Flame Atomic Absorption Spectrometry Research Articles

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 < 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.

Petroleum spills and assessment of heavy metals in water, sediment, soil from Afiesere River, Ughelli, Delta State, Nigeria

The study which was to determine the concentrations of heavy metals in water, sediment and soil of Afiesere river because of the anthropogenic activities of petroleum exploration and attendant spills in the area. Surface water, sediment, surface soil and sub-surface soil samples were collected from Afiesere River, Ughelli, Delta State. Some physiochemical parameters of water were analysed using standard methods and Hanna water quality checker. The concentrations of five heavy metals, namely; lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu) and nickel (Ni) were determined in water, sediment, surface soil, and sub-surface soil using Flame Atomic Absorption Spectrophotometer (Flame-AAS). The results obtained show the mean values of pH, temperature, total dissolved solid, conductivity, dissolved oxygen, biological oxygen demand, phosphate, nitrate, and sulphate as follows: 6.87 ± 0.18, 27.40 ± 0.28oC, 4.00 ± 0.00 mg/L, 8.67 ± 0.25 µs/cm, 4.23 ± 0.08 mg/L, 0.65 ± 0.17 mg/L, 0.01 ± 0.00 mg/L, 0.01 ± 0.03 mg/L, and 2.17 ± 0.18 mg/L respectively. The heavy metals; Pb, Cd, Zn, Cu and Ni mean concentrations are as follows: in water, 0.06 ± 0.02, 0.02 ± 0.01, 0.46 ± 0.01, 0.03 ± 0.01 and 3.56 ± 0.07 mg/L; in sediment, 0.52 ± 0.03, 0.02 ± 0.00, 0.21 ± 0.02, 0.07 ± 0.01 and 0.26 ± 0.01 mg/kg; in surface soil, 0.50 ± 0.03, 0.02 ± 0.00, 0.07 ± 0.01, 0.03 ± 0.00 and 2.91 ± 0.03 mg/kg; in sub-surface soil, 0.55 ± 0.02, 0.02 ± 0.01, 0.26 ± 0.02, 0.06 ± 0.01 and 0.36 ± 0.08 mg/kg respectively. The results showed a significant difference at P&lt;0.05. The results obtained in this study were within and above the set standard for water, sediment and soil by World Health Organization (WHO). The metals are toxic, can bio-accumulate and are potential carcinogens; therefore treatment of water is very important. Periodic medical examination of the inhabitants of the area must be a top priority.

Chemical composition, anti-hypertensive properties, and sensory attributes of salt extracted from ash of Hygrophilia schulli.

The traditional usage of salt taken from vegetables for the treatment of blood pressure and diabetes is seen in several regions of Ethiopia, particularly in Gambella. The aim of the study was to investigate the mineral content, anti-hypertensive properties, and sensory attributes of salt obtained from the Hygrophilia schulli. The salt was extracted from the ashing of stems of Hygrophilia schulli. Optical Emission Spectroscopy with Inductively Coupled Plasma was used to identify macro-minerals, micro-minerals, and some toxic metals. Flame Atomic Absorption Spectroscopy was used to assess the levels of arsenic and mercury. The anti-hypertensive property of the salt was determined invivo using the Wistar rats. The extracted salt was rich in potassium and was deficient in sodium from the analyzed macro-minerals. It was free from mercury, cadmium, chromium, and arsenic. Lead and nickel were below the Tolerable Weekly Intake Provisional specified by the European Union. Among carbonate and sulfate, chloride was the main anion in this salt. The salt was discovered to have a low taste characteristic compared to common salt. However, the taste attribute of the combination of vegetable and common salt in different proportions was better than common salt. Rats fed with salt from Hygrophilia schulli showed a statistically significant lower systolic, diastolic, and mean blood pressure compared to normal-fed and common salt-fed rat groups. Generally, this study suggests that Hygrophilia schulli salt has the potential to be a viable alternative to common salt, particularly for those suffering from hypertension and other related chronic conditions.

Validation of high-resolution continuum source flame atomic absorption spectrometry for determination of selected toxic and potential toxic metals in the decontamination process of wastewater discharged in natural receivers.

A new method based on high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS) was validated for the determination of selected toxic and potentially toxic metals in wastewater resulting from mining activity. The results were compared with inductively coupled plasma optical emission spectrometry (ICP-OES). The HR-CS-FAAS method was characterized by detection limits in the range (µg L-1) 0.9(Mn)-33.6(Pb), better than ICP-OES for Cu, Fe, Ni, Co, Pb and Mn, and poorer for Cd, Zn and Cr. The Dunnett's and Tukey's statistical test showed that both methods were not affected by significant bias against certified value and between them. The recovery in HR-CS-FAAS method was in the range of 98-103% with relative extended uncertainty of 9-25%, and precision of 1.5-14.1%. The results indicated that the HR-CS-FAAS method is suitable for the determination of toxic and potentially toxic elements directly in filtered water samples without any chemical treatment.

Evaluation of lipid profile, liver function enzymes, and trace elements in Iraqi diabetic nephropathy patients.

Diabetic nephropathy, a common complication of type 2 diabetes (T2DM), is associated with abnormal lipid profiles, liver dysfunction, and kidney impairment. However, research on its association with trace elements in Iraqi patients is limited. The objective of the present study is to evaluate the association between lipid profile, liver function, and trace elements in diabetic nephropathy (DN) patients. In this study, 120 individuals were selected. Sixty of these individuals were labeled as the DN patient group, and 60 individuals were labeled as the healthy control group. A flame atomic absorption spectrophotometer (FAAS) was utilized to assess the levels of zinc (Zn), copper (Cu), and magnesium (Mg), whereas a flameless atomic absorption (FAA) was used to assess manganese (Mn). A colorimetric method was used based on the protocols included in the leaflets by Spinreact kits to determine the levels of lipid profiles and liver function enzymes in the serum. The mean value of high-density lipoprotein (HDL) decreased significantly in the DN patient group compared to the control group (p < 0.001) while cholesterol and low-density lipoprotein (LDL) decreased insignificantly. Conversely, the mean value of triglycerides (TGs) increased significantly in patient group ((p < 0.001) while very low-density lipoprotein (VLDL) increased insignificantly. On the other hand, the mean values of aspartate aminotransferase (AST), alanine transferase (ALT), alkaline phosphatase (ALP), and γ- glutamyl transferase (GGT) were significantly greater in DN patients compared to the healthy controls. Conversely, the mean values of total protein (TP) and albumin (Alb) were significantly lower in the DN patient group. In terms of trace elements, the mean values of Zn, Mg, and Mn were significantly lower in each of the patient groups compared to the healthy group. Conversely, a significant elevation in the means of Cu and Fe was observed in patients compared to the healthy group. Additionally, the findings revealed no association between BMI and lipid profile, liver enzymes, or trace elements. However, an association with age was limited to TGs, ALP, and GGT. The study's results show that the DN patients have abnormalities in their serum trace element levels. This means that these elements could be valuable indicators for monitoring and assessing the progression of DN. Understanding the correlation between lipid profile, liver function, and trace elements could offer valuable insights for managing and preventing diabetic nephropathy. More extensive studies, including an additional group of DM patients without nephropathy complications, are required, and could be used in practice due to the progression of the disease.

Assessment and bioaccumulation of heavy metal contaminants in Golden Mahseer (Tor putitora Hamilton, 1822)

Unpolluted freshwater is a crucial component for maintaining the health of humans. This study aimed to investigate the bioaccumulation and potential health hazards of heavy metal contaminants (Fe, Cd, Cr, Cu, Pb) in water, sediments, and tissues of the golden mahseer fish (Tor putitora) from Zhob River to assess their suitability for human consumption. Samples (soil, water, and fish) were collected from the Zhob River, and Flame Atomic Absorption Spectrometry (FAAS) was employed to measure the concentration of these metals found in soil, water, and various fish body tissues (muscles, skin, gills, and liver). The overall results revealed that water quality parameters, i.e., temperature and pH were found within tolerable ranges, while electrical conductivity and turbidity exceeded the permissible limits of FAO/WHO for fish. Furthermore, this study also identified elevated concentrations of Pb in water and soil, as well as Fe and Cd in soil beyond the standards set by the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA). In contrast, the concentrations of other targeted metals examined in fish body tissues were found below the permissible limits set by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO), indicating the suitability of this fish species for human consumption. The estimated daily intake (EDI) of these targeted metals in various fish body tissues was found to be within the recommended dietary allowance (RDA), suggesting no associated health risks for the local population. Furthermore, both the Target Hazard Quotient (THQ) and Total Target Hazard Quotient (TTHQ) values measured in this study were less than one, indicating the absence of potential non-carcinogenic health risks related to the consumption of this riverine mahseer fish, but combined metal intake may pose potential health risks. Carcinogenic risk assessment for some metals like Cd, Cr, and Pb revealed no cancer risk for consumers. Moreover, our present research observed comparatively high bioaccumulation (BAF) of each targeted metal in the fish liver from both Zhob River water and soil as compared to other body tissues. Multivariate analysis, including the correlation matrix, revealed strong and significant correlations (P < 0.05) among heavy metal pairs (Fe/Cr, Fe/Pb, Cr/Fe, Cr/Pb, Pb/Fe, Pb/Cr). Hierarchical cluster analysis and Principal Component Analysis (PCA) were utilized to trace the origins of these metals, attributing their presence to nearby rock weathering, mining, as well as municipal and agricultural activities. These factors were recognized as potential sources of heavy metal bioaccumulation in riverine fish. Thus, our current study concluded that the Zhob River was contaminated with these heavy metals and emphasized the need to prevent domestic and industrial sewage inflow. The monitoring of these metals in the food chain was also underscored as crucial for reducing all kinds of associated health risks. This study provides the first report on heavy metal distribution in highly abundant and edible mahseer fishes of the Zhob River.

Elevated Cadmium Drives Calcium Deficiency in Renal Failure Patients

Background: Renal failure (RF) is a significant health issue with various etiological factors, including environmental toxins. Specific Background: Cadmium (Cd), a known toxic heavy metal, has been implicated in renal damage, while calcium (Ca) levels may also be affected. Knowledge Gap: The relationship between Cadmium and Calcium levels in RF patients, despite the well-established link between heavy metals and renal impairment, remains underexplored. Aims: This study aimed to evaluate changes in blood serum Cd and Ca levels in RF patients and investigate their correlation. Methods: The study, conducted in Iraq from July 2023 to February 2024, involved 150 participants, including 100 RF patients and 50 healthy controls, and used Flame Atomic Absorption Spectroscopy for analysis. Results: The mean Cd level was significantly higher in RF patients (2.30 µg/L) compared to controls (1.44 µg/L, P &lt; 0.05). Conversely, the mean Ca level in RF patients was significantly lower (36.06 mg/dL) compared to controls (51.85 mg/dL, P &lt; 0.05). A significant negative correlation between Cd and Ca levels was found (P ≤ 0.001). Novelty: This study provides novel insights into the detrimental impact of elevated Cd levels on Ca status in RF patients. Implications: The study underscores the necessity of controlling Cd exposure and Ca levels in renal function (RF) management to mitigate its environmental impact on renal health. Highlights: Higher Cd Levels: Increased cadmium in RF patients. Lower Ca Levels: Decreased calcium in RF patients. Negative Correlation: Cadmium inversely affects calcium levels. Keywords: Cadmium, Calcium, Renal Failure, Heavy Metals, Blood Serum

Metal bioaccumulation and translocation potential of three herbal plant species at mine tailings

Phytoremediation as a technique for cleaning soil contaminated with potentially toxic metals uses plants that can absorb them, and then translocate and accumulate them in above-ground parts. Its effectiveness depends on the selection of adequate plants. Therefore, this study aimed to investigate the potential of three wild herbaceous plant species (Holcus lanatus L., Agrostis alba L., and Eupatorium cannabinum L.) growing on mine tailings for phytoremediation applications. The content of selected metals in soil and plant samples was determined by flame atomic absorption spectrophotometer. The research results indicate that the content of Pb and Cu in the soil of the rhizosphere of the studied species was higher than their remediation values, after the exploitation of polymetallic ore (lead-zinc-copper), which made the tailings an ecological hazard. The species H. lanatus proved to be a good candidate for the phytoaccumulation of Cr, and the species A. alba of Ca, while the species E. cannabinum proved to be phytoaccumulator of all tested metals in the researched mine tailings. Potential for phytoextraction applications were shown by the species H. lanatus for Cd, Cu, Mg and Ni, and A. alba for Cd and Zn.

Adaptation and Heavy Metal Degradation by Bacillus sp.: Insights Into Biofilm Formation, Exopolysaccharide (EPS) Production, and Antibiotic Resistance Under Copper (Cu) and Lead (Pb) Stress

ABSTRACTAn extensive concentration of heavy metals in our environment creates a harmful impact on living organisms, including microorganisms. Regardless of exploring the remediation potential of bacteria, their corresponding changes have not been extensively examined, which might be crucial before promoting bioremediation technology. The present study aimed to determine the effects of both essential (Cu) and nonessential (Pb) heavy metals on the bioactivity of a ubiquitous bacterium Bacillus sp., to gain knowledge about the adaptive mechanisms the strain has developed to withstand exposure to these metals. Bacterial adaptation is related to the formation of biofilm and the production of exopolysaccharides (EPSs) along with other tactics that assist in the survival of bacteria. When Bacillus sp. was cultured with Cu and Pb, changes in its bioactive characteristics were observed, such as a significant reduction in biofilm formation by 30.13% compared to the initial value. Moreover, the output of EPS by the bacterial strain in the presence of Pb increased to 0.782 mg/mL compared to the control condition, where no EPS was formed. In the presence of Cu, a low concentration of EPS (0.103 mg/mL) was detected. Moreover, the bacterial strain demonstrated adapted resistance to 6 out of 11 tested antibiotics, where the strain transformed from intermediate sensitivity to being susceptible to doxycycline, chloramphenicol, and gentamycin. Finally, the Cu‐ and Pb‐degrading capacity of the bacterium was scrutinized using a flame atomic absorption spectrophotometer, where the bacterium exhibited significant degradation rates, breaking down 14.49% of Cu and 37.30% of Pb within 7 days. This research revealed the adaptability of the bacterial strain to survive in the presence of Cu and Pb while degrading them, by changing its bioactive properties, through the downregulation of biofilm formation, the productivity of EPS, and the heavy metal degradation process.

Content of Biogenic Elements in Sheep Wool by the Regions of Slovakia.

The quality of nutrition and environmental pollution are crucial chemical indicators influencing animal health, reflected in element concentrations in animal tissues and coats. This study investigates the concentrations of biogenic elements (calcium, potassium, magnesium, sodium, copper, and iron) in sheep wool from various regions of Slovakia to compare concentrations and identify possible correlations between individual elements. Samples were collected from six different regions, and concentrations of elements were measured using flame atomic absorption spectrometry. Statistical analysis revealed significant differences in element levels among the examined regions. Calcium concentrations ranged from 729.2 to 4065ppm, with the highest concentrations in the Kysuce region and the lowest in the Šariš region. Potassium concentrations ranged from 2315 to 3282ppm, with the lowest values in the Zemplín region and the highest in the Liptov region. Magnesium, sodium, copper, and iron also exhibited varying concentrations across the regions. Correlation analysis identified significant associations between several elements. The findings suggest that regional environmental differences influence element concentrations in sheep wool, highlighting the importance of monitoring biogenic elements for assessing environmental pollution and animal health. Further research is warranted to explore the underlying mechanisms driving element accumulation in wool and its implications for animal welfare and environmental management.

Health risk assessment of trace metal concentrations in cereal-based infant foods from Arba Minch Town, Ethiopia

The study aimed to determine the trace metal concentrations and assess the associated health risk of consuming cereal-based infant foods sold in supermarkets and local shops (baltena) in Arba Minch town, Ethiopia. Samples were subjected to a microwave digestion process and the trace elements were analyzed using Flame Atomic Absorption Spectrometry (FAAS). The method’s accuracy was validated through a recovery test, yielding optimal results within the range of 94–100 %. The average concentrations of trace elements in the infant food samples were as follows: Iron (36.51–47.58 mg/kg), Copper (1.86–2.57 mg/kg), Zinc (13.90–21.56 mg/kg), Nickel (0.02–0.04 mg/kg), Chromium (0.034–0.10 mg/kg), Cobalt (0.012–0.02 mg/kg). Notably, potentially toxic heavy metals like Cadmium and Lead were not detected in the samples. The hazard quotient (HQ) for (6−9) month old infants was less than one (HQ<1) for all the trace elements analyzed. The same holds good for (9−12) month old infants except few food samples such as Selam, Zini, Mimi and Mulga baltena, which had HQ values greater than one (HQ>1). It is inferred that the continuous consumption of these foods might cause risk over a longer period.

A simple and efficient supramolecular solvent based liquid phase microextraction method for the preconcentration of nickel from dandelion tea samples before FAAS quantification, and the practicality and greenness assessment of developed method

A sensitive, accurate and practical analytical method (supramolecular solvent based liquid phase microextraction – flame atomic absorption spectrometry (SUPRAS-LPME-FAAS) was developed for the determination of nickel in dandelion tea samples. All influential parameters of SUPRAS-LPME were optimized to attain low detection/quantification limits using a univariate optimization approach. Under the optimum SUPRAS-LPME-FAAS conditions, dynamic range, limit of detection (LOD) and limit of quantification (LOQ) were found to be 25.86–497.64 µg/kg, 8.20 µg/kg and 27.35 µg/kg, respectively. The detection power of FAAS system was augmented as 28-fold with the help of SUPRAS-LPME method. Recovery experiments were performed for the evaluation of the accuracy and the applicability of the SUPRAS-LPME-FAAS method and percent recovery results for the spiked dandelion tea samples were calculated between 86.0 and 131.8 % via matrix matching calibration strategy. Additionally, the practicality and greenness evaluations for the SUPRAS-LPME-FAAS method were carried out using BAGI and AGREEprep software, respectively.

PAIT effect: Padlock activator inhibits the trans-cleavage activity of CRISPR/Cas12a

The CRISPR/Cas12a system is increasingly used in biosensor development. However, high background signal and low sensitivity for the non-nucleic acid targets detection is challenging. Here, a padlock activator which could inhibit the trans-cleavage activity of CRISPR/Cas12a system in the intact form by steric hindrance effect (PAIT effect) was designed for non-nucleic acid targets detection. The PAIT effect disappeared when padlock activator was separated into two split activators. To verify the feasibility of padlock activator, a Ca2+ sensor was developed based on PAIT effect with the assistance of DNAzyme, activity of which was Ca2+ dependent. In the presence of Ca2+, DNAzyme was activated to cleave its substrate, a padlock activator modified with adenine ribonucleotide, into split padlock activators which would trigger the trans-cleavage activity of Cas12a to generate fluorescence. There was a mathematical relationship between the fluorescence intensity and the logarithm of Ca2+ concentration ranging from 10 pM to 1 nM, with a limit of detection of 3.98 pM. The little interference of Mg2+, Mn2+, Cd2+, Cu2+, Na+, Al3+, K+, Fe2+, and Fe3+ indicated high selectivity. Recovery ranged from 93.32% to 103.28% with RSDs from 1.87% to 12.74% showed a good accuracy and reliability. Furthermore, the proposed sensor could be applied to detect Ca2+ in mineral water, milk powder and urine. The results were consistent with that of flame atomic absorption spectroscopy. Thus, PAIT effect is valuable for expanding the application boundary of CRISPR/Cas12a system.

Pb(II) solid-phase extraction in wastewater samples prior to flame atomic absorption spectrometry analysis using chitosan and alginate modified carbon

ABSTRACT The sustainability concept was kept in view by designing and synthesising a novel adsorbent for Pb(II) ion, using natural and metal-free precursors which are renewable and biodegradable, i.e. alginate, chitosan, and carbon. The study was aimed to introduce the synthesis of Carbon/Alginate/Chitosan composite (CAC) as a beneficial adsorbent tailored for the solid-phase extraction (SPE) of Pb(II) prior to its analysis via flame atomic absorption spectrometry (FAAS). The successful preparation of the CAC material is elucidated, characterised through FTIR for functional group analysis, and evaluated for surface morphology and elemental composition via SEM-EDX. Optimisation of SPE parameters was carefully conducted to enhance adsorption-desorption efficiency across diverse conditions. These optimised factors were a pH level of 6, initial Pb(II) concentration of 20 mg/L, sample flow rate 5 mL/min, elution utilising Na2EDTA at a rate of 5 mL/min, sample volume of 20 mL, Na2EDTA eluent volume of 10 mL, and Na eluent concentration of 0.5 M. Application of CAC-based SPE for Pb(II) analysis in wastewater samples under these optimised conditions yielded exceptional recovery rates of 93–96%, with a limit of detection (LoD) value of 71.4 µg/L. Moreover, a notable preconcentration factor of 4–8 times is achieved for Pb(II) in wastewater samples, facilitating the detection of Pb(II) concentrations as low as 30 µg/L.