Analysis of Tea for Metals by Flame and Graphite Furnace Atomic Absorption Spectrometry with Multivariate Analysis

The concentrations of iron, zinc, manganese, copper, chromium, nickel, lead, arsenic, and cadmium were determined using flame and graphite furnace atomic absorption spectrometry in nine herbal tea samples. Hawthorn, yarrow, elderflower, and bearberry are herbal teas for which the metal content has been rarely determined. The concentration of cadmium in St John’s wort exceeded the maximum permissible limit of 0.3?mg/kg. The metals were also determined in aqueous extracts following 5, 10, and 20?min of boiling and using different preparations, including acidification with lemon juice. The influence of these factors on metal release was demonstrated using multivariate analyses by redundancy analysis and principal component analysis. The metal release was not considerably affected by the boiling time, while the acidity of the medium was generally positively correlated. For the infusions, arsenic was detected only in acidified mint tea. The extraction efficiencies of metals were determined and classified as highly, moderately, and poorly extractable, with chromium showing largest variations.     

Determination of Lead,Cadmium and Mercury in Surface Marine Sediments and Mussels

Abstract

Lead, cadmium and mercury were determined in sediments and mussels, and the ability of these indicators to record metal variations in coastal marine environment is described in this work. The results of an extended investigation of the status of three gulfs at Northern Greece are given, regarding the content of these metals in surface sediments and Mytilus galloprovincialis. The samples were collected during a four-year period. The total concentration of the above heavy metals was determined after digestion of the samples by suitable mixtures of acids, including nitric, perchloric and hydrofluoric acid. The digestion was carried out in a steel pressurised bomb with closed teflon vessels. Lead and cadmium were determined by means of electrothermal atomic absorption spectrometry (ETAAS), and mercury by cold vapour atomic absorption spectrometry (CVAAS). The results were statistically evaluated by analysis of variance, and emphasis was given to annual, seasonal and spatial sources of variation. The annual changes during the last four years and the spatial distribution of heavy metals load is also discussed.     

萃取液浓度对火焰原子吸收光谱法测定日用陶瓷铅、镉溶出量的影响研究

采用火焰原子吸收光谱法测定日用陶瓷的铅、镉溶出量和标准曲线,通过对不同浓度的萃取液及其稀释液在各自相应的标准曲线条件下进行重金属溶出量检测,运用单因素多水平方差分析法(F检验)验证结果数据的显著性差异水平,并依据Lambert-Beer定律研究差异形成原因.推导在置信度为95%的条件下,当样品中铅的质量浓度低于80.00 mg/L、镉的质量浓度低于1.000 mg/L时,原始样液与其稀释液的测定结果间无显著性差异.当样液中铅的质量浓度高于100.00 mg/L、镉的质量浓度高于1.000 mg/L时,原始样液与其稀释液测定结果之间的显著性差异程度将随重金属元素浓度升高而加大.     

Cloud point extraction for the determination of cadmium and lead employing sequential multi-element flame atomic absorption spectrometry

A cloud point extraction procedure for pre-concentration and determination of cadmium and lead in drinking water using sequential multi-element flame atomic absorption spectrometry is described. 4-(2-thiazolylazo)-orcinol (TAO) has been used as complexing agent and the micellar phase was obtained using the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) and centrifugation. The conditions for reaction and extraction (surfactant concentration, reagent concentration, effect of incubation time, etc) were studied and the analytical characteristics of the method were determined. The method allows the determination of cadmium and lead with quantification limits of 0.30?µg?L^?1 and 2.6?µg?L^?1, respectively. A precision expressed as relative standard deviation (RSD, n?=?10) of 2.3% and 2.6% has been obtained for cadmium concentrations of 10?µg?L^?1 and 30?µg?L^?1, respectively, and RSD of 1.3% and 1.7% for lead concentrations of 10?µg?L^?1 and 30?µg?L^?1, respectively. The accuracy was confirmed by analysis of a natural water certified reference material. The method has been applied for the determination of cadmium and lead in drinking water samples collected in the cities of Ilhéus and Itabuna, Brazil. Recovery tests have also been performed for some samples, and results varied from 96 to 105% for cadmium and 97 to 106% for lead. The cadmium and lead concentrations found in these samples were always lower than the permissible maximum levels stipulated by World Health Organization and the Brazilian Government.     

Determination of Tributyltin in Oysters by Electrothermal Atomic Absorption Spectrometry

Abstract

Graphite-furnace atomic absorption spectrometry for tributyltin in oysters is described. Tributyltin is extracted by n-hexane after digestion with hydrochloric acid. The 3[sgrave] detection limit for tributyltin is better than 0.01 mg Sn/kg. Typical absorbance values are about 0.10 for tributyltin contents as low as 0.03 mg Sn/kg. Tributyltin contents of 29 oyster samples are given.     

Elemental Analysis and Metal Intake of Romanian Vegetables

ABSTRACT

Inductively coupled plasma-mass spectrometry multielemental profiling was performed to determine eight elements in 54 vegetable samples. The range of concentrations of Fe and Ni was 1.91?±?0.09 to 443.31?±?22.32?mg/kg and 0.05?±?0.004 to 16.36?±?0.36?mg/kg, respectively. The concentrations of Pb and Cd were up to 1.56?±?0.04 and 0.78?±?0.04?mg/kg, respectively. Some samples exceeded the maximum admissible limits imposed by national and international regulations. The mean concentrations of Mn and Cu were between 20.93?±?0.43 and 13.98?±?0.30?mg/kg in tomatoes and 20.60?±?0.53 and 11.25?±?0.22?mg/kg in peppers. For the evaluation of health risk related to the consumption of vegetables, the daily intake rate, target hazard quotient (THQ), and hazard index were evaluated. The daily intakes were low and correspond to 2 to 14% of the tolerable daily values established by legislation. The results showed that the THQ and hazard index for the metals were lower than 1, indicating that the vegetable ingestion does not represent a significant risk for consumer health. Analysis of variance revealed that Zn may be used as a species-specific marker (p?=?0.026). Principal component analysis extracted three main components, explaining a total variance of 72.49% and grouped all determined elements.     

“浙八味”药材中重金属铅、镉、铜含量分析

为对"浙八味"药材质量控制和安全用药提供可靠的依据,采用灰化法处理样品,火焰原子吸收分光光度法测定了其铅、镉、铜含量。结果表明,8种药材中的铅含量为0.828 1~1.747 3 mg.kg-1,镉含量为0.116 9~0.295 0mg.kg-1,铜含量为2.519 5~8.286 4 mg.kg-1。8种药材均检出一定量的有害重金属,但含量较低,未超出国家限量标准,符合《药用植物及制剂进出口绿色行业标准》的有关规定。     

Determination of Copper,Cadmium, Zinc And Lead In ArgeŞ River In Romania During Four Seasons By Inductively Coupled Plasma Atomic Emission Spectrometry And Anodic Stripping Voltammetry

ABSTRACT

The paper represents a continued study of selected heavy metals concentration in the Arge? River, the fifth river in length from Romania.

For the determination of metal ion concentration in Arge? river was used Atomic Absorption Spectrometry for sodium, potassium and magnesium; Direct Coupled Plasma Atomic Emission Spectrometry for calcium; Inductively Coupled Plasma Atomic Emission Spectrometry for copper, cadmium, zinc, aluminium, lead, titanium, zirconium, chromium, molybdenum, manganese, iron and nickel.

Copper, cadmium, zinc and lead concentration were determined by ICP–AES and ASV and results were reliable.

By comparison of the results a good agreement between these two techniques is observed.     

Determination of Heavy Metals in Soil Extracts and Plant Tissues at Around of a Zinc Smelter

Abstract

Extractable contents of heavy metals such as Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb and Bi in soil and plant tissue samples (fruit, leaf, twig and root) collected, along a distance of 1100 m to the West, from the surroundings of a metallurgical factory producing mainly zinc, cadmium and lead were determined by flame atomic absorption spectrometry (FAAS). In addition, the determinations of Ca and Mg, macro nutrient elements for plants, were also performed. Three extractant solutions were used for dissolution of soil samples, namely aqua regia (1 HNO₃₊ 3 HCl) for total metal analysis, 1 mol L^?1 ammonium acetate for exchangeable metal contents, and a dilute acid mixture (0.1 M HCl in 0.025 M H₂SO₄) for acid soluble metal contents. A mixture of HNO₃ and HClO₄ was used to analyze the fruit samples. The analyses of the leaf, the twig, and the root tissue samples were made by dry ashing method. The detection limits of the metals were in the range of 0.04 to 0.45 μg/mL for all soil extracts and 0.01 to 1.50 μg/mL for the fruit samples. The recovery values for all the determinations were higher than 95%. The results obtained from the analyses of plant tissue and soil samples were evaluated using linear correlation analysis and concentration factors to identify the effect of the factory near the grape-vine area.     

Determination of Silver in Plants by Flameless Atomic Absorption Spectrometry and Neutron Activation Analysis

Abstract

Three analytical techniques suitable for determining silver concentrations in plants are presented and compared. Graphite furnace atomic absorption spectrometry performed directly on sample digests was the most sensitive and convenient. Neutron activation analysis, measuring ^110mAg gave good reproducibility, but lower sensitivity. A cyclic activation scheme to generate and detect the short-lived isotope ¹¹⁰Ag was useful as a quick reconnaissance technique, but interference from ⁷⁶As reduced its effectiveness.

Data are presented on the silver content of terrestrial plants. Background silver concentrations for lichens and bryophytes collected from Wales, U.K. were <0.07μgg^?1. Samples collected from areas contaminated by derelict metal mines contained between 0.1-1.0μAgg^?1. The aerial portions of vascular species usually contained less silver than bryophytes growing on the same substrate. Fungi are shown to bioconcentrate silver to a greater extent than cadmium, copper or lead.     

Determination of Copper,Nickel and Cadmium by Faas After Preconcentration with Zinc-Piperazinedithiocarbamate Loaded on Activated Carbon by Solid-Phase Extraction

ABSTRACT

A method was developed for the preconcentration of copper, nickel and cadmium in water samples, prior to their determination by FAAS, using the Zn-piperazinedithiocarbamate complex (ZnPDC) loaded on activated carbon. In this method, Cu, Ni and Cd in liquid phase quantitatively replaced zinc on a ZnPDC-activated carbon solid phase. Afterwards, the metals on the solid phase were easily eluted by Hg (II) solution into aqueous phase, and were measured by FAAS. The optimum experimental parameters such as pH, sample volume, and effect of matrix ions for the preconcentration of the metals were investigated. The range of linearity 0-6, 0-5, 0-3 μgml^?1, correlation coefficient 0.998, 0.996, 0.999, detection limits 15.7, 23.5, 11.8 ngml^?1 and determination limits 136, 179, 98 ngml^?1 in final Hg(II) solution were obtained for Cu, Ni and Cd, respectively. The proposed method has been employed for the determination of Cu, Ni and Cd in various standard metal alloys and natural water samples.     

Coupling continuous ultrasound-assisted extraction, preconcentration and flame atomic absorption spectrometric detection for the determination of cadmium and lead in mussel samples

Continuous ultrasound-assisted extraction has been coupled with preconcentration and flame atomic absorption spectrometry for the determination of cadmium and lead in mussel samples. Experimental designs were used for the optimisation of the leaching and preconcentration steps. The use of diluted nitric acid as extractant in the continuous mode at a flow rate of 3.5 ml min⁻¹ and room temperature was sufficient for quantitative extraction of these trace metals. A minicolumn containing a chelating resin (Chelite P, with aminomethylphosphoric acid groups) was proved as an excellent material for the quantitative preconcentration of cadmium and lead prior to their flame atomic absorption detection. A flow injection manifold was used as interface for coupling the three analytical steps, which allowed the automation of the whole analytical process. A good precision of the whole procedure (2.0 and 2.3%), high enrichment factors (20.5 and 11.8) and a detection limit of 0.011 and 0.25 μg g⁻¹ for cadmium and lead, respectively, were obtained for 80 mg of sample. The sample throughputs were ca. 16 and 14 samples h⁻¹ for cadmium and lead, respectively. The accuracy of the analytical procedures was verified by using a standard reference material (BCR 278-R, mussel tissue) and the results were in good agreement with the certified values. The method was successfully applied to the determination of trace amounts of cadmium and lead in mussel samples from the coast of Galicia (NW, Spain).     

On-line simultaneous pre-concentration procedure for the determination of cadmium and lead in drinking water employing sequential multi-element flame atomic absorption spectrometry

An on-line pre-concentration system for the sequential determination of cadmium and lead in drinking water by using fast sequential flame atomic absorption spectrometry (FS-FAAS) is proposed in this paper. Two minicolums of polyurethane foam loaded with 2-(6-methyl-2-benzothiazolylazo)-orcinol (Me-BTAO) were used as sorptive pre-concentration media for cadmium and lead. The analytical procedure involves the quantitative uptake of both analyte species by on-column chelation with Me-BTAO during sample loading followed by sequential elution of the analytes with 1.0?mol?L^?1 hydrochloric acid and determination by FS-FAAS. The optimisation of the entire analytical procedure was performed using a Box–Behnken multivariate design utilising the sampling flow rate, sample pH and buffer concentration as experimental variables.

The proposed flow-based method featured detection limits (3σ) of 0.08 and 0.51?µg?L^?1 for cadmium and lead, respectively, precision expressed as relative standard deviation (RSD) of 1.63% and 3.87% (n?=?7) for cadmium at the 2.0?µg?L^?1 and 10.0?µg?L^?1 levels, respectively, and RSD of 6.34% and 3.26% (n?=?7) for lead at the 5.0?µg?L^?1 and 30.0?µg?L^?1 levels, respectively. The enrichment factors achieved were 38.6 and 30.0 for cadmium and lead, respectively, using a sample volume of 10.0?mL. The sampling frequency was 45 samples per hour. The accuracy was confirmed by analysis of a certified reference material, namely, SRM 1643d (Trace elements in natural water). The optimised method was applied to the determination of cadmium and lead in drinking water samples collected in Santo Amaro da Purificação City, Bahia, Brazil.     

Salen impregnated silica gel as a new sorbent for on-line preconcentration of cadmium(II)

A new sorbent – salen impregnated silica gel – was prepared and characterised for application as a minicolumn packing for flow-injection on-line preconcentration of cadmium(II). The system was coupled with flame atomic absorption spectrometer (FI-FAAS). The optimal pH for Cd(II) sorption was in the range of 7.4–8.8 and nitric acid (1%, v/v) was efficient as eluent. Sorption was most effective within the sample flow rate up to 7?mL?min^?1. Sorption capacity of the sorbent found in a batch procedure was 26.3?µmol?g^?1 (2.95?mg?g^?1). Enrichment factor (EF) and limit of detection (LOD) obtained for 120-second loading time were 113 and 0.26?µg?L^?1, respectively. The sorbent stability in the working conditions was proved for at least 100 preconcentration cycles. The evaluated method was applied to Cd(II) determination in various water samples.     

二乙胺荒酸钠–四氯化碳萃取连续光源原子吸收法测定磷酸一二钙中的痕量铅、镉

建立连续光源原子吸收分光光度法同时测定磷酸一二钙(MDCP)中铅、镉的方法。MDCP经盐酸消解后,以氢氧化钠溶液调节p H为11,加入KCN作为掩蔽剂,用二乙氨荒酸钠–四氯化碳络合铅、镉离子,再经CCl_4进一步萃取浓缩,采用连续光源原子吸收分光光度法测定铅、镉的含量。该方法铅、镉的检出限为1,0.5 mg/kg;用于不同批次MDCP产品测定,铅、镉测定结果的相对标准偏差分别为3.58%,6.91%(n=11);铅、镉的加标回收率分别为88.9%~104.7%,91.0%~106.4%。该法可用于MDCP中痕量铅、镉的同时测定。     

Determination of Metals in Olive Oil by Electrothermal Atomic Absorption Spectrometry: Validation and Uncertainty Measurements

The determination of trace metals in organic matrices is still highly demanding despite improvements in analytical instrumentation. The present study was undertaken in order to evaluate electrothermal atomic absorption spectrometry for the determination of cadmium, copper, iron, lead, and nickel in olive oil. A variety of approaches were used. The most suitable digestion procedure was heating the samples at 300°C for 24 hours and ashing in a muffle furnace at 450°C for 16 hours. The validation data were detection limits of 0.2–153 ng g^?1; mean trueness on certified reference materials of 81–94%; mean recovery on spikes of 90–120%; and repeatability of 12–53%. The combined relative uncertainty was 0.298–0.766. Oils processed by pressing had higher copper, iron, and lead concentrations than oils processed by centrifugation. The reported method provides an efficient way for monitoring trace metal content during olive oil production.     

Human Enamel and Dentin: Effect of Gender,Geographic Location and Smoking Upon Metal Concentrations

Abstract

The goal of this study was to determine the content of 12 metals in 23 samples of teeth from two cities in Bosnia and Herzegovina (B&H): Sarajevo, a capital city with heavy traffic, industrial facilities, and long periods of smog during winter and Bihac, a picturesque small city, with no industrialization, settled among vivid national park and rivers. The teeth were separated into enamel and dentin. Dissolution of samples was performed in concentrated HNO₃ with the addition of H₂O₂ followed by flame atomic absorption spectroscopy (FAAS) analysis. The results showed expected high contents of Ca, Na, Mg, and K, while elevated contents of Cu, Fe, and Zn were present in some samples. K and Na showed uniform distributions throughout enamel and dentin. Alkaline and earth-alkaline metals showed significant positive correlations. Zinc and manganese exhibited differences in the dentin content based on the place of residence. Zinc also displayed statistically significant differences between smokers’ and nonsmokers’ dentin samples. The differences were more pronounced between intra groups (within one sample) than for inter groups (within different groups, such as location, gender, and smoking).     

Determination of Cadmium and Lead in Sea Water after Extraction Using Electrothermal Atomisation. Minimisation of Interferences from Co-Extracted Sea Salts

Abstract

Interferences from small amounts of sea salt in the determination of cadmium and lead were investigated. Test samples were made to mimic solutions obtained after extraction of sea water for trace metal analysis. Sea salt concentrations in the range 0–400 mg/l were investigated. Background absorption from this salt was high but easily minimised through the addition of nitric acid (2 % v/v). Sensitivity reductions due to the salt were considerable and varied from one graphite tube to the other. This problem was overcome by the addition of 1000 mg lanthanum per litre of sample. The positive effect of the lanthanum matrix modification is thought to be due to a change of the graphite tube surface.     

Determination of Heavy Metals and Other Water Quality Parameters from the South China Sea

This study investigated the distribution and concentrations of chromium, copper, arsenic, zinc, cadmium, and lead in seawater and suspended particles in the South China Sea by collection of samples from different depths at sixteen stations. The salinity, temperature, pH, dissolved organic carbon, dissolved oxygen, and silicon concentration were also measured in seawater. The results showed that the concentration levels in seawater from 0 m to 4000 m followed this pattern: zinc > arsenic > copper > lead > chromium > cadmium. Significant correlations were observed between lead and chromium and between arsenic, cadmium, and lead at r > 0.728. Very weak correlations were observed between copper and arsenic and between copper and cadmium. The concentrations of dissolved metals and particulate metals had negative correlations except for zinc. The metal concentrations in seawater and suspended particles showed different correlation behavior with salinity, temperature, pH, dissolved oxygen, dissolved organic carbon, and silicon.