Thallium In Water Samples Research Articles

Determination of thallium in water samples via solid sampling HR-CS GF AAS after preconcentration on chromatographic paper

A method for determining thallium in water samples via solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry (SS HR-CS GF AAS) after preconcentration using chromatographic filter paper as a solid support was proposed. The effects of pH, stirring time, and sample volume in the analyte preconcentration step were studied. The presence of potential interferences in the sample and the type of masking agent were also examined. In the proposed procedure, the sample was placed in contact with the solid phase in a polypropylene tube, and after stirring for 3 min, thallium determination was performed via HR-CS GF AAS directly on chromatographic filter paper. A preconcentration factor of 55, a precision of 9.4% (n = 10; 10 μg L−1), a limit of detection of 0.018 μg L−1, and a limit of quantification of 0.059 μg L−1 were achieved. Analyte addition and recovery tests were performed, and the results ranged from 91% to 110%. The accuracy of the method was evaluated by analyzing a water reference material. The procedure was used to determine thallium in water samples collected in Barreiras, Bahia, Brazil. The results were compared with those obtained using inductively coupled plasma‒mass spectrometry (ICP‒MS). Thallium concentrations in the analyzed samples ranged from <0.059 to 0.80 μg L−1.

New Screen-Printed Carbon Sensor for Trace Analysis of Thallium(I)

Thallium is an element classified as a heavy metal. In chemical compounds it occurs on +1 and +3 oxidation levels. In the context of the toxicity of this element, Tl(I) is most often referred to. The similarity of Tl+ ions to K+ ions is the basis of the mechanism of toxic action of Tl(I) on the human body. The main features of thallium poisoning in humans are gastroenteritis, polyneuropathy and alopecia Thallium in the environment comes from both natural and anthropogenic sources. Due to the high toxicity of thallium and its easy absorption by the human and animal organisms, it is extremely important to monitor the amount of this element, including in water. The purpose of this work is to present a new method for determination of thallium in water samples using a screen-printed sensor with carbon working electrode modified with multiwalled carbon nanotubes and in-situ plated bismuth film. The measurements were carried out using square wave anodic stripping voltammetry (SWASV) method. Simultaneous deposition of bismuth and thallium took place at a potential of -0.9 V for 180 s. Under optimized conditions a linear calibration curve was obtained in the range of Tl(I) concentrations from 1·10-8 to 1·10-6 mol L-1. The procedure allows to achieve the limits of detection and quantification of Tl(I), 2.8 × 10-9 and 9.3 × 10-9 mol L-1 respectively. The method was applied for determination of Tl(I) in spiked water samples from Vistula river. [1] Kozak, J., Tyszczuk-Rotko, K., Rotko, M. Physicochemical Problems of Mineral Processing 2019 , 55(6), 1422-1428.

Solid Phase Extraction Method for Separation and Pre-concentration of Thallium in Water Samples Using a Novel Adsorbent

In this study, a new and simple column-mode separation method has been proposed for the pre-concentration and removal of trace amounts of thallium(III) (Tl) from water samples. The procedure was based on sorption of Tl(III) ions by a solid phase extraction column filled with 4-[(2-hydroxy, 3-methoxy benzylidine)4-amino]1,2,4-treeazol-5-thione on microcrystalline naphthalene. The determination was performed directly using flame atomic absorption spectrometry (FAAS) method. The main factors affecting the extraction recovery were investigated and optimized. The interference effect of various ions on the determination of Tl(III) was also studied. In optimum conditions, the precision of the proposed method for sample solutions containing 0.2 μg/mL of Tl(III) was 2.0%, and the enrichment factor was found to be 35. The proposed method was evaluated and employed for pre-concentration and removal of Tl(III) from spiked natural (Tap and well) and industrial water samples.

Simultaneous separation and determination of thallium in water samples by high-performance liquid chromatography with inductively coupled plasma mass spectrometry.

An analytical method for separation and determination of thallium species in water using high-performance liquid chromatography with inductively coupled plasma mass spectrometry was developed. The composition and concentration of mobile phase, injection volume, and pH value were optimized respectively with an anion or cation exchange column. The results showed that Tl(I) and Tl(III) were effectively separated using anion exchange column Hamilton PRP-X100, with the mobile phase consisting of 200mmol/L ammonium acetate and 10mmol/L diethylenetriaminepentaacetic acid (pH=4.2). When using a Dionex cation exchange guard column, CS12A, 15mmol/L HNO3 , and 3mmol/L diethylenetriaminepentaacetic acid as the mobile phase, Tl(I) and Tl(III) could be effectively separated. The detection limits of the methods were 3-6 and 9-12ng/L, respectively. In a solution containing Fe ions and oxalic acid, a significant quantity of Tl(I) was oxidized. Fe ions and oxalic acid in the water samples did not interfere with high-performance liquid chromatography-inductively coupled plasma mass spectrometry measurement results.

Determination of thallium in water samples using inductively coupled plasma optical emission spectrometry (ICP-OES) after ultrasonic assisted-dispersive solid phase microextraction

A rapid and effective ultrasonic assisted-solid phase micro-extraction (UA-DSPME) was developed for the preconcentration of thallium in real water samples. The ZnO-ZrO2@AC composite functionalized with 1-(2-Pyridylazo)-2-naphthol (PAN) was used as an adsorbent and the target analyte was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). The morphological, crystalline physical and chemical properties of the composite were characterized by scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM) and X-ray powder diffraction (XRD). The two-level fractional factorial design and response surface methodology were used to optimize experimental parameters affecting the preconcentration procedure. Under optimum conditions, the enrichment factor (EF), limits of detection (LOD) and quantification (LOQ) were found to be 112, 0.25ngL−1, and 0.84ngL−1, respectively. Furthermore, intra-day and inter-day precisions expressed in terms of relative standard deviation (RSD) were found to be 2.4% and 4.3%, respectively. Moreover, the linear dynamic range was between LOQ and 350μgL−1 with the correlation coefficient of 0.9966.

A portable solution cathode glow discharge-atomic emission spectrometer for the rapid determination of thallium in water samples

A novel and high performance method for rapid determination of thallium in water samples was established by using a portable solution cathode glow discharger with a fiber-optical spectrometer. The operating conditions including the solution acidity, the electrolyte cathode, etc were optimized with 1.0mgL−1 thallium standard solution. The resolution of the fiber-optical spectrometer investigated with the peak width at half height of thallium was tested to be about 1.8nm，and thallium was determined at the emission wavelength of 535.0nm. The caliberation curve was favorably linear when the concentrations of thallium standard solutions were in the range of 0.1mgL−1 ~ 5.0mgL−1. Under the optimized conditions, the limit of detection (LOD) for thallium was 11.8ngmL−1， and the precision evaluated by relative standard deviation was 3.2% for six times 1.0mgL−1 standard solution replicates. This method was used for detection of thallium in water samples. The results were satisfying, and the average recoveries for thallium spiked samples were found to be in the range of 91.3~107.5%，which showed this method was applicable for real samples analysis. Besides，this method is suitable for field tests due to the portable instrumental size and weight as well as the less consumption of time and reagent.

Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Drop Combined with Flame Atomic Absorption Spectrometry for Preconcentration and Determination of Thallium(III) in Water Samples

Dispersive Liquid-Liquid MicroExtraction technique based on Solidification of a Floating Organic drop (DLLME-SFO) combined with flame atomic absorption spectrometry was developed for determination of thallium in water sample. An appropriate mixture of acetone and 1-undecanol was rapidly injected into an aqueous sample containing TlCl4- which forms an ion pair with brilliant green reagent and as a result a cloudy mixture was formed. After centrifugation, the test tube was cooled for 5 min and the solidified 1-undecanol drop formed on the top of the solution was transferred into a suitable vial and it was dissolved in 300µL of acetone and finally introduced into the flame atomic absorption spectrometer. Several factors affecting the extraction process, such as the volume of the extractant and disperser solvents, centrifugation time, concentration of brilliant green, concentration of HCl, ionic strength, volume of diluting solvent and interferences were studied. Under the optimum operating conditions, the calibration graph was linear in the range of 240-6000ng/mL with a limit of detection of 90 ng/mL and preconcentration factor was 17. The Relative Standard Deviation (RSD) for five replicate measurements of thallium was 3.6%. The accuracy of the method was assessed using a certified reference material (unalloyed zinc) and spiked tap water. The results demonstrated high accuracy, recovery and applicability of the presented method.

Ultrasound-assisted emulsification/microextraction based on solidification of trace amounts of thallium prior to graphite furnace atomic absorption spectrometry determination

In the present work, determination of ultratrace amounts of thallium in water samples was performed by ultrasound-assisted emulsification microextraction based on solidification of a floating organic drop as sample preparation method prior to furnace atomic absorption spectrometry. 1-(2-Pyridylazo)-2-naphthol was used as chelating agent. The factors influencing the complex formation and extraction, such as pH of the aqueous solution, the type and the volume of extraction solvent, the volume of chelating agent solution, and the extraction time were investigated. Under optimized conditions, the enrichment factor was 200. The calibration graph was linear from 0.2 to 10.0 μg L−1 with a correlation coefficient of 0.9966, the detection limit was 0.03 μg L−1 and reproducibility was ±3.3% (C = 5.0 μg L−1, n = 8). The method was successfully applied for the determination of thallium in water samples.

Speciation analysis of thallium in water samples after separation/preconcentration with the Empore™ chelating disk

A simple, reliable and novel solid phase extraction procedure using the Empore™ chelating disk has been developed for determination of Tl(I) and Tl(III) in environmental water samples by electrothermal atomic absorption spectrometry (ETAAS). The influence of humic acids on separation/preconcentration of thallium species with the Empore™ chelating disk is investigated. The preconcentration factor and detection limit are 500 and 5 ng L−1, respectively. The recoveries are in the range 93–103% for mineral, pond, sea, snowmelt, waste waters at 28–500 ng L−1 Tl and in the range 82–112% for river waters at 18–28 ng L−1 Tl.

A novel optical chemical sensor for thallium(III) determination using 4-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol

A novel optical chemical sensor has been developed for the determination of thallium(III) in aqueous solutions using 4-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP) as a complex agent. The optode membrane was prepared from plasticized PVC. Formation of the complex between thallium(III) and Br-PADAP caused a new peak to appear with a maximum absorbance at 569 nm and the color of the membrane to change from orange to purple. The parameters involved in the preparation of the optode and determination of thallium(III) were optimized. In the universal buffer with pH 3.0, the optode had a dynamic range of 2.6 × 10 −6 to 4.5 × 10 −4 mol L −1 thallium(III) with a detection limit of 1.1 × 10 −6 mol L −1. The response time of the sensor was 350, 220, and 190 s for 7.0 × 10 −6, 2.4 × 10 −5 and 2.4 × 10 −4 mol L −1, respectively. The optode enjoys a high accuracy and selectivity for determining thallium in water samples.