Determination Of Lead In Water Research Articles

Determination of lead in water from reservoirs for human supply using atomic absorption spectrometry

Determination of lead in water from reservoirs for human supply using atomic absorption spectrometry

Adsorption and determination of Lead in water and human urine samples based on Zn2(BDC)2(DABCO) MOF as polycaprolactone nanocomposite by suspension micro solid phase extraction coupled to UV–VIS spectroscopy

Today, the safety of water resource is the most important challenges which was reported by health and environment organizations. Water pollution can be created by hazardous contaminants of environmental pollutions. Lead as a heavy metal has carcinogenic effects in humans. Metal organic framework (MOF) is a highly porous material with different application. The Zn2(BDC)2(DABCO) is a good candidate of MOF based on zinc metal (Zn-MOF) with potential adsorption/extraction. In this work, Zn2(BDC)2(DABCO) MOF as polycaprolactone (PCL) nanocomposite were applied for lead adsorption/extraction from 50 mL of aqueous solution by ultra-assisted dispersive suspension-micro-solid phase extraction procedure (USA-S- µ-SPE) at pH=8. The samples were characterized by the FTIR, the XRD analysis, the FE-SEM and the BET surface area. The effect of parameters was investigated on lead absorption before determined by UV–VIS spectroscopy. The linear range, the detection limit (LOD) and enrichment factor of adsorbent were obtained 0.05-1 mg L-1, 0.25 μg L-1 and 48.7, respectively (r = 0.9992, RSD%=3.65). The absorption capacity of Zn2(BDC)2(DABCO) MOF for 50 mg L-1 of standard lead solution were obtained 133.8 mg g-1 for 0.25 g of adsorbent. The results indicate that this nanocomposite can have a good potential to develop different adsorbents.

Air-assisted solvent terminated dispersive liquid–liquid microextraction (AA-ST-DLLME) for the determination of lead in water and beverage samples by graphite furnace atomic absorption spectrometry

A preconcentration method based on a novel hybrid air-assisted solvent terminated dispersive liquid–liquid microextraction (AA-ST-DLLME) using a domestic fish-tank pump as a bubble generator was developed for the determination of Pb in water and beverage samples by GFAAS. The important parameters for the microextraction process (pH, concentration of complexing agent, type of extracting solvent, type of disperser, type of demulsifier, air-assisted time, and extraction time) were optimized. Under the optimized conditions, the enrichment factor (EF) of 58.9 was achieved, with the preconcentration factor (PF) of 60.0 and the extraction efficiency of 98.2%. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.025 ng/mL and 0.084 ng/mL, respectively. The relative standard deviation (RSD) was 1.02–3.19%. The proposed method was applied for the determination of trace level of Pb in water, fruit juice, and beverage samples. The spiked recovery at three different spiked concentrations were 82.0–117.3%. Results from the analysis of standard reference materials (SLRS-6) were not significantly different at the 95% of confidence level.

Determining uncertainty in a simple UV–Vis spectrometry method employing dimethyl carbonate as green solvent for lead determination in water

The growth of industrial and urban centers promotes water quality issues. Water is one of the greatest sources of human exposure to lead. This study presents a simple, inexpensive, and fast analytical method for determining lead water employing DLLME followed by a UV–Vis spectrophotometer. Dimethyl carbonate (DMC) is used for the first time as the extraction solvent for lead determination. Carbonates are non-toxic, biodegradable green solvents obtained from renewable resources. For optimization, a two-level Full-Factorial Design was used; the selected conditions for 5.0-mL water analysis were DDTP 0.1%, 1.0% phosphoric acid, and 1.0 mL of DMC. This method was successfully validated through the assessment of specificity, linearity (from 0.2 to 1.0 mg L −1), accuracy (90.0% to 102.5%), precision (RSD from 2.6% to 15.0%), and LOQ of 0.2 mg L−1. Bottom-up measurement uncertainty evaluation provides relative uncertainty values around 13% to14% of lead concentration in water.

Utility of solid phase extraction for colorimetric determination of lead in waters, vegetables, biological and soil samples

A highly sensitive, selective and rapid method for the determination of lead based on the reaction of lead(II) with 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Pb(II)–CPAHPD complex with Amberlite XAD-2000 was developed, in the presence of pH 5.6 buffer solution and Triton X-114 medium. CPAHPD reacts with lead to form a violet complex with a molar ratio of 2:1 (CPAHPD to lead). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol (0.2mL). In isopentyl alcohol medium, the molar absorptivity of the complex is 1.13×106Lmol−1cm−1 at 647nm. Beer’s law is obeyed in the range of 5.0–160ngmL−1 in the measured solution. The relative standard deviation for 10 replicate samples of 50ngmL−1 level is 1.26%. The detection and quantification limits reaches 1.5 and 4.7ngmL−1 in the original samples. The presented procedure was successfully applied for determination of lead content in real samples such as vegetables, waters, biological and soil samples with satisfactory results.

Semi-automated continuous sample drop flow microextraction with swift preconcentration and atomic absorption spectrometry determination of lead in water and apple leaves

In this paper, we present novel developments to our recently developed method so-called “continuous sample drop flow microextraction (CSDF-ME)” technique. Previously, we showed that the CSDF-ME technique offers several advantages, including stability of extraction solvent, no need for holder device, and easy to operate. The merit of current study is to make the extraction steps faster with sample required for the analysis. The key novelty of proposed method includes usage of a solvent mixture (i.e., methanol and carbon disulfide), allowing to pump aqueous samples with a higher flow rate than the former technique which led to reduce the extraction time. Results show that the technique is cable to become faster by five times with an enrichment factor of 93 for 4.0 mL of aqueous sample. The linear range and limit of detection for Pb are found to be 0.1–6.0 and 0.03 µg L−1, respectively. The relative standard deviation for determination of 1.0 µg L−1 of Pb in a sample is 2.9% (n = 5). Furthermore, the relative recoveries of the developed CSDF-ME method for Pb in tap water, mineral water, and Standard Reference Material for apple leaves (1515) are shown to be 98, 100, and 94%, respectively.

A simple and green deep eutectic solvent based air assisted liquid phase microextraction for separation, preconcentration and determination of lead in water and food samples by graphite furnace atomic absorption spectrometry

In this study, an air assisted liquid phase microextraction based on deep eutectic solvent (AA-DES-LPME) method was developed for separation, preconcentration and determination of lead followed by graphite furnace atomic absorption spectrometry (GFAAS). The complexation of Pb(II) was carried out by using 4-(2-thiazolylazo) resorcinol as complexing agent at pH6. Deep eutectic solvent was prepared by using choline chloride phenol (ChCl-Ph) and was added to an aqueous solution containing analyte, and then mixture was sucked up and injected nine times with the help of a syringe, and a cloudy state was attained. After extraction, the solution was centrifuged and upper layer was separated and Pb(II) ions was determined by GFAAS. Different parameters were investigated and optimized including pH, volume and type of DES, effect of ligand volume, effect of pulling and pushing cycles. Under optimum conditions, the detection limit, limit of quantitation were observed as 0.60ngL−1 and 1.98ngL−1, respectively. Preconcentration factor (PF) and relative standard deviation (RSD) were found to be 60 and 2.9%, respectively. Certified reference materials (CRMs) were used to check the accuracy of developed technique. Finally, present procedure was fruitfully used for analysis of Pb(II) in various food and water samples.

Determination of Lead in Water by Linear Sweep Anodic Stripping Voltammetry (LSASV) at Unmodified Carbon Paste Electrode: Optimization of Operating Parameters

This study presents the elaboration of a simple and cheap electrode made by carbon paste introduced into a cavity of electrode body, and used for the lead traces determination in tap water. A potentiostatic pre-electrolysis at constant voltage enables the reduction of the lead (Pb2+) and the accumulation of the metallic lead at and into the carbon paste; the reoxidation of the Pb (Linear sweep voltammetry) leads to the anodic striping peak. The effect of the main operating parameters on the shape of the peak and the magnitude of the current was examined and their optimal values were determined. Then calibration was achieved and the method was successfully applied (using all the optimized parameters) to the determination of lead in water, with a detection limit of 0.138 μg·L-1. Compared to other methods (ICP-AES for example), the proposed method offers a satisfactory detection limit of the Pb2+ (0.138 μg·L-1) because of the important specific area of the carbon paste electrode, for a significantly lower cost. Besides, there is no observed loss in the electrode answer in terms of peak current, which means that there is no any irreversible steps nor deactivation of the electrode, even after ten successive measurements; only reduction of the lead followed by the deposit oxidation was observed at the electrode.

Cuban zeolite for lead sorption: application for water decontamination and metal quantification in water using nondestructive techniques

In the present paper, a Cuban clinoptilolite-type zeolite was used as lead sorbent. The effect of chemical conditioning with 1 mol L−1 NaCl, NaOH and NH3 solutions at room temperature on the ion exchange capacity for lead uptake by clinoptilolite has been investigated. According to the batch experiments, NH3-treated clinoptilolite exhibited the highest sorption capacity. For this material, the effect that contact time, solid-to-liquid ratio and pH have on the removal of lead from aqueous solutions was comprehensively analyzed, and the most suitable values for these parameters were selected afterward. The pseudo-second-order kinetic model was appropriate for the description of the kinetic performance of the sorption. The Langmuir and Freundlich isotherm models were applied to describe sorption process, and the best fit was reached by using the Freundlich model. The nondestructive techniques, namely particle-induced X-ray emission and X-ray fluorescence, have successfully been evaluated for determining lead concentration in water by its concentration in zeolite. In addition, the more traditional flame atomic absorption spectrometry determination of lead in water was also improved.

Ionic liquid-linked dual magnetic microextraction of lead(II) from environmental samples prior to its micro-sampling flame atomic absorption spectrometric determination

A novel and rapid microextraction approach termed as ionic liquid-linked dual magnetic microextraction (IL-DMME), was developed for the atomic absorption spectrometric determination of lead. The developed method based on a combination of dispersive liquid–liquid microextraction (DLLME) and dispersive micro solid-phase extraction (D-μ-SPE). In the first DLLME step, 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6], was selected to extract the lead-pyrrolidine-dithiocarbamate (Pb-PDC) complex from sample solution by the assistance of vortex agitator. After the first step, fifty milligrams of Fe3O4 magnetic nanoparticles (MNPs) were added to extraction of the ionic liquid and Pb-PDC complex in aqueous solution. The effective factors in proposed IL-DMME procedure, including volume of 1-butyl-3-methylimidazolium hexafluorophosphate, amount of Fe3O4 magnetic nanoparticles, vortex time, amount of ammonium pyrrolidinedithiocarbamate, sample volume and matrix effect were optimized in details. Under the optimal conditions, the method present has low detection limit (0.57μgL−1), high preconcentration factor (160) and good repeatability (<7.5%, n=10). The accuracy of the developed method was evaluated by the analysis of the certified reference materials and addition-recovery tests. The method was successfully applied to the determination of lead in water, plant and hair samples.

An on-line separation and preconcentration system coupled with flame atomic absorption spectrometry for the determination of lead

A simple on-line separation/preconcentration procedure is described for the determination of trace levels of Pb(II) by flame atomic absorption spectrometry (FAAS). A mini-column packed with Dowex Marathon C (DMC) ion-exchange resin was used for the on-line preconcentration of Pb(II) at pH 3.5. Pb(II) was sorbed on the resin, from which it could be eluted with 3 mol L−1 HCl and then introduced directly to the nebulizer–burner system of FAAS. The parameters influential on the determination of Pb(II) ions such as the pH of sample solution, eluent type, interfering ions and flow variables were studied. Under the optimum conditions, the calibration graph obtained was linear over the concentration range of 0.01–0.1 mg L−1. The detection limit of the method was 1.3 μg L−1 while precision was 1.1% (n = 15) at a 0.05 mg L−1 Pb(II) level. The accuracy of the method was proven using standard reference materials. The developed method has been applied successfully to the determination of lead in water and various environmental samples with satisfactory results.

Preconcentration of lead using solidification of floating organic drop and its determination by electrothermal atomic absorption spectrometry

A simple microextraction method based on solidification of a floating organic drop (SFOD) was developed for preconcentration of lead prior to its determination by electrothermal atomic absorption spectrometry (ETAAS). Ammonium pyrolidinedithiocarbamate (APDC) was used as complexing agent, and the formed complex was extracted into a 20μL of 1-undecanol. The extracted complex was diluted with ethanol and injected into a graphite furnace. An orthogonal array design (OAD) with OA16 (45) matrix was employed to study the effects of different parameters such as pH, APDC concentration, stirring rate, sample solution temperature and the exposure time on the extraction efficiency. Under the optimized experimental conditions the limit of detection (based on 3s) and the enhancement factor were 0.058μgL−1 and 113, respectively. The relative standard deviation (RSD) for 8 replicate determinations of 1μgL−1 of Pb was 8.8%. The developed method was validated by the analysis of certified reference materials and was successfully applied to the determination of lead in water and infant formula base powder samples.

Determination of Lead in Water Using Amberlite XAD-2 Functionalized With Xylenol Orange Resin as Column Material for On-line Flow Injection- Flame Atomic Absorption Spectrometry Analysis

Determination of Lead in Water Using Amberlite XAD-2 Functionalized With Xylenol Orange Resin as Column Material for On-line Flow Injection- Flame Atomic Absorption Spectrometry Analysis

Determination of lead in water by combining precolumn adsorption and fluorimetric detection in a microfluidic device

A microfluidic device equipped for in situ fluorescence detection and combined with an off-line microcolumn adsorption is proposed for the determination of lead in natural water. The precolumn adsorption is based on a microcapillary filled with aminopropyl silica. An efficient Pb2+ adsorption on aminopropyl silica was proved by Langmuir isotherm adsorption experiments. The maximum adsorption capacity was found to be 5.7 × 10−4 mol g−1. By using this solid phase extraction procedure (SPE), a 100-fold specific lead concentration was obtained. The concentrated solution was then run into a microfluidic device equipped for fluorescence detection and the complete procedure allows lead determination with a detection limit of 2 μg L−1. Furthermore, it was found that these measurements are not disrupted by the addition of a large excess of other interfering cations.

A micro-extractor for concentration and determination of lead in water

In this work, we present the design, fabrication and characterization of a novel micro-extractor that performs on-line extraction–concentration–detection (ECD) of target molecules flowing in a carrier liquid. The system comprises a primary microchannel containing a flowing aqueous carrier liquid and a secondary organic storage fluid circulating in an adjacent channel. The interfaces between the two immiscible fluids are stabilized by vertical micro-pillars. The system encompasses three functions: (i) extraction of the target molecules from the carrier fluid through the pillar-stabilized interfaces, (ii) concentration of the targets in the secondary organic solvent due to its very low—or zero—velocity and (iii) on-line detection via optical spectrometry. We successively present the analysis of the physics of the system, which has led us to a specific design, then the microfabrication of the chip, and finally we demonstrate the extraction, concentration and detection of lead ions (Pb 2+) from a water flow.

Determination of lead in environmental waters with dispersive liquid–liquid microextraction prior to atomic fluorescence spectrometry

This paper established a new, rapid and sensitive method for the determination of lead in water samples preconcentrated by dispersive liquid–liquid microextraction (DLLME) prior to atomic fluorescence spectrometry. Dithizone was used as the chelating agent. In the DLLME procedure, lead formed lead–dithizone complex and migrated into the carbon tetrachloride micro-droplets. Important factors that would affect the extraction efficiency had been investigated including the kind and volume of extraction solvent and dispersive solvent, sample pH, the amount of chelating agent, extraction time and centrifugation time. The results showed that the coexisting ions containing in water samples had no obvious negative effect on the determination of lead. The experimental results indicated that the proposed method had a good linear range of 0.01–100 ng mL −1 ( r 2 = 0.9990). The precision was 2.12% (RSD, n = 7) and the detection limit was 0.95 ng L −1. Proposed method was validated with four real environmental samples and the results indicated that the proposed method was excellent for the future use and satisfied spiked recoveries were in the range of 92.9–97.4%.

Novel Polymeric Resin for Solid Phase Extraction and Determination of Lead in Waters

AbstractInterest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry and the high costs of other sensitive methods in compared to flame atomic absorption spectrometry (FAAS). Among preconcentration techniques, solid‐phase extraction is the most popular because of a number of advantages. In this work, thiol‐containing sulfonamide resin was synthesized, characterized, and applied as a new sorption material for solid phase extraction and determination of lead in natural water samples. The optimization of experimental conditions was performed using the parameters including pH, contact time, and volumes of initial and elution solutions. After preconcentration procedure, FAAS was used for determinations. The synthesized resin exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent as well as high sorption capacity. Consequently, 280‐fold improvement in the sensitivity of analytical scheme was achieved by combining the slotted tube atom trap‐atomic absorption spectrometry (STAT‐FAAS) and the developed preconcentration method. The limit of detection was found to be 0.15 ng mL−1. The Pb2+ concentrations in the studied water samples were found to be in the range of 0.9–6.7 ng mL−1.

Continuous flow hydride generation laser induced fluorescence spectrometry for trace determination of lead in water and sediment samples

Continuous flow hydride generation coupled with laser induced fluorescence spectrometry (HG-LIF) has been used for the determination of Pb in aqueous samples. Lead hydride is generated in K3Fe(CN)6-HCl medium using NaBH4 as the reducing agent. Parameters such as acidity and the concentrations of oxidising and reducing agents have been studied in order to obtain the highest sensitivity. Laser excitation of Pb has been performed at 283.306 nm and fluorescence has been detected at 365 nm and 405.8 nm. The limit of detection calculated for the optimised conditions (1% K3Fe(CN)6 in 0.3% Oxalic Acid, 0.055 mol L−1 HCl, 1% NaBH4 in 0.1% NaOH) is 0.3 ng mL−1. However, a significant Pb background was observed for blank measurements, which degraded the limit of detection. The limit of detection that is estimated for a Pb free blank was determined by detuning the laser to a wavelength of 282.806 nm and was found to be 0.45 pg mL−1. Method repeatability is 3.5% RSD at the 10 ng mL−1 level. The accuracy of this method has been evaluated by analysis of a water reference material. The results obtained for a multielement standard determined using the HG-LIF approach have been found to be in agreement with those obtained by using a comparison ICP-AES approach. The HG-LIF approach has been applied to the measurement of Pb in a contaminated sediment sample material. The results of this study demonstrate that a small tunable laser system combined with hydride generation sample introduction can be used to measure Pb with high sensitivity, precision and selectivity in different sample matrices.

Ultra-trace determination of lead in water and food samples by using ionic liquid-based single drop microextraction-electrothermal atomic absorption spectrometry

An improved single drop microextraction procedure was developed for the preconcentration of lead prior to its determination by electrothermal atomic absorption spectrometry. Ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C 4MIM][PF 6], was used as an alternative to volatile organic solvents for extraction. Lead was complexed with ammonium pyrroldinedithiocarbamate (APDC) and extracted into a 7-μL ionic liquid drop. The extracted complex was directly injected into the graphite furnace. Several variables affecting microextraction efficiency and ETAAS signal, such as pyrolysis and atomization temperature, pH, APDC concentration, extraction time, drop volume and stirring rate were investigated and optimized. In the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.015 μg L −1 and 76, respectively. The relative standard deviation (RSD) for five replicate determinations of 0.2 μg L −1 Pb was 5.2%. The developed method was validated by the analysis of certified reference materials and applied successfully to the determination of lead in several real samples.

Sensitive adsorptive stripping voltammetric method for determination of lead in water using multivariate analysis for optimization

A sensitive adsorptive cathodic stripping voltammetric (AdCSV) method is presented for direct determination of Pb(II) at nanomolar levels in water based on metal complexation with 2-acetylpyridine salicyloylhydrazone (2-APSH) and subsequent adsorptive deposition onto hanging mercury drop electrode (HMDE). The instrumental and chemical factors were optimized using exploratory (Plackett–Burman) and sequential (Simplex) designs. Under optimal conditions (pH 5.6, −0.552 V for deposition voltage, 0.0083 V for voltage step and 0.87 s for time interval for voltage step) a limit of detection of 0.17 nM was obtained and the relative standard deviation of five measurements of 17.3 nM was 1.20%. The voltammetric responses increased linearly with metal ion concentrations ranging from 2.4 to 145 nM. The method was free from interferences of inorganic salts and trace metals usually present in seawater. The proposed method was successfully validated using certified reference estuarine water (LGC 6016) with relative error of −2.15% and applied to real seawater samples (relative errors of −4.40% and +1.84%).