Flame Atomic Absorption Spectrophotometry Research Articles

Rapid preconcentration and determination of Co (II) ions in aqueous medium using ultrasound assisted cloud point extraction method

A flame atomic absorption spectrophotometric technique was studied for the preconcentration and determination of of Co2+ ions in trace amounts after ultrasound enhanced enrichment of its 1-(2-pyridylazo)-2-naphthol (PAN) complexes by cloud point extraction. The Co2+ ions were firstly complexed with PAN molecules at pH 4 and the complex transferred to a surfactant (Tergitol NP-7) rich phase with a very small volume under ultrasound waves. The surfactant rich phase was separated and dissolved by 1 mL, 1.0 M HNO3 in ethanol prior to determination of Co2+ concentration by flame atomic absorption spectrophotometry. The optimization steps of ultrasound interaction time, solution pH and surfactant volumes were achieved by response surface methodology (RSM) which is a combination of statistical approaches. Sample volume, PAN concentration and and possible interfering ions were optimized conventionally. The Co2+ ions were extracted only in 150 s at pH 4 quantitatively under optimum conditions (˃95%). The accuracy and validity of developed UA-CPE was granted by employing a certified reference material wastewater UME CRM 1204. The technique was applied to wastewater and natural water with satisfactory results.

Heavy metal contamination and environmental risk assessment: a case study of surface water in the Bahr Mouse stream, East Nile Delta, Egypt

Water, as an indispensable constituent of life, serves as the primary source of sustenance for all living things on Earth. The contamination of surface water with heavy metals poses a significant global health risk to humans, animals, and plants. Sharkiya Governorate, situated in the East Nile Delta region of Egypt, is particularly susceptible to surface water pollution due to various industrial, agricultural, and urban activities. The Bahr Mouse Stream, crucial for providing potable water and supporting irrigation activities in Sharkiya Governorate, caters to a population of approximately 7.7 million inhabitants. Unfortunately, this vital water source is exposed to many illegal encroachments that may cause pollution and deteriorate the water resource quality. In a comprehensive study conducted over two consecutive seasons (2019–2020), a total of 38 surface water samples were taken to assess the quantity of heavy metals in surface water destined for human consumption and other applications, supported by indices and statistics. The assessment utilized flame atomic absorption spectrophotometry to determine the concentration of key heavy metals including iron (Fe), manganese (Mn), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn), nickel (Ni), cobalt (Co), and chromium (Cr). The calculated mean value of the Water Quality Index (WQI) was found to be 39.1 during the winter season and 28.05 during the summer season. This value suggests that the surface water maintains good quality and is suitable for drinking purposes. Furthermore, the analysis indicated that the concentrations of heavy metals in the study area were below the recommended limits set by the World Health Organization and fell within the safe threshold prescribed by Egyptian legislation. Despite the identification of localized instances of illegal activities in certain areas, such as unauthorized discharges, the findings affirm that the Bahr Mouse stream is devoid of heavy metal pollution. This underscores the importance of continued vigilance and regulatory enforcement to preserve the integrity of these vital water resources.

Analytical Compatibility between Various Techniques for Determining Dissolved Manganese in Produced Water

Petroleum-produced water is the primary effluent generated during the oil extraction process, presenting high flow rates, and containing a series of chemical components that are harmful to the environment, such as dissolved manganese. The proof of metrological compatibility between laboratories and different test methods or techniques is an analytical challenge when complying with environmental laws and regulations, which is the aim of this study. The first step of this study was to compare the results of manganese content in real test samples of produced water between some laboratories that used different test methods, that is, flame atomic absorption spectrophotometry, inductively coupled plasma optical emission spectroscopy, and inductively coupled plasma mass spectrometry. Based on one-way analysis of variance, systematic errors were found. The following step was to visit a specific lab, where one could confirm the relevance of the wavelength parameters, operating conditions for the view configuration, and effects of the saline matrices. Finally, a compatibility assessment between the reference laboratory and a new laboratory, which implemented and validated its analytical methodology based on these analytical adjustments, and the experiences and lessons learned in the previous step, was undertaken by a paired t-test.

Method Development and Optimization of Liquid-Liquid Microextraction Based on the Decomposition of Deep Eutectic Solvent for the Determination of Chromium (VI) in Spinach: Assessment of the Greenness Profile Using Eco-scale, AGREE, and AGREEprep

A simple, effective, and ligandless liquid-liquid microextraction (LLME) procedure based on the decomposition of hydrophobic deep eutectic solvents (HDES) was developed for the separation and pre-concentration of chromium (VI) ions in spinach leaves, before the determination by flame atomic absorption spectrophotometry. In the proposed study, the first stage involved the leaching of chromium (VI) from spinach leaves with 0.1 M Na2CO3, and in the second stage, chromium (VI) extract was preconcentrated with the LLME procedure using a DES prepared from the combination of DL-menthol and formic acid as a chelating agent and extraction solvent. The DES decomposed in an aqueous donor phase resulting in the dispersion of menthol and extraction of Cr (VI) ions. Under optimal experimental conditions, the limits of detection (LOD) and quantification (LOQ) were 0.63 and 2.1 µg L−1, respectively. The relative standard deviation (RSD) was less than 7%, and the pre-concentration factor (PF) was found to be 31.25. The accuracy of the present methodology was tested by recovery experiments. The greenness of the developed method was assessed using three quantitative green metrics tools: Analytical Eco-scale, AGREE, and AGREEprep, with only Analytical Eco-scale qualifying the proposed method as green.

A simple and effective graphene oxide-zinc oxide nanocomposite based solid phase extraction method for the determination of cadmium in tea matrix at trace levels by flame atomic absorption spectrophotometry

In this study, an easy, environmentally friendly and fast approach was introduced for the synthesis of GO-ZnO nanocomposite (NC). Characterization tools including X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to verify the synthesized nanomaterial. Afterward, the combination of GO-ZnO NC based dispersive solid phase microextraction (dSPME) and flame atomic absorption spectrophotometry (FAAS) was used to preconcentrate and determine Cd with high precision and accuracy. In the optimization experiments, all parameters that affecting extraction yield were optimized. Limit of quantification (LOQ) and detection (LOD) values for the GO-ZnO NC-dSPME-FAAS system were calculated as 12.76 µg L−1 and 3.83 µg L−1, respectively. In order to check the applicability and accuracy of the developed method, recovery experiments were performed on three different hibiscus tea samples. The percent recovery values calculated from the spike experiments were in the range of 84 – 111%.

Metal concentrations (Fe and Zn) in Macrobrachium amazonicum from Brazilian Amazon rivers

The objective of this work was to analyze the contamination by iron (Fe) and zinc (Zn) in the shrimp Macrobrachcium amazonicum in the region of the mouth of the Amazon River in the State of Amapá, taking into account aquaculture and fishing activities. 90 shrimp were used, 45 females and 45 males of M. amazonicum. The animals (30) were found in three different points, being Mazagão Velho in Mazagão, a community on Ilha de Santana, a district in the Brazilian municipality of Santana and Arquipélago do Bailique. Fe and Zn determinations were performed by conventional flame atomic absorption spectrophotometry. The greatest accumulation of Zn in the organs and the lowest concentration of Zn in the muscle and exoskeleton of M. amazonicum was observed. Fe had the highest accumulation in organs, followed by exoskeleton and muscle. Zn accumulation in male organs was greater than in muscle and exoskeleton while Fe concentrations were greater in organs, followed by exoskeleton and muscle. In females, Zn accumulation was greater in our organs, with no difference between muscle and exoskeleton. According to the present study, to maintain levels of food security, the consumption of freshwater shrimp caught and farmed in Mazagão, Bailique Archipelago and community of Ilha de Santana should be limited to a daily shrimp intake dose of 96. 52 g for Fe and 226.81 g for Zn.

Maternal Serum Copper and Some Metabolic Indexes in Late Second Trimester of Gestational Diabetes Mellitus Pregnancy.

Copper (Cu) is a physiologically important trace element during pregnancy. The study aim is to assess the altered level of serum Cu and its association with some metabolic indexes in Gestational Diabetes Mellitus (GDM). A total of 108 pregnant women (aged 18 - 40, second trimester) are included in the study and divided into two groups (GDM n = 54; pregnant with normal glucose tolerance (NGT), n = 54) after performing a 2-hour 75-g oral glucose tolerance test (OGTT). Maternal blood samples are collected at 26 - 28 gestational week. All biochemical parameters are measured in serum from fasting venous blood. Serum Cu levels are analyzed by flame atomic absorption spectrophotometry (Perkin Elmer AAnalyst 300, USA). Body Mass Index (BMI), insulin sensitivity/resistance, triglyceride-glucose (TyG), TyG-BMI (triglyceride glucose-body mass) indexes are calculated by formulas. The following data were observed: significantly higher levels of serum Cu (p = 0.009), pre-pregnancy BMI (pre-pBMI), BMI at the GDM diagnosis (pBMI), TyG, pregnancy TyG-BMI (pTyG-BMI) p < 0.001, and triglycerides (Tgl) (p = 0.02) in GDM compared to NGT pregnancy. The study presents a positive correlation between serum Cu and pre-pBMI (p < 0.02), pBMI and pTyG-BMI (p < 0.001). Besides, pre-pBMI (mean ≥ 25 kg/m2), pBMI (mean ≥ 30 kg/m2), and pTyG-BMI are associated with 14.5% (OR 1.145, 95% CI: 1.064 - 1.232; p < 0.001), 15.3% (OR 1.153, 95% CI: 1.070 - 1.243; p < 0.001), and 5.9% (OR 1.059, 95% CI: 1.022 - 1.086; p < 0.001) increased risk for GDM development. No association is found between Cu and Tgl levels, fasting plasma glucose e(FPG) and TyG. ROC analysis suggests the serum Cu as a possible risk factor for GDM development. The analysis shows that at a cutoff point of ≥ 31.9 µmol/L, serum Cu presents a sensitivity and specificity of 64.8% and 66.7% in the prediction of GDM development (AUC = 0.659, p < 0.012). After adjustment for maternal age, gestational age, and family predisposition, the odds ratios (ORs) (95% CIs) still show association of Cu levels with increased GDM risk (OR 1.099, 95% CI 1.018 - 1.184, p = 0.013). pTyG-BMI index exhibits a better interaction than TyG index, Tgl, and glucose separately with serum Cu levels where BMI has a mediator's role.

Determination of copper ion at trace levels in apple tea samples by simultaneous complexation and spray assisted microextraction method prior to detection by flame atomic absorption spectrophotometry

In the present study, a green and sensitive analytical method for the determination of copper ion at trace levels in apple tea samples was developed. Simultaneous complexation/extraction of the analyte were achieved by spraying-based fine droplet formation liquid-phase microextraction (SFDF-LPME). Copper ion was complexed with a Schiff base chelating agent called as N,N′-Bis(salicylidene)-1,2-phenylenediamine (BSP). Under the optimum conditions, the developed SFDF-LPME-FAAS and FAAS system were assessed with respect to limit of detection (LOD), limit of quantitation (LOQ), linearity and percent relative standard deviation (%RSD). LOD and LOQ values for SFDF-LPME-FAAS method were found to be 6.0 and 19.9 µg/kg, respectively. Enhancement in calibration sensitivity for developed method was found as 23 folds. In addition, accuracy/suitability of the developed SFDF-LPME-FAAS method were confirmed by spiking experiments. Two different apple tea samples were spiked to different concentration values and percent recovery results from 91.1 and 123.8 % proved the accuracy/suitability of the method.

The concentration of Pb, Cd, and Sn in vegetables from ex-tin mining land in Bangka, Indonesia

Utilization of ex-tin mining land as agricultural land is thought to have the potential to contribute heavy metals in agricultural products. The research objective was to obtain data on the metal content of Pb, Cd, and Sn in various vegetable crops such as spinach, cucumber, tomato, cayenne pepper, bitter guard, eggplant, pumpkin, and pepper. In addition to obtaining data on bioconcentration factors (BCFs) of metals in various vegetables. Vegetables were obtained from ex-mining vegetable fields in Jelitik Village, Gunung Pelawan, and Rebo Village, and metal measurements used Analytical Flame Atomic Absorption Spectrophotometry (F-AAS) Jena ContrAA 300. The results showed that the Sn metal in all vegetables analyzed ranged from 4.71 -10.86 mg/kg, Pb ranged from 0 – 5.0 mg/kg, and Cd metal was not found in all the vegetables and soil samples analyzed. The highest of Sn was found in spinach, and Pb in pepper. Generally, the Pb, Cd, and Sn content in vegetables still meets the Indonesian National Standard (SNI) No. 7387:2009, because not exceed the recommended quality standards. Soil from the three villages of ex-tin mining is not categorized as polluted with Pb, Cd, and Sn metals because it does not exceed the target values recommended by WHO. The TFs (Transfer Factors) value of metals in all types of vegetables analyzed was < 1, meaning that the ex-tin mining lands in Jelilik Village, Gunung Pelawan, and Rebo Village, Bangka are still relatively safe for growing vegetables because they do not contribute to the pollution of Pb, Cd, Sn.

Concentration of Heavy Metals in Pollen and Bees Osmia bicornis L. in Three Different Habitats in the Łowicz District in Central Poland

The aim of our research was to compare the levels of pollution in different habitats based on the concentrations of heavy metals found in pollen and the organisms of Osmia bicornis L. bees in three habitats: orchards, berry plantations, and urban habitats (near by power plant, landfill, residential areas, and heavy vehicle traffic). The concentration of Ag, Cd, Cu, Fe, Mn, Ni, Pb and Zn were determined. Samples were quantified using flame atomic absorption spectrophotometry (AAS), with evaluations being carried out three times for each sample. Bee nests were also analyzed concerning reproduction and the presence of parasites. There were no significant differences in the content of heavy metals Ag, Cd, Cu, Fe, Mn, Ni, Pb and Zn in pollen samples between the three habitat types. Bee samples differed only in their Zn content, which was significantly higher in orchards (2.67 mg/kg) than urban habitats (0.80 mg/kg) and berry plantation (0.94 mg/kg). Habitat type had no effect on most bee reproductive parameters (percentage of occupied nest tubes, population growth). Our results show that bees pollinating crops in, for example orchards or berry plantations are exposed to heavy metals to a similar extent to those urban areas.

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

Abstract 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.

Groundwater Quality Analysis in Eleme Metropolis: A Physiochemical Perspective

This study aims at assessing the physiochemical variation of groundwater quality in Eleme metropolis, rivers state Nigeria. The level of chemical concentration in the groundwater samples was analysed using the flame atomic absorption spectrophotometry. The quality of the borehole was analysed using a physical visibility survey. Groundwater samples from five (5) locations in Eleme metropolis was collected from public boreholes namely Alesa, Alode, Ogale, Ebubu and Agbonchia. Analysis of the groundwater samples was carried out in the Laboratory to ascertain the physical, chemical and microbiological characteristics. After due analysis, it was observed that most of the groundwater samples were still within permissible limits with little differences across the different locations. The temperature of the groundwater samples was different in Alode and Ogale as their temperatures were not within the permissible limits of WHO. The groundwater samples were also slightly different in Alode, Ogale and Ebubu with pH values of 5.20, 5.34 and 5.28 respectively. It was discovered that little treatment is needed in the study area since most of the values fall within the permissible limits of WHO.

Validation of the Randox colorimetric assays for serum copper and zinc.

Serum copper and zinc are measured to assess deficiency and toxicity. Atomic absorption spectrophotometry and mass spectrometry methods are expensive and require highly trained staff. Colorimetric assays are available from Randox which are inexpensive and can be automated. We validated serum copper and zinc colorimetric assays on the Binding Site Optilite analyser including comparison with flame atomic absorption spectrophotometry (FAAS) and inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy, imprecision, lower limit of quantitation, and linearity were ascertained. The impact of triglycerides, bilirubin, nickel, and iron on assay performance was also investigated. Comparison of results from colorimetric analysis of patient and external quality assurance samples with those obtained by FAAS and ICP-MS was undertaken. Intra-, and inter-assay imprecision was <9%. Serum copper and zinc assays were linear between 1.8-35.6 and 2.3-45.7 µmol/L, respectively. Agreement was good between colorimetry and FAAS (intercept = -0.7, slope = 1.04) and ICP-MS (intercept = 0.6, slope = 0.99) for serum copper in patients' samples. For serum zinc, agreement was poor between colorimetry and FAAS (intercept = 2.2, slope = 0.87) and ICP-MS (intercept = 1.9, slope = 0.98) in patients' samples. There was a poor concordance in assessment of hypozincaemia between colorimetry and FAAS/ICP-MS. The Randox colorimetric assay for serum copper on the Optilite is simple to perform, has a short analysis time, and measured concentrations compare well with FAAS and ICP-MS. Due to poor agreement with FAAS and ICP-MS, colorimetry is not suitable for the measurement of serum zinc.

Determination of Cd, Co, Cr, Ni and Pb metals in lipsticks samples by Flame atomic absorption spectrophotometry (FAAS)

The study was conducted this work to analyze levels of toxic metals in lipsticks specifically sold in the Bhopal area. Acid digestion process was used to prepare the samples and to quantify the levels of heavy metals, including Cd, Co, Cr, Ni, and Pb Flame Atomic Absorption Spectrophotometry was used. Calibration curves were prepared with good linearity for accurate measurement of concentrations of these metals. All heavy metal observed were within the allowable limit. To assess the health risks, Average daily dose (ADD) and Hazard quotient (HQ) (Ingestion) for all the lipstick samples were calculated. Among these samples, three samples shows higher values among them one belonged to a branded category, while the remaining two were from the non-branded category. These particular Lipsticks samples exhibited higher HQ values (higher than 1), indicating a probable hazard linked of toxic-metals.

Determination of lead in different brands of lipsticks marketed in Mexico

Cosmetics have become a common use product among people around the world being the reason why it is important to know their components specifically, the presence of heavy metals. The content of lead in branded lipsticks was analyzed due to the cause of a large number of diseases and disorders in users. The study was aimed at assessing the levels of lead concentration in 5 lipsticks of different brands sold in Mexico but produced in different countries. Characterization was carried out through a flame atomic absorption spectrophotometry in which the analyses showed the presence of lead in all the samples with a concentration ranging between 1.1775 ppm to 1.8242 ppm, with an average concentration of 1.457ppm, these concentrations are within the average parameter established by the FDA (Food and Drug Administration). However, lead content in daily products, even if it is below the established limit, can be harmful to health. Besides, carrying out an analysis of various investigations we can conclude that the lead concentration in lipsticks produced in the first world countries is lower than the one in those distributed in the developing countries. As a result, it is suggested the research for new components that can avoid the presence of lead, that are sustainable and don´t constitute potential health risk to users.

Ultra-Sensitive Determination of Cadmium in Food and Water by Flame-AAS after a New Polyvinyl Benzyl Xanthate as an Adsorbent Based Vortex Assisted Dispersive Solid-Phase Microextraction: Multivariate Optimization.

Background: Cadmium (Cd) is a very toxic and carcinogenic heavy metal even at low levels and it is naturally present in water as well as in food. Methods: A new polyvinyl benzyl xanthate (PvbXa) was synthesized and used as a new adsorbent in this work. It contains pendant sulfide groups on the main polystyryl chain. Using this new adsorbent, PvbXa, a vortex-assisted dispersive solid-phase microextraction (VA-dSPµE) procedure was developed for the determination of cadmium from food and water samples via flame atomic absorption spectrophotometry (FAAS). Synthesized PvbXa was characterized by 1H Nuclear magnetic resonance (NMR) Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). The different parameters of pH, sample volume, mixing type and time, sorbent amount, and eluent time were optimized using standard analytical methods. Results: The optimized method for assessment of Cd in food and water samples shows good reliability. The optimum conditions were found to be a 0.20-150 µg L-1 linear range, 0.06 µg L-1 LOD, 0.20 µg L-1 LOQ, 4.3 RSD %, and a preconcentration factor of 160. Conclusions: The statistically experimental variables were utilized using a central composite design (CCD). The present method is a low-cost, simple, sensitive, and very effective tool for the recovery of Cd.

On the chemistry of small waterbodies linked to marine aerosols and local geology on the Windmill Islands and mainland near Casey Station, Antarctica

Context In total, 43 shallow waterbodies were sampled in 1983 in the vicinity of Casey Station and nearby islands in Antarctica. The following physico-chemical parameters were obtained: water and air temperature, pH, conductivity, dissolved oxygen, plus major and minor elements. Aims To identify the physico-chemical characteristics of these waters and determine their origin, and calculate their mineral saturation indices. Methods Waters were analysed using standard methods, including for some elements, flame-atomic absorption spectrometry, spectrophotometry, ion chromatography and gravimetric determination. Mineral saturation indices were calculated using the PHREEQ program. Key results Water salinities were generally low and in the range of 120–1200 mg L−1 (total dissolved solids, TDS), except for one site connected to the sea, and four slightly saline sites. The Na/Cl, Cl/Br and Ca/SO4 ratios of several waters were in the vicinity of seawater ratios, implying a contribution of marine aerosols. However, the Mg/Ca ratio of most waters departed from the seawater ratio, plus there was concordance between the molar ratios of (Na + K)/(Ca + Mg) of many of the waters sampled and those calculated from rock geochemical analyses from diverse lithologies. Such chemical ‘provincialism’ appears to be dictated by rock composition. Nitrate and phosphate concentrations were high in the vicinity of penguin rookeries. Conclusions Two sources of ions are identified, one as marine aerosols as shown by three sets of ratios (Na/Cl, Cl/Br and Ca/SO4) with known marine values, and the other from the weathering of local rocks as shown by (Na + K)/(Ca + Mg) of the lake waters compared to the same ratios for the surrounding rocks. Only a few waterbodies have saturation levels for several carbonate minerals (calcite, aragonite, dolomite and rhodochrosite). Implications Future work is recommended for monitoring the waterbodies surrounding Casey Station as a result of the increased atmospheric CO2 concentration that has occurred over the past 40 years, and likely also with the cessation of building activities around Casey Station.

Effect of combined germination and spontaneous fermentation on the bioactive, mineral, and microbial profile of red sorghum and pearl millet flours

The aim of the study was to evaluate the influence of combined germination and spontaneous fermentation on the phytochemical, mineral, and microbial profile of red sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R.Br.) flours. The analysis of the studied flours were performed by molecular spectrophotometry and flame atomic absorption spectrophotometry, respectively. Bioavailability of the iron, zinc, and calcium was estimated using the phytates/minerals molar ratios. The microbial load was counted using culture media specific to total bacteria, lactic acid bacteria, yeast and moulds, and Gram-negative bacteria. Combined processing resulted in flours exhibiting the lowest (p ˂ 0.05) total phenols, flavonoids, 3-deoxy-anthocyanidins, phytates contents, and DPPH scavenging activity and the highest (p ˂ 0.05) ABTS inhibition, mineral contents, and bioavailable iron, zinc, and calcium contents. Combined processing also resulted in the highest (p ˂ 0.05) microbial cell counts, with lactic acid bacteria being the most abundant species in both processed cereals. Combining germination and spontaneous fermentation of red sorghum and pearl millet flours could be a useful and simple processing technique to develop food products that alleviate mineral deficiencies and promote human health.

Distributions of Chromium, Copper, and Cadmium in the estuary-coastal surface sediment of Tin-Rich Island

Belitung Island known as one of the tin producer in the world, as it lied in the South East Asian tin belt. The study was conducted in the North Belitung Island to investigate some metal elements concentration of sediment along the estuary river and coastal area near to carbonate reef environment system. Thirteen sediment samples were collected from estuarine riverbed, shoreline, and offshore of North Belitung. The concentrations of metal elements were analysed to assess the environmental pollution characteristics by using flame AAS (Atomic Absorption Spectrophotometry) method. The result indicated that the average concentrations of chromium (Cr), copper (Cu), and cadmium (Cd) were 1.62-18.26, 5.72-80.07, and 1.4-4.59 mg/kg dry weight, respectively. The calculation of geo-accumulation index (Igeo) was adopted in this study to evaluate the heavy metal pollution. The Igeo values revealed that this research area has been moderately polluted by Cr and Cu, and unpolluted-moderately polluted by Cd. Based on the contamination level to adverse biological effect, the heavy metals concentration in this research area has the low potential to adverse biological effect by Cr and Cu, and low-moderately potential by Cd. This information is important to lead the study about any other elements and heavy metals to evaluate the risk assessment in the tropical area.

Aptamer-Based Electric-Double -Layer (EDL) Extended-Gated FET Biosensor for Detection of Cadmium Ion

Cadmium ion (Cd2+) is a highly toxic heavy metal pollutant. It causes irreversible damage to human health even at low doses due to a long biological half-life and strong bioaccumulation. Common heavy metal detection includes Inductively Coupled Plasma with Atomic Emission, Spectroscopy (ICP-AES), Inductively coupled plasma mass spectrometry (ICP-MS), Flame Atomic Absorption Spectrophotometry (FAAS), and Graphite Furnace Atomic Absorption Spectrometry (GFAAS), and. However, these technologies are high-cost, time-consuming, complicated operations, and can't be detected immediately and accurately.In this study, we developed an electric double-layer (EDL) extended-gate field effect transistor sensor based on aptamers to detect cadmium ions (Cd2+). Use N-channel enhanced-mode MOSFETs to connect the extended-gate array chips with aptamer modified. The aptamers were self-assembled on the gold electrode surface through Au-S bonds. Since the aptamer has a specific binding ability to cadmium ions, it will bind to the aptamer to form a stem-loop structure. The gate voltage changes caused by the structure change and then amplify the electrical signal through the transconductance of the field effect transistor. The linear detection range of this sensor for cadmium ions is from 1nM to 10uM. The Cd2+ calibration curve is shown a high correlation coefficient (R2 = 0.99001) and an excellent detection limit as low as 99.5 nＭ. Importantly, it responds to Cd2+ within 10 seconds. The sensor exhibits high selectivity in the presence of other heavy metals such as arsenic, chromium, lead, and mercury for electrical signal measurements. It also can be reused without significant signal attenuation.The advantages of this method are convenient portability, short detection time, high sensitivity, and simple operation. It has a good prospect for detection in the daily life of cadmium environmental pollution. Figure 1