonic acid (SPADNS) at pH 7.0 and subsequent extraction of the complex in a mixed surfactant medium (cethyltrimethyl ammonium bromide and Triton X-114). The separation was carried out in the presence of 1% Na2SO4 at room temperature. The calibration curve was linear up to 3000 µg L−1. The enrichment factor, detection limit and precision were 16.0, 1.05 µg L−1, and 2.3%, respectively. The method was employed for the determination of U(VI) in real samples with different matrices.

To evaluate Cu and Zn levels in bladder cancer (BC) patients and their relationship with expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 (HIF-1). Plasma levels of Cu and Zn were determined in 66 transitional bladder cell carcinoma patients (BC group) and 60 matched controls. The concentration of Cu and Zn as well as the expressions of both VEGF and HIF-1 were also estimated in cancerous and non-cancerous bladder tissues in the BC group. The results showed that plasma Cu and Cu/Zn ratio were significantly higher in BC group when compared with the control group. In contrast, the plasma Zn in BC group was significantly lower than in the controls. Comparing levels of Cu and Zn in cancerous and non-cancerous bladder tissues among the BC group indicated a significantly higher Cu levels in the cancerous tissues, while Zn levels was significantly lower. There were higher expressions of both VEGF and HIF-1 in the cancerous samples. Moreover, the Cu concentration in cancerous tissues was significantly correlated with expressions of VEGF and HIF-1. Logistic regression analysis revealed that the increase in plasma Cu/Zn ratio and plasma Cu and the decrease in plasma Zn may be risk factors for development of bladder cancer. We concluded that alteration of plasma and bladder tissue levels of both Cu and Zn is correlated with pathogenesis of bladder cancer. The increase in Cu level in cancerous tissues of BC group has an important role in angiogenesis in bladder cancer cells.

An eco-friendly, selective, accurate and rapid procedure was developed for determination of Th4+ in the presence of U6+, Sm3+, La3+, Ce4+, Ho3+ and Er3+. Morin selectively forms a complex with Th4+ at pH range 2.0–4.0 that quantitatively extracted into the surfactant-rich phase in the presence of 0.1% (v/v) Triton X-114 and 0.1% (w/v) KI at room temperature. The developed procedure was optimized and used for determination of Th4+ in complex specimens (waste water and phosphate rocks) by inductively coupled plasma - optical emission spectrometry. The procedure possesses wider analytical range (0.3–500.0 µg L−1) and lower detection limit (0.11 µg L−1) compared to other published CPE procedures for Th4+. For a 50.0 mL sample, the enrichment factor was 49.5. The interference effect of most concomitant ions was negligible. The accuracy of the method was estimated by good recoveries (95.0–100.0%) of Th4+ from spiked samples.

A sensitive and selective method for speciation and determination of iron was developed using cloud point extraction combined with spectrophotometry. The method depends on formation of complex between Fe3+ and a newly synthesized reagent, 4-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2-hydroxybenzoic acid (DOPHHBA), and its extraction into Triton X-114 rich phase prior to spectrophotometric determination at 438 nm. Total Fe was determined as Fe3+ by the same methodology after oxidation of Fe2+. The method exhibited dynamic linear range from 4.0 to 500 µg L-1 with limit of detection and enrichment factor of 1.2 µg L-1 and 95.2, respectively. The accuracy of the method was tested by analysis of certified reference materials and spiked samples. The method was applied for speciation of Fe in natural water samples and determination of Fe in food samples with satisfying results. The analytical results are statistically comparable with those obtained by a standard ICP-OES method.

This article covers the applications of cloud point extraction (CPE) methodology for separation and preconcentration of different substances including metal ions, nano-particles and organic molecules. The CPE as any extraction procedure separates the analyte from whole sample into small volume to increase the sensitivity of analysis and to eliminate effect of interference from sample background. The major features of CPE technique over the other separation methods are effectiveness, rapidness, simplicity and safety. It minimizes or ignores the utilization of toxic organic solvents and therefore the procedure is termed as “eco-friendly tool”. In the present review, the application of CPE in the determination of wide range of analytes was discussed with special concern to recent developed procedures. The main advantages and limitations of the technique were also provided.

A total of 1291 drinking water samples were examined for nitrite and nitrate during 6 months from December, 2015 to May, 2016 at 17 cities of Dakahlia governorate (Nile Delta, north of Egypt), and the results were utilized for assessment of health risk of the exposure from drinking water by calculating average daily intake (ADI), hazard quotient (HQ), and the hazard index (HI). The nitrite and nitrate in drinking water had a concentration range of 0.030–0.113 and 2.41–8.70 mg L−1, with mean values of 0.059 ± 0.014 and 5.25 ± 1.61 mg L−1, respectively. Nitrite and nitrate levels in rural areas and ground water samples were significantly higher than that in the urban ones. None of the analyzed samples exceeded WHO guideline values that set out to prevent methemoglobinemia. The values of HQ and HI for all age groups do not exceed unity indicating a low risk of methaemoglobinaemia for the population in this area. Results of the present study indicate that there is no health risk of residents from nitrite and nitrate through drinking water in the studied area. However, the other sources of exposure to nitrite and nitrate should be investigated in further studies.

A selective and effective cloud point extraction procedure was presented for separation of Gd3+ from other f-block elements (i.e. La3+, Ce3+, Nd3+, Sm3+, Ho3+, Er3+, Th4+ and U6+). The procedure depends on the formation of stable hydrophobic complex between Gd3+ and quercetin at pH 3.0. The formed complex was extracted at room temperature into surfactant rich phase “Triton X-114” in the presence of 0.1 mol L−1 KI. The procedure was also used for enrichment of Gd3+ prior its determination by ICP-OES. At optimum conditions, the proposed procedure displays good analytical linearity (0.1–200 μg L−1) with limit of detection and limit of quantification of 0.03 and 0.11 μg L−1, respectively. The enrichment factor was 49.2 for 50 mL sample. The analyte was quantitatively tolerated in the presence of most concomitant ions. The procedure was then employed for the analysis of Gd3+ in ore, urine and synthetic samples.

Amino silica gel functionalized with 2-hydroxy-5 -(2-hydroxybenzylideneamino)benzoic acid was synthesized, characterized and used as adsorbent for the removal of Ga3+, In3+ and Tl3+ from aqueous solution prior to their determination by flame atomic absorption spectrometry. Experimental parameters that affect the separation process were investigated in both batch and column modes. The maximum adsorption capacities of the sorbent are 61.7 mg g−1, 81.3 mg g−1 and 133.0 mg g−1 for Ga3+, In3+ and Tl3+, respectively. The preconcentration factor is 200 and the limits of detection of Ga3+, In3+ and Tl3+ are 4.10 μg L−1, 1.55 μg L−1 and 1.21 μg L−1, respectively. Interference by Al3+ can be masked by the addition of F−; and that of Fe3+ by its reduction to Fe2+ using 10% ascorbic acid. The method was successfully applied for the determination of these ions in water, sediments and liquid crystal display samples.