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The polymer, polystyrene polydimethyl siloxane was loaded into the micropipette tip of the syringe system as an adsorbent to developed miniaturized solid phase microextraction. Standard solutions of arsenate and arsenite were passed through the adsorbent loaded in micropipette tip to check the adsorption behaviors. It was observed that arsenate adsorbed on the polystyrene polydimethyl siloxane in the pH rang of 6-8, while arsenite was directly passed through the micropipette tip of syringe system. The adsorbed arsenate in micropipette tip of syringe system were eluted by 1.0M hydrochloric acid. The total inorganic arsenic contents were obtained by the addition of oxidizing agent potassium permanganate into the studied samples before passing to the micropipette tip of syringe system. Arsenite concentration in water samples were measured by subtracting arsenate from total inorganic arsenic concentration. Different characteristics which effect the determination of arsenate specie like amount of adsorbent, adsorption capacity, pH, pulled and pushed cycles for adsorption and desorption, volume of sample, eluent type and it volume were also studied in detail. Enrichment factor and detection limit of arsenate by desired method were 218 and 6.9ngL -1 respectively. The relative standard deviation was 4.1% (n=10, C=0.12µgL -1 ). Accuracy of the desired technique was confirmed by analysis of the CRMs (Lake Ontario Water TM-28.3 and Riverine Water NRCC-SLRS-4). Desired technique was significantly useful for determination of the total arsenic, arsenate, and arsenite contents in different natural water samples., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A green and sensitive temperature controlled dispersive liquid-liquid microextraction (TIL-DLLME) methodology based on the application of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [C4mim][PF6], as an extractant solvent was proposed for the preconcentration of trace levels of aluminium (Al(3+)) in scalp hair samples of Alzheimer's (AD) patients, prior to analyzing by flame atomic absorption spectrometry (FAAS). The Al(3+) was complexed with 8-hydrooxyquinoline (oxine) (L1) and 3,5,7,2'-4' pentahydroxy flavone (morin) (L2) separately and then extracted by IL at temperature (50±2.0°C). Some effective factors that influence the TIL-DLLME efficiency such as pH, ligands concentrations, volume of IL, ionic strength, and incubation time were investigated and optimized by multivariate analysis. In the optimum experimental conditions, the limit of detection (3s) and enhancement factor were 0.56 μg L(-1), 0.64 μg L(-1) and 85, 73 for both ligands, respectively. The relative standard deviation (RSD) for six replicate determinations of 100 μg L(-1) Al(3+) complexed with oxine and morin were found to be 3.88% and 4.74%, respectively. The developed method was validated by the analysis of certified reference material of human hair (NCSZC81002).and applied satisfactorily to the determination of Al(3+) in acid digested scalp hair samples of AD patients and healthy controls. The resulted data shows significant higher level in scalp hair samples of AD male patients with related to referents of same age and socioeconomic status., (Copyright © 2014 Elsevier B.V. All rights reserved.)

An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu(2+)) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu(2+) using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046μgL(-1) and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu(2+) in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu(2+) in serum samples of different viral hepatitis patients and healthy controls., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The aim of this study was to evaluate the translocation of arsenic (As) by different vegetables grown in agricultural soil irrigated for long period with tube well water as test vegetable samples and compared those vegetables of same species grown in agricultural soil irrigated with fresh canal water marked as control vegetable samples. Moreover, the total and ethylene-diamine-tetra acetic acid (EDTA) extractable contents of As in soil irrigated by tube well and canal water were determined and correlate with total concentrations of As in edible parts of vegetables. Statistically significant correlations were obtained between the total and EDTA extractable fractions of As in soil. High level of total and EDTA extractable As were found in tested vegetable samples as compared to controlled vegetable samples. This investigation highlights the increased danger of growing vegetables in the agricultural land continuously irrigated by As contaminated water., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The antagonistic effects between selenium (Se) and arsenic (As) suggest that low Se status plays an important role in arsenism development. The objective of present study was to assess Se contents in biological samples of As exposed females have skin lesions and cancer with related to non-exposed skin cancer patients. The biological samples (blood and scalp hair) of As exposed group comprises, female skin cancer (ESC) patients admitted in cancer hospitals have skin lesions (ESL) and exposed referents have not both diseases (ER), belongs to As exposed area of Pakistan. For comparative purposes, age matched female skin cancerous patient (RP) and non-cancerous females (NER) belong to non-exposed areas were also selected. The As and Se in acid digests of biological samples were pre-concentrated by complexing with chelating agent (ammonium pyrrolidinedithiocarbamate), and resulted complexes were extracted into non-ionic extractant (Triton X-114), prior to analysis by electrothermal atomic absorption spectrometry. The enhancement factor of about 25 was obtained by pre-concentrating 10 mL of sample solutions. The accuracy of the optimized procedure was evaluated by using certified reference material (BCR 397) with certified values for Se and As and standard addition method at three concentration levels in real samples. No significant differences was observed (p>0.05) when comparing the values obtained by the proposed method, added and certified values of both elements. The biological samples of ESC patients had 2-3 folds higher As and lower Se levels as compared to RP (p<0.001). Understudied exposed referents have high level of As and lower Se contents as compared to referents subjects of non-exposed area (p<0.01). The higher concentration of As and lower levels of Se in biological samples of cancerous patients are consisted with reported studies., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A cloud point extraction (CPE) method has been developed for the determination of trace quantity of vanadium ions in pharmaceutical formulations (PF), dialysate (DS) and parenteral solutions (PS). The CPE of vanadium (V) using 8-hydroxyquinoline (oxine) as complexing reagent and mediated by nonionic surfactant (Triton X-114) was investigated. The parameters that affect the extraction efficiency of CPE, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of CPE of V was checked by standard addition method in real samples. The extracted surfactant-rich phase was diluted with nitric acid in ethanol, prior to subjecting electrothermal atomic absorption spectrometry. Under these conditions, the preconcentration of 50 mL sample solutions, allowed raising an enrichment factor of 125-fold. The lower limit of detection obtained under the optimal conditions was 42 ng/L. The proposed method has been successfully applied to the determination of trace quantity of V in various pharmaceutical preparations with satisfactory results. The concentration ranges of V in PF, DS and PS samples were found in the range of 10.5-15.2, 0.65-1.32 and 1.76-6.93 microg/L, respectively., (2010 Elsevier B.V. All rights reserved.)

In present study a biomass derived from the stem of Acacia nilotica has been investigated to remove As ions from surface water samples of different origins (lake, canal and river). The effects of various parameters viz. pH, biosorbent dosage, contact time and temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. It was observed that As biosorption best fitted to the Langmuir and Freundlich isotherms. The mean sorption energy (E) calculated from D-R model, indicated physico-chemical biosorption. Study of thermodynamic parameters revealed the endothermic, spontaneous and feasible nature of biosorption process. The pseudo-second-order rate equation described better the kinetics of As biosorption with good correlation coefficients than pseudo-first-order equation. The biomass of A. nilotica was found to be effective for the removal of As with 95% sorption efficiency at a concentration of <200 microg/L of As solution, and thus uptake capacity is 50.8 mg As/g of biomass. The A. nilotica biomass could be used as a low-cost biosorbent for As ion removal., (Copyright 2010 Elsevier B.V. All rights reserved.)

A new method is reported for the separation of aluminum ions [Al(III)] from interfering elements in parenteral and pharmaceutical solutions (PS) and bottled mineral water (BMW) samples, through solid-phase extraction with 2-methyl-8-hydroxyquinoline (quinaldine) adsorbed onto activated silica gel. While the enrichment step of separated Al(III) was carried out by cloud point extraction (CPE) using 8-hydroxyquinoline as complexing reagent, the resulted complex was entrapped in a non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114). The enriched Al(III) in sample solutions were determined by spectrofluorometry (SPF) at lambda(excitation) 370 nm and lambda(emission) 510 nm, and flame atomic absorption spectrometry (FAAS) for comparative purpose. The variables affecting the complexation and extraction steps were studied and optimized. The validity of methodology was checked with certified reference material of water and standard addition method. The enrichment factor and detection limit of Al(III) for the preconcentration of 50 ml of PS and BMW were found to be 100 and 0.25 microg/L, respectively. The proposed method has been applied for the determination of trace amount of Al(III) in PS and BMW samples with satisfactory results. In PS the levels of Al(III) are above than permissible limit (25 microg/L).

A separation/preconcentration of aluminum (III) (Al(3+)) has been developed to overcome the problem of high matrix species, which may interfere with the determination of trace quantity of Al(3+) in natural water samples. The separation of Al(3+) in water samples was carried out from interfering cations by complexing them with 2-methyle 8-hyroxyquinoline (quinaldine) on activated silica. Whereas the separated trace amounts of Al(3+) was preconcentrated by cloud point extraction (CPE), as prior step to its determination by spectrofluorimetry (SPF) and flame atomic absorption spectrometry (FAAS). The Al(3+) react with 8-hydroxyquinoline (oxine) and then entrapped in non-ionic surfactant Triton X-114. The main factors affecting CPE efficiency, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of separation/preconcentration of Al(3+) was checked by certified reference material of water (SRM-1643e). After optimization of the complexation and extraction conditions, a preconcentration factor of 20 was obtained for Al(3+) in 10 mL of natural water samples. The relative standard deviation for 6 replicates containing 100 microg L(-1) of Al(3+) was 5.41 and 4.53% for SPF and FAAS, respectively. The proposed method has been applied for determination of trace amount of Al(3+) in natural water samples with satisfactory results.

The simple and rapid pre-concentration techniques viz. cloud point extraction (CPE) and solid phase extraction (SPE) were applied for the determination of As(3+) and total inorganic arsenic (iAs) in surface and ground water samples. The As(3+) was formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, after centrifugation the surfactant-rich phase was diluted with 0.1 mol L(-1) HNO(3) in methanol. While total iAs in water samples was adsorbed on titanium dioxide (TiO(2)); after centrifugation, the solid phase was prepared to be slurry for determination. The extracted As species were determined by electrothermal atomic absorption spectrometry. The multivariate strategy was applied to estimate the optimum values of experimental factors for the recovery of As(3+) and total iAs by CPE and SPE. The standard addition method was used to validate the optimized methods. The obtained result showed sufficient recoveries for As(3+) and iAs (>98.0%). The concentration factor in both cases was found to be 40.

The concentrations of heavy metals (HMs) in plants served to indicate the metal contamination status of the site, and also revealed the abilities of various plant species to take up and accumulate them from the soil dressed with sewage sludge. A study to comprehend the mobility and transport of HMs from soil and soil amended with untreated sewage sludge to different newly breaded varieties of wheat (Anmol, TJ-83, Abadgar and Mehran-89) in Pakistan. A pot-culture experiment was conducted to study the transfer of HMs to wheat grains, grown in soil (control) and soil amended with sewage sludge (test samples). The total and ethylenediaminetetraaceticacid (EDTA)-extractable HMs in agricultural soil and soil amended with domestic sewage sludge (SDWS) and wheat grains were analysed by flame atomic absorption spectrometer/electrothermal atomic absorption spectrometer, prior to microwave-assisted wet acid digestion method. The edible part of wheat plants (grains) from test samples presented high concentration of all HMs understudy (mgkg(-1)). Significant correlations were found between metals in exchangeable fractions of soil and SDWS, with total metals in control and test samples of wheat grains. The bio-concentration factors of all HMs were high in grains of two wheat varieties, TJ-83 and Mehran-89, as compared to other varieties, Anmol and Abadgar grown in the same agricultural plots.

A fast microwave assisted extraction procedure was developed and optimized for their eventual exploitation in the three-stage sequential extraction procedure proposed by modified BCR protocol (the community Bureau of Reference now the European Union "Measurement and Testing Programme"). The effects of the microwave treatment on the extraction of Cd, Cr, Cu, Ni, Pb and Zn from untreated sewage sludge collected from Hyderabad city (Pakistan) were compared with those obtained from sequential BCR extraction procedure. In sequential BCR method, each extraction step takes 16 h, where as with the use of compromised microwave conditions, extraction steps could be completed in about 120 s, for each step, respectively. Extractable Cd, Cr, Pb and Ni obtained by both comparable methodologies were measured by electrothermal atomic absorption spectrometry (ETAAS), while for Cu and Zn flame atomic absorption spectrometry (FAAS) was used. The validations of both extraction techniques were compared by the analysis of certified reference material of soil amended with sewage sludge (BCR 483). The results of the partitioning study of untreated waste water sewage sludge, indicate that more easily mobilized forms (step 1) were predominant for Cd, Ni and Zn (28.3, 28.4 and 43.7%), in contrast, the largest amount of Cd and Pb (66.4 and 72.8%) was associated with the iron/manganese oxide while Cr and Ni (71.2 and 38.7%) in organic matter/sulphide fractions. The overall metal recoveries in steps 1-3 (excluding residual step) were 95.3-104% of those obtained with the sequential BCR protocol. The accuracy of the proposed microwave extraction method (expressed as %R.S.D.) was lower than 10% for all metals.

In this study, a sample preparation method based on ultrasonic assisted acid digestion (UAD) has been evaluated for total heavy metals (Cd, Cr, Ni and Pb) determination in different environmental (soil, sediment and sewage sludge), and biological (fish muscles, vegetables and grains) samples, using electrothermal atomic absorption spectrometry (ETAAS). The investigated parameters influencing UAD such as presonication time, sonication time, temperature of ultrasonic bath, and different acid mixtures were fully optimized, whereas power was maintained constant at 100% of nominal power of ultrasonic bath. Six different sets of above parameters were applied on six certified reference materials (CRMs) having different matrices. The accuracy of the method was also tested by comparing the results with those obtained from conventional hot plate assisted acid digestion method on same CRMs. Analytical results for HMs by both methods showed no significant difference at 95% confidence limit (p<0.05). Recoveries of HMs ranging from 96.2% to 102% and 96.3% to 98.6% were obtained from biological and environmental samples, respectively. The average relative standard deviation of UAD method varied between 3.5% and 8.2%, depending on the analyte.

Sequential extraction procedure proposed by the European Standards, Measurements and Testing (SM&T) Program, formerly the Community Bureau of Reference (BCR), has been applied for the heavy metals (HMs) partitioning in fresh water lake sediment samples. The results obtained by conventional sequential extraction BCR method (SEB) for Cd, Cu, Cr, Ni, Pb and Zn were compared with those estimated from three alternative single extractions, conventional (CSE), ultrasonic (USE) and microwave assisted (MSE), using identical operating conditions applied in each individual BCR fraction and validated by the CRM BCR 701. Extractable HMs contents obtained by all compared methodologies were measured by atomic absorption spectrometery. With the use of compromised sonication and microwave conditions, steps 1-3 of the sequential extraction (excluding the hydrogen peroxide digestion in step 3) could be completed between 15-30 min using ultrasonic bath, while 60-120 s were required for MSE. The total extractable metal contents obtained by three single extractions ranged from 75.1% to 114.0% except Cr in first step, which was extracted (125.3%) by MSE method as compared to those obtained by SEB procedure. The precision of the proposed BCR single extraction methods (expressed as RSD%) was found in the range of (3.99-9.6%) for all metals.

A sample preparation method based on ultrasound-assisted pseudo-digestion of Al from Juices and soft drink samples under ultrasonic effect has been described. A Plackett-Burman experimental design was used as a multivariate strategy for the evaluation of the effects of varying several variables at once. The effects of five different variables preintensification time (without ultrasonic stirring), intensification time in ultrasonic bath (UB), temperature of UB, two acid mixtures (HNO(3)-H(2)SO(4)-H(2)O(2) and HNO(3)-H(2)O(2)), on the recovery of Al have been investigated. From these studies, certain variable showed up as significant, and they were optimized by a using 2(3)+star central composite design, which involved 16 experiments. The best conditions for pseudo-digestion were as follows: a preintensification time 10min, intensification time 20min, volume of acid mixtures 3.0ml and temperature of ultrasonic bath 80 degrees C. A conventional acid digestion on electric hot plate was used to obtain total Al for comparative purpose. Final solutions obtained from both methods, were analysed by electrothermal atomic absorption spectrometry. Analytical results for the Al by ultrasound-assisted pseudo-digestion, and conventional wet digestion methods showed a good agreement, thus indicating the possibility of using ultrasonic-assisted digestion sample preparation instead of intensive treatments inherent with the acid digestion methods on electric hot plate. The procedure proposed allowed the determination of Al with detection limit (3alpha/s) 10mugl(-1).

Background: The causes of night blindness in children are multifactorial and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence hair composition., Method: An ultrasonic-assisted acid leaching procedure was developed as a sample pretreatment for the determination of Zn, Cu, Cd, As and Pb in human scalp hair samples of night blindness male children with age between 5 to 15 y and compared with the children without vision anomalies that lived in the same localities. The effects of different factors on acid leaching of metals, such as preintensification time (without ultrasonic stirring) after treatment of acid mixture, exposure time to ultrasound and temperature of the ultrasonic bath have been investigated. The proposed method was validated by certified reference samples of scalp hair CRM 397. The wet acid digestion method was used to obtain the total metal concentration in both scalp hair and CRM samples. Cu and Zn in leachates and digests were measured by flame atomic absorption spectrometry (FAAS) using a conventional air/acetylene flame, while Cd and Pb were determined by electrothermal atomic absorption spectrometry (ETAAS) under optimized conditions., Results: It was observed that at optimal conditions, the recovery for Zn, Cd, Pb, As and Cu were 98%, 98.5%, 96%, 97.2% and 94% respectively. The mean values of Zn and Cu in scalp hair samples of children having night blindness were significantly lower as compared to normal healthy children (p for Zn<0.001 and Cu<0.003), while the level of toxic metals As, Cd and Pb were significantly higher in children having ocular problems as related to normal children (p As<0.0074, Cd<0.001 and lead<0.004)., Conclusion: These data present guidance to clinicians and other professional investigating deficiency of essential trace metals and excessive level of toxic metals in biological samples.