Determination of ultratrace amounts of plutonium in high saline groundwater by inductively coupled plasma mass spectrometry

For determination of ultratrace amounts of plutonium in high saline groundwater, large-volume sampling and preconcentration are necessary. However, traditional co-precipitation methods, such as Fe(OH)₃, Ca(OH)₂–Mg(OH)₂ and hydroxide-carbonate co-precipitation, are unable to meet the requirements of preconcentration of the ultratrace plutonium in high saline groundwater. In this paper, the ultratrace plutonium in high saline groundwater was concentrated by sequential co-precipitation with MnO₂ and Fe(OH)₃, and purified by two-stage anion-exchange separation on Dowex1 × 4 resin column. Quadrupole ICP-MS was employed for the determination of ²³⁹Pu with ²⁴²Pu spiked. After co-precipitation and purification, the major matrix elements were significantly decreased to μg mL^?1 level and decontamination factor of uranium is better than 10⁶. The detection limit for ²³⁹Pu in 50 L high saline water is 2.1 × 10^?16 g L^?1. Three high saline fountain samples (total dissolved solids more than 20 g L^?1) from Dunhuang region of China were analyzed using this method. The concentrations of ²³⁹Pu in these samples were 0.48 ± 0.2 × 10^?15, 1.40 ± 0.10 × 10^?15 and 2.13 ± 0.21 × 10^?15 g L^?1 respectively. The recovery obtained for 7 pg of ²⁴²Pu spiked into real high saline-water samples was all above 70 %.     

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.     

Radiological impact from natural radionuclide activity concentrations in soil and vegetables at former tin mining area and non-mining area in Peninsular Malaysia

The radionuclide concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were measured in eleven different types of vegetables from nine sample locations in Peninsular Malaysia by using gamma spectrometry with high purity germanium detector. Radiological impact and cancer risk arising from the ingestion of vegetables was also determined in this study. The annual ingestion dose of vegetables from former tin mining area and non-mining area were found to be 0.64 and 0.61 µSv y^?1. Corresponding cancer risk estimated for adults were 2.24 × 10^?6 and 2.15 × 10^?6 for former tin mining area and non-mining area, respectively. Both of them were lower than predicted value recommended at international level by ICRP, 3.5 × 10^?3. The present study concludes that vegetables planted at both areas would not pose any significant radiological impact to the population, despite the higher concentration of radionuclide in soil. External hazard indices from soil in this study are less than one. Thus, the soils are suitable for use in agriculture.     

Electrochemical Enzyme‐Linked Immunoassay for the Determination of Estriol Using Methyl Red as Substrate

Abstract

A new electrochemical substrate for horseradish peroxidase, methyl red, is reported. In this reaction system, horseradish peroxidase can catalyze the redox reaction of methyl red and H₂O₂. Methyl red exhibits a sensitive voltammetric peak at?0.51 V vs. Ag/AgCl reference electrode, the decrease of the peak current of methyl red is in proportion to the concentration of horseradish peroxidase (HRP). The linear range for determination of horseradish peroxidase is 5.0×10^?8～5.0×10^?7 g mL^?1 and the detection limit is 1.8×10^?8 g mL^?1. The relative standard deviation is 3.3% when 2.0×10^?7 g mL^?1 HRP was sequentially determined 11 times. A voltammetric enzyme‐linked immunoassay method for the determination of estriol was developed, based on this electrochemical system. The linear range for determination of estriol is 1.0～1000.0 ng mL^?1, and the detection limit is 0.33 ng mL^?1. The relative standard deviation for 11 parallel determinations with 200 ng mL^?1 estriol is 4.8%. Some pregnancy serum samples were analyzed with satisfactory results.     

A New Flow‐Injection Chemiluminescence Method for the Determination of Acyclovir and Gancyclovir

Abstract

A rapid and sensitive flow‐injection chemiluminescence (FI‐CL) method, which is based on the CL intensity that generated from the redox reaction of Ce(IV)‐rhodamine B in H₂SO₄ medium, for the determination of acyclovir and gancyclovir is described. For acyclovir, the determination range is 3×10^?8 g mL^?1–7×10^?5 g mL^?1, with 1.56×10^?8 g mL^?1 as its determination limit. During 11 repeated measurements for 1×10^?6 g mL^?1 acyclovir, the relative standard deviation was 2.08%. For gancyclovir, the determination range was 5×10^?8 g mL^?1–7×10^?5 g mL^?1, with 2.35×10^?8 g mL^?1 as its determination limit. The relative standard deviation is 2.83% with 11 repeated measurements of 1×10^?6 g mL^?1 gancyclovir. This method can be successfully used to determine the content of acyclovir and gancyclovir in injections, acyclovir in eye drops, and, maybe, also for other ciclovirs.     

Simple and fast voltammetric procedure of U(VI) determination in the presence of high concentrations of surface active substances

In this work, a simple and fast procedure for elimination of interfering surface active substances and for U(VI) adsorptive stripping voltammetric determination was developed. The adsorption in the form of U(VI)-cupferron complexes was performed, because as it was proved before, U(VI) forms with cupferron stable complexes, which were employed in voltammetric procedures. The procedure is based on two steps: the first is an adsorption of surface active substances onto an Amberlite XAD-16 or XAD-7 resin and the second is a voltammetric determination of U(VI) with a pulsed potential of accumulation alternate –0.65–0.3 V with the frequency of 0.5 Hz and then the differential pulse voltammogram was recorded, whereas the potential was scanned from –0.65 to –1.2 V. The detection limit estimated from three times the standard deviation for a low U(VI) concentrations was equal to 1.7 × 10^?10 mol L^?1 (7.2 × 10^?8 g L^?1). The linear range of U(VI) was observed over the concentration range from 5.0 × 10^?10 mol L^?1 (2.1 × 10^?7 g L^?1) to 2.0 × 10^?8 mol L^?1 (8.5 × 10^?6 g L^?1) for an accumulation time of 60 s. The influence of different kinds of surfactants, such as non-ionic, cationic and anionic on the uranium voltammetric signal was studied. The results confirm the possibility of U(VI) determination in water samples containing high concentrations of surface active substances even up to 50 mg L^?1.     

Radon (222Rn) in underground drinking water supplies of the Southern Greater Poland Region

Activity concentration of the ²²²Rn radionuclide was determined in drinking water samples from the Sothern Greater Poland region by liquid scintillation technique. The measured values ranged from 0.42 to 10.52 Bq/dm³ with the geometric mean value of 1.92 Bq/dm³. The calculated average annual effective doses from ingestion with water and inhalation of this radionuclide escaping from water were 1.15 and 11.8 μSv, respectively. Therefore, it should be underlined that, generally, it’s not the ingestion of natural radionuclides with water but inhalation of the radon escaping from water which is a substantial part of the radiological hazard due to the presence of the natural radionuclides from the uranium and thorium series in the drinking water.     

Uranium isotopes in carbonate aquifers of arid region setting

Groundwater in arid and semiarid regions is vital resource for many uses and therefore information about concentrations of uranium isotopes among other chemical parameters are necessary. In the study presented here, distribution of ²³⁸U and ²³⁵U in groundwater of four selected locations in the southern Arabian peninsula, namely at two locations within the United Arab Emirates (UAE) and two locations in Oman are discussed. The analyses of the uranium isotopes were performed using ICP-MS and the results indicated a range of concentrations for ²³⁵U and ²³⁸ U at 3–39 ng L^?1 (average: 18 ng L^?1) and 429–5,293 ng L^?1 (average: 2,508 ng L^?1) respectively. These uranium concentrations are below the higher permissible WHO limit for drinking water and also comparable to averages found in groundwater from similar aquifers in Florida and Tunisia. Negative correlation between rainfall and uranium concentrations suggests that in lithologically comparable aquifers, climate may influence the concentration of uranium in subtropical to arid regions.     

Post‐chemiluminescence Method of the Determination of Loperamide Hydrochloride in Human Plasma and Pharmaceutical by Using Dichlorofluorescein as Chemiluminescence Reagent

Abstract

A post‐chemiluminescence (PCL) was observed when loperamide hydrochloride solution was injected into the reaction mixture after the finish of CL reaction of alkaline N‐Chlorosuccinimide (NCS) and dichlorofluorescein. Based on this phenomenon, a simple, sensitive and fast flow injection PCL method was established for the determination of loperamide hydrochloride. The possible mechanism for the PCL reaction was discussed via the investigation of the CL kinetic characteristics, the CL spectra, the fluorescence spectra. The PCL intensity responded linearly to the concentration of loperamide hydrochloride in the range 8.0×10^?10 to 6.0×10^?7 g · ml^?1 with a linear correlation of 0.9995. The detection limit was 4×10^?10 g · ml^?1. The relative standard deviation was 2.4% for 4.0×10^?8 g · ml^?1 loperamide hydrochloride (n=11). This method has been applied to the determination of loperamide hydrochloride in human plasma and pharmaceutical samples with satisfactory results.     

Molecular Imprinting-Chemiluminescence Sensor for the Determination of Amoxicillin

The amoxicillin-imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The binding characteristic of the imprinted polymer to amoxicillin was evaluated by equilibrium binding experiments. Using the imprinted polymer as recognition material, 3-(3′-nitrophenyl)-5(2′-sulfonylphenylazo)-rhodanine (4NRASP) was synthesized by the authors and was used as chemiluminescence (CL) reagent. A novel chemiluminescence (CL) sensor for the determination of amoxicillin was developed based on the CL reaction of amoxicillin with potassium permanganate in an acidic medium. The sensor displayed excellent selectivity and high sensitivity. The linear response range of the sensor was from 5.0 × 10^?9 to 1.0 × 10^?6 g · mL^?1 (r = 0.9985) and the detection limit was 1.3 × 10^?9 g · mL^?1. The relative standard deviation for the determination of 1.0 × 10^?7 g · mL^?1 amoxicillin solution was 1.7% (n = 11). The sensor was applied to the determination of amoxicillin in urine samples with satisfactory results.     

Chemiluminescence Determination of Organophosphorus Pesticides Chlorpyrifos in Vegetable

Abstract

A novel chemiluminescence method for the quantitative assay of the organophosphorus pesticide chlorpyrifos in vegetable samples is presented. The determination is based on the reaction of chlorpyrifos with luminol-H₂O₂ in alkaline medium with sodium chloride being enhancer. Under the optimum conditions, the increased CL intensity was proportional with the concentration of chlorpyrifos in the range of 1.0 × 10^?8 g · ml^?1 ? 1.0 × 10^?6 g · ml^?1 and the detection limit was 3.5 × 10^?9 g · ml^?1 (3σ). The relative standard is less than 3.9% for 5.0 × 10^?7g · ml^?1 chlorpyrifos (n = 7). This method has been successfully applied to the determination of chlorpyrifos residue in vegetable sample. Further study was focused on the mechanism of chlorpyrifos and the possible mechanism was proposed.     

Development of a facile sensor for the determination of Brilliant Blue FCF in beverages

A facile method was developed for the detection of Brilliant Blue FCF (BB FCF) (E133), a synthetic soluble colorant in common beverages. The method is based on a new composite of multi-walled carbon nanotube (MWCNT)-graphite oxide (GO)-room temperature ionic liquids (MWCNT/GO-RTIL) of 1-butyl-3-methylimidazolium hexafluorophosphate with high dispersibility and strong conductivity. Differential pulse stripping voltammetry (DPSV) and the MWCNT/GO-RTIL composite-modified glassy carbon electrode (GCE) were used to determine the BB FCF in this work. Under the optimum experimental conditions, the oxidation current of BB FCF was proportional to its concentration in two linear ranges, from 6.34 μg kg^?1 to 7.93 × 10² μg kg^?1 and 7.93 × 10² μg kg^?1 to 7.93 × 10³ μg kg^?1.

The detection limit was down to 3.01 μg kg^?1 at signal-to-noise ratio of 3. Also, this method has been successfully applied in the determination of BB FCF in common beverage samples, including RIO cocktail, Bacardi Breezer and Reinnbow rum dinks. The assay results of BB FCF in drink samples obtained by the proposed method were in a good agreement with the reference values detected by high performance liquid chromatography (HPLC). The proposed method provided a useful tool for the assay of BB FCF in drink samples.     

Enhanced chromatographic separation of cobalt and uranyl ions using tin (IV) antimonate column from aqueous solution

The effect of electric field on tin (IV) antimonate column bed to separate cobalt and uranium was investigated. Separation was carried out from nitrate solution and ionic strength of 0.6. Variation of applied potential, time and pH were investigated. Ion mobilities at pH 1 are calculated and given to be 5.5 × 10^?4 and 2.73 × 10^?4 cm² V^?1 s^?1 for cobalt and uranyl ion respectively. Number of theoretical plate heights were calculated from the breakthrough curve and given to be 354 and 210 for cobalt and uranyl ions, respectively. Diffusion coefficient were calculated according to Nernst equation and found to be of 7.6 × 10^?6 and 3.5 × 10^?6 cm² s^?1 for cobalt and uranyl ions, respectively. Also, breakthrough capacities were calculated and found to be 0.7 mmol g^?1 for cobalt ion and 0.4 mmol g^?1 for uranyl ion, respectively.     

Determination of uranium concentration in urine of workers in an Iraqi phosphate mine and fertilizer plants

Precise determination of uranium concentration in human urine is quite important in assessment of occupational and public exposure to uranium. In the present work, a pulsed dye nitrogen laser-induced kinetic phosphorescence analysis (KPA) was used to determine uranium in urine of Iraqi phosphate mine and fertilizer plant workers and in the population living near the mining region. A total of 92 urine samples were collected from workers of the Akashat phosphate mine, the Al-Qaim fertilizer complex, and the Akashat residential region. Uranium concentration in urine of all samples ranged between 0.49 to 5.26 μg L^?1 with a total average of 1.47 ± 0.01 μg L^?1. For comparison, all samples were also analyzed using a completely different technique; the nuclear fission track analysis using CR-39 SSNTD. Both techniques were capable of such measurements, although not with an equal degree of uncertainty. KPA technique is found to be more suitable for analysis of urine samples having high concentrations of uranium.     

A new sensitive and selective sensor for heavy metal ions based on tannin extracted from the skin of Punica granatum L

This article presents the development of a sensor made from a gold electrode and a receiving polymeric membrane based on tannin extracted from the skin of Punica granatum. L (pomegranate) for real-time detection of heavy metals in a hydrous environment. The basic principle of this device is the complexing (chelating) of metal ions through the adjacent hydroxyl groups contained in the chemical structures of the tannins. The electrochemical characterisation was performed by using electrochemical impedance spectroscopy and square wave voltammetry. Other morphological and structural analyses were performed by using Fourier transform infrared spectroscopy and atomic-force microscopy. The results obtained showed the high sensitivity of the developed device (detection limits of 6.35 × 10^?9 g L^?1 for Cu²⁺, 1.1 × 10^?8 g L^?1 for Cd²⁺ and 2 × 10^?7 g L^?1 for Pb²⁺) and the possibility of simultaneously detecting several heavy metals, each one in a highly selective manner with highly acceptable response time (48s).     

Flow Injection Chemiluminescence Sensor with Novel Rhodanine Ramification for Determination of Fenfluramine Based on Molecularly Imprinted Polymer

Abstract

Flow injection chemiluminescence (FI-CL) with molecularly imprinted polymer (MIP) was applied to determine fenfluramine. The fenfluramine-imprinted polymer was prepared with acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. Methyl and sulfonic group were introduced to rhodanine matrix, and a novel rhodanine ramification 3MORASP was synthesized by the author, and it was used as chemiluminescence reagent. 3-(3′-Methoxyphenyl)-5(2′-sulfonylphenylazo)-rhodanine (3MORASP), first synthesized by the authors, was used as chemiluminescence (CL) reagent. The novel flow path of FI-CL was designed, which made three merged streams of reactants injected into MIP column move through different pathways simultaneously. Fenfluramine was detected based on the reaction of fenfluramine, 3MORASP, and potassium permanganate in an acidic medium. The CL intensity was correlated linearly with the concentration of fenfluramine over the range of 1.0 × 10^?7 to 5.0 × 10^?6 g · mL^?1, and the detection limit was 9.48 × 10^?9 g · mL^?1. The relative standard deviation (RSD) was 2.4% for determination of 1.0 × 10^?6 g · mL^?1 fenfluramine (n = 11). This method was successfully applied to the determination of fenfluramine in weight-reducing tonic.     

Synthesis of L-tyrosine-capped ZnSe quantum dots and its application to hypochlorite determination in water

In this study, a new sensitised spectrofluorometric method was presented as a probe sensor for hypochlorite analysis in oral and tap water samples. By capping L-tyrosine (Tyr) on ZnSe nanoparticles, stable quantum dots (QDs) were obtained. In comparison with Tyr, the fluorescence (FL) emission of Tyr-capped ZnSe is enhanced and shifted to greater wavelength, which causes to enhance the sensitivity for the determination of hypochlorite. Based on the FL quenching of the Tyr-capped ZnSe QDs, hypochlorite concentration was detected at buffering pH of 7 in the range of 5.15 × 10^?5?2.57 × 10^?2 g L^?1. Relative standard deviation and detection limit were found to be 0.83% and 2.06 × 10^?5 g L^?1, respectively. In comparison with the other methods of hypochlorite determination, this method is simple, fast and inexpensive, with low sample volume consumption. It also exhibits a good selectivity.     

Novel potentiometric sensor for the trace-level determination of Zn2+ based on a new nanographene/ion imprinted polymer composite

In this research, a new strategy for construction of a development potentiometric carbon paste Zn²⁺-ion selective electrode based on a novel nano-sensing layer is suggested. The proposed nano-sensing layer was prepared with the addition of a synthesised Zn²⁺-ion imprinted polymer nanoparticles ‘as an efficient sensing agent’ into the carbon paste matrix consisting of graphite powder, nanographene-composite ‘graphene nanosheets decorated with silver nanoparticles’ and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ‘ an ionic liquid ’, as the conducting binder. Under the optimised experimental conditions, the suggested nanographene-composite potentiometric sensor presented a low detection limit of 1.93 × 10^?1 μg L^?1 and a linear analytical range from 2.62 × 10^?1 to 6.54 × 10⁵ μg L^?1 with an excellent Nernstian slope of 29.80 mV decade^?1. The proposed zinc selective sensor was successfully applied for the highly sensitive determination of trace amounts of Zn²⁺ in environmental and biological samples with satisfactory results.     

A Novel Method for the Determination of Streptomycin Using Sodium Nitroprusside as a Chromogenic Reagent by Spectrophotometry

Abstract

A rapid and simple spectrophotometric method for the determination of streptomycin has been developed and validated. The method was based on the reaction of streptomycin with sodium nitroprusside in the alkaline medium forming a red product measured at the maximum absorption of 495 nm. The stoichiometric ratio of the product is 1:1. Beer's law is obeyed in a range of 1.87 µg mL^?1 ～ 279.8 µg mL^?1 of streptomycin and ?₄₉₅ is 6.0 × 10³ L·mol^?1 cm^?1.Under the optimum condition, the equation of linear regression is A = 0.00742 + 0.05683 C (× 10⁵ mol·L^?1), with a linear correlation coefficient of 0.9990. The detection limit (3σ/k) is 0.96 µg mL^?1, the relative standard deviation (RSD) is 2.40%, and the average recovery rate is 98.3%–102.7%. Every parameter has been optimized, and the reaction mechanism has been studied. The proposed method has been successfully applied to the determination of streptomycin for injections and tablets of pharmaceutical preparation. Analytical results obtained by this new method were very gratifying.     

Study on Chemiluminescence Assay of Surfactant PEG-400 Using Luminol–Hydrogen Peroxide System

Abstract

Based on the fact that nonionic surfactant polyethylene glycol-400 (PEG-400) catalyzed the chemiluminescence of luminol-H₂O₂ system, a novel and simple chemiluminescence method has been developed for the determination of PEG-400. Under the optimal conditions, the standard curve was Y = 198835X–2091.8, where the correlation coefficient (R) was 0.9999. The detection limit was 4 × 10^?5 g·ml^?1 PEG-400 and the linear range was 1.0 × 10^?4–4.0 × 10^?2g·ml^?1. The relative standard deviation was 3.2% at 2.0 × 10^?3 g·ml^?1 PEG-400 (n = 7). This method has been applied to the determination of PEG-400 in cosmetic samples with satisfactory results. Furthermore, the dynamics characteristic curve of PEG-400 in luminol-H₂O₂ system was compared to typical metallic ion and other surfactants. Moreover, the mechanism of the luminol-H₂O₂-PEG-400 chemiluminescence system was studied, assisted by fluorescence spectra and UV spectra.