Determination Of Arsenic Research Articles

Natural mineral assisted photochemical vapor generation for determination of trace inorganic arsenic by inductively coupled plasma mass spectrometry

Photochemical vapor generation (PVG) is regarding as an alternative sampling technique of atomic spectrometry, which not only has the advantages of traditional chemical vapor generation (CVG), but also is simple, safe and environmentally friendly. The addition of transition metal ions (such as Fe, Ni, Co, and Cd) can significantly improve the conversion efficiency of elements in PVG and achieve high sensitivity. In this work, the natural mineral (the tailing of vanadic titanomagnetite) is firstly reported as the sensitizer in PVG for highly sensitive detection of elements with inductively coupled plasma mass spectrometry (ICP MS) measurement. As (III) was selected as the analyte. The main factors affecting the photocatalytic activity of the natural mineral and the analytical sensitivity of As(III) were systematically investigated. Under the selected conditions, the analytical sensitivity of the proposed method is about 3 and 4 times higher than that of the ferric ions and the nano-Fe3O4 assisted PVG systems of As(III), respectively. Compared with commercial nano-Fe3O4, the nature mineral shows better stability in PVG medium. In addition, the possible mechanism of the tailing of vanadium titanomagnetite assisted PVG of As (III) was also investigated. It was found that the presence of V and Ti facilitates the photochemical reduction of As. The new finding in this work is important for developing novel catalytical materials in PVG and understanding the environmental impact of the tailings on ecological environment. The proposed method has been successfully applied for the detection of As in natural waters and certified reference materials (GBW 07305a and GBW 07303a).

Determination of Arsenic(III) and Total Arsenic at Trace Levels in Baby Food Samples via a New Functionalized Magnetic Graphane Oxide Nanocomposite.

Baby food safety is an essential issue in health policy. For this reason, a simple, cheap, and fast analytical procedure to developed arsenic(III) and total arsenic determination in baby food samples using functionalized magnetic graphane oxide nanocomposite. A new nanocomposite anchored of tiopronin (TSH) magnetic graphane oxide (GO-PG4@Fe3O4-TSH) was first synthesized/characterized and used as an adsorbent to determine arsenic(III) and total arsenic for baby food samples. Arsenic(III) was directly determined on GO-PG4@Fe3O4-TSH nanocomposite at pH 4.5. The determination of total arsenic used KI and L( +) ascorbic acid solution as reducing reagents. The parameters influential on arsenic(III) determination in the baby food samples including the sample's pH, adsorption time, amount of GO-PG4@Fe3O4-TSH, eluent type, sample volume, reducing reagent type and amount, and also foreign ion effect were investigated. The GO-PG4@Fe3O4-TSH carrying As(III) could easily be separated from baby food samples via applying an external magnetic field. The detection limit for arsenic(III) was found as 0.11μg L-1, while the limit of quantification values was computed as 0.37μg L-1. The precision of results, expressed as relative standard deviation, was always lower than 1.6% at 1mg L-1 As(III) levels. The accuracy of this method was confirmed by analysis of certified reference material. The method was successively applied to determine arsenic(III) and total arsenic in baby food samples.

UV-Vis Spectrophotometric Determination of Selected Heavy Metals (Pb, Cr, Cd and As) in Environmental, Water and Biological Samples with Synthesized Glutaraldehyde Phenyl Hydrazone as the Chromogenic Reagent

A simple, sensitive, selective, and non-extractive UV-Vis spectrophotometric method for the determination of cadmium, lead, chromium, and arsenic in biological, soil and water samples using synthesized and characterized phenyl hydrazone; glutaraldehydephenyl hydrazone (GPH) as the chromogenic reagent was developed. GPH was synthesized as new chromogenic analytical reagents for the direct UV-Vis spectrophotometric determination of the selected metals of interest in a slightly acidic pH of 6.5-7.5 and 20 % dimethylformamide (DMF) solution to give stable coloured metal-ligand complexes. The reactions were instantaneous; the wavelengths of maximum absorptions were followed spectrophotometrically and noted. The reagent GPH revealed a wavelength of maximum absorption between 360.0 (Cr) to 395.0 nm for (Pb and As) at a working pH of 6.5 to 7.5 room temperature (37 °C). The reagent GPH had a molar absorptivity (L mol-1 cm-1) ranging from 2.213×104 (Pb) to 2.460×104 (As), a mole ratio of metal to ligand of 2:1, the detection limit (µg/g) ranging from 0.3432 (As) to 0.5250 (Pb) and the metal-ligand complex was stable for 0-48 hours. The reagents had a Beer’s law validity range (mg L-1) of 0.001 to 100. The Sandell’s sensitivities (µg/cm2) ranged from 0000409 (As) to 0.00499 (Pb) for APDH and 0.00406 (As) to 0.00452 (Pb) respectively. Large excess of cations and anions as possible interferences up to 15 folds were studied and do not interfere with the determination of the selected metals of interest. The developed method is highly selective for Cd, Pb, and Cr and As and was successfully used for the determination for the said elements in soil, water, and biological samples. The results of the developed methods were comparable with AAS and were found to be in good agreement. The method had very high precision and very good accuracy.

Determination of inorganic arsenic, heavy metals, pesticides and mycotoxins in Indian rice (Oryza sativa) and a probabilistic dietary risk assessment for the population of Saudi Arabia

In this study, total arsenic (As), inorganic arsenic (iAs), cadmium (Cd), lead (Pb), mercury (Hg), pesticides, and aflatoxins (B1, B2, G1, G2) in Indian rice (Oryza sativa) and their dietary exposure risks for the general Saudi population were evaluated. A total of 483 samples were acquired from various ports and supermarkets throughout the country. Average elemental concentrations were found to be in the following order: As (0.1 ± 0.024)>iAs (0.038 ± 0.015)>Pb (0.023 ± 0.008)>Cd (0.019 ± 0.005)>Hg (0.002 ± 0.0004), and results did not exceed maximum residue limits (MRLs). Out of the 294 analyzed pesticides, 15 were detected in rice, of which six were fungicides, and nine were insecticides with a detection frequency of 22% and 26%, respectively. Eight of the detected pesticides were non-approved by the European Union (EU) commission, but their detection frequencies were low. Surprisingly, rice samples analyzed for aflatoxins were below the limit of quantification (LOQ). Risk assessment coupled with Monte Carlo simulation based on the hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) approaches revealed that exposure to metal(loid)s and pesticides in rice were below levels that might pose a health risk.

Limits for the Content of Heavy Metals and Arsenic as a Means of Ensuring Safe Use of Herbal Medicinal Products

Herbal medicinal products (HMPs) are widely used in medical practice due to their availability, ease of use, and relatively safe pharmacological profile. However, medicinal plants are capable of accumulating heavy metals and arsenic which can have toxic effect on the human body when found in HMPs. The aim of the study was to summarise and analyse requirements of the Russian and foreign pharmacopoeias for the limits of heavy metals and arsenic in HMPs. National and regional pharmacopoeias have limits for the content of the major toxic elements (lead, cadmium, mercury, chromium, and arsenic) in HMPs. The study showed that the Indian and Japanese pharmacopoeias include only semi-quantitative methods for determination of heavy metals and arsenic, while the Russian and Chinese pharmacopoeias allow for the use of both quantitative and semi-quantitative methods. It was demonstrated that the limits for heavy metals and arsenic are the same for herbal substances and HMPs. The development of consistent approaches to determination of heavy metals and arsenic content, a systematic transition to quantitative methods of analysis, and establishment of individual limits for toxic elements in different HMP dosage forms, will make it possible to achieve the so-called consistent harmonisation, ensure reliable assessment of the content of heavy metals and arsenic, and minimize the risk of their entering human body with HMPs.

Regulation of transgelin and GST-pi proteins in the tissues of hamsters exposed to sodium arsenite

Regulation of transgelin and GST-pi proteins in the tissues of hamsters exposed to sodium arsenite

Determination of elemental impurities of Arsenic, Cadmium, Mercury, Lead and Palladium content in Testosterone propionate by using ICP-MS

The aim of the present work is to develop and establish a validated analytical method for the determination of arsenic, cadmium, mercury, lead and palladium content in testosterone propionate by using inductive coupled plasma mass spectroscopy (ICP-MS). Samples were analyzed after a preparation of sample solution by dissolving in suitable solvents of concentrated nitric acid and concentrated hydrochloric acid. In the present method, RF power of 1550 watts, RF matching is 1.80 V, nebulizer flow of 0.10 rps and plasma view at spectrum mode were used. Octopole conditions are He flow is on, He flow rate is 4.3 mL/min and energy discrimination is 3.0 V were used. Significant savings in sample volumes, reagents, analysis cost and time are realized. Arsenic, cadmium, mercury, lead and palladium are primary concerned due to their high toxicity and potential contaminants should be limited in testosterone propionate and the developed method was validated according to ICH and USP guidelines. The correlation coefficient, recovery rate, LOD and LOQ reached the acceptable limits. The validated method was selective, sensitive, rapid and capable of the determination of elemental impurities of arsenic, cadmium, mercury, lead and palladium content in bulk drugs.

Evaluation of Arsenic Concentration in Poultry and Calf Meat Samples by Hydride Generation Atomic Fluorescence Spectrometry

A simple, cost effective hydride generation atomic florescence spectrometry (HG-AFS) method was used for determination of total arsenic (As) in poultry and calf meat samples. The samples were digested in long necked glass digestion tubes using concentrated HNO3, HClO4 and H2SO4 as a mixture. The volume of acids (HNO3, HClO4) and the amount of sample to be used for digestion were optimized to achieve appropriate digestion. The accuracy of the proposed HG-AFS method was tested with certified reference material (DOLT 3 Dogfish Liver, NRC, Canada) and obtained results were in good agreement with certified value. The method limit of detection (LOD) value was calculated as 0.3 ng/g and dynamic range was 25 – 5000 pg/ml. Arsenic concentrations of poultry and calf meat samples were determined accurately by using aqueous calibration standards. Totally 31 samples (calf, chicken and turkey) obtained from local markets were analyzed. It was found that the average As concentration in calf meat (12.1 ± 3.9 ng/g) was significantly higher than the poultry samples whereas the arsenic concentrations were similar in turkey (3.1 ± 1.2 ng/g) and chicken (2.8 ± 1.1 ng/g) samples. In addition, dietary intake estimation of arsenic through consumption of calf and poultry meat was calculated and according to the gathered results daily intake of arsenic via calf meat was almost two times higher than poultry meat.

Highly selective and sensitive colorimetric detection of arsenic(III) in aqueous solution using green synthesized unmodified gold nanoparticles

A simple, efficient, economically viable, and fast analytical method to perform arsenic (As3+) determination using silk sericin capped gold nanoparticles (SS-AuNPs) and UV–Visible spectroscopy as a detection technique is reported. In this work, biomediated AuNPs were synthesized using an eco-friendly biomaterial Bombyx mori SS. Formation of the AuNPs was verified by surface plasmon spectrum using UV–Visible spectroscopy. The crystalline structure of the AuNPs was characterized by X-ray diffraction technique. Morphologically spherical in shape with good dispersion and average diameter of 12.5 nm was revealed by transmission electron microscope (TEM). The size and shape of the AuNPs are greatly associated with their optical properties. When the As3+ions are added to SS-AuNPs the color change occurs due to the aggregation of AuNPs allowing the detection of As3+at parts per billion (ppb). Results showed an excellent correlation (R2=0.985) exists between the decrease in the absorbance signal and the As3+ concentrations over the range from 1 ppb to 10 ppb. The limit of detection (LOD) of As3+ ions is found to be 2.94 ppb (3σ) and is many folds lower than the world health organization (WHO) recommended limit of 10 ppb. The described study could be a very useful method for the detection of As3+ ions in water and offers a basis for developing an optical sensing system for different applications.

Speciation of As(III) and As(V) in Food by Magnetic Dispersive Microsolid Phase Extraction with Dispersive Liquid–Liquid Microextraction with Graphite Furnace Atomic Absorption Spectrometry (GFAAS) Detection

Magnetic dispersive microsolid phase extraction (MDMSPE) was coupled with dispersive liquid–liquid microextraction (DLLME) for the separation and preconcentration of arsenic(V) and arsenic(III) prior to graphite furnace atomic absorption spectrometry detection. In the first step, magnetic ZnFe2O4 nanotubes were employed for adsorbing arsenic(V). The adsorbent was separated from the aqueous phase by the use of an external magnetic field. Next, arsenic(III) in the upper aqueous phase from MDMSPE was enriched by DLLME. Samples were prepared with artificial gastric juice to avoid inter-conversion of the determined species. The parameters affecting the separation and preconcentration of the determined species were optimized. The detection limits of this protocol were determined to be 1.3 and 2.0 pg mL − 1 for arsenic(III) and arsenic(V) with relative standard deviations of 4.5% and 5.6% for a concentration of 1.0 ng mL − 1 (n = 9). The enrichment factors were equal to 175-fold for arsenic(III) and 163-fold for arsenic(V). The developed protocol was employed for the determination of arsenic(III) and arsenic(V) in dairy products without preoxidation or prereduction. The recoveries of spiked samples were from 90.8% to 105%. A milk powder certified reference material was analyzed by this approach and the measured results were in good agreement with the certified value.

Determination and uncertainty analysis of inorganic arsenic in rice by UHPLC-ICPMS

The present study arose from the need of to determine inorganic arsenic (iAs) at low levels in rice. Ultra-high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (UHPLC-ICPMS) using Kinetic Energy Discrimination (KED) mode to eliminate spectral interferences was used for analysis of iAs. Sample preparation involves extraction of inorganic arsenic (sum of As3+ and As5+) with water by heating at 90 °C for 5 min in water bath. Separation is accomplished with a reversed-phase ion pack column using a gradient chromatographic method followed by ICPMS analysis within 5 min. The method was validated in accordance with Commission Regulation (EU) No 836/2011 and performance characteristics were verified. Acceptable values were obtained for specificity, repeatability (HorRatr < 0.6), within-lab reproducibility (HorRatR < 0.3) with recovery 80-90%, limit of quantification (0.02 mg/kg), fitness-for-purpose and trueness (using CRM); thus, the method can be considered for official control purposes.

Image Reversal Resist Photolithography of Silicon-Based Platinum and Silver Microelectrode Pattern

Silicon-based platinum (Pt) and silver (Ag) microelectrodes are constructed using photolithography technique and used in detecting arsenic activity in different electrolytes. Pt and Ag have good properties either as a working, a counter, or a reference electrode due to their low electrical resistance, high melting point, and high chemical stability. This chemical sensor has the ability to detect the changes in the level or activity of arsenic in electrolytes. Patterning these metals by wet chemical or dry etching is not a feasible process as these metals cannot be etched properly. The lift-off process can be applied to ease the etching process, but it has a major problem whereby the metal particles or ears may remain at the edges at the end of the process. The process variables, particularly the resist slope, were investigated to reduce possible defects using an image reversal resist. The thickness and angle of the resist side wall were measured by SEM. The effects of many factors that may influence or resist steep angle formation were analyzed and optimized with the Design of Experiment (DOE) technique to achieve the target recipe of resist angle < 60°. The lower angle of the resist side wall resulted in a better percentage yield of good electrode pattern after the lift-off process. The ability of fabricated microelectrode and influence of supporting electrolytes in arsenic determination were discussed.

MnFe2O4 micromotors enhanced field digestion and solid phase extraction for on-site determination of arsenic in rice and water

Despite the increased interest and great progress obtained on arsenic test, it is still a challenge to accomplish the on-site determination of arsenic in rice due to the expensive instrumentation and harsh digestion process. In this work, MnFe2O4 micromotors were found to retain high catalytic activity to simultaneously produce large amounts of hydroxyl radicals and O2 bubbles in the presence of H2O2. Interestingly, the generated bubbles autonomously propel the micromotors and prevent them from depositing, thus keeping their high catalytic activity. As a result, a MnFe2O4 micromotors enhanced digestion method was developed for the field digestion of rice samples within 100 min only using H2O2, which was further utilized to realize the on-site detection of arsenic in rice by coupling with the Gutzeit method followed headspace solid phase extraction. A quantification limit of 40 μg kg−1 was obtained for the determination of arsenic in rice. Owing to their capabilities of the efficient and rapid adsorption of arsenic and continuous movement, a MnFe2O4 micromotors enhanced solid phase extraction was also established for the sensitive determination of arsenic in water with a 1 μg L−1 of quantification limit. The accuracy of the developed method was validated via analysis of a Certified Reference Material of rice (GBW10043) and a series of rice and water samples with satisfactory results, showing promising potential in the sensitive on-site detection of arsenic in rice and water samples.

Interference-free determination of arsenic in urine by atomic absorption using two-stage probe atomization in a graphite furnace

Inductively coupled plasma mass spectrometry, hydride generation atomic absorption spectrometry and graphite furnace atomic absorption spectrometry are presently used to determine total arsenic in urine, but after labor consuming sample pretreatment. Therefore, we proposed a new approach to solve this problem using two-stage probe atomization. High-resolution continuum source graphite furnace atomic absorption spectrometer was equipped with the probe accessory for that. The sample consisting of 15 μL urine and 20 μg Pd-modifier was dried on the furnace bottom at smooth heating up to 120 оС and atomized at 2300 оС with internal Ar flow. The resulting vapors of As condensed on a tungsten probe installed above the dosing hole. At the same time, Ar flow removed an essential part of the matrix components without condensation. At the second atomization stage at 2300 оС and interrupted internal gas flow, the probe was lowered into the furnace and heated by electric current to accelerate condensate evaporation. This procedure fully separates the analytical signal from the finely structured molecular background. Matrix interference disappears due to significantly different rates of As and urinary phosphates binding with Pd at temperature of 120 °C and distillation on the probe. The limit of As detection in urine is 1.5 μg L−1 and quantification range is 50–1000 μg L−1 that almost covers the entire patients' urine concentration range of interest for environmentalists and physicians.

Simultaneous determination of arsenic and uranium by the diffusive gradients in thin films technique using Lewatit FO 36: Optimization of elution protocol

The sorption ability of Lewatit FO 36-DGT resin gel, which has been developed for arsenic determination, towards uranium was tested by batch experiments within this study for the first time. Since the uptake efficiency of uranium was 99.0 ± 0.4% and the maximum uptake capacity was not achieved even at the U spike of 1250 μg in the solution, the Lewatit FO 36 resin seems to be a suitable binding phase for DGT resin gels for the determination of uranium. The resin gel also does not display any significant sorption selectivity in favour of one element over another. A novel protocol for simultaneous elution of arsenic and uranium from Lewatit FO 36 resin gel was therefore proposed in this study. The elution efficiencies of 90.3 ± 3.9% and 85.2 ± 3.1% for As and U, respectively, were obtained using 5 mL of 1 M NaOH at 70 °C for 24 h. The comparison with the original elution protocol using microwave-assisted elution by 0.25 M NaOH and 0.17 M NaCl at 130 °C for 16 min indicates, that the novel elution protocol provides good results in the performance of arsenic elution and, in addition, allows simultaneous elution of uranium. Moreover, the elimination of NaCl from the elution process allows a fast and simple analysis of both elements using ICP-MS, and therefore, the Lewatit FO 36-DGT technique can become more commonplace among laboratories without the need to modify the analytical method as proposed in the original study.

Spectrometric Determination of Lead, Cadmium, Arsenic, Copper and Iron in Drinking Water Samples Across Kogi State, Nigeria.

The aim of the study was to determine the levels of lead, cadmium, arsenic copper and iron in 25 water samples collected from across Kogi State. Atomic absorption spectrometry was used in the determination of copper, iron, lead and cadmium while UV-visible spectrophotometer was employed in the determination of arsenic, based on the formation of Molybdoarsenate. The ranges of mean values obtained for the heavy metals are: Arsenic (0.0014to 0.0252 mg/L), Copper (0.0013to 0.0095 mg/L), Lead (0.0001to 0.024 mg/L), Cadmium (0.003 to 0.072 mg/L) and Iron (0.0068 to 0.1242 mg/L). The results revealed that the River, Stream and Tap water sampled were contaminated with Arsenic (As), whereas, the levels of Fe, Cu and Pb were within the recommended limit set by WHO and NAFDAC. Though the level of cadmium (Cd) falls within acceptable limit in some of water samples, its high concentration in Isanlu should attract the attention of the authority in this area in curbing the growing threat.

Uncertainty in Analytical Measurements: Approaches, Evaluation Methods and Their Comparison Based on a Case Study of Arsenic Determination in Rice

All measurements have uncertainty and they are not absolute. Therefore, identification, determination and evaluation of critical influencing factors based on recent approaches are important and necessary. Laboratories shall identify and evaluate all components and contributions to measurement uncertainty. In this article, two different approaches for evaluation of measurement uncertainty of arsenic in rice are studied and compared. These different approaches are GUM approach and Monte Carlo approach. The results clarified, evaluated uncertainty for the measurand was the same in the GUM and MCA, statistically and it is clarified that evaluated uncertainty by these approaches have no significant difference.

Hydrophobic deep eutectic solvent-based ultrasonic-assisted dispersive liquid-liquid microextraction for preconcentration and determination of trace cadmium and arsenic in wine samples

In present study, DL-lactic acid/trioctylmethylammonium chloride-based deep eutectic solvent (DES), which was considered as an environmental friendly extraction solvent to replace traditional organic reagent, was firstly presented for monitoring of trace cadmium (Cd) and arsenic (As) in wine samples by ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) method. Moreover, different extraction conditions, including the type and volume of DES and dispersive solvent, pH of the solution, salt amount, time of vortex and sonication, were systematically evaluated. At the optimized extraction conditions, good linear relationships (0.50–8.0 μg·L−1 for Cd, 2.0–50 μg·L−1 for As) were obtained and limits of detection of Cd and As were 0.080 and 0.30 μg·L−1, respectively. In addition, the accuracy (as recoveries %), and intra-/inter-day precision (as relative standard deviation %) were in the ranges of 90.6–103.6% and 2.9–4.5%, respectively. Finally, the proposed method was applied to analyze 6 kinds of wine samples, which possessed wide practical application value in monitoring heavy metal residues in wine and even complex food matrices.

Label-free colorimetric assay for arsenic(III) determination based on a truncated short ssDNA and gold nanoparticles.

A short ssDNA (Apt-21) rationally truncated from the parent 100nt As(III) aptamer was used for colorimetric determination of As(III). Apt-21 serves dual functions, i.e., recognition of trace As(III) and regulation of AuNPs dispersion by surface attachment, while gold nanoparticles (AuNPs) functioned as colorimetric signal reporters. Under the optimal conditions, the ratio of the absorbance at 650nm to 520nm (A650/A520) of AuNPs changed proportionally with increasing concentration of As(III), which showed a linear relationship within the concentration ranges 1-30 ppb and 30-100ppb with a detection limit of 0.18ppb. The feasibility of this assay was demonstrated by determining As(III) in spiked water samples with mean recoveries ranging from 96.5-107.1%. Schematic representation of colorimetric detection of As(III) based on the short ssDNA (Apt-21) and gold nanoparticles (AuNPs).

An Investigation of Toxic Metal Levels (Pb, Cd, Cr, As, Hg) in Dried Porphyra and Laminaria Collected from Coastal Cities, China.

This investigation was aimed at determining the concentration levels of five toxic heavy metals (lead, cadmium, chromium, arsenic, and mercury) in dried Porphyra and Laminaria samples from coastal city of China. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for determination of lead, cadmium and total arsenic. Atomic fluorescence spectrometry was used for mercury, and liquid chromatography coupled with ICP-MS was used for arsenic speciation. The mean concentrations of lead, cadmium, chromium, total arsenic, and mercury were 0.96 ± 0.03mg/kg, 2.62 ± 0.07mg/kg, 1.64 ± 0.08mg/kg, 36.67 ± 0.53mg/kg, and 7.56 ± 0.42μg/kg for Porphyra samples and 0.61 ± 0.03mg/kg, 0.48 ± 0.02mg/kg, 3.78 ± 0.56mg/kg, 43.85 ± 1.42mg/kg, and 46.61 ± 2.02μg/kg for Laminaria samples. The results were comparable with previous similar research. The potential health risk assessment was conducted by comparing the calculated weekly intakes of toxic metals from Porphyra and Laminaria with provisional tolerable weekly intake. Consumption of these seaweeds does not seem to pose a risk for the consumers' health regarding their content of heavy metals. However, the potential health risk of cadmium should not be overlooked for consumers with high intake of Porphyra.