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In this study, a simple, fast and eco-friendly ultrasound-assisted-cloud point extraction method for extraction and pre-concentration of zinc, nickel and cobalt from vegetables and foods prior to their determination by flame atomic absorption spectrometry (FAAS) was proposed. Ultrasound energy was used to shorten extraction time and reduce steps needed or to improve selectivity. The method is based on complex formation of metal ions with carmine in presence of cationic surfactant at pH 5.0, and then extraction of their hydrophobic complexes into the micellar phase of Igepal CO-630 as extractant. After optimisation, calibration curves for Zn, Co and Ni were linear in the range of 2-120, 2-220 and 2-180 μg kg−1, respectively. Limits of detection, which is described as ratio of 3×standard deviation of 12 replicate measurements of blank analysis to slope of calibration curves, were 0.5, 0.6 and 0.6 μg kg−1 for Zn, Ni and Co, respectively. Relative standard deviations (RSDs%, n: 5) for 25 μg kg−1 of each analyte were less than 3.1%. The recovery rate was higher than 94% with a lower RSD than 3.1% for five replicate measurements of 25 μg kg−1 of each analyte. The accuracy was verified using two different standard reference materials (SRM 1570a-Trace elements in spinach leaves and SRM 1548a-Typical diet), and the results were in good agreement with the certified values. The method was applied to the determinations of Zn, Ni and Co in vegetables and foods by FAAS. [ABSTRACT FROM AUTHOR]

In this work, a new polymer resin with a functional groups capable of holding trace metals has been synthesized. The structure of polymer resin has been examined by BET-N2 method analyzer, IR spectrometer, scanning electron microscope (SEM) and elemental microanalyser. The synthesized polymer resin was used for the simultaneous separation and preconcentration of the trace metals from various tea and herbal plants samples. After extraction process, flame atomic absorption spectrometry (FAAS) was used to determine the trace metals. The analytical parameters and solid phase extraction (SPE) performance such as pH, sample volume, flow rates of sample, flow rates of eluent, concentration, volume and type of eluent and effect of interference ions, were investigated. The limits of detection (DL) of the SPE procedure for trace metals, were calculated to be (3s) in the range of 0.9−4.0 μg L−1 (n = 21) and the factors of preconcentration (PF) were obtained at 200 for Cd, Co, Cu, Fe, Ni and Zn, and at 50 for Cr, Mn and Pb ions and the relative standard deviation (RSD) at ≤ 2% (n = 11). [ABSTRACT FROM AUTHOR]

In this work, a polyurethane foam (PUF) functionalized with phenylfluorone (PUF-PF) was packed in a minicolumn and used as an on-line preconcentration system for cadmium and copper determination in water samples. The experimental conditions (both chemical and physical) were optimized to achieve the highest sensitivity. A study of possible ion interference on the retention of cadmium and copper was also performed. The enrichment factors obtained were 14 and 16 for copper and cadmium, respectively, using a preconcentration time of 1 min. The proposed system allowed the determination of metals with limits of detection (3 σ ) of 0.8 and 0.3 μg L − 1 for Cu(II) and Cd(II), respectively. The precision of the procedures was also calculated as 7.6% for Cu(II) (at 25 μg L − 1 ) and 4.0% for Cd(II) (at 10 μg L − 1 ). The limits of quantification obtained were 2.6 and 0.8 μg L − 1 for Cu(II) and Cd(II), respectively. Cadmium and copper contents in water samples (from rivers and swimming pools) were determined by applying the proposed procedure. In these samples, recovery tests were conducted in order to evaluate the accuracy of the method; the recovery percentages varied between 83 and 109%. [ABSTRACT FROM AUTHOR]

In this study, dispersive liquid-liquid microextraction was systematically optimized for the preconcentration of nickel after forming a complex with diphenylcarbazone. The measurement output of the flame atomic absorption spectrometer was further enhanced by fitting a custom-cut slotted quartz tube to the flame burner head. The extraction method increased the amount of nickel reaching the flame and the slotted quartz tube increased the residence time of nickel atoms in the flame to record higher absorbance. Two methods combined to give about 90 fold enhancement in sensitivity over the conventional flame atomic absorption spectrometry. The optimized method was applicable over a wide linear concentration range, and it gave a detection limit of 2.1 µg L−1. Low relative standard deviations at the lowest concentration in the linear calibration plot indicated high precision for both extraction process and instrumental measurements. A coal fly ash standard reference material (SRM 1633c) was used to determine the accuracy of the method, and experimented results were compatible with the certified value. Spiked recovery tests were also used to validate the applicability of the method. [ABSTRACT FROM AUTHOR]

3-(chloro(2-methyl-1H-indol-3-yl)methyl)-2-methyl-1H-indole (MIMI) was chosen for separation and preconcentration of iron (III), copper (II), and zinc by solid-phase extraction (SPE). Ion-MIMI chelates are adsorbed onto synthesized graphene oxide (GO) as adsorbent, eluted with HNO3 and determined by flame atomic absorption spectrometry (FAAS). The adsorption mechanism of titled metal complexes on GO was investigated by using computational chemistry approach based on PM7 semi-empirical potential energy surface. The influences of analytical parameters were investigated. The interference effect of common cations tested did not interfere with the recovery of understudied ions. The preconcentration factor of 312.5 and the detection limits of 0.62, 0.28, and 0.05 ng mL−1 for iron (III), copper (II), and zinc, respectively, were obtained. The developed SPE method was successfully utilized for the determination of trace metal ions in different certified reference materials and real samples (including water, cheese, honey, tomato, leaves of spinach, and milk) by FAAS. [ABSTRACT FROM AUTHOR]

Lead is a toxic metal which affects human health badly due to its high toxicity. The wide application range of lead causes environmental contamination of air, water and soil. Flame atomic absorption spectrometry is one of the simple and economical instrument used for the determination of heavy metals, but it has low sensitivity due to low sample introduction efficiency. In this study, a sensitive analytical method was developed by using T-shaped slotted quartz tube as an atom trap unit to get lower detection limit for lead. The trapped atoms were released using hydrogen gas which supplies reducing environment in T-SQT-AT-FAAS system. Factors such as trapping period, sample and fuel flow rates were optimized to obtain high sensitivity. Under the optimum conditions, limits of detection and quantitation were found to be 0.6 and 2.1 μg L − 1 , respectively. Accuracy of the developed method was checked and results found under the optimum conditions agreed with the certified value of coal fly ash standard reference material. The developed method was applied to water samples to figure out its suitability. [ABSTRACT FROM AUTHOR]

Firstly, poly[phenyl thiadiazole methacrylamide-co-divinylbenzene-co-2-acrylamido-2-methylpropane sulfonic acid] (PTMAAm-co-DVB-co-AMPS), a new polymer resin was synthesized. This polymer resin was characterized by elemental analyzer, X-ray diffractometer, scanning electron microscope (SEM) and IR spectrometer. The glass column packed with the synthesized polymer resin was used for solid phase extraction (SPE). At the same time, the analytes were separated and preconcentrated from various water, dried vegetables samples and standard reference material (CRM) with SPE and determined by flame atomic absorption spectrometer (FAAS). The experimental conditions of this method such as pH, flow rates of sample, flow rates of eluent, type / concentration / volume of eluent, sample volume and matrix ions were examined. The limits of detection (µg L−1) were calculated (3s) 0.9 for Mn(II), 1.4 for Cd(II), Co(II) and Zn(II), 1.5 for Cr(III), 2.2. for Cu(II), 1.9 for Pb(II),1.5 for Ni(II) and 1.9 for Fe(III) (n= 21). The low relative standard deviation, ≤ 2% (n= 11) and preconcentration factor as 75 for analytes were obtained. [ABSTRACT FROM PUBLISHER]

A solid phase extraction method is established for preconcentration of nickel, lead, cadmium, copper and cobalt using pipette tip solid phase extraction. The presented process was dependent on chelation of analytes with 1,3,4-thiadiazole-2,5-dithiol, then allowing the solution to flow through an activated carbon cloth packed pipette tip. The adsorbed metal chelates on the surface of activated carbon cloth were eluted by 5 mL of 3 M HNO3. The concentrations of nickel, lead, cadmium, copper and cobalt were detected using a flame atomic absorption spectrometer (FAAS). The pipette tip solid phase extraction exhibit a preconcentration factor of 120. The limit of detection values were 2.7, 1.7, 1.3, 2.0 and 2.9 µg L−1 for Ni(II), Pb(II), Cd(II), Cu(II) and Co(II), respectively. Validation of the method was checked by the analysis of TMDA-53.3 and TMDA-64.2 certified reference materials. The method was successfully applied for water and fertiliser samples. [ABSTRACT FROM AUTHOR]

The mineral profile was determined from commercial potato flour (Solanum tuberosum var. granola) and native potato flour samples (Solanum tuberosum var. arbolona negra and S. tuberosum var.arbolona rosada) collected in the town of Gavidia, Mérida state, Venezuela. Flame atomic absorption spectroscopy (FAAS) was used to determine Na, K, Mg, Ca Fe, Mn and Zn, while Cu was determined by using electrothermal atomic absorption spectroscopy (ETAAS). Three combinations of reagents for the digestion of potato flour (HNO3, HNO3/H2SO4 and HNO3/H2O2) were tested, being the mixture of HNO3/H2O2 the most suitable, achieving quantitative recovery (96 to 106 %) of the analytes. Additionally, a colorimetric method was used to determine the P content by visible molecular absorption spectroscopy. One-way analysis of variance (ANOVA) was used to compare the mean values of the concentrations of the elements in the analyzed samples (GP, BTAN, IPAN, BTAR, RHAN), where the factor was the potato variety. Significant differences between the values of the concentrations of K, Na, Ca, Cu and P in the native potatoes and the concentrations in the commercial variety Granola were observed, while, for some samples, non-significant differences between the concentrations of Mg, Fe, Zn and Mn in the native potato and the commercial variety Granola were observed. It is expected that once these genetically improved potatoes are incorporated into plots with well fertilized soils, they will be able to express their full potential in terms of chemical composition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Determination of Cd2+ contents in sediments, tobaccos and mushrooms by FAAS. • High repeatable microextraction values by automated syringe discharge system. • Hydrophobic immiscible chelating fluid (HICF) based micro-extraction of Cd2+. • Selective, extraordinary and superior approach for micro-extraction of Cd2+. • Simultaneous chelation, micro-extraction and masking with only one fluid. The novel, extraordinary and highly selective separation and preconcentration approach based on hydrophobic immiscible chelating fluid (HICF) having superior features (simultaneous chelation, extraction and masking) and combined with automatized syringe discharge system by peristaltic pump was established firstly for simultaneous chelation and micro-extraction of Cd2+. Mixture of tetra butyl ammonium iodide, tetra butyl ammonium fluoride, n-pentanol (1:1:10) and dithizone were used to formulate HICF. The parameters including pH, chelator concentration on both characteristic of HICF and extraction of Cd2+, time of vortex mixing, amount of HICF and sample volume were optimized and investigated in detail. The optimized method has permitted to obtain 25 preconcentration factor (PF) and detect the lowest cadmium concentration having 2.1 µg L−1 (LOD) in the aqueous solution. Interference effect of defiant metal cations was investigated in detail. The dynamic range of the method (LDR) was obtained linearly between 7.2 and 1500 µg L−1. Relative standard deviations (% RSD) were below than % 4.2 throughout the experiments. The envisaged possible extraction mechanisms were explained. The proposed novel method was validated with applications of multiple analyte-addition recovery tests in water samples (tap, lake and natural spring water) and analysis of standard reference material (UME EnvCRM 03 Elements in Soil). Quantitative satisfactory recovery values changing between 98 and 106 % were obtained. Validated method was also applied to determine Cd contents of sediment, mushroom and raw tobacco samples. The main advantage of HICF is that it contains masking and chelating agents and extraction solvent in only one liquid. Therefore, possible concentration and volume errors were minimized by single micropipette injection that ensured time saving and simplicity for applicability of the method by the analysts. Moreover, automated syringe discharge system has provided repeatable and precision extraction results. [ABSTRACT FROM AUTHOR]

• Glycogen metabolism was mainly affected by Karlodinium veneficum. • FAAs content decreased in clam feeding on Karlodinium. • Anabolic metabolism of carnosine was initiated by feeding on Karlodinium. • K. veneficum affect the production of endogenous C 18 PUFA precursors. • VOCs composition differed by feeding different microalgae. • High density of Karlodinium affected the taste and odor. Phytoplankton composition is an important factor affecting the growth and physiological biochemical characteristics of filter-feeding bivalves. With the increasing trend in dinoflagellate biomass and blooms in mariculture areas, how the physio-biochemical traits and seafood quality of the mariculture organism are affected by the dinoflagellates, especially those at nonfatal levels, is not well understood. Different densities of two Karlodinium species, namely K. veneficum (KV) and K. zhouanum (KZ), mixed with high quality microalgal food Isochrysis galbana was applied in feeding manila clam Ruditapes philippinarum in a 14-day temporary culture, to comparatively study how the critical biochemical metabolites such as glycogen, free amino acids (FAAs), fatty acids (FAs), volatile organic compounds (VOCs) in the clam were affected. The survival rate of the clam showed dinoflagellate density and species specificity. The high-density KV group inhibited survival to 32% lower than that of the pure I. galbana control, respectively, while KZ at low concentrations did not significantly affect the survival compared with the control. In the high-density KV group, the glycogen and FAA contents decreased (p < 0.05), indicating that energy and protein metabolism were significantly affected. Amount of carnosine (49.91 ± 14.64 to 84.74 ± 8.59 μg/g of muscle wet weight) was detected in all the dinoflagellate-mixed groups, while it was not present in the field samples or in the pure I. galbana control, showing that carnosine participated in the anti-stress activities when the clam was exposed to the dinoflagellates. The global composition of FAs did not significantly vary among the groups. However, contents of the endogenous C 18 PUFA precursors linoleic acid and α-linolenic acid significantly decreased in the high-density KV group compared to all the other groups, indicating that high density of KV affected the metabolisms of fatty acids. From the results of the changed VOC composition, oxidation of fatty acids and degradation of free amino acids might occur in the clams exposed to dinoflagellates. The increased VOCs, such as aldehydes, and decreased 1-octen-3-ol probably produced a more fishy taste and reduced food flavor quality when the clam was exposed to the dinoflagellates. This present study demonstrated that the biochemical metabolism and seafood qulity of the clam were affected. However, KZ with moderate density in the feed seemed to be beneficial in aquaculture for increasing the content of carnosine, a high-valued substance with multiple bioactivities. [ABSTRACT FROM AUTHOR]

In the world of cloud technologies, serverless computing has now settled as a stable and promising resident. This gives a cloud provider the flexibility to provide its users with both Platform-as-a-Service (PaaS), i.e., the back-end application runs in a dedicated container, or Function-as-a-Service (FaaS), i.e., the back-end logic is offered as elementary functions that are invoked by the client applications. In parallel, edge computing has attracted a significant interest, due its enticing promises of reducing the outbound traffic of telco operators, while at the same time cutting down the user latency. As a result, in the near future, PaaS and FaaS containers are going to cohabit in a versatile computation infrastructure spanning from the far edge up to the cloud. In this paper we propose a mathematical formulation of a resource allocation problem that optimizes the assignment of both types of containers and can be solved efficiently by an edge orchestrator. We evaluate the proposed solution via extensive simulation experiments, which show that our approach, which takes into account the characteristics of PaaS vs. FaaS, provides significant performance benefits compared to less sophisticated strategies, despite its relatively low run-time complexity. [ABSTRACT FROM AUTHOR]

A simple in situ solvent formation microextraction (ISFME) methodology based on the application of ionic liquid (IL) as an extractant solvent and sodium hexafluorophosphate (NaPF6) as an ion-pairing agent was proposed for the preconcentration of the trace levels of cobalt ions. In this method cobalt was complexed with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) and extracted into an ionic liquid phase. After phase separation, the enriched analyte in the final solution is determined by flame atomic absorption spectrometry (FAAS). Some effective factors that influence the microextraction efficiency were investigated and optimized. Under the optimum experimental conditions, the limit of detection and the enrichment factor were 0.97 μg L−1 and 50, respectively. The relative standard deviation (R.S.D.) was obtained as 2.4%. The proposed method was assessed through the analysis of certified reference water and recovery experiments.

A new, simple and cheap dispersive liquid-liquid microextraction (DLLME) procedure was optimized for the preconcentration of trace amounts of Ni(II) as a prior step to its determination by flame atomic absorption spectrometry (FAAS). It is based on the microextraction of nickel, where appropriate amounts of the extraction solvent (CHCl3), disperser solvent (ethanol) and chelating agent, name 5-[(Z)-isoxazol-3-yl-diazenyl]-2-methyl-quinolin-8-ol (MMD), were firstly synthesized/characterized and used. Various parameters that affect the extraction procedure such as pH, centrifugation rate and time, the chelating agent (MMD) concentration and sampling volume on the recovery of Ni(II) were investigated. The preconcentration of a 20 ml sample solution was thus enhanced by a factor of 80. The resulting calibration graph was linear in the range of 0.24-10 mg L−1 with a correlation coefficient of 0.9998. The limit of detection (3 s/b) obtained under optimal conditions was 1.00 μg L−1. The relative standard deviation for certified reference material determinations was 1.2%. The accuracy of the method was verified by the determination of Ni(II) in the certified reference material of wastewater (Waste water CWW TMD). The proposed procedure was successfully applied to the determination of Ni(II) in some fake jewelry and cosmetics samples. [ABSTRACT FROM AUTHOR]

A new unconventional room temperature ionic liquid, cetyl pyridinium naphthenate (CPN) was synthesized and was ascertained by IR, NMR and CHN analysis. Cloud point extraction of Cu(II) was carried out by using CPN for a synergistic enhancement effect. Triton X 100 was used as surfactant in cloud point extraction and cloud point temperature was 750 C. Quantification was carried out by FAAS. The mean recovery, enrichment factor, tolerance limit, RSD, LOD and LOQ were found to be 99.8%, 40, 1000 ppm, 0.15%, 27 ppt and 93 ppt respectively. Method was validated by analyzing natural water and blood samples. [ABSTRACT FROM AUTHOR]

The concentration of cadmium in human tissues obtained on the basis of autopsies of non-poisoned Polish people ( n = 150), aged from 1 to 80 years, examined between 1990 and 2010, is presented. The following values were found in wet digested samples by flame atomic absorption spectrometry (FAAS) (mean ± SD, median, and range, μg/g of wet weight): brain 0.020 ± 0.031, 0.084, 0-0.120 ( n = 41); stomach 0.148 ± 0.195, 0.084, 0-1.25 ( n = 89); small intestine 0.227 ± 0.231, 0.130, 0-0.830 ( n = 39); liver 1.54 ± 1.55, 1.01, 0.015-9.65 ( n = 99); kidney 16.0 ± 13.2, 14.0, 0.62-61.3 ( n = 91); lung 0.304 ± 0.414, 0.130, 0-1.90 ( n = 25); and heart 0.137 ± 0.107, 0.140, 0.017-0.250 ( n = 4). Additionally, results ( n = 13 people, aged from 2 to 83 years, 63 samples) obtained by inductively coupled plasma optical emission spectrometry (ICP OES) between 2010 and 2015 are given. The obtained data on Cd concentration in the human body can be used to estimate the amounts occurring in 'healthy' people and those occurring in cases of chronic or acute poisonings with Cd compounds, which are examined for forensic purposes or to assess environmental exposure levels. [ABSTRACT FROM AUTHOR]

BACKGROUND Apple is one of the staple fruits worldwide which are a good source of mineral nutrients. However, little is known about genetic variation for mineral nutrition in apple germplasm. In this study, the calcium and zinc contents in mature fruits of 378 apple cultivars and 39 wild relatives were assessed. Mineral concentrations were quantified using flame atomic absorption spectroscopy (FAAS). RESULTS Both calcium and zinc accumulation showed great variation among accessions tested. Overall, wild fruits were significantly richer in zinc than cultivated fruits, while the average concentration of calcium was similar between cultivated and wild fruits. The difference in zinc concentration between wild and cultivated fruits may be an indirect result of artificial selection on fruit characteristics during apple domestication. Moreover, calcium concentration in fruit showed a decreasing trend throughout fruit development of apple, while zinc concentration in fruit displayed a complex variation pattern in the late stages of fruit development. CONCLUSION The finding of a wild genetic variation for fruit calcium and zinc accumulation in apple germplasm could be helpful for future research on genetic dissection and improvement of calcium and zinc accumulation in apple fruit. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The obesity epidemic has turn into a major health threat worldwide and extensively responsible for the increased incidence of many diseases such as diabetes, cardiovascular disease and certain types of cancer. Excessive food intake along with the insufficient physical exercise is the basic impetus for this development. The aim of the present study is to evaluate the serum levels of leptin, zinc and tryptophan (TRP) in obese and non-obese subjects, which play major role in obesity. With the verbal and written consent eighty men were identified from the various areas of Karachi, Pakistan. The socio-demographic data including; age, body mass index (BMI), education and residence, of participants was collected. After providing informed consent, fasting blood samples were taken and serum was collected. The serum concentration of leptin, zinc and TRP were analyzed by ELISA (Enzyme-linked immunosorbent assay), FAAS (Flame atomic absorption spectrophotometer) and HPLC (High performance liquid chromatography) respectively. Results showed that levels of leptin were increased in obese than non-obese subjects significantly. On the other hand levels of zinc and TRP were significantly decreased in obese than non-obese subjects. Furthermore, there was a positive correlation found among leptin, zinc and TRP with obesity. Based on these facts the involvement of leptin, zinc and TRP with obesity will be discussed. [ABSTRACT FROM AUTHOR]

In the paper an application of solid phase extraction technique for speciation analysis of manganese in water samples with the use of flame atomic absorption spectrometry is presented. Two types of sorbents, activated silica gel and Dowex 1 × 4, were used respectively for simultaneously Mn 2 + and MnO 4 2 − retention and preconcentration. The whole procedure was realized in multicomutation flow system. Different conditions like: type and concentration of eluent, sample pH and loading time were tested during the study. Under appropriate conditions, it was possible to obtained enrichment factors of 20 and 16 for Mn(II) and Mn(VII), respectively. Precision of the procedure was close to 4% (measured as relative standard deviation), whereas the detection limit (3σ) was 1.4 μg·L − 1 for Mn(II) and 4.8 μg·L − 1 for Mn(VII). [ABSTRACT FROM AUTHOR]

The authors describe the synthesis of a nanosorbent for fast magnetic solid phase extraction of trace levels of Ag(I), Au(III), Pd(II) and Pt(II). It consists of graphene oxide sheets modified with magnetite nanoparticles (mGO) coated with silica. This material was further modified with a polypyrrole-polythiophene copolymer via oxidative polymerization to end up with a material of the type mGO@SiO@PPy-PTh. Successful synthesis of the nanocomposite and its components was corroborated by FT-IR, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry and thermogravimetric analysis. The presence of nitrogen- and sulfur-containing functional groups on both sides of the nanocomposite sheets facilitates the formation of strong complexes between target (i.e. noble metal ions) and the surface of the sorbent. Following elution with thiourea-HCl, the ions were quantified by FAAS. Under optimized conditions, the lower limits of detection range from 0.1 to 1.0 μg L. The maximum sorption capacities are 49, 50, 45, and 50 mg g for Ag(I), Au(III), Pd(II) and Pt(II), respectively. The method was successfully applied to the extraction and determination of the analytes in wastewater (electroplating, radiological and photographical wastewater), sea water, and road dust. [ABSTRACT FROM AUTHOR]

Wheat flour is the most widely produced cereal in the world, most of which is destined for human consumption. In different countries, wheat flour is generally fortified with vitamins such as, B complex, A, D and etc. In some countries iron, zinc and copper are added to wheat flour in direct and indirect ways. The bread produced from wheat flour has major role in Iranian food basket. Thus, adding micronutrients to the bread assists to improve the health of community. In this study, iron, zinc and copper contents in wheat flour samples have been determined by Flame Atomic Absorption Spectrometry (FAAS) technique. In order to measure the mentioned elements in flour, 40 samples have been collected in Ahvaz City (Khouzestan, Iran). Sample preparation and determination of these elements were performed according to AOAC 999.11 standard method. Mean levels of iron, zinc and copper in samples were 105.65, 14.08 and 6.62 mg Kg-1, respectively. In order to study the reliability of the method, 6 samples were randomly selected. Certain quantities of the elements were spiked into the wheat flour samples. Recoveries of the samples were between 96.6-104.4 %. [ABSTRACT FROM AUTHOR]

A new approach to the analysis of Cu, Fe, Mn and Zn in flaxseed was developed based on infrared-assisted acid digestion. Quantitation by flame atomic absorption spectrometry yields results in agreement with those arising from aggressive total decomposition using conventional microwave-assisted (MW) digestions. A full factorial design in two levels was applied to evaluate the impact of significant variables for all elements to determine optimal experimental conditions. A desirability function revealed these to be: 2.0 g sample mass, 8 mL of HNO 3 and 8 min of heating time in the IR system. Precision better than 10% (RSD) was obtained, superior to that of a combined IR-MW approach. Sample preparation based on IR-assisted digestion provides a rapid and inexpensive alternative to other conventional techniques for the analysis of complex samples and is able to accommodate relatively large masses of sample, alleviating potential homogeneity issues as well as enhancing detection power. [ABSTRACT FROM AUTHOR]

The soluble forms of aluminum are now considered toxic or potentially toxic and they have been associated or related with neurological alterations, liver, bone, hematological disorders and breast cancer. To estimate the expanded uncertainty of a previously validated analytical method to quantify aluminum in tissues of Sprague Dawley rats through flame atomic absorption spectroscopy (FAAS) and electrothermal (ETAAS). The sources of uncertainty through an Ishikawa diagram have been established and the relative and combined standard uncertainty of the concentration of aluminum was determined from the curves of calibration, volumetric material and the dilution factor, repeatability, the purity of a standard aluminium and the concentration of aluminium in two certified reference materials (SRM-S-B and NIST 1566b). The estimates of each source of uncertainty were determined following the Eurachem/Citac Guide. It was possible to estimate the expanded uncertainty ( U) with a factor k = 2, and the results were of 3.709 mgL and 3.717 µgL of aluminium in tissues of Sprague Dawley rats with FAAS and ETAAS, respectively. There are few works in which the expanded uncertainty of an analytical method has been found to determine aluminum in tissue, however the results are acceptable and comparable against the results obtained with other methods that estimate the uncertainty of other metals and different matrix or tissue. [ABSTRACT FROM AUTHOR]

A preconcentration procedure has been developed by using a thiocarbohydrazide derivative (1,5-bis(phenylthiocarbamoyl) thiocarbohydrazide) as a novel sorbent. The ligand was synthesized and used for preconcentration of Cu(II), Ni(II), Pb(II), and Cd(II) ions from water samples by batch and column procedures to enrich metal concentrations appropriate for flame atomic absorption spectrophotometry (FAAS). The optimum pHs for effective solid-phase extractions were 5 and 7 for Cu(II), and Ni(II), Pb(II) and Cd(II) adsorptions, respectively. The method detection limits 0.73, 0.05, 1.14 and 0.04 ng mL-1; the method determination limits 2.4, 0.15, 3.76 and 0.13 ng mL-1 and the enrichment factors 30, 65, 26 and 50 were found for Cu(II), Ni(II), Pb(II) and Cd(II), respectively. The sorption and desorption yields and overall recoveries of metals were almost quantitative except Pb(II) of which sorption yield was around 72% with relative standard deviation value around 1.8%. Langmuir, Freundlich and Temkin models were examined for the metal adsorptions. The Langmuir isotherm model provided a better fit with high correlation coefficients. Regarding the Langmuir parameters, the maximal adsorption capacities on 1,5-bis(phenylthiocarbamoyl) thiocarbohydrazide were 18.25, 7.99, 13.26 and 12.96 mg g-1 for Cu(II), Ni(II), Pb(II) and Cd(II), respectively. The adsorption kinetics for the adsorptions of metals were studied by using linear forms of pseudo-first-order and pseudo-second-order kinetic models. Pseudo-second-order kinetic model fitted very well. The developed method has been successfully applied to the preconcentration of Cu(II), Ni(II), Pb(II) and Cd(II) in water samples (tap water, seawater and mineral water samples), and satisfactory and reproducible results were obtained in FAAS analysis. [ABSTRACT FROM AUTHOR]

A solid phase extraction method based on the immobilisation of Penicillium chrysogenum on silica was developed for preconcentration and flame atomic absorption spectrometric determination of Pb(II). The immobilised sorbent was packed in a column to optimise the conditions for its quantitative sorption and desorption. Various parameters such as pH, type of eluent, sample and eluent flow rate and influence of others ions were systematically studied. Pb(II) was quantitatively sorbed at pH 4.0 at a flow rate of 2.0 mL min and eluted with 10.0 mL of 1.0 M HCl at 0.2 mL min flow rate. The devised procedure applied for Pb determination in tap water, an industrial effluent and sludge sample, black tea, spinach leaves and green beans (canned food) was reproducible, with a relative standard deviation of 0.8%. The method was validated by a BCR 701 standard lake sediment sample. The limit of detection and limit of quantification for Pb(II) were 7.16 and 23.88 μg L, respectively, with an enrichment factor of 100. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the elemental composition of black tea samples and their infusions in view of their geographical origin. In total, 14 elements were analyzed, 13 (Ca, K, Mg, Na, Mn, Fe, Zn, Cu, Cr, Ni, Co, Cd, and Pb) by flame atomic absorption spectrometry, and P by UV-Vis spectrometry, after mineralization of samples. It was found that K was the most abundant macroelement in the analyzed samples, whereas among microelements, the highest concentration was found for Mn. Based on the obtained data, the percentage of elements leached into the infusions as well as the daily elemental intake from tea were calculated. The daily intake from tea was compared to the recommended daily allowances (RDAs), and the highest percentages of the RDAs were found for Mn (15 %) and Co (10 %). To study the relations between elemental composition and country of origin of samples, factor analysis and cluster analysis were applied. These multivariate techniques proved to be efficient tools able to differentiate samples according to their provenance as well as plantation within the common regions. [ABSTRACT FROM AUTHOR]

This study was performed to develop a sensitive analytical method for the determination of cadmium by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after dispersive liquid-liquid microextraction (DLLME). The parameters affecting the cadmium complex formation and its extraction output were optimized to obtain high extraction efficiency. These included the pH and amount of the buffer solution, and the concentration of the ligand. The DLLME method was comprehensively optimized based on the type and amount of extraction solvent, dispersive solvent and salt. The type and period of mixing needed for a more effective extraction was also investigated. In order to further improve the sensitivity for the determination of cadmium, the flame atomic absorption spectrometry was fitted with a slotted quartz tube to increase the residence time of cadmium atoms in the pathway of incident light from a hollow cathode lamp. The limits of detection and quantitation (LOD and LOQ) for the FAAS were found to be 42 and 140 μg L − 1 , respectively. Under the optimum conditions, LOD and LOQ of the FAAS after DLLME were calculated as 1.3 and 4.4 μg L − 1 , respectively. Combining both optimized parameters of the DLLME and SQT-FAAS gave 0.5 and 1.5 μg L − 1 as LOD and LOQ, respectively. Accuracy of the method was also checked using a wastewater certified reference material (EU-L-2), and the result was in good agreement with the certified value. [ABSTRACT FROM AUTHOR]

In this study, the determination of Fe, Mn, and Zn by flame atomic absorption spectrometry (FAAS) was performed in nine bee pollen samples from different cities. The efficiency of acid digestion in bee pollen samples using nitric acid at different concentrations (3.5, 7.0, and 14.0 mol L) and hydrogen peroxide in a microwave oven was evaluated. The proposed procedure using nitric acid diluted to 3.5 mol L was effective for the digestion of all the pollen samples. The samples showed low levels of Fe. However, Mn and Zn were the elements which presented the highest concentrations in the samples. The bee pollen samples studied showed a great Mn and Zn contribution to the recommended daily intake (RDI) of the human diet, contributing with 71.7 and 15.1 %, respectively. The accuracy of the measurements by FAAS was evaluated by adding aliquots of the elements in the digestates. Recoveries obtained ranged from 89 to 106 % for Fe, 94 to 100 % for Mn, and 88 to 108 % for Zn. [ABSTRACT FROM AUTHOR]

The characterization of inorganic elements in the produced water (PW) samples is a difficult task because of the complexity of the matrix. This work deals with a study of a methodology for dissolved Fe quantification in PW from oil industry by flame atomic absorption spectrometry (FAAS) after cloud point extraction (CPE). The procedure is based on the CPE using PAN as complexing agent and Triton X-114 as surfactant. The best conditions for Fe extraction parameters were studied using a Box-Behnken design. The proposed method presented a LOQ of 0.010 μg mL − 1 and LOD of 0.003 μg mL − 1 . The precision of the method was evaluated in terms of repeatability, obtaining a coefficient of variation of 2.54%. The accuracy of the method was assessed by recovery experiments of Fe spiked that presented recovery of 103.28%. The method was applied with satisfactory performance to determine Fe by FAAS in PW samples. [ABSTRACT FROM AUTHOR]

In this study, a miniaturized liquid-liquid extraction (LLE) method for pre-concentration of Na, K, Ca, and Mg in crude oil was proposed. Analytes in crude oil were quantitatively extracted to the aqueous phase, followed by flame atomic absorption spectrometry (FAAS) determination. The following parameters were evaluated: type of extraction solution, sample mass, heating temperature and time, stirring time, centrifugation time, and the use of toluene and chemical demulsifier. Accuracy was evaluated by comparing the results obtained by the proposed method (LLE-FAAS) with those obtained after high-pressure microwave-assisted wet digestion and FAAS determination (reference values). No statistical difference was observed between the reference values and those using the optimized conditions for LLE-FAAS: 2.5 g of sample; 1000 μL of 2 mol L−1 HNO 3 , 50 mg L−1 of chemical demulsifier in 500 μL of toluene, 10 min of heating at 80 °C, 60 s of stirring, and 10 min of centrifugation. Relative standard deviations were lower than 6%. The limits of quantification (LOQ) were 1.2, 1.5, 5.0, and 0.50 μg g−1 for Na, K, Ca, and Mg, respectively. The proposed miniaturized LLE method presents several advantages, such as ease-of-use, high throughput (up 10 samples can be processed per 1 h), uses a high sample mass reaching low LOQs. In addition, the use of a diluted solution for extraction reduces the amount of reagents (around 40 times) and consequently laboratory residue generation, becoming an environmental friendly method. Suitable LOQs were achieved for analyte determination at low concentration even using a simple and low-cost sample preparation system (miniaturized LLE method) and a relatively low-cost determination technique (FAAS), avoiding the use of microwave ovens and more sensitivity techniques, which are required for routine analyses. [Display omitted] • Miniaturized LLE method was applied for crude oil samples. • Determination of Ca, K, Mg, and Na was performed by FAAS. • Only diluted acid was used as extraction solution. • Suitable LOQs were achieved to analyte determination at low concentration. [ABSTRACT FROM AUTHOR]

Metals are persistent in the environment and can cause bioaccumulation in the food chain, and contamination of agricultural soils is a growing concern due to food safety concerns and potential health risks. Plants accumulate metals from multiple sources, but soil plays a major role. This study aimed to determine the levels of metals including Mn, Fe, Co, Ni, Cu, Zn, Cr, Cd, and Pb in lupine and agricultural soil in four districts from South Gondar Zone with flame atomic absorption spectroscopy (FAAS). The levels of Mn (292–309 mg/kg), Co (44.5–48 mg/kg), Fe (148–155 mg/kg), and Zn (92.5–98.8 mg/kg) in lupine were below the World Health Organization (WHO) maximum allowable limits, but the concentrations of Ni (68.5–73.4 mg/kg), Cu (85.4–92.2 mg/kg), Cr (36.6–39.9 mg/kg), Cd (9.23–10.5 mg/kg), and Pb (12.2–12.7 mg/kg) exceeded the recommended WHO allowable limits in legumes and thus, need attention from concerned bodies. Besides, the concentrations of Co, Ni, Cu, and Cd in soil samples were above the maximum permissible limits set by WHO. Bioaccumulation Factor (BAF) of lupine at both study sites were less than one for all metals and the metal accumulation index (MAI) values of Fe and Mn were relatively higher than other metals. Therefore, the relatively low BAF values (<1) indicated that lupine has less capability of accumulating these metals from the soil. • Lupine and soil samples were collected and then digested. • Among analyzed metals in lupine samples, Ni, Cu, Cr, Cd and Pb in were found above FAO/WHO recommended level. • Bioaccumulation Factor (BAF) were found in the range of 0.460–0.824. • Good positive correlations between most metals were obtained. [ABSTRACT FROM AUTHOR]

The present study reports the contents of macroelements such as calcium, magnesium, potassium, and sodium in tropical fruits samples from Solomon Islands. The fruit samples were analyzed using flame atomic absorption spectrometer. The method used was validated by analyzing standard reference material of Blueberry fruit (NIST-SRM3287). The macroelemental concentrations in fruits revealed the highest content of K (480 ± 13 mg/100 g) in breadfruit while the maximum concentrations of Ca (41.9 ± 2.0 mg/100 g) and Mg (150 ± 8 mg/100 g) were found in cutnut. Banana exhibited the highest concentration of Na as 14.7 ± 0.6 mg/100 g. Potassium showed dominance while Na showed the least concentration in the studied fruits except for starfruit which had Ca as the least concentrated element. The estimated recommended dietary allowance (RDA) coverage for macroelements in fruits showed the highest percentage covering for children followed by adolescents and adults, in respective ranges of 0.173–188, 0.138–71.4 and 0.173–48.4% RDA. The individual macroelements RDA coverage for children, adolescents and adults were estimated to be K (3.87–16.0, 3.13–10.7 and 3.00–10.2% RDA), Ca (0.393–5.99, 0.302–3.22 and 0.330–4.19% RDA) and Na (0.173–1.47, 0.138–0.980 and 0.138–1.23% RDA), respectively. Based on the estimated percentage RDA coverage, the studied fruits have been classified as sources and rich sources of different macroelements for children, adolescents and adult diets. • This is the first report on macroelements composition in tropical fruits. • Na, Mg, K & Ca in the fruits determined and K content is the highest in breadfruit. • The recommended dietary allowance (RDA) % coverage of macroelements is estimated. • RDA coverage of macroelements is high for children than adolescents & adults. • RDA coverage allowed to classify fruits as sources or rich sources of macroelements. [ABSTRACT FROM AUTHOR]

A magnetic MWCNTs@MgAl 2 O 4 @TiO 2 novel nanocomposite was synthesized using the sol-gel method. The characterization of synthesized nanocomposite was done using FTIR, XRD, and SEM techniques. The adsorbent was used for dispersive solid-phase extraction of Pb(II). The analytical parameters that affect the extraction recovery of the analyte were optimized, involving the pH, adsorbent amount, sample volume, and interfering ions. The figures of merit such as preconcentration factor (PF), the limit of detection (LOD), the limit of quantification (LOQ), correlation coefficient (R2) and relative standard deviation (RSD) of Pb(II) are 100, 0.42 μg L−1, 1.39 μg L−1, 0.996 % and 4.1 % respectively. TMDA 64.3 fortified lake water and NCS DC 73349 bush, branches and leaves certified reference materials were used to validate the presented procedure. The synthesized adsorbent was used for separation-preconcentration and determination Pb(II) from water and food samples prior to its determination by FAAS. [Display omitted] • A novel adsorbent (magnetic MWCNTs@MgAl 2 O 4 @TiO 2) was successfully synthesized. • Solid phase extraction of lead was performed by using novel adsorbent. • Pb was analyzed at low LOD levels via FAAS, independent of the effect of the foreign ions. • Pb was successfully preconcentrated-separated and determined in food samples using this method. [ABSTRACT FROM AUTHOR]