Determination Of Strontium Research Articles

97/01445 Determination of strontium and manganese in coal-fired fly ashes in atmosphere air

97/01445 Determination of strontium and manganese in coal-fired fly ashes in atmosphere air

Determination of Strontium-90 in Environmental Samples Containing Thorium

A method has been developed for the determination of 90Sr at low activities in environmental samples that also contain thorium. 90Sr is determined by separating and measuring its progeny 90Y. Thorium is removed by liquid–liquid extraction using 5% tri-n-octylphosphine oxide (TOPO) in toluene. A second liquid–liquid extraction with tributyl phosphate (TBP) is used to isolate 90Y from 90Sr. 90Y is then coprecipitated with stable yttrium oxalate. The recovery of yttrium, determined by weighing the yttrium oxalate, is 65–85%. The radiochemically separated 90Y is measured with a liquid scintillation analyzer using beta-liquid scintillation counting or Cerenkov counting. For quality control 90Sr was determined in IAEA reference materials. To demonstrate the applicability of the method, concentrations of 137Cs and 90Sr and Cs:Sr ratios are presented for contaminated surface soils from Maralinga, South Australia, and for coastal marine sediments from Port Phillip Bay, Victoria.

Analysis of90Sr in environmental and biological samples by extraction chromatography using a crown ether

The use of crown ethers is a simple and rapid method for the separation and determination of strontium in various samples. After sample dissolution oxalate precipitation was carried out to remove K. Chromatographic separation of strontium from most inactive and radioactive interference was done with a crown ether. The chemical recovery was determined gravimetrically. Radiostrontium was then determined by liquid scintillation counting.

Rapid determination of strontium-90 in environmental samples by single Cerenkov counting using two different colour quench curves

The validation of the Cerenkov radiation measurement of 90Y to determine the activity concentration of 90Sr in environmental samples is described. Liquid–liquid extraction with di-2-ethyhexylphosphoric acid in toluene was used to separate 90Y from 90Sr. Optimum conditions for Cerenkov counting (low-level counting option, counting windows, mass of solution to be measured) were established. The need for a counting efficiency correction by using a colour quench curve is stated to be essential, otherwise a significant error may occur. Two different colour quench curves (counting efficiency versus the channel ratio or spectral index parameter) were used and the results were compared. The method was applied to 12 environmental matrices: sea-water, algae, carobs, milk, almonds, hake, honey, shellfish, lamb meat, sardine, pork meat and shore sand. No significant differences were observed on using either of the two colour quench curves for any of these environmental matrices. In order to validate the proposed method, a certified soil reference material (CRM IAEA-375) was used, together with participation in an interlaboratory exercise to determine 90Sr in a natural water sample. Again, efficiency correction was performed by using either of the two colour quench curves and in both instances the calculated 90Sr activity concentration was in good agreement with the known values.

Determination of strontium-90 in milk samples using a controlled precipitation clean-up step prior to ion-chromatography

Strontium-90 may be determined by β-counting its yttrium-90 daughter following separation by ion-chromatography, using a three column system comprising a chelating concentrator column, a cation-exchange column and an anion-exchange separator column. The column system has previously been applied to the determination of strontium-90 in water and urine samples. The applicability of the system to the analysis of milk is hampered by the large concentrations of calcium present, which significantly reduces the extraction of yttrium-90 by the concentrator column. A maximum of approximately 200 mg of calcium can be present for the successful extraction of yttrium-90, which greatly limits the quantity of milk that can be analysed. The quantity of milk analysed can be increased by the inclusion of a controlled precipitation step prior to the ion-chromatographic separation. The precipitation is carried out on acid digested milk samples by the addition of ammonia solution until the addition of one drop causes a reduction in pH resulting in the precipitation of calcium hydrogenphosphate. Under these conditions, approximately 20% of the calcium present in the original milk sample is precipitated, yttrium-90 is precipitated whereas strontium-90 is not precipitated. Dissolution of the precipitate, followed by separation of yttrium-90 using the ion-chromatography system facilitates the analysis of a litre of milk with recoveries of greater than 80%.

Determination of strontium at low concentration levels by flame atomic absorption spectrometry associated on-line with continuous coprecipitation preconcentration

A sensitive method for the determination of strontium has been developed. In this work strontium was determined by flame atomic absorption spectrometry using a continuous copreconcentration dissolution procedure based on the formation of lead sulfate followed by elution with hot EDTA solution. Manifold parameters and chemical conditions are described in detail. A concentration factor of up to 61 can be achieved at a sampling rate of 20–30 h −1. The detection limit for strontium was 0.9 ng ml −1 (3σ) and the relative standard deviation was 3.5% ( n = 8) at a concentration level of 100 ng ml −1.

Expert system for the ion chromatographic determination of alkali and alkaline earth metals in mineral waters

The main limiting factors (the highest concentration that may be injected, the lowest concentrations that can be determined, attainable quality of results and limitations arising from the interfering effects of ions in much higher concentrations) that could prevent the successful suppressed ion chromatographic determination of lithium, sodium, ammonium, potassium, magnesium, calcium and strontium in any particular mineral water were obtained experimentally and organized into three databases supporting the operation of an expert system. The expert system permits the planning of appropriate dilutions, the prediction of suitable detector output ranges, the planning of the appropriate standard additions or concentrations of calibration solutions necessary for the successful quantitative analysis and predicts interferences for the determination of individual ions in particular real samples. The predictions of the expert system were checked experimentally on two different natural samples. All the predictions were realistic and, although very simple calculations were used by the expert system, appropriate distinction between different extents of interferences was achieved. The described expert system works well and offers significant support to the planning of the analysis of different natural mineral waters.

Application of partial least‐squares calibration methods in low‐resolution EDXRS

AbstractThe partial least‐squares calibration method was studied on some examples of EDXRS applications: determination of strontium and iron in samples of rock, determination of tin in plated deposits, measurements of ash and sulphur in powdered samples of coal and coating thickness gauging. The spectra of the PLS predictors and the scatter plots of the load and score vectors are presented and an analysis of their interpretation is made. A non‐linearity problem which appeared in some cases was approached either by pretreatment of the entry data or modification of the latent variable. Application of this calibration technique in EXDRS gives two main advantages: (i) it allows systematic factors influencing the final results to be included in the calculated model and (ii) it can provide a new insight into some aspects of the measurement methodology since the data in the following steps of the calibration procedure can be studied and analysed.

A rapid and accurate method for the determination of strontium-90 in environmental soil

A rapid and accurate method for the determination of90Sr in environmental soil has been developed; the procedure includes soil leaching by hydrochloric acid, oxalate precipitation, decontamination from210Bi, separation by HDEHP extraction chromatography column, yttrium oxalate precipitation and β-counting. The interference of210Bi was found and studies have been made for the decontamination of90Y from210Bi by Bi2S3 precipitation giving a decontamination factor of 1.05·103. The analytical results obtained by the improved rapid method for 12 soil samples were comparable to that obtained by a previous method within a relative error of 20%. Studies of vertical distribution of90Sr in an environmental soil profile have shown that 90% of the90Sr deposits in the 30 cm surface soil of the earth with a highest concentration of 3.40 Bq/kg. When 50 g soil was analyzed, the yield of yttrium was 73±17% with a detection limit of 0.26 Bq/kg.

Biventricular measurement of blood strontium in real cases of drowning

A simple method for blood strontium determination by spetrophotometry atomic absorption with Zeeman correction is proposed. This method is applied to real cases of death by drowning, where the difference in blood strontium concentration between the left and the right side of the heart could contribute, together with other data, to the investigation of causes of death in cases of drowning in salt water. The differences obtained in blood strontium concentrations between the left and the right side of the heart in cases of supposed ‘typical drowning’ in sea water were always > 75 μg Sr/l, compared to <20 μg Sr/l found in two supposed cases of ‘atypical drowning’.

Ion chromatographic determination of alkali and alkaline earth metals in mineral waters

The rapid, simultaneous, suppressed ion chromatographic determination of alkali, alkaline earth metals and ammonium in highly mineralized waters has been examined using the novel cation exchange IonPac CS12 column. General ability for the determination of lithium, sodium, ammounium, potassium, magnesium, calcium and strontium in concentrations from a few μg to several mg per liter was studied. The relative standard deviations of retention times of all seven cations were below 0.7% and the relative standard deviations of the measurements of peak areas and peak heights were mostly below 5%. Six natural mineral waters of different types were selected for evaluation of the method. It was not possible to determine lithium in the one run and ammonium usually partially coelutes with sodium precluding quantitative determination. Strontium was undetectable because of the necessary dilutions. All the reltionships between peak areas and concentrations or peak height and concentrations were linear and there was also no evidence of the effect of different matrices on the slope of regression lines.

Determination of barium and strontium in calcium-containing matrices using high-performance chelation ion chromatography

High-performance chelation ion chromatography involving dye-coated resins has been used to determine barium and strontium in samples of mineral water and milk powder containing several orders of magnitude higher levels of calcium and other alkali and alkaline earth metals. Detection limits of 0.03 mg dm −3 were achieved for both barium and strontium. The technique was used to determine both metals in a river water certified reference material and all results were compared to inductively coupled plasma optical emission spectroscopy producing overall good agreement between the two methods.

Determination of strontium in human whole blood by ICP-AES

The determination of strontium in human blood samples by ICP-AES is described. For the analysis no chemical separations were required after microwave destruction. A mean value of 11.4 ± 0.83 μg/l is found for normal whole blood. The limit of detection of the method is 0.3 μg/l. As a possible application the enhancement of the strontium level in blood of human beings who died from drowning is examined.

Determination of strontium-90 in water and urine samples using ion chromatography.

A semi-automated method was developed for the determination of 90Sr in water and urine samples using ion chromatography. Yttrium-90 in secular equilibrium with 90Sr was initially extracted from the sample solution buffered to pH 5 using a high-capacity iminodiacetate chelating resin. At this pH, transition metals, lanthanides and actinides were extracted by the resin. The extracted metals were then transferred on to a separator column where they were separated and eluted as weak acid anionic complexes. The transition metals were eluted first by using a pyridine-2,6-dicarboxylate eluent, then the lanthanides, actinides and 90Y were eluted from the column by using an oxalate-diglycolate eluent. The fraction containing 90Y was then collected and beta-counted. For water samples, a minimum of sample preparation was required prior to chromatography, whereas an oxalate coprecipitation was included as a preconcentration step for urine samples. The derived recoveries for 90Sr for surface water, rain water and urine samples were 91.7 +/- 1.8, 91.9 +/- 1.6 and 90.0 +/- 2.7%, respectively, and the minimum detectable activity using gas flow proportional counting was 8 mBq.

Inductively coupled plasma atomic emission spectrometric determination of aluminium, barium, silicon, strontium and titanium in food after sample fusion.

A rapid and accurate method for the inductively coupled plasma atomic emission spectrometric determination of Al, Ba, Si, Sr and Ti in food was developed based on a direct lithium metaborate fusion without sample pre-ashing. Six NIST diet test samples were analysed. Three independent sample preparation procedures were compared for verification.

Simultaneous determination of lanthanum, strontium and copper in superconductor materials by ion chromatography

A precise and rapid procedure for the determination of metallic macro-components in ceramic superconductor samples of the LaSrCuO type is described. Lanthanum, strontium and copper are determined by ion chromatography using a complexing mobile phase (EDTA solution) and UV detection. Calibration graphs were linear in the concentration ranges 0.4–100, 0.1–100 and 0.05–100 μg ml −1, respectively, and practical determination limits of 0.1, 0.04 and 0.025 μg ml −1 of La(III), Sr(II), Cu(II) ions, respectively, were achieved.

Simultaneous Determination of Strontium-90 and Strontium-89 by Cerenkov-Radiation and Liquid-Scintillation Counting: a Re-Evaluation for Low-Level Counting

Simultaneous Determination of Strontium-90 and Strontium-89 by Cerenkov-Radiation and Liquid-Scintillation Counting: a Re-Evaluation for Low-Level Counting

New Algorithm of Spectral Analysis of Elements in Presence of Matrix Interferences

Abstract This work suggests a new algorithm for the elemental analysis, which permits taking into account both the multiplicative and additive matrix effects, a matrix composition being unknown. The use of this algorithm in the development of analysis techniques at any set of objects may appear to be successful at arbitrarily selected measurement conditions. The basis of the algorithm consists of a combination of pattern recognition and standard addition technique (PRSA). The main concept of PRSA is to predict a function approximating satisfactorily a calibration dependence for a specific object and then to determine an unknown concentration using a nonlinear addition technique, all the aforementioned being based on easily obtained information on an analyzed object and measurement conditions. The abilities of the proposed algorithm were demonstrated by the example of strontium determination by the flame atomic absorption spectrometry in superconducting systems.

Trace metal pollutants in el manzala lakes by inductively coupled plasma spectroscopy

Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used to determine a number of toxic heavy metals and other pollutants in the aquatic environment of the El Manzala area. Mean and standard deviations are tabulated for lead, cobalt, copper, chromium, cadmium, zinc, zirconium and strontium determinations in three different zones representing the whole area. The results indicated a several fold increase compared to those reported for other surface waters in Egypt or in the Mediterranean Sea, with peak values towards the north part of the lake, west of Port Said city. Zinc and cadmium concentrations are extremely low. Continual monitoring control of pollutants in surface waters and primary treatment of waste effluents on the waste generation sites are recommended.

Récents développements de la chromatographie avec extraction par solvant

La surveillance du personnel expose aux produits radioactifs repose, selon les radionucelides en cause, sur des dosages qui necessitent la maitrise de techniques radiochimiques appliquees aux echantillons biologiques. Toute optimisation des criteres techniques ou du facteur temps est extremement profitable. Apres un rappel des principales techniques habituellement utilisees pour le dosage des actinides et des radioemetteurs beta, les auteurs presentent les nouveaux composes permettant l'extraction des actinides et du strontium a partir de matrices mises en solution nitrique. Les avantages analytiques sont detailles : dosage de la totalite des actinides sur un meme echantillon, limites de detection ameliorees pour l'uranium, gain de temps, specificite du dosage du strontium.