Method For Determination Of Boron Research Articles

Decay-Associated Fluorescence for Boron Determination in Uranium-Based Nuclear Fuels.

Herein is reported a novel as well as simple, sensitive, and cost-effective method for determination of boron by time-resolved fluorescence spectrometry in uranium-based nuclear fuels. Boron is complexed with fluorescent ligand chromotropic acid, and the complex formed is a measure of boron. Since the steady-state fluorescence spectra of excess ligand and complex are overlapping, the developed method emphasizes the power of time resolution. The signatory fluorescence decay times of ligand and complex are employed to derive their decay-associated spectra (DAS) and, thereby, spectroscopically eliminate the high background of ligand fluorescence. The calibration plot has a wide linear dynamic range of 5-100 ppb with r2 better than 0.998. Precision is better than 5% at the 10 ppb level and 4% at the 50 ppb level (n = 9). The detection limit is 1.5 ppb, and recovery of spiked boron (25 ppb) from the uranium samples was better than 94%. The developed method was validated by analyzing U3O8-based ILCE Standards and applied to enriched uranium fuel samples. The main advantage of the developed method is a reduction in sample size requirement due to better sensitivity and selectivity. This in turn reduces the load of uranium recovery from analytical waste, especially in the case of enriched uranium samples. Additionally, it eliminates the need of organic solvents/medium.

Optimization of Curcumin Method and Usage of Natural Curcumin in Determination of Boron in Steel

Boron containing alloy steels are mainly used in constructional, automotive and many other applications. The presence of even trace amounts of boron affects greatly on the properties of steel such as hardness and machinability. Therefore, it is important to determine it accurately and precisely in the manufacture of these alloys. Due to the drawbacks of common advanced techniques such as Atomic Absorption Spectroscopy (AAS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), the universally accepted method for determination of boron in steel is the spectrophotometric method using curcumin as an auxiliary agent.
 Although curcumin is the most sensitive spectrophotometric reagent for the above analysis, synthetic curcumin is relatively expensive and it tends to degrade rapidly once it is exposed to air. Furthermore this method is time consuming. Therefore, this study was carried out in order to improve and optimize the available spectroscopic method and to investigate the possibility of using natural curcumin extracted from turmeric in the above analysis.
 The results of the study implied that natural curcumin extracted and purified from turmeric can be used as accurately and precisely as synthetic curcumin in the analysis of boron in steel. A boron-steel alloy sample found to be containing 0.26±0.01 percent of boron with synthetic curcumin gave a concentration of 0.25±0.00 percent of boron with natural curcumin, indicating no significant difference in the determination. A steel sample found to be containing 0.27±0.01 percent of boron with filter paper ashing step gave a concentration of 0.26±0.01 percent of boron without filter paper ashing step indicating no significant difference. Altering the refluxing step of current procedure significantly changes the concentration of boron indicating that the refluxing step cannot be optimized further.

Cost-effective voltammetric determination of boron in dried fruits and nuts using modified electrodes

Cost effective, simple and accurate two voltammetric methods for determination of boron in hazelnut, peanut, almond, raisin, prune and date samples were described. Metal nanoparticles-carbon nanotube modified glassy carbon electrode (MNP/CNT/GCE, M = Au or Cu) and poly xylenol orange modified pencil graphite electrode (p-XO/PGE) were used as working electrodes. The oxidation of alizarin red s (ARS) in the boron-ARS complex at MNP/CNT/GCE and the oxidation of tiron in the B-tiron complex at p-XO/PGE were monitored as response. The limit of determination values (based on visual evaluation) for CuNP/CNT/GCE, AuNP/CNT/GCE and p-XO/PGE were calculated as 100 µg/L, 125 µg/L and 80 µg/L, respectively. The results were compared with the results obtained by inductively coupled plasma mass spectrometric method and no significant difference between the results was observed. The accuracy experiments of the methods and uncertainty calculations were also performed using a certified reference material (UME CRM 1202 Elements in Hazelnut).

Metal nanoparticles/carbon nanotube modified electrodes for voltammetric determination of boron

This study describes a sensitive and accurate voltammetric method for determination of boron using metal nanoparticles/carbon nanotube modified electrodes. The oxidation peak of Alizarin Red S (ARS) at -0.59 V in the boron-ARS complex formed in ammonium/ammonia buffer solution (pH 8.5) was evaluated as a response. The electrode modification conditions and experimental parameters affecting the peak height were optimized. The characteristics of modified electrodes were investigated using cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The limits of detection (3s$_{y/x})$ and the analytical ranges for gold nanoparticles/carbon nanotube modified electrode (AuNP/CNT/GCE) and copper nanoparticles/carbon nanotube modified electrode (CuNP/CNT/GCE) for 40 s accumulation times were 55 \textmu g L$^{-1}$ and 83 \textmu g L$^{-1}$ and 182-1500 \textmu g L$^{-1}$ and 278-1000 \textmu g L$^{-1}$, respectively. The method was applied to various water and eye drop samples. The results obtained for two modified electrodes were compared with inductively coupled plasma-mass spectrometry results and there was no statistically significant difference between the methods at 95% confidence level. Moreover, UME CRM 1201 (Elements in Spring Water) was used for the accuracy check of the proposed method.

A simple and rapid method for determination of boron in fast breeder reactor components

The present paper describes a new analytical method developed for direct determination of boron in steels using radio frequency glow discharge optical emission spectrometer. “Single parameter alternative method” technique has been used to optimize the various experimental conditions of glow discharge plasma such as forward power, gas pressure inside plasma chamber, pre-integration time, and integration time. Different emission lines for boron were studied and inter element interference effect is also discussed in the paper. A complete statistical analysis has been done to validate the developed method. A RSD of less than ±5% is achieved for boron in the range of 0.0010–0.020% in Steels using this method.

Simple and rapid voltammetric determination of boron in water and steel samples using a pencil graphite electrode

This paper presents a simple, rapid, and accurate voltammetric method for determination of boron in water and steel samples using a disposable pencil graphite electrode. The oxidation of Tiron in the boron-Tiron complex in phosphate buffer at pH 7.5 was measured as a response. Type and concentration of supporting electrolyte, pH, ionic strength, Tiron concentration, scan rate, step amplitude, pulse amplitude, and pencil grade were investigated as the parameters affecting the peak current. The limit of detection (3s) was estimated as 84 $\mu $g/L. The relative standard deviation of the method was 4.6 for 1 mg B/L (N = 7). The recovery results varied between 90% and 103% for water samples and between 94% and 108% for steel samples. The results were compared with those obtained from the ICP-OES method and no statistically significant difference between the methods was found.

Synchronous derivative fluorimetric determination of boron in Uranium fuel samples

We report a sensitive and selective method for determination of boron in uranium samples by spectrofluorimetry in synchronous derivative mode. This method is based on the complexation of non-fluorescent boron with fluorescent chromotropic acid to form fluorescent boron–chromotrope complex. The spectrum of native fluorescence of chromotropic acid seriously overlaps with that of the complex and hence, synchronous derivative mode was employed in which physical separation of excess ligand and complex is not necessary. With the optimized experimental and instrumental conditions, limit of detection obtained is 2ngmL−1. The linear concentration range is 5–100ngmL−1 with regression coefficient better than 0.997. The precision is better than 5% at 10ngmL−1 level and 3% at 50ngmL−1 level (n=9). Fluorescence quenching by residual matrix elements in the final sample solution is corrected by slope-ratio method. The method is validated with reference materials and successfully applied to the uranium nuclear fuels with the accuracy of ±10%. The proposed method reduces sample size requirement; thereby reducing load of uranium recovery from analytical waste in case of enriched uranium based samples.

Sample preparation for isotopic determination of boron in clay sediments

The procedures of sample preparation for isotopic determination of boron in clay sediments is very cumbersome, by far, there haven’t been relevant reports on that. In order to establish an effective method for sample preparation, a series of experiments were carried out. In this paper, boron in clay sediments was extracted with HCl solution and purified by two-step ion exchange method. Extracted HCl solution should be adjusted to alkalescency before passing through the Amberlite IRA 743 resin column due to the fact that Amberlite IRA 743 resin absorbs boron only from alkalescent solution. However, a mass of hydroxides of Al and Fe will be precipitated when the extracted HCl solution becomes alkalescent. Hydroxides of Al and Fe have a strong adsorption capacity for boron, which can cause boron isotope fractionation. To treat precipitated hydroxides of Al and Fe, four procedures, namely direct ion exchange (DRIE), decationizing ion exchange (DCIE), once sedimentation ion exchange (OSIE) and repeated sedimentation ion exchange (RSIE) were used and assessed. The influences of the four procedures on separation and extraction and isotopic composition of boron in experimental solutions and clay sediments were also discussed. According to the results, the DRIE, DCIE and OSIE are improper. The result of sample determination indicates that when extracting boron via RSIE, with the increase of precipitation times, there’s an obvious decrease in boron content in the precipitated hydroxides while a sharp increase in recovery of boron and it is favorable for weakening the influence of boron isotope fractionation. But the process of RSIE is time consuming and it may introduce boron. It needs further research to establish a more effective sample preparation method for isotopic determination of boron in clay sediments.

Development of effective methods for determination of boron in soils and soil solutions

Development of effective methods for determination of boron in soils and soil solutions

Development of an on-line isotope dilution laser ablation inductively coupled plasma mass spectrometry (LA–ICP-MS) method for determination of boron in silicon wafers

A method has been developed based on an on-line isotope dilution technique couple with laser ablation/inductively coupled plasma mass spectrometry (LA–ICP-MS), for the determination of boron in p-type silicon wafers. The laser-ablated sample aerosol was mixed on-line with an enriched boron aerosol supplied continuously using a conventional nebulization system. Upon mixing the two aerosol streams, the isotope ratio of boron changed rapidly and was then recorded by the ICP-MS system for subsequent quantification based on the isotope dilution principle. As an on-line solid analysis method, this system accurately quantifies boron concentrations in silicon wafers without the need for an internal or external solid reference standard material. Using this on-line isotope dilution technique, the limit of detection for boron in silicon wafers is 2.8 × 10 15 atoms cm −3. The analytical results obtained using this on-line methodology agree well with those obtained using wet chemical digestion methods for the analysis of p-type silicon wafers containing boron concentrations ranging from 1.0 × 10 16 to 9.6 × 10 18 atoms cm −3.

The determination of boron in tea and coffee by ICP–AES method

A method for determination of boron by optical emission spectrometry with inductively coupled plasma has been suggested and sufficient experimental conditions have been found. The effect of the presence of Na, K, Mg, Ca, HCl, HNO 3 on the determination of boron has been studied. The internal standardisation as a correction technique was explored (In). The accuracy of the method was validated using the Chinese reference material GBW 07605 Tea. The efficiency of microwave digestion technique and hot water extraction was studied. The method was applied to the analyses of hot water extracts of tea and coffee samples. The mean extracted amount of boron ranged from 3.21±0.17 to 9.25±0.421 mg kg −1 in black teas; 3.54±0.12 to 5.52±0.15 mg kg −1 in green teas; 2.71±0.13 to 27.7±0.9 mg kg −1 in fruit teas; 13.3±0.4 to 21.3±0.7 mg kg −1 in instant coffees and from 7.57±0.26 to 17.5±0.5 mg kg −1 in ground roasted coffee beans.

Determination of boron by (p, a) reaction

A method for boron determination based on 11B(p, a)8Be reaction is described. The irradiations were performed with 800 keV protons and the alphas were counted with 2 PIPS detectors at an angle of 150° to the beam direction. The method is simple and permits the determination of boron at μg/g level in biological materials and sub-μg/g level in metals, alloys etc.

Atomic Emission Method for Total Boron in Blood during Neutron-Capture Therapy

Boron neutron-capture therapy (BNCT) is a drug-targeted binary radiotherapy for cancer. The (10)B capture of thermal neutrons induces secondary radiation within cells during irradiation. The most widely used boron carrier is 4-dihydroxyborylphenylalanine (BPA). The duration and timing of the irradiation is adjusted by monitoring (10)B concentrations in whole blood. We developed a new method for boron determination that uses inductively coupled plasma atomic emission spectrometry (ICP-AES) and protein removal with trichloroacetic acid before analysis. This method was compared with the established but tedious inductively coupled plasma mass spectrometry (ICP-MS), which uses wet ashing as sample pretreatment. Erythrocyte boron concentrations were determined indirectly on the basis of plasma and whole blood boron concentrations and the hematocrit. The hematocrit was determined indirectly by measuring calcium concentrations in plasma and whole blood. Within- and between-day CVs were <5%. The recoveries for boron in whole blood were 95.6-96.2%. A strong correlation was found between results of the ICP-AES and ICP-MS (r = 0.994). Marked differences in plasma and erythrocyte boron concentrations were observed during and after infusion of BPA fructose complex. The present method is feasible, accurate, and one of the fastest for boron determination during BNCT. Our results indicate that it is preferable to determine boron in plasma and in whole blood. Indirect erythrocyte-boron determination thus becomes possible and avoids the impact of preanalytical confounding factors, such as the influence of the hematocrit of the patient. Such an approach enables a more reliable estimation of the irradiation dose.

A Rapid Method for Accurate Determination of Boron in Glass, Enamel and other Silicate Materials

A simple and rapid method has been worked out for accurate determination of boron in commercial glasses, enamels and other silicate materials by alkalimetric titration of boron as mannitoboric acid. In the method, the error due to the loss of boron during decomposition of a sample at high temperature by fusion with Na2CO3 in existing methods has been eliminated by fusing at low temperature with NaOH. Bromothymol blue has been advantageously used as the indicator at pH 6.5 (pale yellow to bluish green) for neutralization of free acids and titration of mannitoboric acid. The interference of phosphate has been successfully eliminated by precipitating it out as zirconyl monohydrogen phosphate. Fluorine, calcium and magnesium up to 50 mg per 50 ml did not interfere.

Sensitive method for the spectrophotometric determination of boron in plants and waters using crystal violet

A sensitive and rapid spectrophotometric method for the determination of boron is described, which is based on the formation of a blue complex at pH 1–2 between the anionic complex of boric acid with 2,6-dihydroxybenzoic acid and crystal violet; the colour is stabilised with poly(vinyl alcohol). At 600 nm the calibration graph is linear in the range 0.3–4.5 µg of boron per 25 ml of final solution with a relative standard deviation of ±2.6% for 0.069 µg ml–1 of boron. The molar absorptivity is 3.75 × 104 l mol–1 cm–1. The method has been applied to the determination of boron in plants and natural waters.

Comparison of methods for determination of boron in heavy water moderator

Five analysis methods were compared for the determination of boron in heavy water moderator: isotope dilution mass spectrometry, spectrophotometry, neutron activation, inductively coupled plasma – atomic emission spectrometry, and ion selective electrode potentiometry. Ten samples were analysed by each method; the results showed close agreement between all of the methods. Only mass spectrometry achieved the required precision (&lt;1% rsd) for samples taken during initial reactor operation, but all of the methods achieved sufficient precision (&lt;10% rsd) for samples taken during normal operation. For samples for which the 10B concentration must be determined, only mass spectrometry and neutron activation are applicable.

Microanalytical azomethine‐H method for boron determination in plant tissue

Abstract A microanalytical technique for boron determination using the azomethine‐H reagent was developed. The effects of sample size, extractant and extracting conditions were tested. The technique is quite sensitive to minute amounts of B with a minimum threshold of 05 ppm B. Determinations of B in orchard leaves, NBS reference material No. 1571, agreed with the certified value of 33 ± 3 ppm B, routinely producing a 3% coefficient of variation. The most efficacious procedure resulted from dry ashing a 20 mg oven‐dried sample at 500°C and extracting in 200 μl 1.0N sulfuric acid for 1 hr at 20°C.

Automated fluorometric method for determination of boron in waters, detergents and sewage effluents

An automated method for the determination of boron in natural waters, detergents and sewage effluents is described. The method is based on the reaction of 4'-chloro-2-hydroxy-4-methoxybenzophenone (CHMB) with boron to produce fluorescent species, in a 90% sulfuric acid medium. The method has been made specific to remove any interferences from all major and minor ions and other organic compounds normally present in water. The method is capable of measuring different chemical forms of boron such as boric acid, borax, sodium perborate and tetraphenyl boron. The method analyses 10 samples per hour, in the 5–100 μg 1 −1 boron range. The rate of sample analysis can be increased to 20 per hour at higher concentration ranges. The limit of detection is 1 μg 1 −1 boron.

Rapid method for determination of boron in biological materials.

Rapid method for determination of boron in biological materials.

A modified method for determination of boron with curcumin and a simplified water elimination procedure

The formation of boric acid ester with curcumin is usually performed in highly acidic solution in the absence of water. Small water contents are permissible, but the efficiency is lowered. The water content of a sample can be eliminated by a reaction with propionic anhydride catalyzed by oxalyl chloride, thus avoiding methyl borate distillation or evaporation processes. An advantage is that the reaction between boron and curcumin takes place in a completely homogeneous liquid medium. The excess of protonated curcumin is best destroyed with an ammonium acetate buffer. For trace amounts of boron, extraction of the coloured complex with a mixture of methyl isobutyl ketone, chloroform and phenol is recommended. Standard procedures for aqueous solutions with boron contents between 0.0033–40.0 μg B/l are described.