Fast liquid chromatographic determination of radiochemical and chemical purity of [11C]methionine by UPLC technique

Salinity, water logging, high nitrate, fluoride and dissolved uranium concentration in drinking water of southwest Punjab has impacted the local population leading to health issues and additional burden on economy. Though it was known that both U and its daughter products especially Rn contribute to radiological dose to the population through drinking water, there were no correlation studies carried out between these radioactive elements in U impacted regions of southwest Punjab. In this study, an initiative has been taken to assess the doses due to dissolved radon in drinking water. In addition, the U–Rn couple is evaluated in detail along with other hydrochemical parameters. The radon concentration ranges from 360–1700 Bq/m³ for Faridkot and 140–1400 Bq/m³ for Muktsar for both seasons and the related average total dose due to radon for both season of Faridkot and Muktsar are 9.79 µS/year and 7.74 µS/year respectively. The total dissolved uranium is in range of 16–350 µg/L for Faridkot and 14–106 µg/L for Muktsar for both seasons. An inverse correlation was observed between Rn and U, which could be attributed to diverse geochemistry of U and Rn in groundwater.

     

Detection of uranium in industrial and mines samples by microwave plasma torch mass spectrometry

Microwave plasma torch (MPT), traditionally used as the light source for atomic emission spectrophotometry, has been employed as the ambient ionization source for sensitive detection of uranium in various ground water samples with widely available ion trap mass spectrometer. In the full‐scan mass spectra obtained in the negative ion detection mode, uranium signal was featured by the uranyl nitrate complexes (e.g. [UO₂(NO₃)₃]^?), which yielded characteristic fragments in the tandem mass spectrometry experiments, allowing confident detection of trace uranium in water samples without sample pretreatment. Under the optimal experimental conditions, the calibration curves were linearly responded within the concentration levels ranged in 10–1000 µg·l^?1, with the limit of detection (LOD) of 31.03 ng·l^?1. The relative standard deviations (RSD) values were 2.1–5.8% for the given samples at 100 µg·l^?1. The newly established method has been applied to direct detection of uranium in practical mine water samples, providing reasonable recoveries 90.94–112.36% for all the samples tested. The analysis of a single sample was completed within 30 s, showing a promising potential of the method for sensitive detection of trace uranium with improved throughput. Copyright © 2016 John Wiley & Sons, Ltd.     

Occurrence of uranium in groundwater of a shallow granitic aquifer and its suitability for domestic use in southern India

Groundwater used for domestic purpose without proper treatment should be free from chemical and biological contaminants. This study was carried out to assess the groundwater quality with respect to uranium in a part of Nalgonda district, Andhra Pradesh, India. Groundwater was regularly monitored for uranium concentration by collection of samples once every two months from March 2008 to November 2009 from 44 wells. The concentration of uranium in groundwater ranged from 0.2 to 118.4 ppb. Groundwater is unsuitable for domestic use in 2 % of this area based on the limit of 60 ppb prescribed by the Atomic Energy Regulatory Board of India. However, due the wide variation in limit suggested by different organizations and countries, the no-observed-adverse-effect level and lowest-observed-adverse-effect level (in mg/kg day) was used to understand the dosage of uranium that reaches the people through drinking water pathway. This level varied from 0 to 0.02 mg/kg day and 0 to 0.08 mg/kg day based on an uncertainty factor of 10 and 50 respectively for the mean uranium concentration in groundwater in each well. With an uncertainty factor of 50, 5 groundwater samples had uranium above 0.06 mg/kg day which is the lowest-observed-adverse-effect level. This study showed that with the presence of present level of uranium concentration in groundwater of this area there is no major threat to humans through the drinking water pathway.     

Chitosan impregnated Ca-alginate: a new hybrid material for removal of uranium from potable water

Novel sorbent, chitosan impregnated calcium alginate (Cal-Alg-Chi) bead was developed to sorb uranium from potable water without compromising water quality parameters. The uptake study in batch mode, showed more than 98% sorption of uranium in the concentration range of 0.1–50 µg mL⁻¹. Cal-Alg-Chi beads, reduced the concentration of uranium below 15 ng mL⁻¹ from 100 to 450 ng mL⁻¹ in groundwater collected from effected regions in India. Sorption isotherm followed Langmuir model and maximum sorption capacity was evaluated as 36.04 mg g⁻¹. The sorption was endothermic with ΔG ⁰ value of −9.76 kJ mol⁻¹ and kinetics followed pseudo-second order rate law.

     

Assessment of natural uranium and 226Ra concentration in ground water around the uranium mine at Narwapahar, Jharkhand, India and its radiological significance

A brief study on dissolved radionuclides in aquatic environment, especially in ground water, constitutes the key aspect for assessment and control of natural exposure. In the present study the distribution of natural uranium and ²²⁶Ra concentration were measured in ground water samples collected within a 10 km radius around the Narwapahar uranium mine in the Singhbhum thrust belt of Jharkhand, India in 2007–2008. The natural uranium content in the ground water samples in this region was found to vary from 0.1 to 3.75 μg L^?1 with an average of 0.87 ± 0.73 μg L^?1 and ²²⁶Ra concentration was found to vary from 5.2 to 38.1 mBq L^?1 with an average of 13.73 ± 7.34 mBq L^?1. The mean annual ingestion dose due to intake of natural uranium and ²²⁶Ra through drinking water pathway to male and female adults population was estimated to be 6.55 and 4.78 μSv y^?1, respectively, which constitutes merely a small fraction of the reference dose level of 100 μSv y^?1 as recommended by WHO.     

Studies on sorption of uranium on chitin: a solid-state extractant application for removal of uranium from ground water

Studies were carried out to remove uranium from aqueous systems based on the solid phase extraction of uranium by powdered chitin. The effects of various parameters like pH, contact time, and amount of chitin for quantitative sorption of uranium on chitin have been studied. The sorption studies with spiked water samples and natural ground water samples showed that uranium was easily sorbed onto powdered chitin between pH 3 and 6. The effects of various cations and anions, which are present in the water samples, were studied. The method is simple, fast and environmental friendly and it is unaffected by the other ions present in the natural waters. The accuracy of the method was evaluated by applying the present method on ground water samples containing uranium in the range of 100–2,200 μg/L. The uranium remained in water samples is <20 μg/L after treatment with chitin, which is below the AERB limits given for uranium in drinking water. The values are an average of five replicate measurements, with an RSD of ±10 μg/L at 100 μg/L uranium in water samples.     

Pollution at and below Sites used for Mixing and Loading of Pesticides

Sites used for mixing and loading of pesticides in sprayers and for washing tractors and sprayers may be point sources of pesticides. Pollution may be caused by accidental spills during filling, disposal of excess spray solution, rinsing of sprayer and tractor or from leaking nozzles on the sprayer. Ground water sampled 2-4 m below sites used for mixing and loading has been analysed for 23 or 46 different pesticides and metabolites in two Danish counties (Storstrøm and Bornholm). Further, the surface pollution at sites used for mixing, loading and rinsing was determined by elution with water of soil sampled in the top 10 cm. In all ground water samples pesticide pollution was determined to be above the European drinking water level (0.1 µg L m 1 ). The highest concentrations and most pesticides were found below loading and mixing sites at machine pools, where the highest concentrations were the phenoxyacid herbicides dichlorprop (750 µg L m 1 ) and 2,4-D (800 µg L m 1 ). The herbicides bentazone, mecoprop and dinoseb were also found in relatively high concentrations (5-60 µg L m 1 ). The surface soil sampled at the top 0-10 cm at sites used for loading and washing sprayers at six farms was eluted with water. These analyses also showed that many different pesticides and relatively high concentrations could be leached out from the soil. Twenty-four different pesticides and metabolites were found, and though most concentrations were below 10 µg L m 1 about 10% of the water samples contained more than 50 µg L m 1 . The results demonstrate that sites used for mixing, loading and washing can be seriously contaminated with pesticides even in ground water 2-4 m below the sites. This implies that ground water, nearby wells and well borings are at risk of pollution and indicates the need for better farm practice.     

Determination of aromatic amines in environmental water samples by deep eutectic solvent-based dispersive liquid-liquid microextraction followed by HPLC-UV

This study reports a deep eutectic solvent based dispersive liquid-liquid microextraction (DES-DLLME) to extract aromatic amines (4-chloroaniline, 3-nitroaniline, 2-naphtylamine) in environmental water samples before their HPLC-UV determination. The hydrophobic deep eutectic solvent (DES) was prepared by mixing bis(2-ethylhexyl) phosphate (BEHP) as a hydrogen bond acceptor and phenol as a hydrogen bond donor. Affecting factors on the extraction of the aromatic amines were investigated and optimized. Optimum conditions were: DES type: BHHP-Ph ratio: 1 to 2; pH of solution: 8.0; DES volume: 80 µL, salt amount: 10% (w/v). Under optimum conditions, the developed method showed a wide linear range of 0.2–200 µg L^?1 (R² ≥ 0.99) with satisfactory recoveries (≥90.0%). The limit of detections (LODs) and limit of quantifications (LOQs) were in the range of 0.07–0.17 µg L^?1 and 0.2–0.5 µg L^?1, respectively. The enrichment factors were 170, 180 and 190 for 4-chloroaninile, 3-nitroaniline, 2-naphtylamine, respectively. Based on obtained results, the proposed method is straightforward, efficient, sensitive, and eco-friendly for the extracting and determining of the aromatic amines in environmental water samples.     

An efficient biosorption‐based dispersive liquid‐liquid microextraction with extractant removal by magnetic nanoparticles for quantification of bisphenol A in water samples by gas chromatography‐mass spectrometry detection

In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption‐based dispersive liquid‐liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte‐containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5–500 µg/L with a coefficient of determination of R² = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84–120%) and acceptable relative standard deviation (1.8–14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.     

Release and speciation of uranium in low-ionic-strength groundwaters at an abandoned uranium mine in Val Vedello (Orobic Alp—Italy) by adsorptive cathodic stripping voltammetry

Adsorptive cathodic stripping voltammetry (AdCSV) with HDME and a chloranilic acid ligand was used in the trace analysis of uranyl ions at pH?=?2 in low-ionic-strength groundwaters around mining areas. Upon optimization, the limit of detection around 0.10?µg?L^?1 was found with linearity up to 10?µg?L^?1. In the abandoned mining area of Val Vedello (Orobic Alps, Italy), measured uranium concentrations in water ranged from 0.3?µg?L^?1 above the uranium mineralization levels to 145?µg?L^?1 in groundwaters percolating from mine galleries. Such uranium concentrations are related to natural weathering effects of CO₂ and/or hydrogen carbonate ion on uranium mineralizations under oxic conditions. A marked seasonal dependence was then found, in agreement with literature data on a pre-operational survey dating back to 1980–1981. No significant chemical impact of the abandoned mining activity on groundwater quality could be found. Accordingly, no significant increase in contaminants derived from the heat-burn of explosives, such as chloride and nitrate, in groundwaters from mine galleries was found.     

Determination of uranium in water based on enzyme inhibition using a wireless magnetoelastic sensor

The aim of this paper is to develop a wireless magnetoelastic sensing method for the determination of uranium in water based on the inhibitory effect of uranyl cation to α-amylase. In this method, a wireless sensor used for detecting uranium was fabricated by immobilizing a layer of starch gel on the surface of a magnetoelastic foil. When the sensor was in a solution containing α-amylase, the α-amylase catalyzed the hydrolyzation of starch, causing a resonance frequency shift of the sensor. Meanwhile, the catalytic hydrolyzation of starch was inhibited by uranium presented in the above solution, resulting in a decrease in the resonance frequency shift of the sensor. Consequently, the amount of uranium could be determined by measuring the resonance frequency shift. The influence of manifold variables on the determination was investigated in details. A linear range was found to be 9.2 to 103.5?µg?L^?1 under optimal conditions with a detection limit of 3.6?µg?L^?1. The method was applied to the determination of uranium in environmental water samples with satisfactory results.     

A comparative analysis of uranium in potable waters using laser fluorimetry and ICPMS techniques

The main objective of this work is the accurate measurement of uranium in the potable water sources of Muktsar district of Punjab, India. In the present work, a laser fluorimetry technique was used for the analysis of uranium. Inductively coupled plasma mass spectrometry (ICPMS) technique was also applied to verify and compare the uranium content analyzed using laser technique. About 16 samples from waterworks, bore wells, and hand pumps that supply the drinking water to local population were collected for this purpose. An indigenous laser fluorimeter supplied by RRCAT, Indore was employed for the analysis. Uranium concentrations obtained were in the range from 0 to 10???g?L^?1 in ten samples, 11?C30???g?L^?1 in three samples, and more than 100???g?L^?1 in three samples namely Channu ground water, Warning Khera pump, and Killanwale village hand pump. The USEPA guideline value for uranium in safe drinking water is 30???g?L^?1. Also, a data comparison with similar studies carried out in other countries is presented.     

Contribution of flyash from coal-fired thermal power plants to uranium contamination of ground water

The elemental concentration of uranium in flyash and coal samples has been investigated using EDXRF and WDXRF techniques. To check the contribution of flyash to uranium contamination of ground water in the Malwa region of Punjab, the flyash and coal samples are collected from Guru Nanak Dev Thermal Power Plant (GNDTPP) in the Bathinda district of Punjab state, India. It is found that uranium concentration in the flyash is below the detection limit of the XRF set up, i.e.?~?1 ppm. It is concluded that uranium contamination in the ground water of Malwa region is not due to the Thermal Power Plant.     

Aminophenyl Benzimidazole as a New Reagent for the Estimation of NO2/Nitrite/Nitrate at Trace Level: Application to Environmental Samples

Abstract

A simple and sensitive spectrophotometric method for the determination of nitrogen dioxide in ambient air and nitrite/nitrate in water and soil samples has been developed. Nitrogen dioxide in air has been fixed as nitrite ion using alkaline sodium arsenite as absorbing medium. The method is based on the reaction of nitrite with aminophenyl benzimidazole in acid medium to form diazonium ion, which is coupled with N‐(1‐naphthyl)ethylenediamine dihydrochloride to form an azo dye with an absorption maximum at 555 nm in aqueous phase. The method obeys Beer's law in the concentration range 0–10 µg of nitrite in 25 ml solution. The molar absorptivity has been found to be 6.3×10⁴ l mol^?1 cm^?1. The dye can be extracted quantitatively into isoamyl alcohol under alkaline condition and the addition of methanolic hydrochloric acid restores the original dye colour. Beer's law is obeyed in the concentration range 0–2 µg of nitrite with a detection limit of 0.009 µg. The effect of interfering species has been studied and the developed method has been applied to determine trace levels of nitrogen dioxide in ambient air and the results have been compared with the standard method. It is also applied to measure the nitrite/nitrate levels of surface and ground water samples collected from lakes, tube wells as well as soil samples.     

Label-free Microcantilever Immunosensor Based on a Competitive Immunoassay for the Determination of Clenbuterol

A label-free microcantilever immunosensor based on a competitive immunoassay is reported for the determination of clenbuterol. The immunosensor was fabricated by modifying clenbuterol–ovalbumin on the gold surface of the microcantilever with crossing linkage by L-cysteine and glutaraldehyde. Atomic force microscopy was utilized to characterize the construction of immunosensor and to measure the deflection of the microcantilever. The deflection response of the microcantilever was in negatively proportional to the concentration of clenbuterol from 1.0?×?10^?2 to 20?µg/L with a limit of detection of 1.0?×?10^?2?µg/L. The fabricated immunosensor was used to determine clenbuterol in pork samples with satisfactory results. In addition, the results were in accordance with those obtained by high-performance liquid chromatography. The reported immunosensor displayed high sensitivity and specificity together with excellent repeatability and reliability.     

Determination of Ultra-Trace Amouris of Uranium by Icp-Aes Technique

Abstract

An Atomic Emission Spectrometric method based on the use of Inductively coupled argon Plasma source has been developed for the determination of ultra trace concentrations of uranium in aqueous solutions. Using the optimised experimental conditions for the ICP source, uranium can be determined at 0.05 μg/ml concentration in 0.3M HNO₃ solutions with either of the two analytical lines viz. 3859.6 Å or 4090.1 Å. The precision of determinations at the lowest detection limit is better than 2% R.S.D. The uranium estimation has been corrected for the interference due to the presence of eighteen metallic elements using an inter-element correction procedure. A number of spiked samples and NBL reference samples with concomitant impurities have been analysed using the standardised procedure and good agreement has been observed with their certified values.     

Spectrophotometric determination of trace-level bromate in drinking water after post-column reaction with pararosaniline based on multi-walled carbon nanotubes

A simple and sensitive spectrophotometric method is described for low level determinationof bromate in drinking water. This method is based on the reduction of bromate ions into bromine in the presence of pararosaniline by sodium metabisulphite to form a highly stable pink-red complex measured at 540 nm. Maximum colour formation was obtained at about 45 min. Multi-walled carbon nanotubes, a solid phase extraction sorbent, has been described for the removal of cationic interferences of major elements and heavy metals from water samples prior to conducting the assay. Bear’s law is obeyed in the range of 5–80 µg.L^?1 with limit of detection of 0.44 µg.L^?1 and correlation coefficient of 0.998 (n = 5). The mean relative standard deviation (RSD%) of the results within-day precision and accuracy were ≤1.2% which confirmed the reproducibility of the assay technique. The optimum assay conditions and their applicability to the determination of water samples are described. The method was successfully applied for the determination of bromate in water samples with satisfactory results and recommended to be applied in all desalination plant samples.     

Determination of trace amounts of cadmium by modified graphite furnace atomic absorption spectrometry after liquid phase microextraction

A simple and powerful microextraction technique was used for determination of cadmium in water samples using liquid phase microextraction (LPME) followed by graphite furnace atomic absorption spectrometry (GF-AAS). In a preconcentration step, cadmium was extracted from a 2 mL of its aqueous sample in the pH = 6 as cadmium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) cationic complex into a 4 µL drop of nitrobenzene and ammonium tetraphenylborate as counter ion. In the drop, the cadmium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) ammonium tetraphenylborate ion associated complex was formed. After extraction, the microdrop was retracted and directly transferred into a graphite tube modified by [Pd_(c) + Pd_(i)]. Some effective parameters on extraction and complex formation, such as type and volume of organic solvent, pH, concentration of chelating agent and counter ion, extraction time and stirring rate were optimized. Under the optimum conditions, the enrichment factor and recovery were 390 and 78%, respectively. The calibration graph was linear in the range of 0.01–1 µg L^− 1 with correlation coefficient of 0.9952 under the optimum conditions of the recommended procedure. The detection limit based on the 3Sb criterion was 0.0065 µg L^− 1 and relative standard deviation (RSD) for eight replicate measurements of 0.1 µg L^− 1 and 0.4 µg L^− 1 cadmium was 6.4 and 5.8% respectively. The characteristic concentration was 0.0014 µg L^− 1 equivalent to a characteristic mass of 5.6 fg. In order to evaluate the accuracy and recovery of the presented method the procedure was applied to the analysis of reference materials and seawater.     

Electrochemical Oxidation of Astaxanthin on Glassy‐carbon Electrode and its Amperometric Determination Using Batch Injection Analysis (BIA)

This work presents the electrochemical oxidation of the antioxidant astaxanthin on a glassy‐carbon electrode (GCE) and its amperometric determination in salmon samples using a batch‐injection analysis (BIA) system. The proposed BIA method consisted of 80‐µL a fast microliter injection of sample at 193 µL s^?1 on the GCE immersed in the electrolyte, a mixture of acetone, dichloromethane, and water (80 : 10 : 10 v/v), containing 0.1 mol L^?1 HClO₄. Advantages include high precision (RSD of 2.4 %), sample throughput of 240 h^?1, and low detection limit (0.3 µmol L^?1 that corresponds to 0.1 µg g^?1) for the analysis of acetone extracts of salmon samples. Recovery values between 83 and 97 % attested the accuracy of the method.