Flame Atomic Absorption Spectrometry Research Articles

The Development and Evaluation of Biosorbent Composite Spheres for the Adsorption and Quantification of Copper

Separation techniques are employed to treat and preconcentrate samples. Preconcentration commonly employs adsorption due to the wide range of sorbents available. The biosorbent composite has emerged as a highly effective alternative, primarily due to its selectivity for active sites and its impressive adsorption capability. This study aimed to assess and create a spherical biosorbent composite using cellulose acetate and avocado seed. The purpose of this work was to use a biosorbent composite for copper adsorption by flame atomic absorption spectrometry. The copper adsorption follows the Langmuir isotherm, which indicates that it occurs in a monolayer and is homogeneous. Additionally, the adsorption nature is favorable according to the RL factor. The highest capacity for copper adsorption is 0.121 mg g−1. The report describes the methodology and validation process for quantifying copper. The findings demonstrate that the composite biosorbent enables accurate preconcentration and quantification of copper found in decongestants.

Occupational exposure assessment of heavy metals in human scalp hair among tannery workers in Bahir Dar, Ethiopia: Indication of pollution

Ethiopia, is one of the African countries, has immense potential for skins and hides for the leather industries, which will play a crucial role in converting nations into manufacturing-driven economies through industrialization. The chemicals applied in the tanning process are a serious concern for employees and the community if proper safety measures are not taken. The pollution status of employees working in Anbessa and Bahir Dar tannery factories was evaluated by collecting hair samples. After the hair samples washed with acetone, and deionized water, the hair samples were digested with 4 mL of HNO3 and 2 mL of HClO4 for 1:30 h at 250 °C. The levels of metals (Cr, Pb, Zn, Cu, Ni, and Cd) were subsequently analyzed using a Flame Atomic Absorption Spectrophotometer (FAAS). The mean concentrations of Cu, Ni, Zn, Pb, and Cr in the Anbessa tannery factory workers were 17.34–22.75, 16.38–35.03, 235.4–369.2, 30.46–67.31, and 97.56–189.18, respectively, in the various working departments of the factory. Similarly, the concentrations of Cu, Ni, Zn, Cd, Pb, and Cr in the hair of Bahir Dar tannery workers were 30.1–105.9, 17.88–62.20, 216.9–762.1, 0.35–5.21, 33.42–91.42, and 118.5–305.7, respectively. Chromium was found to be the most accumulated metal next to Zn with in both tannery workers that highlighted significant occupational health risks. The principal component analysis (PCA) analysis provide an insights into the interactions between occupational factors and metal exposure. In conclusion, the results of hair analysis from the employees of tannery factories indicates alarming levels of metal exposure, especially for zinc and chromium, which might pose health problems in long time exposure. Thus, it's critical to monitor occupational activities that can harm human health and the environment.

Development, Validation and Application of a Fast Sequential Method for Na, K, Ca and Mg Determination in Hemodialysis Solutions by HR-CS F AAS.

Hemodialysis solutions are liquid concentrates used during hemodialysis sessions. They are commonly used as a renal replacement therapy. This study aimed to develop a method to determine Na, K, Ca and Mg in hemodialysis solutions by high-resolution continuum source flame atomic absorption spectrometry (HR-CS F AAS) using Design of Experiments (DOE). The combination of the Doehlert Matrix with the desirability function was used to establish a compromise condition in the optimization of the significant variables studied: 60 L/h for acetylene flow rate, 8 mm for burner height, 0.25% (w/v) and 0.60% (w/v) for Cs and La concentrations. The method was validated by following the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines and parameters such as the selectivity, linearity, precision, accuracy and robustness were evaluated. Calibration curves with the ranges of 25-130 mg/L for Na, 1.0-5.0 mg/L for K and Ca, and 0.30-0.70 mg/L for Mg were employed. The method proved to be precise (RSD lower than 2.7%) and accurate (mean recovery data, contemplating the three levels added were: 103.0% for Na, 100.5% for K, 101.3% for Ca and 101.5% for Mg). The developed method enables the sequential multielement determination of Na, K, Ca and Mg in a single run. Requiring only one dilution step, this method significantly reduces analysis time for both sample and standard solutions preparation and measurement. This study presents the first method reported in the literature for multielement determination in hemodialysis solutions, offering an alternative approach to the current European Pharmacopeia method.

Health Risk of Heavy Metal and Genotoxicity of Polycyclic Aromatic Hydrocarbons (PAHs) in Extra-Virgin Olive Oils (EVOO) Available in PortHarcourt Metropolis, Nigeria

This research aims at determining the loading of contamination of some popular brands of extra-virgin olive oil (EVOO) in Port Harcourt, Nigeria, with genotoxic PAHs and Heavy Metals to ascertain its safety for consumption. The health risk associated with these heavy metals will be calculated and assessed. Extra virgin olive oil has experienced a surge in its consumption all around the world owing to its high nutritional content. Contamination with genotoxic PAHs and Heavy Metals can cause severe health defects if consumed regularly. PAHs and heavy metals are two distinct groups of ubiquitous contaminants with grave health consequences such as Tumorigenesis, carcinogenesis, organ failures etc. Samples of EVOO were analysed with Gas Chromatography/Mass Spectrophotometer and Flame Atomic Absorption Spectrophotometer (FAAS) for PAHs and heavy metals respectively. After extraction with Dichloromethane and digestion with aqua regia (HCl/HNO3; 3:1) respectively, the results showed the presence of few genotoxic PAHs such as benzo[a]pyrene, PAH4 and PAH8 with concentrations above regulatory limits of 0.002µg/g, 0.01µg/g and 0.01µg/g respectively. Among the heavy metals, Pb and Cd showed the most alarming levels of contamination of the heavy metals, above regulatory limits of 0.1µg/g and 0.05µg/g, however, analysis with Health Risk Index of consumption showed all samples were safe for consumption.

Microbial and Heavy Metal Evaluation of Sachet Drinking Water in the Hohoe Municipality, Ghana

Aim: To study microbial and heavy metal composition in sachet drinking water in the Hohoe municipality in the Volta Region of Ghana. Place and Duration of Study: The study was conducted in the Hohoe Municipality in the Volta region of Ghana and laboratory analyses were carried out at the Microbiology laboratory of the Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology between June 2018 and May 2019. Study Design: Cross-sectional study. Methodology: The study was conducted on three samples each of eight different brands of sachet water randomly selected across various towns from street vendors in the Hohoe Municipality for microbial and chemical analyses. 10ml of each sample was aliquoted under sterile conditions and cultured overnight in nutrient media. Enumeration and qualitative analyses of bacteria were performed using the pour plate method. For heavy metal analysis, 5 ml of concentrated HNO3 was added to 40 ml of each sample and heated at 100 °C for 20–30 minutes to reduce the volume to 20 ml. 30ml of distilled water was subsequently added and the mixture was analyzed using flame atomic absorption Spectroscopy. Results: Out of total twenty-four samples analyzed, 50% of the sachet water was contaminated with total and fecal coliforms with the highest average coliform forming unit (cfu/ml) being 16.2 x 105 cfu/ml and the least 0.01 x 105 cfu/ml. There were Klebsiella spp, and Pseudomonas aeruginosa contamination in 50% of the sachet drinking water but Salmonella spp and E. coli were absent in all brands. Chromium was detected to be within the range of 0.40mg/L - 0.56mg/L in the sachet water while zinc was in the range of 0.03mg/L– 0.94mg/L. Chromium concentration in all sachet brands were above the WHO standard while zinc was within the acceptable range. Cadmium and lead were below detectable limits (BDL). Conclusion: This study indicated that some of the sachet drinking water sold in the Hohoe Municipality is impure for human consumption. Inappropriate water purification procedures and improper handling of sachet water play a significant role in determining the overall quality of sachet drinking water.

Analysis and Detection of Heavy Metals Content in Some Selected Packaged Fruit Juices of Kathmandu City by Flame Atomic Absorption Spectroscopy

The determination of level of heavy metals in packaged fruit juices is crucial, as extended exposure to even small quantities of these toxic element can cause severe health issues and chronic poisoning. Hence, it is essential to gather comprehensive data on the presence of heavy metals in packaged fruit juice samples. The objective of this research work is to determine heavy metals (Fe, Cu, Zn and Pb) in four different types of packaged fruit juice samples viz Apple, Mango, Orange and Lychee of four different popular brands bought from retail market of Kathmandu city by flame atomic absorption spectroscopy and compare with acceptable limit set by WHO/FAO. Wet acid digestion method was used for digestion process of packaged fruit juice samples. The concentration of Iron were ranged from 0.572-0.762mg/L in Orange juices; 0.362-0.624mg/L in Mango juices; 0.277-3.649mg/L in Apple juices; 0.279-1.770mg/L in Lychee juices respectively. Copper concentration were ranged from not detected (ND)-0.574mg/L in Orange juices; ND for all selected samples in Mango juices; ND- 0.023mg/L in Apple juices; ND-0.041mg/L in Lyclee juices. Similarly Zinc concentration were ranged from 0.0511-0.2026mg/L in Orange juices; ND-0.0700mg/L in Mango juices; ND for all selected samples in Apple juices; ND-0.0287mg/L in Lychee juices. The concentration of hazardous element Lead was found below detection limit in all selected packaged fruit juice samples. The heavy metals concentration in selected brand of packaged fruit juice samples was in following order: Fe>Zn>Cu> Pb. Int. J. Appl. Sci. Biotechnol. Vol 12(3): 158-165.

Cloud point Extraction Of Methimazole By Direct (UV- Vis Spectrophotometer) And Indirect (Flame Atomic Absorption) methods

Abstract A new technique based on the formation of a chelate Methimazole-Fe(III) at 400 nm was used for the determination of Methimazole 114 as a surfactant in some pharmaceuticals using indirect flame atomic absorption spectroscopy (FAAS) and UV-visible methods based on Triton turbidity extraction. The optimal turbidity extraction temperature was 75.0°C after 25 min of extraction of the complex [MET-Fe(III)] with ethanol. The structure of the Methimazole-Fe(III) chelate was determined by the molar ratio method. A 1:1 L:M (ligand:metal) ratio was produced. The Beer law was employed in the concentration range of 2.5-30 and 2.5-32.5 g/mL for the UV and FAAS, respectively.. The limits of detection (LOD) and quantification (LOQ) were (0.3784) g/ml and (1.2612) g/ml, respectively, for these techniques. The technique has been approved and successfully used in the production of pharmaceutical preparations such as: B. Methimazole capsules sold in Iraq. The analytical results were validated by statistical and recycling studies with satisfactory results.

Direct determination of lithium in brine samples using handheld LIBS without sample treatment: sample introduction by venturi system.

Splashing is the main problem for the direct analysis of aqueous samples using LIBS since it generates serious precision and accuracy issues. This study demonstrates the direct determination of Li content in brines for the control of industrial mining processes using a portable LIBS device based on the direct laser impact on the sample, without any sample treatment, through the design of a sample injection system based on the Venturi effect. Our results demonstrated that the utilization of the 653.3 nm hydrogen line as an internal standard reduces the model calibration fitting error from 0.440 root mean square error in a standard calibration curve to 0.123 on the internal standard curve. Conversely, the development of a Venturi effect-based injection device using compressed air converts the brine into a fine mist which decrease splashing, resulting in an up to 10-fold error reduction, all without the necessity of employing an internal standard. Our results, evaluated by comparing them to the ASTM D3561-11 standard method using flame atomic absorption spectrometry, indicate that it is feasible to determine the lithium content in brine samples with an error of under 20% and a detection limit of 13 mg kg-1.

A different application of the Aliquat® 336 loaded poly(vinylidene fluoride-co-hexafluoropropylene) based electrospun nanofibers disks for the preconcentration followed by flame atomic absorption spectrometry detection of low-level Bi(III)

It is the first report on the potential of electrospun nanofiber disks inserted in a filtration apparatus as a preconcentration strategy for the analysis of low-level metals. The nanofibers included 60 wt% of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and 40 wt% of ionic liquid Aliquat® 336. The electrospinning process was done by applying a voltage of 16 kV, an injection rate of 1 mL h−1, and 10 cm distance of the needle tip location from the drum collector. A circular piece of the prepared nanofiber disks was placed in a filtration apparatus, and 200 mL solution containing 1 mg of Bi(III) adjusted to 0.5 mol/L of hydrochloric acid was transmitted from inside the nanofiber disk by controlling the flowrate (3.3 mL s−1). The adsorbed Bi(III) was eluted by 10 mL of 0.2 mol/L solution of ethylendiaminetetraacetic acid and ammonium hydroxide mixture, and then was analyzed by flame atomic absorption spectrometry. The introduced technique (nanofiber disks-based solid phase extraction) can be used in the bismuth concentration range of 4–2000 µg/L, with a limit of detection 1.2 µg/L. The determined inter- and intra-day relative standard deviations (3 days and n = 7) for a solution of 100 µg/L of bismuth were 1.1 % and 2.4 %, respectively. The method offers a preconcentration factor of 200-fold. The fabricated nanofiber disks were used at least in 7 consecutive preconcentration experiments. The proposed method was selective towards Bi(III) and can be used satisfactory for its determination in real samples.

A Reliable and Straightforward Combination of vortex-assisted Dispersive Magnetic solid-phase Extraction with Direct Sorbent Sampling for Highly Sensitive Silver Determination in Water Samples Using Flame and Metal Furnace AAS.

In the present paper, the assessment of vortex-assisted dispersive magnetic solid-phase extraction using amino-functionalized mesoporous combined with direct magnetic sorbent sampling (DMSS) in flame or furnace atomic absorption spectrometry (FAAS or FF-AAS) was demonstrated for highly sensitive silver determination in water samples. The developed method showed significant enrichment factors compared to conventional pneumatic nebulization by FAAS, 607 for DMSS-FF-AAS and 114 for DMSS-FAAS. The analytical curve showed linearity in the range from 5.0 to 70.0µg L- 1 and 1.0 to 15.0µg L- 1 and limits of detection of 0.59 and 0.09µg L- 1 for DMSS-FAAS and DMSS-FF-AAS, respectively. The intra and inter-day precision evaluated as a percentage of the relative standard deviation (RSD,%) ranged from 1.89 to 4.71% for levels of 25.0 and 65.0µg L- 1. The method was applied in different kinds of water samples without matrix effects, yielding recovery values from 90 to 110%.

Levels of heavy metals and physicochemical properties of honey from four selected areas of Ethiopia

In this work, the qualities of honey samples were evaluated by assessment of some physicochemical parameters and levels of heavy metals (Cd, Pb, Cr, Ni, Zn and Cu). The honey samples were collected from the major producing regions of Ethiopia; Gojjam, Gondar, Jimma and Tigray. The pH and electrical conductivity (EC) of the samples were determined using digital pH-meter and conductivity meter, respectively. The metal contents were determined by flame atomic absorption spectrometry (FAAS). The validity of the method employed was evaluated by spiking experiments with recoveries ranging from 90.0 to 95.8%. The FAAS results show higher concentration of Cu and Zn compared to other metals. The amount of Cu and Zn were in the range 6.2–18 μg/g and 4.2–10 μg/g. The heavy metals (Cd, Pb, Cr and Ni) were below detection limit in all the honey samples. Moreover, the result obtained regarding the physicochemical properties showed that the pH of all the honey samples were acidic (pH of 3.84–4.00), the EC 0.09–0.34 mScm-1 and the ash content 0.13–0.33%. The results obtained were in agreement with European standard and Codex Alimentarius, indicating the honey samples studied are of good quality and suitable for human consumption. KEY WORDS: Honey, Heavy metals, Physicochemical properties, FAAS, Ethiopia Bull. Chem. Soc. Ethiop. 2024, 38(6), 1521-1531. DOI: https://dx.doi.org/10.4314/bcse.v38i6.2

A simple and accurate method for the determination of Rh, Pd, and Pt in e-waste and spent automotive catalysts using HR-CS FAAS for assessing the value of secondary raw materials

This work presents a simple and accurate method for the fast sequential determination of Rh, Pd, and Pt in spent automotive catalysts and e-wastes using high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Extensive research was carried out in model systems on the impact of potential interfering substances on analyte's signals measured in two types of flame (air-C2H2 and N2O–C2H2). Mutual analyte interactions were also taken into account. Different background corrections offered by the HR-CS AAS spectrometer were tested to obtain interference-free analyte signals and the best detectability. Using an air-C2H2 flame and 1 % La solution as a spectrochemical buffer provided good sensitivity and accurate determinations of Rh, Pd, and Pt using a simple calibration graph. Microwave-assisted leaching of PGE from waste samples with aqua regia at 240 °C for 60 min efficiently leached all target metals, which significantly simplified and shortened the sample preparation step. The detectability of the method (detection limit of 0.4, 0.6, and 5 mg kg−1 for Rh, Pd, and Pt, respectively) and precision (< 7 %) were satisfactory. The accuracy of the method was confirmed by analysis of certified reference materials (spent automotive catalyst (ERM-EB504), electronic scrap (BAM-M505a)), and calculated zeta score values. The recoveries for Rh, Pd, and Pt in ERM-EB504 were 93, 101, and 96 %, respectively, and for Pd in BAM-M505a, 97 %. The developed method can be used to assess the value of secondary raw materials, such as various types of spent catalysts and e-waste containing Rh, Pd, and Pt.

Determination of Trace Elements Content of a Popular Traditional Herbal Medicine Used for Internal Hemorrhoids Treatment in Katsina State, Nigeria

Study’s Excerpt/Novelty Assessment of toxic metal concentrations of a widely used traditional herb in Katsina state, was carried out. Flame atomic absorption spectrophotometry and descriptive statistical analysis was employed in the research. Pb, Cr, and As were found to be beyond WHO/FAO thresholds. Full Abstract There has been an increase in the utilization of traditional herbal drugs for different medications and health care in Katsina state. This is possibly due to the growing need for complementary disease treatment, relative cheapness, availability, and wider distribution. Raw samples of a popularly used traditional herb (locally named - Dan Lambar Rimi) were purchased from local markets, prepared, and analyzed using a flame atomic absorption spectrophotometer for Pb, Cr, As, Co, Ni, and Cd concentrations. The obtained concentrations were then summarized using descriptive statistics in SPSS Version 27. The results for the elements analyzed were Ni (0.83 ± 0.15), Cd (0.20 ± 0.01), Pb (21.5 ± 6.63), As (2.10 ± 0.70), Cr (2.36 ± 0.37), and Co (1.15 ± 0.22) ppm. Cr, Pb and As concentrations were greater than the WHO/FAO threshold limits for herbal medicines, while that of Cd was within the recommended threshold. Furthermore, the concentrations of these metals (As, Cr, and Pb) were greater than the WHO/FAO acceptable threshold in 50% of the herbal samples analyzed. Therefore, these metals can pose a threat to public health, especially considering the conventional way in which this herbal medicine is used. With deliberate improvement in hygiene during its preparation prior to consumption, the risk will be brought to a minimal. Future studies should perform a detailed chemical risk assessment, especially when we look at the increase in the number of diseases of unknown etiology in the region.

Chromium (III) ion determination and speciation in honey & hardaliye samples using magnetic solid-phase extraction and FAAS

ABSTRACT Cr (III) is an essential element for maintaining glucose, lipid, and protein metabolism in mammals. Removal/recovery of such heavy metals is crucial. For this purpose, dendrimer-based novel magnetic nanoparticles to enrich Cr (III) were synthesized and characterized by spectroscopic methods such as SEM-EDX, TEM, FT-IR, XRD, and VSM. The optimum parameters such as pH, eluent type-concentration, adsorbent amount, and time, which are important in the recovery of Cr (III) with solid magnetic-based nanoparticles (MNPs), were determined by flame atomic absorption spectroscopy. After the enrichment of Cr (III) with MNPs, the device’s detection power enhancements were increased by 8653 ± 145 times. The optimum conditions obtained for Cr (III) ions with MNPs were successfully applied to water, honey, and hardaliye samples. Furthermore, the reusability results of the MNPs were determined to be approximately 99% for Cr (III) up to the 10th use.

Comparative study of serum zinc levels in stable asthmatic versus non-asthmatic children

Objective: Zinc is an essential trace element that plays a critical role in various physiological processes, including immune function and antioxidant defense. Serum zinc levels are often used as a marker to assess nutritional status and potential deficiencies. This study aims to compare serum zinc levels between stable asthmatic children and non-asthmatic controls at ESUT Teaching Hospital, Parklane Enugu, to understand whether asthmatic children have different zinc status compared to their non-asthmatic counterparts. Materials and Methods: A comparative cross-sectional study was conducted involving 85 asthmatic and 85 non-asthmatic children aged 5–11 years. Serum zinc levels were assessed using a Flame Atomic Absorption Spectrophotometer (FAAS). Data were analyzed using SPSS version 20. Results: The median serum zinc levels were 11.95 µmol/L in asthmatic children and 8.81 µmol/L in non-asthmatic children (p &lt; 0.001). Nutritional status and socio-economic class did not significantly affect serum zinc levels. Conclusion: Stable asthmatic children have higher median serum zinc levels compared to non-asthmatic children. There was no significant relationship between serum zinc levels and socio-economic or nutritional status in the asthmatic group. Blind zinc supplementation in asthmatic children should be approached with caution.

Electrochemical Sensor Based on Glassy Carbon Electrode Modified with Carbon Nanohorns (SWCNH) for Determination of Cr(VI) via Adsorptive Cathodic Stripping Voltammetry (AdCSV) in Tap Water

In this study, a new and simple glassy carbon electrode modified with carbon nanohorns (SWCNH/GCE) was used for the determination of Cr(VI) in aqueous matrices via adsorptive cathodic stripping voltammetry (AdCSV). The modified electrode was characterized via field emission scanning electron microscopy and cyclic voltammetry, which revealed a homogeneous distribution of spherical agglomerates of SWCNH on the electrode surface. The modification increased the electrochemically active area from 0.10 cm2 ± 0.01 (GCE) to 0.16 cm2 ± 0.01 (SWCNH/GCE). The optimized analytical conditions were as follows: a supporting electrolyte (0.15 mol L−1 HCl), an accumulation potential of 0.8 V versus Ag/AgCl, and an accumulation time of 240 s. Validation of the analytical methodology was performed, obtaining a linear range between 20 and 100 µg L−1, a limit of detection of 3.5 µg L−1, and a limit of quantification of 11.6 µg L−1 with good accuracy and precision. The method was applied to the analysis of spiked tap water samples, and the results were compared using a flame atomic absorption spectrophotometer (FAAS) with no significant statistical differences.

Heavy metal contamination in soil and food crops and associated human health risks in the vicinity of Iringa Municipal dumpsite, Tanzania

Heavy metal contamination and potential risks to human health related to consuming major food crops near Iringa Municipal dumpsite are presented. Soil samples, maize (Zea mays L.) and common beans (Phaseolus vulgaris L.) were collected downslope around the dumpsite during wet season. Soil samples were analyzed using Energy-Dispersive X-Ray Fluorescence (EDXRF) while crop (maize and beans) samples were analyzed using Flame Atomic Absorption Spectrophotometer (FAAS). The potential health risks associated with human exposure to heavy metals in maize and common beans was evaluated according to the method prescribed by the United States Environmental Protection Agency. The concentrations Cd (3.25–10.78 mg/kg), As (1.84–10.98 mg/kg) and Ni (71.74–55.10 mg/kg) in soil samples exceed the maximum allowable limits set by Tanzania Bureau of Standards (TBS). The average heavy metal concentration in food crops followed the trend Cd, As < Cr, Pb < Ni < Cu < Mn < Zn with Pb in maize (0.96 mg/kg) and common beans (0.81 mg/kg) above FAO/WHO regulatory standards of 0.3 mg/kg. This implied health concerns to consuming food crops grown in the vicinity of the dumpsite. Further, lifetime–incremental cancer risk (ILCR) assessment suggest that consuming maize and common beans from the study area could increase the risk of both cancer and non-cancerous diseases in both adults and children. However, the degree of ILCR in children was noticeably higher (1.0 × 10–2) than in adults (5.10. × 10–6) for Pb in common beans. Therefore sustainable waste management should be stressed and continuous monitoring of environments around dumpsites is crucial to mitigate the negative impacts on public and environments.

Development of a new reference material for accurate measurements of lithium in Li-clays

Currently, there are no national and international certified reference materials (CRM) in lithium clays that can make reliable and traceable lithium measurements for the International System of Units (SI). Hence, it is necessary to have references to meet the needs in terms of mining and activities that involve the use of lithium to favor the economy derived from its multiple uses and associated benefits in the exploration, exploitation, and handling of lithium ore. In this study, a candidate for reference material (RM) of Li in clays was developed and certified based on the provisions of ISO 17034:2016 and ISO Guide 35:2017. Different mass sizes of the RM (0.05, 0.1, and 0.25 g) were used to evaluate homogeneity. An isochronous study (short-term stability) was carried out in the assessment of stability, influenced by the effects of transport at different temperatures (20, 40, and 50 °C) for a determined time of 6 weeks, in addition to a classic (long-term) study for 19 weeks. The sample was treated using microwave-assisted acid digestion and Li measurements were performed using the analytical technique of Flame Atomic Absorption Spectrometry (FAAS). The CRM is homogeneous for the sample mass sizes of 0.05 and 0.1 g, and the mass fraction of w(Li) was stable in the RM for temperatures of 20, 40, and 50 °C. The determined period of validity was 3 years.

Development of Analytical Strategy for the Determination of Cadmium by Flame Atomic Absorption Spectrometry After Dithizone/Deep Eutectic Solvent Probe Based Liquid Phase Microextraction

Liquid phase microextraction (LPME) with a dithizone/deep eutectic solvent (DTZ-DES)-based probe was employed for the determination of trace cadmium by flame atomic absorption spectrometry (FAAS). All extraction parameters were univariately optimized to achieve the highest efficiency and the limits of detection and quantification were 3.5 and 11.8 ng mL−1. Good linearity was obtained from 10 to 200 ng mL−1 with a regression coefficient (R2) of 0.9979. The sensitivity of FAAS system was improved 26.9-fold by the microextraction procedure. The accuracy and applicability of the method were investigated with recovery experiments carried out using corn silk tea extracts. The recovery values with matrix matching calibration were from 81.3 to 114.3%, demonstrating that this environmentally friendly method is applicable for determination of cadmium in tea samples with good accuracy.

Comparative analysis of heavy metal accumulation in urban pigeon feathers: A case study in the Zinc Industrial Town of Zanjan

This study assesses heavy metal pollution in Zanjan's Zinc Industrial Town by analyzing cadmium, zinc, and lead in feathers from 200 pigeons (80 males and 80 females, both living and deceased) and 40 control samples using flame atomic absorption spectrometry. The results revealed significantly higher concentrations of these metals in pigeons from the industrial area compared to controls. Specifically, cadmium levels reached 1.927 μgg−1 in deceased female pigeons, compared to 0.729 μgg−1 in the control group. Lead concentrations were 17.455 μgg−1 in the feathers of deceased pigeons, compared to 2.895 μgg−1 in controls. Zinc levels in deceased female pigeons were as high as 378.75 μgg−1, compared to 61.995 μgg−1 in controls. Statistical analysis confirmed a significant correlation between metal accumulation and the gender of the pigeons, underscoring the impact of industrial pollution on local wildlife. These findings demonstrate the effectiveness of using pigeon feathers as bioindicators for monitoring environmental pollution.