Rapid determination of 226Ra in environmental samples

A new rapid method for the determination of ²²⁶Ra in environmental samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine sample analyses. The need for rapid analyses in the event of a Radiological Dispersive Device or Improvised Nuclear Device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. ²²⁶Ra (T1/2?=?1,620?years) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The new method to determine ²²⁶Ra in environmental samples utilizes a rapid sodium hydroxide fusion method for solid samples, calcium carbonate precipitation to preconcentrate Ra, and rapid column separation steps to remove interferences. The column separation process uses cation exchange resin to remove large amounts of calcium, Sr Resin to remove barium and Ln Resin as a final purification step to remove ²²⁵Ac and potential interferences. The purified ²²⁶Ra sample test sources are prepared using barium sulfate microprecipitation in the presence of isopropanol for counting by alpha spectrometry. The method showed good chemical recoveries and effective removal of interferences. The determination of ²²⁶Ra in environmental samples can be performed in less than 16?h for vegetation, concrete, brick, soil, and air filter samples with excellent quality for emergency or routine analyses. The sample preparation work takes less than 6?h. ²²⁵Ra (T1/2?=?14.9?day) tracer is used and the ²²⁵Ra progeny ²¹⁷At is used to determine chemical yield via alpha spectrometry. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory radium particles are effectively digested. The preconcentration and column separation steps can also be applied to aqueous samples with good results.     

Rapid determination of radiostrontium in large soil samples

A new method for the determination of radiostrontium in large soil samples has been developed at the Savannah River Environmental Laboratory (Aiken, SC, USA) that allows rapid preconcentration and separation of strontium in large soil samples for the measurement of strontium isotopes by gas flow proportional counting. The need for rapid analyses in the event of a radiological dispersive device or improvised nuclear device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. The method employs a novel pre-concentration step that utilizes an iron hydroxide precipitation (enhanced with calcium phosphate) followed by a final calcium fluoride precipitation to remove silicates and other matrix components. The pre-concentration steps, in combination with a rapid Sr Resin separation using vacuum box technology, allow very large soil samples to be analyzed for ^89,90Sr using gas flow proportional counting with a lower method detection limit. The calcium fluoride precipitation eliminates column flow problems typically associated with large amounts of silicates in large soil samples.     

Rapid fusion method for determination of plutonium isotopes in large rice samples

A new rapid fusion method for the determination of plutonium in large rice samples has been developed at the Savannah River National Laboratory (Aiken, SC, USA) that can be used to determine very low levels of plutonium isotopes in rice. The recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid, reliable radiochemical analyses for radionuclides in environmental and food samples. Public concern regarding foods, particularly foods such as rice in Japan, highlights the need for analytical techniques that will allow very large sample aliquots of rice to be used for analysis so that very low levels of plutonium isotopes may be detected. The new method to determine plutonium isotopes in large rice samples utilizes a furnace ashing step, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with TEVA Resin? cartridges. The method can be applied to rice sample aliquots as large as 5 kg. Plutonium isotopes can be determined using alpha spectrometry or inductively-coupled plasma mass spectrometry (ICP-MS). The method showed high chemical recoveries and effective removal of interferences. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory plutonium particles are effectively digested. The MDA for a 5 kg rice sample using alpha spectrometry is 7 × 10^?5 mBq g^?1. The method can easily be adapted for use by ICP-MS to allow detection of plutonium isotopic ratios.     

Microwave dissolution for the determination of mercury in biological samples

Microwave dissolution in closed teflon vessels is described for the determination of ng g^?1 contents of mercury in biological materials, prior to two-stage gold amalgamation and cold-vapour atomic absorption spectrometry. Six samples can be decomposed simultaneously within 20 min, with a preset heating programme. The detection limit is 0.84 ng g^?1 for a 100-mg sample. Results for six certified reference materials agreed with the certified values.     

Rapid separations of corrosion and fission products

A separation scheme of a complex mixture of radiohygienically important radionuclides of corrosion and fission products has been worked out. Rapid separation by means of solvent extractions with metal (sodium, antimony, zinc) diethyldithiocarbamates has been achieved. Chloroform containing metal diethyldithiocarbamates has been used as the organic phase. The procedure permits to separate selectively the representative radionuclides. The selectivity of separation was verified by gamma spectrometry.     

Rapid dissolution of sulphide ore for the determination of copper

A mixture of equal volumes of perchloric acid and phosphoric acid is an excellent solvent for sulphide ores preliminary to the determination of copper. The dissolution is rapid, no bumping occurs, and the visual adjustment of pH prior to the iodometric determination of copper is easier.     

Sequential automated fusion/extraction chromatography methodology for the dissolution of uranium in environmental samples for mass spectrometric determination

The ability to predict the amount of time that a light petroleum mixture has been weathered could have many applications, such as aiding forensic investigators in determining the cause and intent of a fire. In our study, an evaporation chamber that permits control of airflow and temperature was constructed and used to weather a model nine-component hydrocarbon mixture. The composition of the mixture was monitored over time by gas chromatography and a variety of chemometric models were explored, including partial least squares (PLS), nonlinear PLS (PolyPLS) and locally weighted regression (LWR or loess). A hierarchical application of multivariate techniques was able to predict the time for which a sample had been exposed to evaporative weathering. A classification model based on partial least squares discriminant analysis (PLS-DA) could predict whether a sample was relatively fresh (< 12 h exposure time) or highly weathered (>20 h exposure time). Subsequent regression models for these individual classes were evaluated for accuracy using the root mean square error of prediction (RMSEP). Prior to regression model calculation, y-gradient generalized least squares weighting (GLSW) was used to preprocess the data by removing variance from the X-block, which was orthogonal to the Y-block. LWR was found to be the most successful regression method, whereby fresh samples could be predicted to within 40 min of exposure and highly weathered samples predicted to within 5.6h. These results suggest that our hierarchical chemometric approach may also allow us to estimate the age of more complicated light petroleum mixtures, such as gasoline.     

Rapid method for determination of plutonium, americium and curium in large soil samples

The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring. There is a need to measure actinide isotopes with very low detection limits. A new, rapid actinide separation method has been developed and implemented that allows the measurement of plutonium, americium and curium isotopes in large soil samples (100–200 g) with high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin®, TRU Resin® and DGA-Resin® cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha-spectrometry. The method combines an acid leach step and innovative matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. This method is unique in that it provides high tracer recoveries and effective removal of interferences with small extraction chromatography columns instead of large ion-exchange resin columns that generate large amounts of acid waste. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.     

Radiochemical determination of fission products of uranium

An analysis has been elaborated to determine the long-living γ-emitting fission products of uranium. It consists of a sodium bisulphate melt of the fission product solution or the U-fuel, followed by liquid-liquid extractions. Afterwards the isotopes are absolutely counted with a standardized 3″×3″ NaI crystal. The total γ-spectrum of the original fission product solution, taken with a NaI crystal or a Ge−Li detector, is also analyzed mathematically by mixed γ-spectrometry. From a short post-irradiation of the fission product solution the concentrations of both²³⁵U and²³⁸U are determined. The absolute amount of fission products related to the U-concentration allows the calculation of the percent atomic burn-up, the irradiation time, the cooling period, the flux of the reactor and the original degree of enrichment of the uranium. Research associate of the I. I. K. W.     

Solid-phase microextraction for herbicide determination in environmental samples

Liquid-liquid extraction or solid-phase extraction followed by gas chromatography (GC) or high-performance liquid chromatography are traditional herbicide residue determination methods for environmental samples. Solid-phase microextraction (SPME) is a solventless, fast, and sensitive alternative herbicide residue extraction method that can be applied to numerous environmental matrices. The objective of this paper was to review SPME literature regarding extraction theory, extraction modes, fiber types, and method optimization in conjunction with present and future SPME applications for herbicide determination in environmental samples.     

Rapid quenchofluorimetric determination of nickel(II) in some real and environmental samples

A fluorimetric method for rapid determination of Ni at trace and ultratrace levels [1 ng/ml- 1 g/ml] has been developed. It is based on the efficient quenching action of Ni (II) on the native fluoresence [_ex(max) = 288 nm, _em(max) = 444.8 nm] of 4,7-diphenyl 1,10-phenanthrolinedisulfonate (bathophenanthrolinedisulfonate) solution at low acidities. The method is very simple, rapid and accurate with high precision (R.S.D. = 0.66% at 50 ng/ml). The method has been applied directly to mineralised solutions of several real and environmental samples and the results of nickel determinations are in excellent agreement with the certified values. It is a quick single-step method that requires no clean-up.     

Rapid determination of atrazine in environmental water samples by a novel liquid phase microextraction

A novel method was described for the rapid determination of atrazine using dispersive liquid phase microextraction in combination with high performance liquid chromatography （HPLC）. Possible impact parameters such as sample pH, extraction and disperser solvents, salting-out effect, and extraction time were investigated. The experimental results indicated that proposed method possessed an excellent analytical performance, The linear range, detection limit, and precision （R.S.D.） were 0.1- 50 ng mL- 1 （R2 = 0.9955）, 0.601 ng mL- 1 and 6,4%, respectively. The proposed method was validated with the real water samples, and the spiked recoveries were in the range of 69.9-89.8%, respectively. These results indicated that the established method with high enrichment factor, short extraction time was an excellent alternative for the routine analysis of atrazine in environmental samples. 2007 Qing Xiang Zhou. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Rapid determination of antimony in biological and environmental samples using instrumental neutron activation analysis

A rapid non-destructive activation analysis method has been developed for the determination of antimony. A high resolution low energy Ge detector is used to measure the 61.6 keV γ-ray from^122mSb (T=4.2 min). Sensitivities and detection limits for biological and environmental samples activated with thermal and epithermal neutrons are listed. The time required for the anlaysis is about 12 min per sample using thermal activation and 22 minutes using epithermal activation analysis.     

Improvements of reliability for methylmercury determination in environmental samples

The determination of methylmercury (MeHg) in environmental samples by ethylation derivation-gas chromatography-atomic fluorescence spectrometry (ED-GC-AFS) is associated with an intimate problem of water moisture accumulation introduced in the ethylation step, which enters the detection system and cause a spectroscopic interference. With a simple modification on the GC-AFS system, this problem was eliminated and the analytical quality of the measurements was significantly improved. The presence of dissolved sulfide in samples can also cause serious chemical interference in the ethylation step resulting in lower or total loss of the MeHg signal. It was found that a masking system of CuSO₄-Na₂C₂O₄ was able to eliminate this interference. With this system, the accurate determination of trace amount of MeHg in high dissolved sulfide containing samples was achieved. Satisfactory analytical results were obtained with the certified reference sediment IAEA405, sulfate reducing bacteria culture and sulfide containing water samples. The limit of detection and quantitation of this masking system is 0.01 and 0.04 ng L⁻¹ respectively. Other factors affecting ethylation are also discussed.     

The quantitative determination of fission and nuclear reaction products

Definitions are given to the terms “per cent atom burn-up” and “per cent atoms consumed” as applied to nuclear fuel analysis at the Argonne National Laboratory. The radiochemical and analytical methods which have been adapted and developed especially for this type of analysis are discussed. The analysis of nuclear reaction products by paper chromatographic methods and scintillation spectrometry is emphasised and demonstrated.     

Optimization of large volume injection-programmable temperature vaporization-gas chromatography-mass spectrometry analysis for the determination of estrogenic compounds in environmental samples

Large volume injection-programmable temperature vaporization-gas chromatography-mass spectrometry (LVI-PTV-GC-MS) was optimized for the determination of estrone (E1), 17β-estradiol (E2), 17α-ethynyl estradiol (EE2), mestranol (MeEE2) and estriol (E3) for their determination in environmental samples (estuarine water, wastewater, fish bile and fish homogenate) after derivatization with 25 μL (BSTFA+1% TMCS) and 125 μL of pyridine. Experimental designs such as Plackett-Burman (PBD) and central composite designs (CCDs) were used to optimize the LVI-PTV variables (cryo-focusing temperature, vent time, vent flow, vent pressure, injection volume, purge flow to split vent, splitless time and injection speed). Optimized conditions were as follows: 45 μL of n-hexane extract are injected at 60°C and 6 μL/s with a vent flow and a vent pressure of 50 mL/min and 7.7 psi, respectively, during 5 min; then the split valve is closed for 1.5 min and afterwards the injector is cleaned at 100 mL/min before the next injection. The method was applied to the determination of estrogenic compounds in environmental samples such as estuarine water, wastewater, and fish homogenate and bile. Limits of detection (0.04-0.15 ng/L for water samples, 0.04-0.67 ng/g for fish bile and 0.1-7.5 ng for fish homogenate) obtained were approx. ten times lower than those obtained by means of a common split/splitless inlet.     

Rapid method for plutonium-241 determination in soil samples

A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied to soil samples contaminated with Chernobyl fallout.