Cadmium In Natural Water Samples Research Articles

Simple, insensitive to environmental matrix interferences method of trace cadmium determination in natural water samples

A simple, fast, and inexpensive anodic stripping voltammetric procedure for trace determination of cadmium in natural water samples containing high concentrations of surface-active substances was described. It was proved that interferences from the organic matrix such as surface-active substances could be removed by the addition of Amberlite XAD-7 resin to the analyzed sample prior to the voltammetric measurement. A renewable mercury film silver-based electrode (Hg(Ag)FE) was used as the working electrode. The following optimum conditions were found: 0.1 mol L−1 acetic acid, accumulation potential of − 0.8 V, and accumulation time of 30 s. The linear range of Cd(II) was observed over the concentration range from 5 × 10−8 mol L−1 to 6 × 10−5 mol L−1, with a correlation coefficient equal to 0.997. The detection limit of Cd(II) for preconcentration time of 30 s was 1.3 × 10−8 mol L−1. The proposed procedure was successfully tested for the detection of cadmium in different non-pretreated and non-deaerated real water samples.

A green and efficient in-syringe ionic liquid-based single step microextraction procedure for preconcentration and determination of cadmium in water samples

An in-syringe ionic liquid-based single step microextraction has been analytically presented. 1-butyl-3-methylimidazolium hexafluorophosphate as extractant and Triton X-100 as dispersing medium were used. Cd-Dithizone was extracted within a syringe. The effects of some variables such as [C4mim][PF6] volume, pH, TX-100 volume, dithizone concentration, incubation time, diluents nature and matrix effect were investigated. The limit of detection and preconcentration factor were found as 0.35μgL−1 and 50, respectively. The validity was checked by using certified reference materials. The relative standard deviation (RSD) was 4.2%. The method was satisfactorily applied to preconcentration of cadmium in natural water samples.

Determination of zinc, nickel and cadmium in natural water samples by flame atomic absorption spectrometry after preconcentration with ion exchange and flotation techniques

Two preconcentration techniques, ion exchange and flotation, were used for the determination of zinc (Zn), nickel (Ni) and cadmium (Cd) in natural water samples. In the first part of our work, the adsorption of zinc(II), nickel(II) and cadmium(II) on Lewatit TP 207 chelating resin containing iminodiacetate groups was studied at different pH values by a batch process. The effects of parameters such as amount of resin, contact time, pH and initial metal concentration on the ion exchange separation were investigated. For the determination of the adsorption behavior of the resin, the adsorption isotherms of metal ions were also studied. The concentrations of metal ions were measured by batch techniques and with atomic absorption spectrometry analysis. Adsorption analysis results obtained at various concentrations showed that the adsorption pattern on the resin followed Langmuir and Freundlich isotherms. The efficiency of removal is higher for Ni and Zn than Cd ions. Here, we report the method that is applied for the sorption and separation of some toxic metals from the solutions. In the second part of our work, the flotation technique was used for preconcentration. The ability of Co(III) hexamethyl­enedithiocarbamate, Co(HMDTC)3, as a flotation collector for metals from natural waters was investigated. The flotation method was compared with the ion exchange method. The recoveries of Zn, Cd and Ni from natural water samples were approximately 99%. Our results showed that the two methods were very effective, but the flotation results were higher than the ion exchange results. In the present study, a method was described for the determination of Zn, Ni and Cd by flame atomic absorption spectrometry (FAAS) after preconcentration and separation in water by ion exchange resin and flotation. Results of these two methods are compared. Analytical parameters such as precision and accuracy of methods were also studied. The equilibrium experimental results of Zn, Ni and Cd ions exchanged were fitted by Langmuir-Freundlich adsorption isotherm models.

Determination of very toxic metal — Cadmium in natural water samples

Abstract A potentiometric stripping method for a direct measurement of cadmium in various natural water samples using a Stripping analyzer M1 (designed and manufactured in Serbia) unit has been developed. In order to ascertain optimum conditions for the determination of the effect of the mercury time electrodeposition, the electrolysis potential and the solution stirring rate of the cadmium analytical signal have been examined. Linearity of the cadmium analytical signal was achieved within the wide range of the mass concentrations, from 1 μg/L to 15 μg/L. A detection limit of 0.10 μg/L was obtained, with a reproducibility of 3.55% expressed as the coefficient of variation. The accuracy of the method was confirmed by parallel analyses by flameless atomic absorption spectrophotometry as the reference method.

Flow injection on-line hydrophobic sorbent extraction for flame atomic absorption spectrometric determination of cadmium in water samples

A flow injection system was developed for on-line sorbent extraction preconcentration and flame atomic absorption spectrometric determination of cadmium in natural water samples. The non-charged cadmium complex with diethyl-dithiophosphate (DDPA) was formed on-line in 0.1 mol L−1 HNO3 and retained on the hydrophobic poly-chlorotrifluoroethylene (PCTFE) sorbent material. The adsorbed complex was eluted with isobutyl methylketone (IBMK) and injected directly into the nebulizer via a flow compensation unit. All major chemical and flow parameters affecting the complex formation adsorption and elution as well as interference were studied and optimized. By processing 2.4 mL of sample, the enhancement factor was 39 and the sampling frequency was 50 h−1. For 30 s preconcentration time the detection limit was 0.3 µg L−1 and the relative standard deviation at 5.0 µg L−1 Cd concentration level was 2.9%. The calibration curve was linear in the range 0.8–40.0 µg L−1. The accuracy of the method was estimated by analyzing a certified reference material NIST-CRM 1643d (Trace elements in water). Good recoveries were obtained for spiked natural-water and waste-water samples.

Determination of traces of cadmium in natural water samples by flow injection on-line preconcentration-graphite furnace atomic absorption spectrometry.

A flow injection on-line preconcentration-graphite furnace atomic absorption spectrometric method was developed for the determination of traces of cadmium in natural water samples. Cadmium in samples was adsorbed on an iminodiacetate-type chelating resin, Muromac A-1 microcolumn (3 mm i.d. and 10 mm long), and then eluted with 2 mol l-1 HNO3. The eluate was introduced into the injection tip of an autosampler. The eluate zone with the highest analyte concentration was injected into the graphite furnace by cooperation of a peristaltic pump and a syringe pump of the autosampler, which were controlled by a programmable controller. The present system was successfully applied to the determination of cadmium in natural water samples. A detection limit of 0.2 ng l-1 was obtained with 12 ml sample loading. The recoveries were 99 and 108% for tap water (4 ml loading) and underground water (12 ml loading), respectively. Analytical results obtained for a river water reference material (JAC-0031, Japan Society for Analytical Chemistry) were close to the reference value.

Preconcentration of trace amounts of cadmium in aqueous samples on minicolumns packed with Chromosorb series gas chromatographic stationary phases and its determination by electrothermal atomic absorption spectrometry.

The adsorption characteristics of five commercially available Chromosorb GC stationary phases towards Cd2+ and their application to the preconcentration and ETAAS determination of Cd2+ in several water samples were studied. The experimental results indicated that although all of the five Chromosorb GC stationary phases studied can retain Cd2+ quantitatively from aqueous solutions at appropriate pH values without adding chelating reagent. Chromosorb 105 displayed the highest adsorption capacity. A highly sensitive, simple methodology for preconcentration and ETAAS determination of trace amounts of cadmium in natural water samples using a Chromosorb 105 packed minicolumn is proposed. Conditions for quantitative and reproducible preconcentration, elution and subsequent ETAAS determination were established. The high retention efficiency (> 95%) for Cd2+ provides a sensitivity enhancement of 100-fold for a 200 mL sample volume with a detection limit of 6.2 ng L(-1) (3 sigma).

Determination of heavy metals in seawater and in marine organisms by flameless atomic absorption spectrophotometry. XII. A method for the determination of total cadmium in natural water samples: limits of mere extraction methods : Sperling, K.-R., 1980. Z. analyt. Chem., 301(4): 294–299

Determination of heavy metals in seawater and in marine organisms by flameless atomic absorption spectrophotometry. XII. A method for the determination of total cadmium in natural water samples: limits of mere extraction methods : Sperling, K.-R., 1980. Z. analyt. Chem., 301(4): 294–299