Cadmium In Environmental Samples Research Articles

Simultaneous Determination of Lead and cadmium in Environmental Samples Using Zinc-diethyldithiocarbamates

تمتلك المعادن الثقيلة السامة تأثيرا خطيرا على البيئة ، وان عملية التقدير الكمي لتركيزهذه المعادن يعطي معلومات مهمة تخص سمية المعادن. في هذه الدراسة تم استخدام طريقة تحليلية طيفية سهلة ، سريعة وانتقائية مع طريقة الاستخلاص بالطورالصلب للتقديرالمتزامن للرصاص والكادميوم في النماذج البيئية باستخدام الزنك - ثنائي إيثيل ثيوكاربامات المترسب ككاشف. تم استخدام طريقة الاستخلاص بالطور الصلب لعملية لتركيز المسبق لمحتوى الرصاص والكادميوم في النماذج البيئية. أظهرت الطريقة المقترحة مدى خطية يتراوح بين 0,1 – 16 مايكروغرام/مل و 0,1 – 14 مايكروغرام/مل لكل من الرصاص والكادميوم على التوالي. وكانت قيمة الاستردادية تتراوح بين 90 – 96 % مع معامل ارتباط (ر2) مقداره 0,9985 و 0,9989 لكل من الرصاص والكادميوم على التوالي. تم دراسة الظروف المثلى مثل (قيمة الاس الهيدروجيني ، وقت الاستخلاص و حجم الطورالمائي) على كفاءة عملية الاستخلاص للمعادن بالاضافة الى دراسة تأثير وجود الاملاح والايونات الاخرى كمتداخلات. تم تطبيق الطريقة المقترحة في الدراسة على عدد من النماذج البيئية (التربة والماء) لتقدير كمية العناصر الموجودة فيها. اظهرت النتائج المستحصلة دقة وانتقائية جيدة تدل على امكانية استخدام الطريقة المقترحة في تقدير الرصاص والكادميوم وامكانية تطبيقها في مجالات اخرى.

Optimization of magnetic solid phase microextraction with CoFe2O4 nanoparticles unmodified for preconcentration of cadmium in environmental samples by flame atomic absorption spectrometry

A method of preconcentration based in the magnetic solid phase microextraction with CoFe2O4 nanoparticles for the determination of cadmium in oyster and water samples using flame atomic absorption spectrometry (FAAS). Magnetic nanomaterials ones have aroused a greater interest in the area of analytical chemistry because of the high area of material and separation facility of the adsorbent. The statistical significance variables, extraction time, nanoparticles mass, pH, eluent concentration and desorption time were evaluated using a fractional factorial design of two levels (25–1). Afterward, a design Doehlert was used to optimize the pre-concentration process. The best experimental conditions were: nanoparticles mass (25 mg), pH (10.0) and eluent concentration of 1.20 mol L−1. The method allowed the determination of cadmium with a LOD of 0.24 μg L−1 and LOQ of 0.80 μg L−1. The precision expressed as relative standard deviation (RSD) of 3.33% for cadmium concentration with 20 μg L−1, the accuracy of the method was confirmed by the analysis of materials certified reference NIST 1566b Oyster tissue, pre-concentration factor 31. The method was applied to the analysis of the oyster and water samples has determined the concentration of cadmium from 4.6 to 7.8 mg kg−1 for oyster and 2.75 to 4.8 μg L−1 for water.

Methods of liquid phase microextraction for the determination of cadmium in environmental samples

Liquid phase microextraction (LPME) has been widely used in extraction and preconcentration systems as an excellent alternative to conventional liquid phase extraction. In this work, a critical review is presented on liquid phase microextraction techniques used in the determination of cadmium in environmental samples. LPME techniques are classified into three main groups: single-drop liquid phase microextraction (SDME), hollow fiber liquid phase microextraction (HF-LPME), and dispersive liquid-liquid microextraction (DLLME). Methods involving these liquid phase microextraction techniques are described, addressing advantages and disadvantages, samples, figures of merit, and trends.

ドデシル硫酸ナトリウム/活性炭前濃縮法を利用した環境試料中微量カドミウムのフレーム原子吸光分析

ドデシル硫酸ナトリウム/活性炭前濃縮法を利用した環境試料中微量カドミウムのフレーム原子吸光分析

Electrothermal atomic absorption spectrometric determination of cadmium in environmental samples with niobium wire preconcentration method

A preconcentration method by adsorption of cadmium on a niobium wire was developed for the environmental waters, followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer. After the preconcentration, the niobium wire was directly inserted into the tungsten tube atomizer. In the preconcentration (adsorption) process of cadmium, the optimal immersing time was 60 s. The effects of large amounts of concomitants on the preconcentration of cadmium were evaluated. When 103–104 fold excess of matrix elements existed in aqueous solution at pH 4 and 9, the cadmium response was profoundly affected by the matrix elements. However, the cadmium absorption signal was not significantly influenced at pH 7. Therefore, pH 7 was selected for the application into the real environmental samples. Under the optimal conditions, the detection limit (3S/N) for cadmium by the niobium wire preconcentration method was 7.0 pg mL−1 and the relative standard deviation was 6.8%. The method with preconcentration on a niobium wire was applied to the determination of cadmium in water and proved to be sensitive, simple and convenient. Because this preconcentration method can be utilized in the in situ treatment of trace cadmium in environmental water samples, it was unnecessary to carry the water samples to the analytical work place. The technique was shown to be useful for the determination of cadmium in environmental water samples at 0.1–1 µg L−1 levels.

Quantitative analysis and sorption of cadmium in environmental samples with a functionalized synthetic polymer

Quantitative analysis of cadmium in environmental samples was achieved with a polymeric sorbent synthesized by copolymerization of N,N-dimethylacrylamide and allyl glycidyl ether/iminodiacetic acid as chelating monomers with N,N′-methylenebisacrylamide as cross-linker. The polymer was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and scanning electron microscopy. The sorption capacity of the functionalized sorbent was 70 mg g−1. The equilibrium sorption data of Cd(II) on polymeric sorbent were analyzed using Langmuir, Freundlich, Temkin, and Redlich–Peterson models. Based on equilibrium adsorption data, the constants at pH 4.2 and 20 °C were determined for the first three as 0.33 (L mg−1), 17.5 (mg g−1) (L mg−1)1/n, and 12.9 (J mol−1). Recovery of 94% of the metal ion was obtained with 0.5 mol L−1 nitric acid as an eluting agent.

Online Preconcentration Using Surfactant Coated Alumina Modified with 1,5-Diphenylthiocarbazone and Determination of Cadmium in Environmental Samples by Flame Atomic Absorption Spectrometry

A rapid and sensitive method for the determination of trace levels of cadmium in cigarettes, soil, and blood samples by flame atomic absorption spectrometry (FAAS) has been developed. It is based on the online sorption of Cd(II) ions on a minicolumn packed by sodium dodecyl sulfate–coated alumina modified with dithizone. The optimum experimental parameters for the adsorption and desorption of cadmium were investigated. The recovery obtained was found to be 96% with preconcentration factor of 150. The calibration curve was linear between 50–600 µg/L Cd with a detection limit of 3 µg/L, sample frequency of 30 h−1 and reuse of column for 10 times without loss of sensitivity. The accuracy of the method was confirmed by applying the standard addition method and quantitative recoveries (95–99%) were obtained.

Direct determination of trace cadmium in environmental samples by dynamic reaction cell inductively coupled plasma mass spectrometry

Cadmium is subject to significant Zr and Mo based oxide/hydroxide interferences in ICP-MS analysis of environmental samples. In this work, a dynamic reaction cell (DRC) technology was used to eliminate these metal oxide/hydroxide interferences. The potentially interfering ions 94Zr 16OH +, 94Mo 16OH + and 95Mo 16O + on 111Cd + were oxidized to higher oxides 94ZrO 2H +/ 94ZrO 3H +, 94MoO 2H +/ 94MoO 3H +, and 95 MoO 2 + / 95 MoO 3 + by O 2 as the reaction gas in DRC. Under the optimized O 2 flow rate (2.0 mL min −1) and DRC rejection parameter q (Rpq, 0.75), the background signal was reduced by up to 100-fold at m/z 111 and the limit of quantitation (LOQ, 10σ) of 0.1 ng g −1 was obtained. The proposed method was applied to direct analysis of trace Cd in a series of soil and sediment standard reference materials and the satisfactory results showed that it has great potential for the direct determination of trace or ultra-trace levels of cadmium in environmental samples.

Separation and solid phase extraction method for the determination of cadmium in environmental samples

A solid phase extraction method was developed for the determination, preconcentration and separation of cadmium. The method is based on the adsorption of cadmium as 4-(2-pyridylazo) resorcinol (PAR) complex on Duolite XAD-761 resin. The extracted cadmium was determined by Flame Atomic Absorption Spectrometry (FAAS). The optimum experimental conditions for the cadmium assay were investigated. The optimum pH value for quantitative sorption of Cd-PAR was found between 3.5 and 5.5. Elution process was performed by using 5 mL of ethanol–2 mol L − 1 HNO 3 mixtures (1:3 v/v). The preconcentration factor was found as 160 for 800 mL aqueous solution containing 2.5 μg Cd. In optimized conditions, the detection limit for cadmium was found to be 0.38 μg L − 1 . The method was applied to the determination of cadmium in different water samples.

Preconcentration of Cadmium in Environmental Samples by Cloud Point Extraction and Determination by FAAS

Cloud point extraction (CPE) has been used for the preconcentration of cadmium, after the formation of a complex with 1, 5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH), and further determination by flame atomic absorption spectrometry (FAAS) using Triton X-114 as surfactant. The main factors affecting the CPE, such as concentration of Triton X-114 and DPTH, pH, equilibration temperature and incubation time, were optimized for the best extract efficiency. Under the optimum conditions i.e., pH 5.4, [DPTH] = 6x10-3%, [Triton X-114] = 0.25% (v/v), an enhancement factor of 10.5 fold was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 0.95 μg L?1. The precision for 8 replicate deter- minations at 20 and 100 μgL?1 Cd were 2.4 % and 2 % relative standard deviation (R.S.D.). The calibration graph using the preconcentration method was linear with a correlation coefficient of 0,998 at levels close to the detection limit up to at least 200 μgL?1. The method was successfully applied to the determination of cadmium in water, environmental and food samples and in a BCR-176 standard reference material.

Vapor Generation Atomic Absorption Spectrometric Determination of Cadmium in Environmental Samples with In-Line Anion Exchange Separation

A novel in-line anion exchange separation method is described for the removal of Mn(2+), Fe(3+), Ni(2+), Co(2+), Cu(2+), Zn(2+), and Pb(2+) from Cd(2+) and for its subsequent determination by vapor generation atomic absorption spectrometry. High Cd(2+) retention efficiency and maximum exclusion of other metal ions were achieved by using Cl(-), Br(-), or I(-) loaded strong base anion exchange resin and fiber in chloride medium. SO(4)(2-) and NO(3)(-) affected the retention of Cd(2+) on Cl(-) or Br(-) loaded exchangers but were beneficial for elution from I(-) loaded exchangers. Fast and efficient elution from the exchangers was achieved by using ethylenediamine solution. The removal of Zn(2+) was unnecessary as it prevents a decline in the sensitivity of cadmium response when ethylenediamine and high acid concentration were used. Under optimum conditions, the achievable detection limits (3sigma) with sample loadings of 0.48 and 9.6 mL were 40 ng L(-1) and 3 ng L(-1), respectively. Interference of residual organic matrix, in sample digests, with the separation and retention of cadmium were eliminated by use of microwave assisted digestion. The method was successfully applied to the determination of Cd in river sediment, fish liver, and water samples.

Determination of lead and cadmium in tap water and apple leaves after preconcentration on a new acetylacetone bonded polyurethane foam sorbent

The present work describes a rapid, cost-effective analytical procedure for the determination of lead and cadmium in environmental samples by off-line preconcentration with polyurethane foam (PUF) functionalised with acetylacetone by covalent coupling through the–N=N–group. The optimum pH ranges for quantitative uptake were 5–7, 6–7 for lead and cadmium, respectively. The kinetics of metal uptake by the new foam was found to be fast, reaching equilibrium in a few minutes. Metal ions were sorbed in the minicolumn, eluted with acid solutions and determined by flame atomic absorption spectrometer (FAAS). Under the optimum conditions, the preconcentration factors obtained were 288 for Cd and 224 for Pb. The limits of detection of the proposed procedure were 0.09 and 0.07 µg L−1 for Pb and Cd, respectively. The relative standard deviation (RSD) was less than 10%. The accuracy of the method was estimated by using environmental samples that were spiked with Cd and Pb ions. The capacity of the acetylacetone bonded PUF (AA-BPUF) sorbent at optimum conditions has been found to be 4.5, 6.9 µmol g−1 of sorbent for Pb and Cd, respectively.

Flow Injection Spectrofluorimetric Method for the Determination of Cadmium

A novel fluorescent reagent, o-vanillin furoylhydrazone (OVFH), was synthesized, and its infrared spectrum, elemental analysis and dissociation constant are reported. The reaction between Cd2+ and OVFH produces an intensely fluorescent complex in ethanol-water medium of pH 10.00, and this finding has led to a simple, rapid, and sensitive flow injection (FI) spectrofluorimetric method for on-line determination of Cd2+. Under the optimum experimental conditions, the fluorescent complex had excitation and emission maxima at 393 and 494 nm, respectively. The linear range is from 0.025 to 8.0 µg mL−1 of Cd2+, the detection limit is 7.6 µg L−1 and the maximum sampling rate is 80 h−1. The effect of interferences was studied. The method was successfully applied to the determination of cadmium in environmental samples.

Determination of cadmium in environmental samples by hydride generation with in situ concentration and atomic absorption detection.

A volatile Cd species (presumed to be the hydride) was generated from aqueous solutions by merging sample and tetrahydroborate reductant in a continuous-flow system. The gaseous analyte was transferred onto the inner wall of a graphite tube furnace for in situ preconcentration at 200 degrees C. Calibration was achieved via the method of standard additions. An absolute detection limit (3 sigma blank) of 10 pg was obtained using KBH4 as reductant. The precision of the determination was 12% (RSD) for a Cd concentration of 0.2 ng ml-1 using KBH4. The method was successfully applied to the determination of Cd in several certified environmental reference materials (soil, sediment, sea-water, biological samples) following pressure digestion of the samples by microwave heating in a mixture of acids.

Determination of lead and cadmium in environmental samples optimized by simplex optimized atomic absorption methods

Simplex optimized methods for the determination of cadmium and lead in environmental samples by use of electrothermal atomic absorption spectroscopy (ETAAS) are presented. The optimum experimental conditions were attained by applying the composite modified simplex optimization method after considering the following variables: ramp to ashing temperature, ashing temperature, atomization ramping time, atomization temperature and modifier concentration. The way of introducing the matrix modifier in the graphite furnace is one of the most important among the numerous factors that must be considered for the development of an ETAAS method. The matrix modifier was injected into a graphite tube provided with a L'vov platform prior to the injection of the sample, leaving the modifier wet. The analytical investigations showed that the optimized systems are ideally suited to the analysis of cadmium and lead in samples of environmental origin offering good accuracy and precision.

Effect of potassium iodide on reducing the adsorptive interference of surfactants and organics in the determination of lead and cadmium in environmental samples by differential-pulse anodic stripping voltammetry

The complexing and adsorbing properties of potassium iodide were investigated for anodic stripping voltammetric measurements of Pb and Cd in the presence of organics and surfactants. Up to 100 ppm of pectic acid, agar and gelatin do not affect the voltammetric response of either Pb or Cd. Up to 100 ppm of dodecylamine (DDCA), alginic acid, 40 ppm of camphor and 6 ppm of humic acid do not affect the voltammetric response of Cd (8 ppb). Up to 100 ppm of camphor, 50 ppm of alginic acid, 20 ppm of humic acid and 10 ppm of Triton X-100 and DDCA do not affect the voltammetric response of Pb (20 ppb). The effect of sodium dodecyl sulfate on Cd can be eliminated completely by DDCA but that on Pb only partly. The sensitivity of the determination increased by 50% and 100% for Pb and Cd, respectively. The behaviour of Pb and Cd with organics was studied in the presence of KI. Pb and Cd were determined in different fractions of dust samples and synthetic waste water.

Determination of cadmium in environmental samples by electrothermal atomic absorption spectrometry using a tantalum-foil platform with the possibility of standardless analysis

A comparison is made between the calculated and experimental values obtained for the characteristic mass, m0, with a tantalum-foil platform in a pyrolytic graphite coated graphite tube, using different chemical modifiers (Pd 0.5 mg ml–1, NaH2PO4 10 mg ml–1 and ascorbic acid 10 mg ml–1), and various solutions of reference materials of environmental samples. All measurements of m0 were performed on an Hitachi Model Z8000 d.c. magnet, Zeeman spectrometer and a Beijing Second Optical Instrument Factory Model WFX-1G2, a.c. magnet, Zeeman spectrometer. Theoretical calculations of m0 for Cd at atomization temperatures ranging from 1000 to 2200 K, made every 100 K, were based on the calculation formula and fundamental parameters proposed by L'vov et al. Quantitative analysis data for Cd in sea-water and in solutions of reference materials (pork liver, wheat powder, peach leaf, tea leaf, tea tree leaf, cabbage, water sediments, coal fly ash and geological samples) by standardless analysis are presented.

Extraction, separation and spectrophotometric determination of cadmium and mercury using triphenylphosphine oxide and its application to environmental samples

A method is proposed for the solvent extraction of cadmium and mercury from salicylate media using triphenylphosphine oxide as extractant. The optimum extraction conditions were evaluated from a critical study of the effect of pH, sodium salicylate concentration and the concentration of triphenylphosphine oxide. The probable composition of the species has been deduced from log-log data and an extraction mechanism is suggested. The method has been used to separate zinc, cadmium and mercury from binary and ternary mixtures and for the spectrophotometric determination of mercury or cadmium in environmental samples.

Solvent extraction and atomic absorption spectrometric determination of cadmium in environmental samples

Abstract Traces of Cadmium can be quantitatively extracted from aqueous thiocyanate solutions into 2‐Benzoylpyridine‐2‐Pyrididylhydrazone (BPPH) Methyl‐Isobutyl‐Ketone (MIBK) solution. Very small amounts of Cadmium can be recovered from a large volume of sample and determined directly by flame Atomic Absorption Spectrometry. A new procedure for Cadmium determination in environmental and biological samples was developed. The proposed scheme for Cadmium determination was found to be simple, selective, sensitive and accurate.

The determination of cadmium in environmental samples by slurry atomization graphite furnace atomic absorption spectrophotometry using platforms and matrix modification

The conditions which allow the accurate and precise determination of cadmium in environmental samples using direct solid introduction and electrothermal atomization atomic absorption spectrometry have been investigated. Cadmium was successfully determined in three certified reference materials (an aquatic plant, olive leaves, and mussels). Utilization of platform atomization and a 0.5% solution of ammonium phosphate as matrix modifier eliminated matrix interference effects. Excellent agreement was obtained with the certified values, with precision equivalent to that found by conventional acid digestion procedures.