Extraction and preconcentration of lead (II) in various water and food samples by orbital shaker-assisted magnetic solid phase extraction method using a new magnetic poly linoleic acid-polystyrene-PDMS block copolymer.

The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7-84 µg L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 µg L-1, 1.7 µg L-1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g-1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.

CoSn(OH)6 nanocubes as a solid sorbent for the effective preconcentration of copper ions in cinnamon (Cinnamomum zeylanicum) extract.

This study was aimed at developing a simple and efficient CoSn(OH)6 nanocubes-based preconcentration method for the preconcentration of copper ions from cinnamon extracts for determination by flame atomic absorption spectrometry. The cube-shaped sorbent was synthesized using the simple stoichiometric co-precipitation method under ambient conditions. Experimental factors of the method were evaluated with a comprehensive optimization approach to maximize the extraction efficiency for the analyte. Under the optimal conditions, the limit of detection (LOD), limit of quantitation (LOQ), and linear dynamic range were recorded as 0.98 µg/L, 3.28 µg/L, and 4.0-75 µg/L, respectively. The enhancement factor was calculated as 101.6-fold by comparing the LODs of the optimized and direct analysis systems. Percent recoveries were found to be within an acceptable range (77.6-115 %), with high repeatability using matrix matching calibration strategy. Results validated the proposed method as a highly efficient extraction approach for the monitoring of copper ions in herbal cinnamon extracts.

Micro solid phase extraction of lead and cadmium using functionalized nanodiamonds@CuAl2O4@HKUST-1 nanocomposite for FAAS analysis in food and water samples.

This study focuses on the development and application of a novel nanocomposite (functionalized nanodiamonds@CuAl2O4@HKUST-1)-based µ-SPE method for the sensitive and selective extraction of Pb and Cd from food and water samples. The technique offers high sensitivity and selectivity, allowing accurate measurement of these metals at trace levels. The detection limit is 0.031 µg kg-1 for Cd and 0.052 µg kg-1 for Pb, with a relative standard deviation of 1.7 % for Cd and 4.8 % for Pb. The method was successfully applied to real samples and efficiently quantified Pb and Cd in food and natural water samples. The highest concentrations were found in red lentils (0.274 µg kg-1 Pb) and fresh mint (0.197 µg kg-1Cd), but still below recommended limits set by FAO/WHO (300 µg kg-1 for Pb and 200 µg kg-1 for Cd). It promises to ensure food safety, monitor environmental contamination, and informs regulatory decisions to protect public health.

Determination of copper in rose tea samples using flame atomic absorption spectrometry after emulsification liquid-liquid microextraction.

Rose tea infusion has gained popularity worldwide due to its health benefits. However, it is known that tea plants can be contaminated with heavy metals including copper. Hence, an accurate and applicable analytical method namely emulsification liquid-liquid microextraction based deep eutectic solvent - flame atomic absorption spectrometry (ELLME-DES-FAAS) was proposed to determine copper at trace levels in rose tea samples. Under the optimum experimental conditions, analytical figures of merit for the developed method were examined, and dynamic range, limit of detection (LOD) and limit of quantification (LOQ) were found to be 5.07-246.61 µg/kg (mass-based) with 0.9992 coefficient of determination, 2.50 µg/kg and 8.32 µg/kg, respectively. A matrix matching calibration strategy was employed to boost recovery results, and the acceptable recovery results were recorded between 95.9 % and 118.4 %. According to recovery results, the developed analytical method can be safely employed to determine the concentration of copper in rose tea samples accurately.

A continuous flow polyurethane foam solid phase microextraction lab-in-syringe platform for the automatic determination of toxic metals.

A novel fully automatic continuous flow polyurethane foam solid phase microextraction lab-in-syringe system for on-line sample preconcentration/separation has been developed as a front-end to flame atomic absorption spectrometry. For the first time lab-in-syringe in continuous flow has been adopted for the determination of toxic metals. The microextraction procedure was performed after on-line metal complexation with ammonium pyrrolidine dithiocarbamate, while the elution was conducted by 400 µL of methyl isobutyl ketone. The main chemical and hydrodynamic factors that affected the performance of the method were optimized using Cd and Pb as model analytes. For 90 s preconcentration time, the limits of the detection were 0.20 and 1.7 µg L-1 for Cd and Pb, respectively, while the enhancement factors were 79 for Cd and 150 for Pb. The relative standard deviation% values were lower than 2.8 % for all analytes. As a proof-of-concept the proposed system was used for environmental water analysis, providing relative recoveries within the range of 94.0 and 104.4 %. The Green Analytical Procedure Index and Blue Applicability Grade Index proved reduced environmental impact and high practicality for the proposed method.

Analytical application of flower-shaped nickel nanomaterial for the preconcentration of manganese in domestic wastewater samples.

In this study, detection sensitivity of the conventional flame atomic absorption spectrophotometer (FAAS) for the determination of manganese (Mn2+) was enhanced by employing a preconcentration method from wastewater samples. Flower-shaped Ni(OH)2 nanomaterials were synthesized and used as sorbent material in preconcentration procedure. With the aim of attaining optimum experimental conditions, effective parameters of extraction method were optimized and these included pH of buffer solution, desorption solvent concentration and volume, mixing type and period, nanoflower amount, and sample volume. The detection limit of the optimized method was determined to be 2.2 µg L-1, and this correlated to about 41-fold enhancement in detection power relative to direct FAAS measurement. Domestic wastewater was used to test the feasibility of the proposed method to real samples by performing spike recovery experiments. The wastewater sample was spiked at four different concentrations of manganese, and the percent recoveries determined were in the range of 95-120%.

Contents and health risk assessments of selected heavy metals in vegetables produced through irrigation with effluent-impacted river.

The widely consumed vegetables, khat, lettuce, and Swiss chard, in Hirna town, West Hararghe, Ethiopia, are extensively cultivated through irrigation with an effluent-impacted river that flows through the town which denotes that monitoring the safety of the vegetables is crucial. Herein, the contents of Pb, Zn, Cu, Cr, and Cd in vegetables, water, and soils were determined by flame atomic absorption spectrometry after a wet digestion procedure based on a mixture of HNO3 and HClO4 at 200 °C. pH and electrical conductivity of the water and soil, and health risks associated with vegetable consumption were determined. The pH of the water (6.64) and soil (6.67) was slightly acidic, and electrical conductivity values were 0.416 and 0.024 mS/cm, respectively, indicating both are in good condition. The metal concentrations were in the range of ND-3.12, 3.43-9.22, and 0.15-10.6 mg/L in the water, soil, and vegetables, respectively, and the contents followed a trend of Cu > Zn > Cr > Pb > Cd. The irrigation water contained all metals above the guidelines except Cd, and the soil contained safe levels except Cd which is above the guideline. The obtained metal levels in the vegetables were below the safe limits. Estimated daily intakes and the total target cancer risks were below the guidelines, and the target hazard quotient and the hazard index were below 1 indicating that the vegetables are safe for consumption. In general, the obtained results suggest that the vegetables are safe for consumption. However, continuous monitoring and policy development are required to mitigate contamination of the river.

A magnetic solid phase extraction procedure for Pb(II) at trace levels on magnetic Luffa@TiO2 in food and water samples.

A novel magnetic Luffa@TiO2 sorbent was synthesized and characterized by using XRD, FTIR and SEM techniques. Magnetic Luffa@TiO2 was used for solid phase extraction of Pb(II) in food and water samples prior to its flame atomic absorption spectrometric (FAAS) detection. The analytical parameters such as pH, adsorbent quantity, type and volume of eluent, and foreign ions were optimized. Analytical features such as the limit of detection (LOD) and the limit of quantification (LOQ) of Pb(II) are 0.04 µg L-1 and 0.13 µg L-1 for liquid samples and 0.159 ng/g and 0.529 ng/g for solid samples, respectively. The preconcentration factor (PF) and relative standard deviation (RSD%) were found 50, and 4 % respectively. The method was validated by using three certified reference materials (NIST SRM 1577b bovine liver, TMDA-53.3 and TMDA-64.3fortified water). The presented method was applied to lead contents of some food and natural water samples.

Using mandelic acid as an extraction solvent in the extraction of Cu(II) and Cd(II) from soil samples.

In this study, an efficient, green, and rapid sample preparation method based on mandelic acid dimer was proposed for the extraction of Cu(II) and Cd(II) from soil samples followed by flame atomic absorption spectrometry. In this research, for the first time, the liquid dimer was prepared by heating solid mandelic acid. Then the mixture of soil and a complexing agent was added into it. The mixture was transferred into a microwave oven. Diluted nitric acid solution as a dilution solvent was added. After centrifugation, two aliquots of the collected phase were removed and injected into the instrument. The relevant optimization parameters such as dimer volume, microwave exposure time, amount of complexing agent, and the type and volume of dilution solvent were investigated and optimized. Under the optimum conditions, detection limits were obtained 0.17 and 0.16 mg Kg-1 for Cu(II) and Cd(II), respectively. The linear ranges were 0.50-50 mg Kg-1 with coefficient of determination ≥ 0.9981. The developed method along with a reference method was applied for the analysis of the selected heavy metal ions in different soil samples and comparable results were obtained. Also, the method was performed on a certified reference material and the obtained concentrations compared with the certificated concentrations to assess accuracy of the proposed method.

Direct magnetic sorbent sampling flame atomic absorption spectrometry (DMSS-FAAS) for highly sensitive determination of trace metals.

A procedure of direct magnetic sorbent sampling in flame atomic absorption spectrometry (DMSS-FAAS) was developed in this work. Metal-loaded magnetic sorbents were directly inserted in the flame of the FAAS for direct metal desorption/atomization. Magnetic graphene oxide aerogel (M-GOA) particles were synthesized, characterized, and used as a proof-of-concept in the magnetic dispersive solid phase extraction of Pb2+ ions from water samples. M-GOA was selected because is a light and porous sorbent, with high adsorption capacity, that is quickly burned by the flame. Magnetic particles were directly inserted in the flame by using a metallic magnetic probe, thereby avoiding the need for a chemical elution step. As all the extracted Pb2+ ions arrive to the flame without passing through the nebulization system, a drastic increase in the analytical signal was achieved. The improvement in the sensitivity of the proposed method (DMSS-FAAS) for Pb2+ determination was at least 40 times higher than the conventional procedure in which the Pb2+ is extracted, eluted, and analyzed by conventional flame atomic absorption spectrometry (FAAS) via the nebulization system. The analytical curve was linear from 5.0 to 180.0 µg L-1 and the limit of detection was found to be 1.30 µg L-1. Background measurements were insignificant, and the atomic absorption peaks were narrow and reproducible. Precision assessed as a percentage of the relative standard deviation %RSD was found to be 17.4, 7.1, and 7.8% for 10, 70, and 180 µg L-1 levels, respectively. The method showed satisfactory results even in the presence of other ions (Al3+, Cr3+, Co2+, Cu2+, Fe3+, Mn2+, Ba2+, Mg2+, and Li+). The performance of the new system was also evaluated for Cd2+ ions, as well as by using other magnetic particles available in our lab: magnetic carbon nanotubes (M-CNTs), magnetic restricted access carbon nanotubes (M-RACNT), magnetic poly (methacrylic acid-co-ethylene glycol dimethacrylate) (M-PMA), magnetic nanoparticles coated with orange powder peel (M-OPP), and magnetic nanoparticles covered with SiO2 (M - SiO2). Analytical signals increased for both analytes in all sorbents (increases of about 4-37 times), attesting the high potential and applicability of the proposed method. Simplicity, high analytical frequency, high detectability and reproducibility, low cost, and possibility of being totally mechanized are the most relevant advantages.

Development of a pH-induced dispersive solid-phase extraction method using folic acid combined with dispersive liquid-liquid microextraction: application in the extraction of Cu(II) and Pb(II) ions from water and fruit juice samples.

In this study, a new pH-induced dispersive solid-phase extraction method using folic acid has been proposed for the extraction of Cu(II) and Pb(II) ions from water and fruit juice samples. For this purpose, at first, a specified amount of folic acid was dissolved in the sample solution containing the studied ions at pH 8.5. Then, by decreasing pH of the solution, solubility of folic acid reduced and its fine particles containing the analytes were produced. They were separated and dissolved in dimethylformamide. For more preconcentration, the developed procedure was combined with a dispersive liquid-liquid microextraction procedure. Finally, the extracted and enriched analytes were determined by flame atomic absorption spectrometry. The effect of important parameters on the extraction efficiency of the method such as pH, folic acid amount, the amount of complexing agent, dimethylformamide volume, ionic strength, and centrifugation conditions were studied. Under optimized conditions, the developed method showed linear ranges of 0.20-40 and 0.25-40 µg L-1 for Pb(II) and Cu(II) ions, respectively. Limits of detection of Pb(II) and Cu(II) were 0.07 and 0.08 µg L-1, respectively. The relative standard deviations (intra- and inter-day precisions) were between 3.8 and 5.4%. Accuracy of the proposed method was studied by determination of the analytes concentrations in a certified reference material; SPS-WW2 Batch 108. Efficiency of the proposed procedure was evaluated by analyzing Pb(II) and Cu(II) ions in various water and fruit juice samples.

A facile approach for grafting ion imprinted polymer onto magnetic multi-walled carbon nanotubes for selective removal and preconcentration of cadmium in food and wastewater samples prior to atomic spectrometric determination.

A 3D Fe3O4@MWCNT-CdIIP was synthesized by the oxidizing surface of multi-walled carbon nanotubes with carboxylic acid end groups and its subsequent termination with an ion imprinted polymer. An artificial neural network manifests better predictability than the central composite design methodology for optimising the adsorption procedure. The adsorption capacity was 109 mg g-1 (2.5 times more than non-imprinted polymer) under optimized conditions (pH; 5.6, time; 15 min, concentration; 800 µg mL-1 temperature; 25 °C), which was in accord with Toth isotherm. Fractal-like pseudo-second-order kinetics was found reasonably fast, with 66 % adsorption in 5 min. Solid phase extraction coupled Flame atomic absorption spectrometry method provides selective recognition towards Cd(II), with limit of detection; 1.13 µg/L, limit of quantification; 3.21 µg/L after preconcentration (preconcentration factor; 50) and good robustness. The developed method was applied for Cd(II) determination in food (tea, coffee, bread, tobacco, radish, spinach), water and wastewater (>99 % removal as well). Cd(II) loaded IIP was further utilized to remove anionic dyes with >95 % removal.

Nickel hydroxide nanoflower-based dispersive solid-phase extraction of copper from water matrix.

In this work, a dispersive solid-phase extraction method based on Ni(OH)2 nanoflowers (Ni(OH)2-NFs-DSPE) was developed to separate and preconcentrate copper ions from tap water samples for determination by flame atomic absorption spectrometry (FAAS). Ni(OH)2-NFs was synthesized using a homogeneous precipitation technique and used as sorbent for copper preconcentration. X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy were used to characterize the synthesized sorbent. All experimental variables were carefully optimized to achieve a high enhancement factor of 107.5-folds with respect to the detection sensitivity of the conventional FAAS. The proposed method's analytical parameters including LOD, LOQ, and linear range were determined as 1.33 µg/L, 4.42 µg/L, and 3.0-40 µg/L, respectively. To assess the applicability and reliability of the developed method, optimal conditions were applied to tap water samples and satisfactory percent recoveries (94-103%) were obtained for the samples spiked at 20 and 30 µg/L. This validated the accuracy and feasibility of the developed method to real samples. The developed method can be described as a simple, efficient, and rapid analytical approach for the accurate determination of trace copper ions in water samples.

Silica-coated modified magnetic nanoparticles (Fe3O4@SiO2@(BuSO3H)3) as an efficient adsorbent for Pd2+ removal.

It is crucial to fabricate cost-effective and efficient strategies for monitoring and eliminating hazardous metals in the water supplies. Among the many techniques, adsorption is one of the most powerful and facile ways for eliminating pollutants from effluents. It is also crucial to engineering high-performance low-cost adsorbents. In this regard, herein, Fe3O4@SiO2@(BuSO3H)3 as a modified core-shell magnetic silica nanoparticle embodies good selectivity to extract toxic metal ions from aquatic media. The present work investigated the removal performance of the magnetic adsorbent towards Pd2+ cation amongst the other heavy metal ions including Co2+, Pb2+, Hg2+, Cd2+, Cu2+, Zn2+ in aqueous solution. The flame atomic absorption spectrometry (FAAS) was utilized to assess the removal efficiency of the adsorbent. Several experimental parameters including elution condition, initial Pd(II) concentration, adsorbent dosage, initial pH of the solution, and contact time were explored to achieve the optimal conditions. The data of adsorption were very well with the Langmuir isotherm model, according to the adsorption isotherm mechanism experiments. In conclusion, this study lays the way for the development of novel magnetic adsorbents with high removal efficiencies for the removal of toxic metal ions from aqueous environment.

Tailored-designed material for the preconcentration of Cd(II) on glycidyl methacrylate-based ion-imprinted polymer for flame atomic absorption for trace determination in real samples: multivariate optimization.

A new Cd(II)-imprinting polymer was synthesised based on glycidyl methacrylate (Fe3O4@GMA@IIP) and employed to develop a dispersive magnetic solid-phase extraction method for the preconcentration prior to the determination of Cd(II) from the environmental samples. A central composite design (CCD) based on response surface methodology was used for optimization of the process variables and the material shows the promising saturation adsorption capacity of 28.21 mg g-1 under the optimum pH of 4.9 within 15.2 min at saturation concentration 914 µg mL-1. The experimental data were well described by Sips isotherm model and Brouers-Sotolongo fractal kinetic model that indicated the surface heterogeneity and involvement of both chemisorption and physisorption process. Thermodynamic results documented the endothermic and spontaneous nature of adsorption. The sorbent manifest the economic feasibility maintaining its sorption efficiency after the regeneration by 1 M HNO3 and reusability up to 6 adsorption/desorption cycles. The developed method exhibited the preconcentration factor of 30 and a high degree of tolerance for matrix ions. Limit of detection (LOD) and quantification (LOQ) were calculated as 3.054 and 10.182 µg L-1 respectively. The developed method was validated by the standard reference material and spiking addition method in real samples, and obtained results showed good agreement in accordance with spiking values. The ease of magnetic separation, high selectivity, good adsorption capacity and faster kinetics made this material a promising candidate for Cd(II) determination in various food and aqueous samples.

Polystyrene-coated magnetic nanoparticles based dispersive solid phase extraction for the determination of cadmium in cigarette ash prior to slotted quartz tube flame atomic absorption spectrometry system.

A sensitive, accurate and simple analytical method was developed to determine cadmium by slotted quartz tube-flame atomic absorption spectrometry after preconcentration/extraction with polystyrene coated magnetic nanoparticles based dispersive solid phase extraction. The surface of Fe3O4 based magnetic nanoparticles was modified with polystyrene to yield higher selectivity and sensitivity in adsorption efficiency of cadmium. The nanoparticles were dispersed into the aqueous solution to extract/separate cadmium. Significant parameters of the method including magnetic nanoparticle amount, mixing effect, effect of ionic strength, eluent concentration and sonication period were optimized to achieve optimal conditions for the analyte. The limit of detection and quantification values of the developed method were found to be 0.62 and 2.1 ng/mL, respectively. Under the optimum conditions, enhancement of the detection power for cadmium were calculated as 102 folds for the developed method. The developed method was then applied to cigarette ash to test its accuracy and applicability. Total cadmium was found to be between 402 and 450 ng/g in the ashes of different cigarette brands commercially available in Turkey. The accuracy of quantifying cadmium in the complex ash samples was enhanced by using the matrix matching calibration strategy. The developed method provides sensitive and selective determination of cadmium at ng/mL levels even at complex cigarette ash samples. High percent recovery results (90-102%) were obtained from spiked real samples.

Synthesis of green nano sorbents for simultaneous preconcentration and recovery of heavy metals from water.

The wastewater containing Cd, Co, Fe, Cu, Cr, Mn, Ni and Pb ions are as trace metal pollutants. Water pollution caused by increment in industrialization and overpopulation reveals a major threat to human health. Adsorption is recognized as the effective and optimum method to remove water contaminations. The amorphous and porous form of silicon dioxide is silica gel widely used as an adsorbent. It can absorb moisture with traces of the target heavy metal ions. This research elaborates a simplistic, and reliable preconcentration column method highly developed for the determination of Cd2+, Fe3+, Co2+, Cr3+, Cu2+, Mn2+, Pb2+ and Ni2+ ions in model solutions and real water samples by flame atomic absorption spectrometry (FAAS). The proposed operation depends on the retention of the target ions from buffered model solutions on a silica gel filled up a column modified with vanadium(V) oxide sorbent followed by their desorption. SiO2/V2O5 is an efficient adsorbent due to its low cost, eco-friendly and high availability. The adsorbent morphological and interfacial physicochemical characterization was done using scanning electron microscopy, and Fourier transmission infrared spectroscopy, respectively. The 2.92 value achieved for the point of zero charges supports the experimentation for the heavy metal efficient adsorption. Quantitative recoveries were achieved at pH 10 with 50 mg of SiO2/V2O5 mass and adsorption capacity ranged from 28.96 µmol/g (Pb) to 214.86 µmol/g (Fe) with 1114.79 µmol/g in total. Simultaneous preconcentration effect was determined by the interference cations on the sorbent. The LOD varies from 8.42 to 50.56 µg/L and LOQ is achieved from 20.06 to 72.41 µg/L of 15 blank solutions. The developed preconcentration procedure was adequately implemented for the simultaneous analysis of eight metallic ions content in local river samples. The developed vanadium(V) oxide incorporated with silica gel is practicable as an economical and effective adsorbent to eliminate metallic ions from a liquid solution.

Comparison Studies on Several Ligands Used in Determination of Cd(II) in Rice by Flame Atomic Absorption Spectrometry after Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction.

Ligands plays an important role in the extraction procedures for the determination of cadmium in rice samples by using flame atomic absorption spectrometry (FAAS). In the present study, comparative evaluation of 10 commercially available ligands for formation of Cd(II)-ligand complex and determination of cadmium in rice samples by ultrasound-assisted dispersive liquid-liquid microextraction (UADLLME) combined with FAAS was developed. Sodium diethyldithiocarbamate (DDTC) provided a high distribution coefficient as well as a good absorbance signal, therefore DDTC was used as a ligand in UADLLME. A low density and less toxic solvent, 1-heptanol, was used as the extraction solvent and ethanol was used as the disperser solvent. In addition, the experimental conditions of UADLLME were optimized in standard solution first and then applied in rice, such as the type and volume of extractant and dispersant, pH, extraction time, and temperature. Under the optimal experimental conditions, the detection limit (3σ) was 0.69 µg/L for Cd(II). The proposed method was applied for the determination of Cd(II) in three different rice samples (polished rice, brown rice, and glutinous rice), the recovery test was carried out, and the results ranged between 96.7 to 113.6%. The proposed method has the advantages of simplicity, low cost, and accurate and was successfully applied to analyze Cd(II) in rice.

Development of a metal sieve-linked double syringe liquid phase microextraction method for the determination of copper in olive leaf extract samples by flame atomic absorption spectrometry.

This work reports the development of a simple, sensitive and low-cost analytical method for the trace determination of copper. A metal sieve-linked double syringe liquid phase microextraction method was used to preconcentrate copper into measurable quantities for FAAS system. The pressurized mixing offered by the automated syringe system and the sieve connector enhanced surface area for analyte and extraction solvent interaction, this significantly increased the extraction efficiency for copper. There was therefore no need for auxiliary organic solvents as disperser solvents for the extractant dichloromethane. The limits of detection and quantification, linear dynamic range and percent relative standard deviation values calculated for copper under optimum conditions of the method were 1.5 and 5.1 µg L-1, 5.0-500 µg L-1 and 8.4%, respectively. The developed method was successfully employed to determine copper (0.75-8.06 mg kg-1) in unspiked olive leaf samples.

Lower calcium levels in hair of Parkinson's disease patients are associated with presence of sleeping disturbances.

Objectives: To investigate the correlation between sleep disorders and the concentrations of three metals analyzed from hair samples of PD patients.The hypothesis of an involvement of an imbalance of metals in the development of Parkinson's Disease (PD) has been strengthened by several clinical chemistry studies. Interestingly, while sparse, some studies have correlated the imbalance of metals in PD patients with comorbidities present in this disease. Although not all PD sufferers present sleep disturbances, significant disorders of sleep are common in this population. Methods: Sleep evaluation was divided into three parameters: sleep quality, excessive daytime sleepiness and clinically probable REM Sleep Behavior Disorder. Flame atomic absorption spectrometry (F AAS) was used to assess the concentrations of calcium, iron and zinc in hair samples collected from a population of PD patients registered in a Brazilian city and from controls (a total of 53 subjects). All subjects lived within a restricted geographical region and were exposed to similar environmental conditions. Results: PD patients with poor sleep quality and excessive daytime sleepiness exhibited significant differences in concentrations of calcium, but not iron or zinc when compared to levels found in controls and PD patients who do not report these sleeping problems. Discussion: Our data suggest that different subgroups of PD patients exist, and clinical chemistry could be useful as a biomarker for these subgroups, which needs to be confirmed in a larger patient population. Further, our data raise the question regarding whether normalization of calcium levels could improve the sleep quality and somnolence in PD patients.