Lead In Environmental Samples Research Articles

Study of Effect of Lockdown during Pandemic of COVID-19 on Percentage of Lead in Environmental Samples of Bhandara District

Increasing urbanization, industrialization and over population is one of the leading causes of Environmental degradation and pollution. Heavy metals (HMs) such as Pb, Zn, Cd, As etc. are one of the most toxic pollutants which shows hazardous effects on all living creators. Lead is one such pollutant which disrupts the flora and fauna found to be lethal even at low concentration. Even emission of heavy metals from traffic activities is an important pollution source to road side farm kind or forest area ecosystems. During the lockdown of pandemic there was tremendous decrease traffic activity on highways of Bhandara district. In this study, investigation was carried out on influence of transportation activities on lead percentage in environment taking plant leaves samples from various locations on highway and state highway passes through Bhandara district. During lockdown period and recently after unlock period in the month of July leaf samples collected along roadsides from prominent spot on national and state highways. Percentage of lead was determined by using diphenylthiocarbazone (Dithizone) colorimetrically. The Double beam spectrophotometer was used to determine the percentage of lead in leaf samples. The results shows that the concentration of lead in the roadside leaves was found to be much lower during lockdown period while it is much higher in plant leaves after unlock period due to tremendous increase in traffic activities on highways specially NH-06 passing through Bhandara. The use of leaded gasoline is thought to be responsible for the high concentration of lead in the roadside leaves of plant.

Switchable hydrophilicity solvent-based preconcentration for ICP-OES determination of trace lead in environmental samples

In this work, switchable hydrophilicity solvent-based extraction (SHSE) was combined with inductively coupled plasma-optical emission spectrometry (ICP-OES) for the determination of trace lead (Pb) in environmental water and soil samples. During the phase transformation of SHSE, the organic phase appeared to capture the target analytes effectively. The resultant sample solution was heated to remove the organic phase, realizing the successful combination with ICP-OES. The sensitivity was obviously improved by adding non-ionic surfactant Triton X-114 (TX-114) and the sensitization factor of 3.8 was achieved. Under the optimal conditions, the limit of detection (LOD) and enhancement factor (EF) were 0.07 μg/L and 38, respectively. The established method was applied to analyze environmental samples and certified reference material with satisfactory results. The analytical results of environmental samples were in great agreement with those obtained by inductively coupled plasma-mass spectrometry (ICP-MS). The established method provides a promising, simple and sensitive approach for the determination of trace Pb in environmental samples.

Magnetic Dispersive Solid Phase Extraction Using Recycled-graphite for GO-Fe3O4-dithizone Composite Combined with FAAS for Determination of Lead in Environmental Samples.

Magnetic dispersive solid phase extraction (MdSPE) was developed to determine the concentration of lead (Pb) in real water samples, while graphene oxide-magnetite-dithizone (GO-Fe3O4-DTZ) from the used graphite tubes (recycled graphite) of electrothermal technique was simply employed as a new sorbent to improve extraction efficiency, separated by external magnetic field and analyzed with FAAS. The synthesized sorbent was evaluated for its surface property, functional group and surface morphology by Zeta potential, Fourier transform infrared spectrophotometer (FTIR), and scanning electron microscope (SEM), respectively. The relevant measurement parameters, such as pH, extraction time, type and concentration of eluent, sample volume and reusability, were optimized. Under the optimal conditions, preconcentration factor was 13.33. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 0.070 and 0.23 mg/L, respectively. The relative standard deviation (%RSD) was 3.41%. Recovery values were 90.1 - 123%. In addition, the robustness of the method was affirmed in terms of tolerance limit obtained from interference studies.

Solid-phase extraction method for preconcentration of cadmium and lead in environmental samples using multiwalled carbon nanotubes

A new sensitive and accurate solid-phase extraction method for preconcentration of trace amounts of cadmium and lead in various environmental samples prior to flame atomic absorption spectrometry determination has been developed. The proposed method is based on the utilization of multiwalled carbon nanotubes in combination with 5-benzyl-4-[-chlororbenzylidene amine]-4H-1,2,4-triazole-3-thiol (BCBATT) as a solid-phase sorbent with the aid of ultrasonication. The effect of the preconcentration parameters was investigated. Good recoveries ranging from 95% to 102% with relative standard deviations of 3.2% and 2.8% for Cd$^{2+}$ and Pb$^{2+}$, respectively, were obtained, indicating high accuracy and precision. The limits of detection were 0.2 and 0.5 $\mu $g/L for Cd$^{2+}$ and Pb$^{2+}$, respectively. The preconcentration factor was 100. The validation of the proposed preconcentration procedure was performed using certified reference materials with satisfactory and compatible results. The proposed method was applied to various real environmental samples for determination of Cd$^{2+}$ and Pb$^{2+}$ concentrations and satisfactory results were obtained.

Pre-concentration and determination of fluorescence quenching of CdS quantum dots of Pb ions by dispersive liquid–liquid microextraction in the presence of the ionic liquids

Purpose This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic liquids based dispersive liquid–liquid microextraction (IL–DLLME) before spectrofluorometry. Design/methodology/approach Cadmium sulphide quantum dots have been synthesised using thioglycolic acid as capping agent through a one-step process with stability and excellent water-solubility, and have strong affinity for lead (Pb). This probe is based on the fluorescence quenching effect of functionalised cadmium sulphide quantum dots. Findings Factors affecting the extraction efficiency and fluorescence quenching of metals, such as the amount of ionic liquid, amount of metanol, microextraction and centrifugation time, volume of quantum dots and buffer pH, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.01-3 µg.L-1, with the detection limit of 0.004 µg.L-1 for Pb2+. The relative standard deviation (RSD%, n = 5) of 5.4 per cent at 1 µg.L-1 of Pb2+ was obtained. Originality/value This method for pre-concentration of the Pb ions by dispersive liquid–liquid microextraction is novel and could be used for various applications in the synthesis of a wide variety of determination of fluorescence quenching of cadmium sulphide quantum dots.

A Facile Synthesis of Ferrocene Functionalized Graphene Oxide Nanocomposite for Electrochemical Sensing of Lead

Ferrocene, an organometallic compound has the potential to undergo reversible oxidation even at low potential which makes it suitable for electrochemical sensor applications. The potential of graphene oxide has been widely exploited in electrochemistry, since they serve as an excellent platform for electrochemical molecules and increase the electrochemical properties. The potential of Graphene oxide-ferrocene (GO-Fc) nanocomposites has not been realized much in fabrication of electrochemical sensors. Hence, the electrochemical properties of the pure Ferrocene and GO-Fc nanocomposites were investigated. Graphene oxide (GO) was synthesised by modified Hummer’s method and was conjugated with ferrocene at different weight ratio after thermal treatment. The as-prepared pure GO and GO-Fc nanocomposites were characterized by various analytical methods. Monoclinic phase of Ferrocene was observed in XRD. Surface functionalization of Ferrocene on GO was imaged by TEM. Ferrocene particles were observed to be rod shaped and functionalized on surface of GO in TEM images. The composite formation was validated by FTIR and Raman by the presence of aromatic ring and ferrocene bands respectively. AAS results showed 87% ferrocene loading capacity in GO-Fc composite 2 (GF2) which decreased to 77% in GO-Fc composite 5 (GF5). Based on the CV curves, and ferrocene loaded on GO, GO-Fc composite 4 (GF4) was chosen for evaluating the lead sensing property. The sensing studies showed a detection limit of 0.168 µg/l with significant sensitivity up to 250 µg/l. The results indicate that GO-Fc nanocomposites can be potentially used for sensing lead in environmental samples.

Analytical Methods for the Determination of Lead in the Environment.

A survey of the methods for the determination of lead in environmental samples is given. These are mainly based on sensitive atomic spectrometry, but alternatives, such as electrochemical and separation methods are also possible. Discussed are also sample preparation and speciation for differentiation between different organometallic forms as well as applications of isotope-selective determinations.

Metal ion-assisted photochemical vapor generation for the determination of lead in environmental samples by multicollector-ICPMS.

A novel and sensitive approach for the accurate and precise determination of Pb in environmental samples is presented using transition metal ion-assisted photochemical vapor generation (PVG) for sample introduction with multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) detection. A significant improvement in PVG efficiency of lead is achieved in the presence of transition metal ions (Co(2+) and Ni(2+)) in solutions of 5% (v/v) formic acid. The determination of Pb in digests of sediment or soil samples is readily achieved due to coexisting transition metal ions which facilitate the PVG reaction. The method detection limit of 0.005 ng g(-1) (3σ) using external calibration is comparable to that obtained using hydride generation (HG) ICPMS. However, PVG methodology is simpler, results in lower blanks, and avoids unstable reagents. The accuracy of the proposed method was demonstrated by analysis of several environmental certified reference materials (CRMs; SLRS-5 and SRM1640a river water CRMs and MESS-3, MESS-4, and SRM2702 sediments) with satisfying results. High precision of determination (<0.4% RSD) of Pb in river water and sediments was realized on the basis of isotope dilution calibration.

Solid-State Lead-Selective Electrodes- a New Insight into Measurements of Ions at Low Analyte Concentrations

In environmental analysis of ions, ion-selective electrodes (ISEs) are frequently investigated as candidates to improve already existing techniques. Potentiometric sensors have several advantages over other analytical techniques, e.g. portability, low energy consumption, and small size. This creates an opportunity to perform analysis at overall lower cost [1, 2]. Despite obvious advantages, ISEs due to the need of re-calibration and fouling are not yet implemented in environmental analysis of ions on an industrial scale [3, 4]. Vast majority or scientific reports dealing with measurements of ions in diluted samples are devoted to solid-contact and conventional (with inner filling solution) ISEs, however, the concept of lowering the detection limit was firstly introduced and studied with solid-state ISEs [5-8].In this study solid-state membrane electrodes were re-vitalized in measurements of ions at low analyte concentration in environmental samples. We used lead(II)-selective electrodes with PbS/Ag2S membranes to develop two methods lowering of the detection limit based on the concentration time-dependent adsorption of the primary ion on the surface of the membrane [9] and tuned galvanostatic polarization (chronopotentiometry) [10]. Furthermore, solid-state electrodes were used to determine lead concentration in environmental sample. Tuned galvanostatic polarization method was found suitable in measurement of lead(II) in environmental samples collected nearby industrially exposed terrain [11]. The chronopotentiometric determination was compared to the analysis done with inductively coupled plasma mass spectrometry (ICP-MS) and differential pulse anodic stripping voltammetry (DPASV). The tuned galvanostatic polarization method for the determination of lead in environmental sample was employed in our study for the very first time. By this application we open a new important direction for electrochemical measurement of ions at low analyte concentrations.

Dithizone functionalized CdSe/CdS quantum dots as turn-on fluorescent probe for ultrasensitive detection of lead ion

An ultrasensitive fluorescent probe is developed for the determination of lead ion by utilizing dithizone (Dz) functionalized CdSe/CdS quantum dots (QDs). Dithizone was bound to the QDs via a surface coordinating reaction to form QDs–Dz conjugates and quench fluorescence of the QDs by fluorescence resonance energy transfer (FRET) mechanism. Upon the addition of Pb2+, a dramatic enhancement of the fluorescence intensity was observed, which resulted from the FRET pathway shutting off, and hence the fluorescence of the QDs was recovered. Two successive linear ranges of 0.01–1000nmolL−1 and 1–20μmolL−1 allow a very wide determination of Pb2+ concentration from 0.01nmolL−1 to 20μmolL−1, with a detection limit of 0.006nmolL−1. The fluorescent probe was successfully applied to the determination of lead in environmental samples with satisfactory results.

Bamboo Charcoal as Solid-Phase Extraction Adsorbent for the Simultaneous Enrichment and Sensitive Determination of Copper and Lead in Environmental Samples

Bamboo Charcoal as Solid-Phase Extraction Adsorbent for the Simultaneous Enrichment and Sensitive Determination of Copper and Lead in Environmental Samples

The use of silica gel modified with allyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate for selective separation and preconcentration of lead in environmental samples

The aim of the present work is the assessment of a new sorbent, prepared using silica gel coated with a pyrimidine derivative (allyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate), for extraction and preconcentration trace amount of lead from different samples prior to determination by flame atomic absorption spectrometry. Common coexisting ions did not interfere with the separation and determination of lead at pH 6, so that lead ion completely adsorbed on the column. The limit of detection based on three times the standard deviation of the blank was found to be 0.53 ng mL(-1) in original solution. Obtained sorption capacity for 1 g sorbent was 5.0 mg Pb. The linearity was maintained in the concentration range of 0.1-30.0 ng mL(-1) for the concentrated solution. Eight replicate determinations of 2.0 μg mL(-1) of lead in the final solution gave relative standard deviation of ±2.6 %. The proposed method was successfully applied to the determination trace amounts of lead in the environmental samples such as carrot, rice, zardchoobe, and real water samples.

Performance of a Bismuth Bulk Rotating Disk Electrode for Heavy Metal Analysis: Determination of Lead in Environmental Samples

AbstractThe bismuth bulk electrode is proposed here for the first time in the rotating configuration (BiB‐RDE) as the electrode of choice for voltammetric analysis of selected heavy metal ions. Optimization of chemical and instrumental parameters was carried out to develop a reliable and convenient method for the determination of Zn(II), Cd(II) and Pb(II) by SWASV. Appropriate detection limits were found for environmental monitoring applications in the medium – low µg/L range. The method was validated for Pb(II) determination by certified reference materials. Successful application to the determination of Pb(II) in samples of fortified rainwater and sewage sludge from a steel industry is described.

Cloud point extraction for the preconcentration of palladium and lead in environmental samples and determination by flow injection flame atomic absorption spectrometry

An online cloud-point extraction (CPE) coupled with flow injection method is developed for the separation and preconcentration of palladium and lead from various matrices using flame atomic absorption spectrometry (FAAS). The method employs the formation of complexes of the metallic species with dimethylglyoxime, which are subsequently entrapped in the micelles of the surfactant Triton X-114, upon increase of the solution temperature to 60°C and loaded into the flow injection system at a flow rate of 4.6 mL min(-1). The surfactant rich-phase was retained in a minicolumn packed with animal wool at pH 6 and eluted with 1.0 mol L(-1) nitric acid in methanol at a flow rate of 1.1 mL min(-1) directly into the nebulizer of the FAAS. The CPE variables and flow injection conditions affecting the analytical performance of the combined methodology was studied and optimized. Under the optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 51 and 44, and the limit of detections were 1.0 and 1.4 ng mL(-1) for palladium and lead, respectively. Finally, the developed method was applied for the determination of palladium and lead in street dust, soil, radiology waste, catalytic converter, and urban aerosol samples. Cloud-point extraction coupled with flow injection-FAAS was proposed as an effective preconcentration and separation method for Pd and Pb determination in radiology waste, road dust, soil, and urban aerosol samples. The most favorable feature of this method is its much higher selectivity, sensitivity, rapidity, good extraction efficiency, and employs the green chemistry concept, as it does not require the addition of toxic chemicals. In addition, this proposed method gives very low detection limits and good relative standard.

Synthesis, Characterization and Selective Recognition of Lead Using a New Ion Imprinted Polymer Material

A new ion-imprinted polymer (IIP) material was synthesized by copolymerization of 4-vinylpyridine(VP) as monomer, ethylene glycol dimethacrylate(EGDMA) as crosslinking agent and 2,2΄-azobisisobutyronitrile(AIBN) as initiator in the presence of Pb–1,5-diphenylcarbazone(Pb-DHCB) complex. Blank non-imprinted polymer (NIP) were prepared under identical conditions without the use of lead imprint ion. The synthesized polymers were characterized by IR spectroscopy and elemental analyzer techniques. Of the several polymers synthesized, only the imprinted polymer formed with binary complex of Pb2+–DHCB showed quantitative enrichment of lead ion from aqueous solution. The relative standard deviation of the five replicate determinations of Pb (II) was3.26%. The detection limit for 150 mL of sample was 1.6 µg L-1 using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace lead in environmental samples with satisfactory results.

On-line solid-phase extraction using alizarin violet functionalized silica gel for determination of trace lead in environmental samples and wastewater by sequential injection spectrophotometry

Trace of Pb(II) has been on-line separated and enriched from environmental samples and wastewater by using the self-made alizarin violet functionalized silica gel micro-column coupling with a sequential injection sampling technology. The determination is based on the color reaction of Pb(II) with iodide and crystal violet to form an ionic association complex in the presence of polyvinyl alcohol and hydrochloric acid. The use of the microcolumn can prevent the interference of most familiar metal ions, and therefore improve the selectivity and sensitivity of this analytical technique. The proposed method was used for the determination of Pb(II) in environmental samples and wastewater. No statistically significant difference was observed between the results determined by the present method and atomic absorption spectrometry.

Separation and preconcentration of Pb(II) using ionic liquid-modified silica and its determination by flame atomic absorption spectrometry

A new method based on microcolumn packed with ionic liquid-modified silica combined with flame atomic absorption spectrometry has been developed for the determination of lead in environmental samples. Several factors influencing the preconcentration efficiency of lead and its subsequent determination, such as pH of the sample, flow rate, mass of ionic liquid, and interfering effect, have been investigated. Lead could be quantitatively retained by ionic liquid-modified silica in the pH range of 5–7, and then eluted completely with 3.0 mL 1.0 mol L −1 HCl. The detection limit of this method for lead was 0.7 μg L −1 with preconcentration factor of 185, and the relative standard deviation (RSD) was 4.2% at 0.1 μg mL −1 Pb(II). This method has been applied for the determination of trace amount of lead in NIST standard reference material 2709 (San Joaquin Soil) and river water samples with satisfactory results.

An Environmentally Friendly, Cost-Effective Determination of Lead in Environmental Samples Using Anodic Stripping Voltammetry

Contamination of the environment with heavy metals such as lead presents many health risks. Simple, effective, and field-portable methods for the measurement of toxic metals in environmental samples are vital tools for evaluating the risks that these contaminants pose. This article describes the use of new developments in anodic stripping voltammetry (ASV) in an experiment that analyzes environmental samples for Pb content. In this experiment, students extract a sample such as riverbed sediment with dilute acid, facilitated by ultrasonic extraction, and analyze it for Pb using ASV. Owing to complex matrix effects of these samples, the standard addition method is used to determine the concentration of Pb. Determinations of Pb in sediment from the Little Miami River in Ohio showed average Pb levels of 9.3 ± 1.4 ppm. This experiment replaces traditional, costly working electrodes such as glassy carbon with inexpensive, disposable graphite pencil "lead" electrodes. Additionally, bismuth film electrodes are used, which are more environmentally friendly than traditional mercury films and eliminate the cost and hazards of mercury usage and disposal. The primary goal of this experiment is to teach the analytical electrochemical method of ASV for trace metal analysis, and it is targeted for an upper-level undergraduate instrumental methods course, with possible applications in an environmental chemistry course.

Application of Factorial Design and Doehlert Matrix for Determination of Trace Lead in Environmental Samples by On-line Column Preconcentration FAAS Using Silica Gel Chemically Modified with Niobium(V) Oxide

In this study a new method for Pb determination in water using solid phase extraction coupled to a flow injection system and flame atomic absorption spectrometry was developed. The sorbent used for Pb preconcentration and extraction was silica gel chemically modified with niobium(V) oxide. Flow and chemical variables of the system were optimized through a multivariate procedure. The factors selected were buffer type, eluent concentration, and sample and eluent flow rates. It was verified that the aforementioned factors as well as their interactions were statistically significant at the 95% confidence level. The effect of foreign ions was evaluated using a fractionary factorial experimental design. The detection limit was 0.35 microg L(-1) and the precision was 1.6%. Results for recovery tests using different environmental samples were between 90 and 104%. Certified reference materials were analyzed in order to check the accuracy of the proposed method.

Determination of lead in sediments and sewage sludge by on-line hydride-generation axial-view inductively-coupled plasma optical-emission spectrometry using slurry sampling

Among the "traditional" hydride-forming elements, lead is probably the most difficult, and its determination in this form has rarely been reported in the literature. In this paper a simple and rapid method, axial-view inductively-coupled plasma optical-emission spectrometry using on-line hydride generation (HG-ICP-OES) from samples prepared as slurry, is proposed for determination of lead in environmental samples. The samples (20-50 mg, particle size <or=120 microm) were treated with 1 mL aqua regia in a 40-kHz ultrasonic bath for 60 min. The slurry was diluted to a final volume of 50 mL with a 10% m/v solution of (NH(4))(2)S(2)O(8). The concentrations of NaBH(4), tartaric acid, and (NH(4))(2)S(2)O(8), used for on-line plumbane generation were optimized by means of a complete factorial analysis applied to an aqueous standard solution and to the slurry of a sediment certified reference material (CRM). External calibration against aqueous standards in the concentration range 10-100 microg L(-1) was used for analysis of six CRM--three marine sediments, one river sediment, and two sewage sludges. Analysis of the filtered slurry showed that Pb was only partially extracted into the liquid phase. Several major concomitants tested did not affect the Pb signal. The detection limit (3s, n = 10) for 20 mg sample in a final volume of 50 mL was 5.0 microg g(-1). Tin was the only other hydride-forming analyte that could be determined satisfactorily with Pb; for tin the detection limit was 1.0 microg g(-1). The values obtained for Pb and Sn were not significantly different from the certified concentrations, according to the t-test at the 95% confidence level. Nine river sediments collected locally were also analyzed and the concentrations were in agreement with results obtained after total digestion.