A novel slurry sampling analysis of lead in different water samples by electrothermal atomic absorption spectrometry after coprecipitated with cobalt/pyrrolidine dithiocarbamate complex

A green and simplified approach for the quantitative and sensitive analysis of heavy metal ions in sea and stream waters

Elimination of the matrix effect is a major challenge in developing a method for the quantification of heavy metals (HMs) in water samples. In this regard, the current research describes the simultaneous analyses of Cu(II), Cd(II), and Ni(II) ions in water matrices through flame atomic absorption spectrophotometry (FAAS) after preconcentration with carrier element-free co-precipitation (CEFC) technique by the help of an organic co-precipitant, 3-{[5-(4-Chlorobenzyl)-3-(4-chlorophenyl)-1H-1,2,4-triazol-1-yl]-methyl}-4-[2,4-(dichlorobenzylidene)amino]-1H-1,2,4-triazole-5(4H)-thione (CCMBATT). Based on our literature research, CCMBATT was employed for the first time in this study as an organic co-precipitant for the preconcentration of HMs. Factors such as solution pH, concentration of co-precipitant, sample volume, standing time, centrifugation rate, and time were thoroughly examined and optimized to achieve the highest efficiency in terms of HM recovery. The limits of detection (LODs) (with 10 number of tests) of 0.54, 0.34, and 1.95 μg L-1 and the relative standard deviations (RSD %) of 2.1, 3.3, and 3.0 were determined for Cu(II), Cd(II) and Ni(II) ions, respectively. Recovery results of HMs for the spiked samples were in the range of 92.8-101.0%, demonstrating the trueness of the method and its applicability to the water samples matrix.

Determination of propineb in vegetable samples after a coprecipitation strategy for its separation-preconcentration prior to its indirect determination by FAAS

In the presented work, a coprecipitation method was developed for separation-preconcentration, and determination of trace quantities of propineb in vegetable samples. Propineb was coprecipitated by using Al(OH)₃. The zinc contents in complex structure of propineb was determined by flame atomic absorption spectrometry (AAS). The propineb concentration was calculated by using stoichiometric relationship between the zinc and propineb. Several parameters including the amount of aluminum(III) as carrier element and hydroxide concentration and sample volume were examined. The effects of matrix ions were also investigated. The preconcentration factor was calculated as 15. The limit of detection (LOD) value for propineb was calculated as 15.2 μg L^-1. The presented coprecipitation procedure was successfully applied to determination of propineb in vegetable samples.

Magnetic dithiocarbamate functionalized reduced graphene oxide for the removal of Cu(II), Cd(II), Pb(II), and Hg(II) ions from aqueous solution: Synthesis, adsorption, and regeneration

In this study, dithiocarbamate(DTC)-modified magnetic reduce graphene oxide (rGO-PDTC/Fe₃O₄) was synthesized for the removal of heavy metal ions (Cu(II), Cd(II), Pb(II), and Hg(II)) in synthetic waste water. The rGO-PDTC/Fe₃O₄ nanocomposite was prepared via a novel synthesis route that includes GO bromination, nucleophilic substitution of polyethylenimine (PEI), the reaction with carbon disulphide (CS₂) and Fe₃O₄ nanoparticle loading. The prepared rGO-PDTC/Fe₃O₄ nanocomposite was characterised by XPS, FTIR, TEM and XRD, suggesting that DTC functional groups were chemically bonded to rGO surfaces. N₂ adsorption-desorption results revealed that rGO-PDTC/Fe₃O₄ nanocomposite exhibited high BET surface area (194.8 m²/g) and large pore volume (0.33 cm³/g) which are crucial to the function of adsorbent. Adsorption experiments showed that rGO-PDTC/Fe₃O₄ nanocomposite is an excellent adsorbent for heavy metal removal, which exhibits large adsorption capacities, fast kinetics and solid-liquid separation. The pseudo-second-order kinetic model and Langmuir adsorption model were used to unveil the adsorption mechanisms. The maximum adsorption capacities of the Langmuir model were 113.64, 116.28, 147.06, and 181.82 mg/g for Cu(II), Cd(II), Pb(II), and Hg(II) ions, respectively. After adsorption and desorption process, the spent rGO-PDTC/Fe₃O₄ nanocomposite was easily regenerated via one-step organic reaction. The regenerated rGO-PDTC/Fe₃O₄ composite exhibited good adsorption capacities for different metals in five adsorption-desorption-regeneration cycles.

Determination of Lead in Water Samples by GFAAS after Collection on Montmorillonite with Slurry Introduction

In this study, a highly accurate, fast and practical separation/enrichment technique is described to determine the Pb in tap water samples by graphite furnace atomic absorption spectrometry. For this purpose, at first, Pb was collected on montmorillonite by batch technique, the supernatant was decanted and the solid phase was slurried in a mixture of 0.1% Triton X-114 and 0.1 mol L^-1 HNO₃ then directly introduced into graphite furnace without elution. Since the elution step was not applied, the method was simpler and faster compared to conventional techniques. The risks of elution step on the precision and recovery were eliminated. Up to 50-fold enrichment could be obtained by this method. The limit of detection (3δ, N = 10) and characteristic concentration of the method for Pb were 0.46 and 1.13 μg L^-1, respectively. In addition, the Pb in water samples (tap and river) collected from different regions of Turkey were determined.

Preconcentration procedures for the determination of chromium using atomic spectrometric techniques: A review

Chromium is one of the regulated toxic metals in the environment. Naturally, this element exists mainly in two oxidation: Cr(III) and Cr(VI). In general, Cr(VI) is more toxic than Cr(III). Cr(VI) affects human physiology, accumulates in the food chain and causes severe health problems ranging from simple skin irritation to lung carcinoma. Hence, the determination of chromium traces as well as its speciation in environmental samples is a very important task. In recent years, several preconcentration methods such as coprecipitation, liquid-liquid extraction, dispersive liquid-liquid microextraction, cloud point extraction, and solid phase extraction have been developed and widely used. The aim of this study is to review the recent literature (mainly last 5 years) on the preconcentration technologies those have been used in chromium removal before the determination step by atomic spectrometric techniques. Their advantages and limitations in application are also evaluated.

Slurry analysis of cadmium and copper collected on 11-mercaptoundecanoic acid modified TiO2 core-Au shell nanoparticles by flame atomic absorption spectrometry

Separation/preconcentration of copper and cadmium using TiO(2) core-Au shell nanoparticles modified with 11-mercaptoundecanoic acid and their slurry analysis by flame atomic absorption spectrometry were described. For this purpose, at first, titanium dioxide nanoparticles were coated with gold shell by reducing the chloroauric acid with sodium borohydride and then modified with 11-mercaptoundecanoic acid. The characterization of modified nanoparticles was performed using ultra-violet spectroscopy and dynamic light scattering. Copper and cadmium were then collected on the prepared sorbent by batch method. The solid phase loaded with the analytes was separated by centrifugation and the supernatant was removed. Finally, the precipitate was slurried and directly aspirated into the flame for the determination of analytes. Thus, elution step and its all drawbacks were eliminated. The effects of pH, amount of sorbent, slurry volume, sample volume and diverse ions on the recovery were investigated. After optimization of experimental parameters, the analytes in different certified reference materials and spiked water samples were quantitatively recovered with 5% RSD. The analytes were enriched up to 20-fold. Limits of detection (N=10, 3σ) for copper and cadmium were 0.28 and 0.15 ng mL(-1), respectively.

Solid-phase extraction of Mn(II) and slurry analysis of the sorbent by electrothermal atomic absorption spectrometry

In this study, a challenging preconcentration/separation method based on the sorption of manganese on ethylene glycol dimethacrylatemethacrylic acid copolymer (EGDMA-MA) treated with ammonium pyrrolidine dithiocarbamate (APDC) and its slurry analysis by electrothermal atomic absorption spectrometry was described. Optimum conditions for quantitative sorption, as well as for preparing a homogeneous and stable slurry were investigated. A 100-fold enrichment factor could be reached. The analyte element in certified sea-water and bovine-liver samples were determined in the range of 95% confidence level. The proposed technique is fast, simple, and the risk of contamination is low. The limit of detection of the method for manganese in the slurry of the blank subjected to the proposed procedure was 0.07 microg L(-1) (3delta, N:10) corresponding to 0.56 microg kg(-1) slurry.