Graphite Furnace Atomic Absorption Research Articles

Correlation between lithium concentrations in drinking water and suicide attempt in the southeast of Iran.

Suicide, as an avoidable cause of death in public health systems, currently lacks effective global strategies to prevent it. However, several epidemiological studies found a correlation between the concentration of lithium (Li) in drinking water and lower suicide rates in the general population. Our ecologicalstudy investigated this hypothesis in the Rafsanjan districtof Iran. Samples from the public water supply in 16 areas in the district were analyzed using the graphite furnace atomic absorption. The resulting data were examined in relation to the suicide attempt from March 2019 to March 2020 obtained from Iran's Ministry of Health's registration system. During that period, 239 suicide attempts were recorded, resulting in an average of 69 individuals (85 women and 54 men) per 100,000 residents of the area. The average Li concentration in the drinking water was 47.30 µg/L (ranging from 9.4 to 141 µg/L). A negative significantcorrelation (r = -0.551, p = 0.027) between Li concentration in water and the rate of suicide attempt were observed in the studied population. Notably, these findings indicate an inverse significantrelationship between Li levels and suicide attempt rate in women (r = -0.725, p = 0.001). This is the first study in Iran that examines the relationship between Li levels in drinking water and suicide attempt rate. The findings of this study support an inverse relationship between the level of Li in public drinking water and the rate of womensuicide attempt.

Online Flow-Batch Dispersive Liquid-Liquid Microextraction System for ET AAS Determination of Molybdenum in Water and Complex Matrices

Online Flow-Batch Dispersive Liquid-Liquid Microextraction System for ET AAS Determination of Molybdenum in Water and Complex Matrices

Assessing Metal Exposure and Leaching from Discarded Cigarette Butts: Environmental Analysis and Integrated Waste Management Approaches.

Cigarette butts, often discarded as litter, are considered a common form of waste, containing a variety of pollutants within this hazardous residue. This study, which was designed to assess the environmental release of certain metals from cigarette butts, investigates a variety of scenarios under varying climatic conditions. Thus, in order to assess the level of metal contamination, samples of cigarette butts were collected in urban areas from seven popular brands in China, smoked artificially, and examined through graphite furnace atomic absorption (GF-AAS). The findings indicated mean concentrations of 1.77 for Cr, 2.88 for Ni, 12.93 for Cu, 24.25 for Zn, and 1.77 µg/g for Pb in the case of newly smoked butts. The emission of each of the metals increases to 8-10% when cigarette butts remain in the environment for an extended period of time. Furthermore, rainfall can accelerate metal leaching, reaching values of 18-20% compared to the controlled scenario. The worst-case scenario releases 2129.31 kg/year of metals into the environment, while the best-case scenario sees a lower release of 844.97 kg/year. The data reflect variations in metal emissions across different scenarios. There was also a strong correlation between cigarette butts in public spaces and cities. This research highlights the need to educate smokers and increase urban maintenance efficiency to reduce this litter and the metals it leaches into the environment.

Certified reference material (CRM) of tea powder (BARC - D3201) for K, Ca, P, Mg, Mn, Al, Fe, Ba, Zn, Cu, Sr, Pb, As, Cd, and Hg: Method validation and its production

A certified reference material (CRM) for major and trace elements in black tea powder has been developed at National Centre for Compositional Characterization of Materials/Bhabha Atomic Research Centre (BARC), Hyderabad. The study describes an acid assisted microwave digestion of tea powder followed by quantitation of K, Ca, P, Mg, Mn, Al, Fe, Ba, Zn, Cu and Sr by ICP-AES; Pb, Cd by GFAAS and As, Hg by AFS in the digests. The method was validated in terms of selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), trueness, precision, traceability, ruggedness and combined uncertainty using a CRM of tea powder (NMIJ CRM 7505-a) and spike recovery studies. The obtained values of LOQ ranged from 0.018 % m/m for Ca to 0.35mg kg−1 for Hg. Precision of the method was found to be <5% for all the analytes (K, Ca, P, Mg, Mn, Al, Fe, Ba, Zn, Cu, Sr, Cd and Hg) excepting for Pb and As (6.5 % at 95% confidence level). The obtained LOQ values, trueness and precision established that the validated method could be used for the characterization of candidate tea CRM during homogeneity and stability studies. Candidate tea CRM (∼3.6 Kg) was processed (which included spiking, drying grinding and sieving) and its homogeneity was assessed at various levels with respect to all 15 property values. The assignment of the property values for each element was carried out after an interlaboratory comparison exercise (ILCE), where 11 laboratories from various government and private sectors participated. A total of four techniques inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), graphite-furnace atomic-absorption spectrometry (GFAAS) and atomic-fluorescence spectrometry (AFS) were used during ILCE. Property values were assigned for 14 elements (K, Ca, P, Mg, Mn, Al, Fe, Ba, Zn, Cu, Sr, Pb, Cd, and Hg) along with combined uncertainties. The concentration with expanded uncertainties of the property values were between 0.458 ± 0.025 for Ca (% m/m) to 0.60 ± 0.084 mg kg−1 for Hg. Long-term stability studies suggested that the produced tea CRM is stable at storage temperature (4 °C) for the last two years, whereas, short-term stability studies (at temperatures 4, 25 and 40 °C) established its transportation stability at tested temperatures for a period of three weeks. Preparation and certification of tea CRM (BARC-D3201) was carried out in accordance with ISO Guides 17034 and 35.

DIETARY FIBER IN REDUCING OF ELEVATED BLOOD LEAD CONCENTRATION IN CHILDREN

The aim of the study was to evaluate the effectiveness of dietary fiber in reducing elevated blood lead concentration (BLC) of Ukrainian children. Materials and methods. 80 random children aged 4 to 15 years were examined. The lead content in venous blood was detected by atomic absorption spectrometry with electro-thermal atomizer (ET AAS). Indicators of morphological and biochemical blood tests were determined by generally accepted methods. Results. About a quarter of the children had BLC ≥ 5μg/dL. They had a higher content of eosinophil cells, an increase of ALT activity in the blood compared to children with lower BLCs. As a nutritional supplement for the rehabilitation of these children, dietary fiber from cereals of 10 g per day was used for 30 days, as an addition to main dishes and salads during lunch. As a result, BLC significantly decreased. At the same time, the number of eosinophils in blood and the activity of ALT significantly decreased. The thiol-disulfide ratio increased. Children tolerated nutritional intervention well. Its safety was also indicated by the absence of changes in indicators of the functional state of the liver. This allows us to recommend this dietary supplement for the improvement of children undergoing environmental lead pressure.

Factors associated with blood lead levels in children in Shenyang, China: a cross-sectional study

BackgroundAlthough blood lead levels (BLLs) in children are gradually decreasing, low-concentration lead exposure can still exert adverse effects. We studied the factors that affect BLLs in children in Shenyang, China.MethodsWe conducted a cross-sectional study by administering structured questionnaires on family demographics and food intake. The concentrations of lead in venous blood were determined by graphite furnace atomic absorption spectrometry.ResultsA total of 273 children aged 1–6 years were enrolled. The geometric mean (geometric standard deviation) of BLLs was 24.94 (12.70) μg/L in boys and 23.75 (11.34) μg/L in girls. The prevalence of BLLs of ≥35 μg/L was 22.7% and was mainly observed in children aged under 3 years. Often hand washing before meals was protective against BLLs ≥20 μg/L (adjusted OR: 0.427, 95%CI: 0.238–0.767, p = 0.004). Consumption of puffed grains and eggs had an adjusted OR (95%CI) for BLLs ≥20 μg/L of 1.714 (1.012–2.901) (p = 0.045) and 1.787 (1.000–3.192) (p = 0.050), respectively.ConclusionsBLLs of children in Shenyang are still higher than in developed countries. Consumption of puffed grains and eggs is associated with higher BLLs. Often hand washing before meals may be protective against high BLLs.

Vortex-Assisted Ionic Liquid-Based Liquid-Phase Microextraction: A Simple, Low-Cost, and Environmentally Friendly Method for Speciation of Antimony in Water

A sensitive method is proposed to determine antimony species using vortex-assisted ionic liquid-based liquid-phase microextraction and digital imaging colorimetry. SbIII forms a ternary complex with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol, ascorbic acid, and iodide in an acid medium. The acceptor phase consists of the ionic liquid 1-butyl-3-methylimidazole hexafluorophosphate, dispersed in the aqueous solution with a vortex stirrer. After centrifugation, SbIII was determined directly in the rich phase. SbV can also be measured by converting to reduced species. The method presented a limit of detection of 1.4 and 4.2 μg L−1 and an enrichment factor of 360. The precision (relative standard deviation) of the method is 7.0%. The procedure was applied to the speciation of antimony in river water and mineral water samples. Some results were compared with those obtained by electrothermal atomic absorption spectrometry (ET AAS). The method is an attractive alternative for determining antimony species, considering the aspects of green analytical chemistry.

Organic Ion-Associate Phase Microextraction/Back-Microextraction for Preconcentration: Determination of Nickel in Environmental Water Using 2-Thenoyltrifluoroacetone via GF-AAS

An ion-associate phase (IAP) microextraction/ back-microextraction system was applied for the enrichment, separation, and detection of trace amounts of nickel from environmental water samples. Thenoyltrifluoroacetone (HTTA) acted not only as a chelating reagent for nickel, but also as a component of the extraction phase, i.e., IAP. Nickel in a 40 mL sample solution was pH-adjusted with phenolsulfonate (PS−) and tetramethylammonium hydroxide and converted by chelation reaction in the presence of thenoyltrifluoroacetonate (TTA−). When benzyldodecyldimethylammonium ion (C12BzDMA+) was added, a suspension of IAP formed in the solution. The IAP consisted of TTA−, a chelating reagent, the PS−, a component of pH buffer, and C12BzDMA+, which helps extract the chelating complex. When the solution was centrifuged, the IAP separated from the suspension and the nickel-TTA chelate was extracted into the bottom phase of the centrifuge tube. After the aqueous phase was taken away, 100 µL of nitric acid (2 M) solution containing phosphate was used to back-microextract nickel from the IAP. The acid phase was measured via graphite-furnace atomic-absorption spectrometry (GF-AAS). The proposed method facilitated a 400-fold enrichment. The limit of detection was 0.02 µg L−1. The proposed method was applied for the determination of nickel in river water and seawater samples.

Determination of plasma and erythrocyte levels of copper, magnesium and zinc by atomic absorption spectrometry in type-2 diabetes mellitus patients with metabolic syndrome.

Background and purpose:Imbalance in blood levels of trace elements is independent risk factor for metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM), and its complications. This study investigated plasma and erythrocyte levels of copper, magnesium, zinc, and their correlations with biochemical components of the MetS in T2DM patients compared to the healthy controls.Experimental approach:Forty men recently diagnosed T2DM with MetS without complications and thirty six age-matched healthy controls were enrolled in this cross-sectional study. Plasma and erythrocyte levels of selected elements were measured by graphite furnace atomic absorption spectroscopy.Findings/Results:The results of the present study showed significantly lower plasma levels of copper, magnesium, and zinc and lower erythrocytes copper in the patients’ group compared to the controls; while erythrocyte levels of magnesium and zinc were not significantly different between the two groups. Significant negative correlations were observed between plasma levels of copper with waist and hip circumferences, waist to hip ratio, systolic and diastolic blood pressures, fasting blood glucose, and glycated hemoglobin levels in all subjects; while erythrocyte copper levels showed significant negative correlation with triglyceride, and erythrocyte zinc was positively correlated with diastolic blood pressure and negatively with triglyceride.Conclusion and implications:Alterations of trace elements may have a significant role in the pathogenesis of MetS and T2DM patients. It is suggested that the body status of copper, magnesium, and zinc might be significantly correlated with components of MetS in T2DM patients; and plasma copper levels may be correlated with complications of type 2 diabetes mellitus.

Sequential and Simultaneous Determination of Cd, Fe and Ni in Toothpastes Employing Slurry Sampling High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry

Here is reported an analytical method for the multielemental determination of Cd, Fe and Ni in toothpaste employing slurry sampling high-resolution continuum source electrothermal atomic absorption spectrometry (HR-CS ET AAS). Using a single sample aliquot, Cd was determined at 228.802 nm, and, sequentially, Fe (232.036 nm) and Ni (232.003 nm) were simultaneously determined. Pyrolysis and atomization temperatures were 800 and 1500 °C for Cd, respectively. An atomization temperature of 2600 °C was used for Fe and Ni. A Pd and Mg mixture was used as the chemical modifier for standards and samples. The procedure for the slurry preparation was optimized using multivariate methodology with a multiple response function while employing a sample mass of about 250 mg. The optimized conditions were: 0.8 mol L−1 HNO3, 0.5% (m/v) Triton X-100 and a sonication time of 15 min. Using aqueous standards for the calibration, limits of detection and quantification were of 3.2 and 10.8 ng g−1 for Cd, 2.2 and 7.4 µg g−1 for Fe, and 0.044 and 0.148 µg g−1 for Ni. The precision estimated as relative standard deviation (n = 5) was 6.1% for Cd, 3.5% for Fe and 4.4% for Ni. The method accuracy was evaluated by standard addition and recovery tests and the recoveries varied from 93 to 114%. The method was applied for the analysis of five toothpaste samples of different brands. The concentrations ranged from 52.0 to 73.6 µg g−1 for Fe, and < 0.148 to 0.227 µg g−1 for Ni. For Cd, the concentrations were below the limit of detection.

Solid - phase extraction of Lead in saline matrix using by GF- AAS with multivariate optimization

This work presents a novel method investigated in the pre-concentration of lead ion as well as the matrix effect eliminated in high salinity medium using solid phase extraction by graphite furnace Atomic Absorption spectroscopy (GFAAS). Fe 3 O 4 -graphene was used as the sorbent while 1M HNO 3 was used as the extraction solvent. Parameters such as: pH, amount of sorbent, time of adsorption, time of desorption and, stirring rate affecting the extraction efficiency of the method were studied and optimized by utilizing two decent optimization methods; factorial design and central composite design (CCD). The limit of detection and limit of quantification were 4.4 and 14.8 ng/mL, respectively The accuracy of the method was evaluated by analyzing a spiked real sample. Good spiked recoveries over the range 98.8-103.6 % were obtained. Under the optimum conditions, the calibration graph was linear over the range 5-50 ng/mL. The relative standard deviation was 4.4 % for four repeated determinations at a concentration of 20 ng/mL.

Cadmium tissue level in women diagnosed with breast cancer – A case control study

Breast cancer is at the forefront of female malignancy and the leading cause of cancer death among women. Gender, age, hormone therapy, smoking, exposure to endocrine disruptors and family history are significant breast cancer risk factors according to epidemiological data. Considering metalloestrogenic Cd property and a plethora of research work on hormone involvement in breast cancer the study aimed to determine Cd concentration in three compartments of breast cancer patients in relation to their blood hormone status. Further, as oxidative stress is a critical mechanism of Cd toxicity, the objective of this study was to determine potential changes in oxidative status homeostasis.The study enrolled 55 patients with breast cancer diagnosis and 41 healthy women with benign breast changes. Concentration of Cd was determined using graphite furnace atomic absorption spectrometry.Cadmium concentration in tumor tissue was significantly higher than control and almost four times higher than Cd concentration in the healthy surrounding tissue. Strong positive correlation was observed between Cd concentrations in changed breast tissue and FSH and LH levels, while the correlation was negative with estradiol level. Cancer patients had significantly increased blood total antioxidative status while total oxidative status did not significantly differ between study groups. The study revealed Cd implication in breast cancer onset following a significant odd ratio for Cd levels in changed tissue samples. Moreover, presented data confirmed sex hormone and oxidative status imbalance caused by Cd presence, closely related to cancer development.

Assessment of heavy metal contamination in herbal medicinal products consumed in the Iranian market.

Herbal medicines have been reported to contain many contaminants that are potential harmful to health. These include heavy metals, such as lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg). Therefore, this study aimed to measure the levels of Pb, Cd, As, and Hg in several orally administered herbal products available in the Iranian market. Fifteen products labeled (A-O) of different brands from three different production batches (n = 45) were purchased from traditional herbal medicine factories in Iran. Each sample was digested with nitric acid by the wet digestion method, and the resultant solutions were used to determine the concentrations of Pb, Cd, As, and Hg. These measurements were performed using flame atomic absorption spectrometry, graphite furnace atomic absorption, or cold vapor atomic absorption. The lead, cadmium, arsenic, and mercury contents in the investigated samples did not show significant levels that may be associated with toxicity. All four metals were present at concentrations below the limits recommended by the WHO (World Health Organization), American Herbal Products Association (AHPA), and Canadian standard, but in several herbal products, the concentrations of these trace elements exceeded the Agency for Toxic Substances and Disease Registry (ATSDR). The concentrations of Pb, Cd, As, and Hg in commercially available herbal remedies were well below the acceptable intake recommended by global recommendations. Our findings revealed that at present, the amount of heavy metals in medicinal herbs processed at the level of supply by pharmacies licensed is favorable.

Determination Of Trace Cd And Pb In Edible Salt And Soy Sauce By ETAAS Using Fluorescent Carbon Nanoparticles (FCNs) As Matrix Modifier

Determination Of Trace Cd And Pb In Edible Salt And Soy Sauce By ETAAS Using Fluorescent Carbon Nanoparticles (FCNs) As Matrix Modifier

A survey of arsenic, mercury, cadmium, and lead residues in seafood (fish, crustaceans, and cephalopods) from the south-eastern Mediterranean Sea.

Seafood is capable of bioaccumulating heavy metals (HM), making it a potentially major dietary source of HM for humans. Presently, little data exists on seafood from the eastern-most boundary of the Mediterranean Sea. This study aims to provide exposure insight of the Israeli population to HM through the consumption of locally caught seafood by assessing the levels of arsenic, mercury, cadmium, and lead in raw tissues of seafood. A wide survey of local fisheries was conducted providing 296 samples from 11 different species, including seven fish, two crustacean, and two cephalopod species. Total arsenic, cadmium, and lead were analyzed by graphite-furnace atomic absorption. Total mercury was measured by cold-vapor mercury analyzer. Arsenic speciation was performed by anion chromatography-inductively coupled plasma sector field mass spectrometry. Results suggested that the total arsenic concentrations were significantly higher in crustaceans and cephalopods than fish. Arsenic speciation revealed two samples that exceed 1 mg/kg of inorganic arsenic, whereas methylated arsenic was below the detection limit. Elevated mercury levels were detected in the commercial benthic species Mullus barbatus (red mullet), cadmium was detected in one-third of the samples, and lead detected in eight samples. Comparing the results to health guidelines, 99.4% of seafood tested in this study abide with acceptable levels of heavy metals in seafood, as defined by both Israeli and European Union guidelines.

Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Based on Melting of the Donor Phase: a New Approach for the Determination of Trace Elements in Solid Samples

A novel ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) based on melting of the donor phase for the determination of Cd, Cu, and Fe in margarine samples using high-resolution continuum source electrothermal atomic absorption spectrometry (HR-CS ET AAS) is proposed. Considering that margarine is in the solid phase at room temperature, requiring heat for melting, the microextraction process was assisted by an ultrasonic bath to ensure the melting point of the samples and to increase the extraction efficiency of the analytes by UA-DLLME. After the extraction procedure, the aqueous phase was collected and directly introduced into a graphite furnace. The procedure was applied for extraction and multi-element determination, exploring the strategy of simultaneous and sequential determination of analytes by HR-CS ET AAS. A low volume of nitric acid solution in the presence of ethanol and hydrogen peroxide allowed the metals to be separated from the sample in an aqueous phase with subsequent determination by HR-CS ETAAS. In the extraction procedure, 5.0 g of each margarine sample was sonicated under heating in the presence of 100 μL of a solution containing HNO3 0.1 mol L−1, ethanol (95.1%, v v−1), and H2O2 3% (v v−1) in a volume proportion of 2:1:1. The influences of the time of extraction, temperature of extraction, and amplitude of sonication were examined, and the proposed conditions were as follows: extraction time, 10 min; temperature, 60 °C; and amplitude, 100%. Using 5 g of margarine sample, limits of detection of 0.03, 0.52, and 224 ng g−1 were obtained for Cd, Cu, and Fe, respectively. Recovery tests were performed, and the results ranged from 87 to 108% for Cd, 91 to 115% for Cu, and 85 to 112% for Fe. The results obtained by the proposed extraction procedure agreed with those obtained after wet digestion of the sample and determination by inductively coupled plasma optical emission spectrometry (ICP OES).

Use of ultrasound for cleaning of components of historical vehicles in Technical Museum in Brno

Abstract In the collections of Technical Museum in Brno, large number of historical vehicles is placed. During the operation, parts of their motors are being fouled. Frequently, they become even immobile (e. g. due to a fouled fuel system). In this case, the method using ultrasound with a suitable concentrate appears as the most suitable. In fact, ultrasound works also in inaccessible places with large efficiency. Not only the chosen solution influences the cleaning efficiency, but also parameters as time, bath temperature and ultrasound frequency. The cleaning process was evaluated according to the volume of removed dirt and by observing wettability change using the measuring of contact angle of a water drop. The ultrasound shock waves influence the surface to a certain extent also mechanically. That is why, the ultrasound effect on defects in the structure was observed. The aggressivity of cleaning concentrates was evaluated on the ground of determination of dissolved metals in the baths by ET AAS method.

Urinary arsenic is associated with wasting and underweight status in young children in rural Bangladesh

BackgroundDeficits in child growth are associated with poor cognitive outcomes and an increased risk for infection and mortality globally. One hundred forty million people are chronically exposed to arsenic from contaminated drinking water worldwide. While arsenic exposure has been associated with cognitive developmental delays in children, there is limited research on the association between arsenic exposure and growth deficits in young children. PurposeThe objective of this study was to assess the association between chronic arsenic exposure and deficits in growth among children under 5 years in a rural setting in Bangladesh. MethodsUrinary arsenic measurements were collected from 465 children between the ages of 28 days–59 months in rural Matlab, Bangladesh, and analyzed by graphite furnace atomic absorption. Height and weight measurements were collected from children according to World Health Organization child growth standards. A z-score cutoff2 standard deviations below the mean was used to define stunting (height-for-age z-score), underweight (weight-for-age z-score), and wasting (weight-for-height z-score). ResultsChildren under 5 years with urinary arsenic concentrations in the third tertile (greater than 31 μg per liter (μg/L)) had a two times higher odds of being underweight after adjustment for age, creatinine, paternal education, breastfeeding, number of individuals using the same sleeping room, and physician-diagnosed pneumonia (Odds Ratio (OR): 2.29 (95% Confidence Interval (CI): 1.16, 4.52)). Children under 2 years of age had a two times higher odds of being wasted after adjustment for age, creatinine, paternal education, breastfeeding, number of individuals using the same sleeping room, and physician-diagnosed pneumonia (OR: 2.85 (95% CI: 1.18, 6.89)). ConclusionsThese findings suggest that arsenic exposure is associated with an increased odds of being wasted and underweight among young children in rural Bangladesh.

Strontium and antimony serum levels in healthy individuals living in high- and low-risk areas of esophageal cancer.

BackgroundIt has been shown there is an upward trend for strontium (Sr) and antimony (Sb) levels from low‐risk (LR) to high‐risk (HR) areas of etiology of esophageal cancer in water, soil, and grains grown in Golestan province. In the present study, the serum levels of Sr and Sb were determined in healthy individuals living in these areas.MethodsThis cross‐sectional study was performed on fasting blood serum of adult healthy individuals collected by cluster sampling. Subjects were divided into two groups, those living in either HR or LR areas. Strontium and antimony serum levels were measured using a graphite furnace atomic absorption spectroscopy.ResultsA total of 200 volunteers were enrolled from which 96 persons (48%) and 104 persons (52%) were from either HR or LR areas, respectively. The sex distribution was 40.9% male and 59.1% female, and the average age of enrolled people was 50.9 years. The average strontium levels were 30.44 ± 4.05 and 30.29 ± 3.74 μg/L in LR and HR, respectively. It also has been shown the average antimony levels were 15.21 ± 3.40, 14.81 ± 3.17, 15.13 ± 3.62, and 15.07 ± 3.62 μg/L in LR, HR, urban, and rural populations, respectively.ConclusionThe serum levels of strontium and antimony were not significantly different in healthy adults living in high‐ and low‐risk areas of esophageal cancer. However, the average antimony serum levels in Golestan Province were above the reference interval in different countries.

Organic Ion-associate Phase Extraction/Back-microextraction for the Preconcentration and Determination of Lithium Using 2,2,6,6-Tetramethyl-3,5-heptanedione by Liquid Electrode Plasma Atomic Emission Spectrometry and GF-AAS in Environmental Water.

We developed an ion-associate phase (IAP)-extraction/acid back-extraction system for the preconcentration and atomic spectrometric determination of lithium trace amounts in water. The chelating reagent for lithium also works as a constituent of the extraction phase. The lithium in a 10 mL sample solution was converted through a chelate complex reaction with 2,2,6,6-tetramethyl-3,5-heptanedione (HDPM). The addition of a benzyldimethyltetradecylammonium ion caused the formation of IAP suspension in the solution. Centrifugation of the solution led to the isolation of a liquid organic phase and the lithium complex was extracted as the upper phase from the centrifuge tube. After the aqueous phase was removed, lithium was back-extracted with a 400 μL nitric acid solution from the IAP. The acid phase was measured using liquid-electrode-plasma atomic-emission-spectrometry (LEP-AES) or graphite-furnace atomic-absorption spectroscopy (GF-AAS). The detection limits were 0.02 mg/L for LEP-AES and 0.02 μg/L for GF-AAS. This system was applied to the determination of environmental water. The HDPM in the organic phase was reusable.