Determination Of Cadmium In Foods Research Articles

Ultra-Sensitive Determination of Cadmium in Food and Water by Flame-AAS after a New Polyvinyl Benzyl Xanthate as an Adsorbent Based Vortex Assisted Dispersive Solid-Phase Microextraction: Multivariate Optimization.

Background: Cadmium (Cd) is a very toxic and carcinogenic heavy metal even at low levels and it is naturally present in water as well as in food. Methods: A new polyvinyl benzyl xanthate (PvbXa) was synthesized and used as a new adsorbent in this work. It contains pendant sulfide groups on the main polystyryl chain. Using this new adsorbent, PvbXa, a vortex-assisted dispersive solid-phase microextraction (VA-dSPµE) procedure was developed for the determination of cadmium from food and water samples via flame atomic absorption spectrophotometry (FAAS). Synthesized PvbXa was characterized by 1H Nuclear magnetic resonance (NMR) Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). The different parameters of pH, sample volume, mixing type and time, sorbent amount, and eluent time were optimized using standard analytical methods. Results: The optimized method for assessment of Cd in food and water samples shows good reliability. The optimum conditions were found to be a 0.20-150 µg L-1 linear range, 0.06 µg L-1 LOD, 0.20 µg L-1 LOQ, 4.3 RSD %, and a preconcentration factor of 160. Conclusions: The statistically experimental variables were utilized using a central composite design (CCD). The present method is a low-cost, simple, sensitive, and very effective tool for the recovery of Cd.

Ultrasound-assisted alkanol-based nanostructured supramolecular solvent for extraction and determination of cadmium in food and environmental samples: Experimental design methodology

Herein, a new and green analytical method was described for extraction and determination of cadmium in food and environmental samples using ultrasound assisted alkanol-based nano structured supramolecular solvent microextraction (UA-alkanol-based-SUPRAS-ME) coupled with flame atomic absorption spectrometry (FAAS) detection. The SUPRAS was easily prepared from reverse micelles of 1-tetradecanol (as extraction solvent) in tetrahydrofuran (THF as dispersive solvent). The Box-Behnken design based on the analysis of variance and the desirability function guide was used to optimize the key variables (pH, SUPRAS volume, ligand amount, ultrasonic time) of the UA-alkanol-based-SUPRAS-ME procedure. Under the optimum conditions, the calibration graphs were linear in the range of 50–3500 µg kg−1 and 1–400 ng mL−1 for foods and environmental samples, respectively. Acceptable limits of detection (LODs) of 15 µg kg−1 and 0.3 ng mL−1 were calculated for food and environmental samples, respectively. Inter day RSDs% lower than 4.9% with an average recovery of 99.8%, and intraday RSDs% lower than 4.1% with an average recovery of 97% were obtained. Total cadmium was determined in the range of 48.2–186.4 µg kg−1 and 35.4–124.6 ng mL−1 in food and environmental samples, respectively.

Response surface methodology and hydrophobic deep eutectic solvent based liquid phase microextraction combination for determination of cadmium in food and water samples

In this work, an ecologically friendly, cheap, and highly efficient hydrophobic deep eutectic solvent based liquid phase microextraction procedure was developed and coupled with flame atomic absorption spectrometry for determination of cadmium. Hydrophobic deep eutectic solvent (HDES) was prepared by mixture of trihexyltetradecylphosphonium chloride and pivalic acid and used as extraction solvent. The formation of cadmium complex was achieved by sodium diethyldithiocarbamate trihydrate. Response Surface Methodology by Box–Behnken Design and three different models was used for optimizing experimental conditions and statistical analysis. Analytical parameters such as limit of detection, limit of quantification, relative standard deviation and enhancement factor were calculated as 1.6 µg L−1, 5.0 µg L−1, 3.3% and 43, respectively. Finally, the developed liquid phase microextraction method was applied to some food and water samples.

A highly selective and sensitive ultrasonic assisted dispersive liquid phase microextraction based on deep eutectic solvent for determination of cadmium in food and water samples prior to electrothermal atomic absorption spectrometry

A simple, fast, green, sensitive and selective ultrasonic assisted deep eutectic solvent liquid-phase microextraction technique was used for preconcentration and extraction of cadmium (Cd) in water and food samples by electrothermal atomic absorption spectrometry (ETAAS). In this technique, a synthesized reagent (Z)-N-(3,5-diphenyl-1H-pyrrol-2-yl)-3,5-diphenyl-2H-pyrrol-2-imine (Azo) was used as a complexing agent for Cd. The main factors effecting the pre-concentration and extraction of Cd such as effect of pH, type and composition of deep eutectic solvent (DES), volume of DES, volume of complexing agent, volume of tetrahydrofuran (THF) and ultrasonication time have been examined in detail. At optimum conditions the value of pH and molar ratio of DES were found to be 6.0 and 1:4 (ChCl:Ph), respectively. The detection limit (LOD), limit of quantification (LOQ), relative standard deviation (RSD) and preconcentration factor (PF) were observed as 0.023 ng L−1, 0.161 ng L−1, 3.1% and 100, correspondingly. Validation of the developed technique was observed by extraction of Cd in certified reference materials (CRMs) and observed results were successfully compared with certified values. The developed procedure was practiced to various food, beverage and water samples.

Ultrasound-assisted emulsification of solidified floating organic drop microextracted for pre-concentration of cadmium in food and water samples

This work showed the developed of analytical method for determination of cadmium in foods and water samples using ultrasound assisted emulsification of solidified floating organic drop microextraction with 1-(2-thiazolylazo)-p cresol (TAC).

Application of Supramolecular Microextraction and Flame Atomic Absorption Spectrometry for Ultra-trace Determination of Cadmium in Food and Water Samples

Application of Supramolecular Microextraction and Flame Atomic Absorption Spectrometry for Ultra-trace Determination of Cadmium in Food and Water Samples

Direct determination of cadmium in foods by solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry using a tungsten coil trap

In this work, a solid sampling device consisting of a tungsten coil trap, porous carbon vaporizer and on-line ashing furnace of a Ni–Cr coil was interfaced with inductively coupled plasma mass spectrometry (ICP-MS). A modified double gas circuit system was employed that was composed of carrier and supplemental gas lines controlled by separate gas mass flow controllers. For Cd determination in food samples using the assembled solid sampling ICP-MS, the optimal ashing and vaporization conditions, flow rate of the argon–hydrogen (Ar/H2) (v:v=24:1) carrier gas and supplemental gas, and minimum sampling mass were investigated. Under the optimized conditions, the limit of quantification was 0.5pg and the relative standard deviation was within a 10.0% error range (n=10). Furthermore, the mean spiked recoveries for various food samples were 99.4%–105.9% (n=6). The Cd concentrations measured by the proposed method were all within the certified values of the reference materials or were not significantly different (P>0.05) from those of the microwave digestion ICP-MS method, demonstrating the good accuracy and precision of the solid sampling ICP-MS method for Cd determination in food samples.

Heated Slurry Sampling for the Determination of Cadmium in Food by Electrothermal Atomic Absorption Spectrometry

A heating procedure is reported with slurry sampling electrothermal atomic absorption spectrometry to improve the accuracy of cadmium determination in food. In comparison to conventional slurry sampling, the heating significantly increased cadmium recovery and improved the precision. For the optimized procedure, 25–250 mg of food were treated with 2% HNO3 and 1% H2O2 with heating at 120°C for 20 min, followed by the addition of 50 µL of 10% Triton X-100, and homogenization in an ultrasonic bath prior to analysis. Tungsten and rhodium were employed as a permanent modifier with optimum pyrolysis and atomization temperatures of 500°C and 1500°C. Calibration with aqueous standards resulted in good agreement between certified or information values and measured results at the 95% confidence level. A characteristic mass of 0.8 ± 0.1 pg and a detection limit of 0.7 ng g−1 for a 2% slurry were obtained. The method was employed for the direct determination of cadmium in food certified reference materials.

Dispersive liquid–liquid microextraction combined with flame atomic absorption spectrometry for determination of cadmium in environmental, water and food samples

A simple and reliable method for rapid and selective extraction and determination of trace levels of Cd2+ was developed by dispersive liquid–liquid microextraction (DLLME) coupled to flame atomic absorption spectrometry (FAAS) detection. The main factors affecting the DLLME, such as concentration of DPTH, pH, extraction and disperser solvent type and their volume, were optimized for the best extract efficiency. Under the optimum conditions, i.e., pH 5.4, [DPTH] = 6 × 10−3%, a preconcentration factor of 55 was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 0.4 μg L−1. The precision for 14 replicate determinations at 30 and 100 μg L−1 of Cd was 2.7% and 1.9% relative standard deviation (R.S.D.), respectively. The calibration graph using the preconcentration method was linear from 5 to 100 μg L−1, with a correlation coefficient of 0.9898. The proposed method was successfully applied to the preconcentration and determination of cadmium in food, vegetation, and water samples and in a BCR-176 standard reference material.

Determination of ultratrace cadmium in food and environmental samples by ETAAS after vapor generation and in situ preconcentration

A method is described for the determination of ultratrace cadmium by coupling a continuous flow vapor generation system with in situ preconcentration technique and electrothermal atomic absorption spectrometry (ETAAS). A graphite tube coated with Ir as permanent chemical modifier was used for trapping cadmium vapor species. The effects of the flow rates of carrier gas and sample injection in vapor generation systems on the trapping measurement for cadmium were respectively investigated. Graphite tubes with different characteristic surfaces were comparatively studied for trapping cadmium vapor. The experimental results showed that the permanent chemical modifier of Ir is an alternative to the thermolabile modifier of Pd for simplifying the trapping measurement. The trapping efficiency of cadmium on the graphite tube coated with Ir was estimated. The trapping temperature and time were also investigated. A detection limit (3σ) of 0.005 μg·L−1 was obtained for this proposed method. The relative standard deviation (RSD) was 1.4% for 0.5 μ·L−1 of Cd (n = 11). This method can be applied to the determination of ultratrace cadmium in food and environmental samples with good agreement between the certified and found values.

Development of a slurry technique for the determination of cadmium in dried foods by electrothermal atomisation atomic absorption spectrometry

A method is described for the the determination of cadmium in foods by atomic absorption spectrometry with direct slurry introduction into an electrothermal atomiser. Oxygen infusion facilitates in situ ashing of samples and avoids the build up of carbonaceous residue in the tube. The optimised conditions obtained for instrumental and slurry formation are detailed. Statistical evaluation of results from certified material indicate that the slurry method is both accurate and comparable in precision to traditional wet- and dry-ashing procedures. Calibration is achieved by a simple standard additions technique.

Determination of Low Levels of Cadmium in Foods Using a Chelating Ion Exchange Resin

Abstract A method is described for the determination of cadmium in foods which utilizes the AOAC HN03, H2S04, H202 digestion procedure catalyzed by V2O5. The cadmium is separated from the neutralized digest by a chelating ion exchange resin, eluted with H2S04, and determined by atomic absorption spectrophotometry. The average recovery of 0.30 ppm cadmium added to 7 commodities was 94% with a standard deviation of 2.8%, which compares favorably with the AOAC dithizone extraction method. The transfer, washing, and elution of 6 samples by the proposed method requires approximately 2 hr. The method allows the determination of as little as 10 ppb cadmium.

Collaborative Study of a Method for the Atomic Absorption Spectrophotometric and Polarographic Determination of Cadmium in Food

Abstract The method studied involves acid digestion, dithizone extraction, and determination by atomic absorption spectrophotometry and polarography. This study consisted of 2 phases, with 10 laboratories participating in Phase I and 15 laboratories in Phase II. The 12 commodities studied (lettuce, potatoes, orange juice, shredded wheat, milk, sugar, eggs, fish, frankfurters, rice, beans, and oysters) were spiked at 0.05, 0.1, 0.2, 0.4, 0.5, 1.0, 1.5, and 2.0 ppm cadmium. Only 3 collaborators submitted polarographic results. There were no statistically demonstrable differences for the atomic absorption method between spiking levels, commodities, or laboratories. Coefficients of variation were acceptable. The atomic absorption spectrophotometric method for determining cadmium has been adopted as official first action.