Determination Of Boron Research Articles

Determination of boron in high-temperature alloy steel using non-linear inter-element correction and microwave plasma-atomic emission spectrometry

The determination of B in high-temperature alloy steel using microwave plasma-atomic emission spectrometry (MP-AES) is presented. This instrumental emission technique was developed recently using 2.45 GHz microwaves to generate atmospheric pressure N2-plasma, self-sustained inside a modified inductively coupled plasma (ICP) torch. The sample introduction to the MP is pneumatic using a conventional concentric nebulizer and a cyclonic spray chamber system. The emission line detection is sequential using a Czerny-Turner monochromator and charge-coupled device (CCD) system. Boron in steel, generally considered an analytically difficult element in a highly impacted matrix, was determined using HNO3–HCl digested steel solutions and 249.773 nm B emission line. Iron spectral interference on this B emission line was corrected using a non-linear inter-element correction (NL-IEC) method. Steel matrix effects on B recovery were attenuated using the method of standard addition. The amount of B in NBS 348a steel is found to be 58 ± 1 mg kg−1 and the certified amount of B is 55 ± 4 mg kg−1.

Determination of boron and fluoride sources in groundwater: Batch dissolution of carbonate rocks in water

Determination of boron and fluoride sources in groundwater: Batch dissolution of carbonate rocks in water

Спектрофотометрическое определение бора бериллоном III

A new spectrophotometric technique has been developed for the determination of boron in the waters using berillon III and 8 % glycerol in slightly acidic reaction conditions, reaction time is 20 min. The total amount of time spent on the definition of boron, is 90 minutes. The determination range is 0.008 – 0.8 μgL -1 . Keywords: boron, boric acid, spektrophotometry, berillon III, glycerol (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.016 T . A . Kazakova 1 , O . A . Tutunnik 2 , Yu . M . Dedkov 1 1 Moscow Regional State University, Moscow region, Mytischi , Russian Federation 2 V.I. Vernadsky Institute of geochemistry and analytical chemistry of the Russian Academy Science , Moscow, Russian Federation

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

Intercomparison of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples

Boron determination in blood and tissue samples is a crucial task especially for treatment planning, preclinical research, and clinical application of boron neutron capture therapy (BNCT). Comparison of clinical findings remains difficult due to a variety of analytical methods, protocols, and standard reference materials in use. This paper addresses the comparability of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples. It was possible to demonstrate that three different methods relying on three different principles of sample preparation and boron detection can be validated against each other and yield consistent results for both blood and tissue samples. The samples were obtained during a clinical study for the application of BNCT for liver malignancies and therefore represent a realistic situation for boron analysis.

Tetrafluoroborate Selective Electrodes on the Basis of Cations with Delocalized Charge

AbstractScreening of active substances based on styryl and trimethine cyanine dyes was carried out to prepare tetrafluoroborate ion‐selective electrodes. Correlations between the nature of the organic cation (pKa) and working pH ranges of the sensors were studied. New tetrafluoroborate‐selective PVC membrane electrodes based on an active substance formed by the ion pair of 2‐(n‐ethylcarbazol‐3)‐ethenyl‐1,3,3‐trimethyl‐3H‐indolium and 2‐[3‐(5,6‐dimethyl‐3‐nonyl‐1,3‐benzothiazol‐2(3H)‐ylidene)propenyl]‐5,6‐dimethyl‐3‐nonyl‐1,3‐benzothiazolium with tetrafluoroborate ion were developed. The electrodes are non‐sensitive to pH in the range of 2–8 and can be used for boron determination in acidic media of 6–7 mol L−1 H2SO4. The developed sensor was successfully applied for the determination of B2O3 in CdS(Se) nanocrystal‐doped glasses.

A monosegmented flow-batch system for slow reaction kinetics: Spectrophotometric determination of boron in plants

This work introduces the monosegmented flow-batch (MSFB) analysis concept. This system combines favourable characteristics of both flow-batch and the monosegmented analysers, allowing use of the flow-batch system for slow reaction kinetics without impairing sensitivity or sampling throughput. The MSFB was evaluated during spectrophotometric determination of boron in plant extracts, which is a method that involves a slow reaction between boron and azomethine-H. All calibration solutions were prepared in-line, and all analytical processes completed by simply changing the operational parameters in the MSFB control software. The limit of detection was estimated at 0.008mgL−1. The measurements could be performed at a rate of 120 samples per hour with satisfactory precision. The proposed MSFB was successfully applied to analyse 10 plant samples and the results are in agreement with the reference method at a 95% level of confidence.

Substoichiometric Isotope Dilution Mass Spectrometry of Boron by the Ion-Pair Extraction with Halogenated Salicyl Alcohol Derivatives and a Quaternary Ammonium Salt

Novel salicyl alcohol derivatives (H(2)X(n)sal), 5-bromo-, 3,5-dibromo-, and 3,5-diiodosalicyl alcohol which were abbreviated to H(2)Brsal, H(2)Br(2)sal, and H(2)I(2)sal, respectively, were synthesized and used for the selective extraction of boric acid. Boric acid was extracted with each H(2)X(n)sal into chlorobenzene containing trioctylmethylammonium chloride (TOMACl) as an ion-pair complex, TOMA·B(X(n)sal)(2), at a different pH range. The extraction constant (K(ex)) of boric acid was determined by the equilibrium analyses including the formation of hydrogen-bonded complex of each H(2)X(n)sal with TOMACl in the organic phase. The K(ex) values obtained by salicyl alcohol (H(2)sal) and its derivatives were decreased in the order of H(2)I(2)sal ≥ H(2)Br(2)sal > H(2)Brsal > H(2)sal. The most powerful extractant, H(2)I(2)sal, was employed for the substoichiometric extraction of boric acid, which was extracted at pH 5 - 9 with a substoichiometric amount of TOMACl in the presence of an excess of H(2)I(2)sal. The present substoichiometric separation method combined with the stable isotope dilution analysis using inductively coupled plasma mass spectrometry (ICP-MS) could be successfully applied to the determination of boron in a reference material of high-analysis compound fertilizer (FAMIC-A-08) without any correction as to the isotopic abundance.

Microwave sample preparation of facing materials for analysis using the method of atomic emission spectroscopy with inductively coupled plasma

A technique for microwave decomposition of the powder for plasma-jet hard-facing and determination of boron, iron (III), and chromium (III) by ICP-AES is presented. The solvent composition and parameters of the microwave decomposition of the samples in an autoclave are optimized. The detection limits for B, Cr (III) and Fe (III) are 3.0 × 10−3, 7.6 × 10−5, and 2.0 × 10−2 wt %, respectively.

Boron Determination in Liver Tissue by Combining Quantitative Neutron Capture Radiography (QNCR) and Histological Analysis for BNCT Treatment Planning at the TRIGA Mainz

The typical primary malignancies of the liver are hepatocellular carcinoma and cholangiocarcinoma, whereas colorectal liver metastases are the most frequently occurring secondary tumors. In many cases, only palliative treatment is possible. Boron neutron capture therapy (BNCT) represents a technique that potentially destroys tumor tissue selectively by use of externally induced, locally confined secondary particle irradiation. In 2001 and 2003, BNCT was applied to two patients with colorectal liver metastases in Pavia, Italy. To scrutinize the rationale of BNCT, a clinical pilot study on patients with colorectal liver metastases was carried out at the University of Mainz. The distribution of the (10)B carrier (p-borono-phenylalanine) in the liver and its uptake in cancerous and tumor-free tissue were determined, focusing on a potential correlation between the uptake of p-borono-phenylalanine and the biological characteristics of cancerous tissue. Samples were analyzed using quantitative neutron capture radiography of cryosections combined with histological analysis. Methodological aspects of the combination of these techniques and results from four patients enrolled in the study are presented that indicate that the uptake of p-borono-phenylalanine strongly depends on the metabolic activity of cells.

Study of boron behaviour in two spanish coal combustion power plants

A full-scale field study was carried out at two Spanish coal-fired power plants equipped with electrostatic precipitator (ESP) and wet flue gas desulfurisation (FGD) systems to investigate the distribution of boron in coals, solid by-products, wastewater streams and flue gases. The results were obtained from the simultaneous sampling of solid, liquid and gaseous streams and their subsequent analysis in two different laboratories for purposes of comparison. Although the final aim of this study was to evaluate the partitioning of boron in a (co-)combustion power plant, special attention was paid to the analytical procedure for boron determination. A sample preparation procedure was optimised for coal and combustion by-products to overcome some specific shortcomings of the currently used acid digestion methods. In addition boron mass balances and removal efficiencies in ESP and FGD devices were calculated. Mass balance closures between 83 and 149% were obtained. During coal combustion, 95% of the incoming boron was collected in the fly ashes. The use of petroleum coke as co-combustible produced a decrease in the removal efficiency of the ESP (87%). Nevertheless, more than 90% of the remaining gaseous boron was eliminated via the FGD in the wastewater discharged from the scrubber, thereby causing environmental problems.

Boron in coral skeletons determined by prompt γ-ray analysis

A systematic and non-destructive technique is proposed for the determination of boron in coral samples by neutron-induced prompt γ-ray analysis (PGA) using a thermal neutron guide beam of the JRR-3M reactor. About 50–150 mg samples in sealed FEP film were irradiated and measured for 5000 s in the PGA system at a neutron flux of 2.4 × 107 n cm−2 s−1. In order to determine B content in coral skeletons, the Doppler-broadened γ-ray peak of 478 keV (10B) was used together with the correction of interference from the Na-peak of 472 keV. The analytical precision was ~3% for the JCp-1 coral standard. The data (n = 56) obtained by the present method showed a range of B content from 40.7 to 76.9 ppm which is similar to reported values. Boron in corals showed the highest levels in Rukan-sho (Okinawa) with an average B content of 62.5 ppm, whereas corals collected from Mizugama (Okinawa), Cebu (the Philippines) and Khang Khao (Thailand) exhibited B contents of 56.5, 53.0 and 45.7 ppm, respectively. The uptake of boron by living corals may be influenced by seawater pH related to higher seawater B(OH) 4 − . In this paper we discuss factors controlling the B levels in corals.

A dispersive liquid–liquid microextraction procedure for determination of boron in water after ultrasound-assisted conversion to tetrafluoroborate

A novel, simple and green procedure is presented for the determination of boron. The method is based on ultrasound-assisted conversion of boron to tetrafluoroborate anion and the formation of an ion pair between BF4− and Astra Phloxine reagent (R), followed by dispersive liquid–liquid microextraction of the ion pair formed and subsequent UV–vis spectrophotometric detection. The conversion of boron to tetrafluoroborate anion is performed in an acidic medium of 0.9molL−1 H2SO4 in the presence of 0.1molL−1F– by means of 10min of ultrasonication. The extraction of the ion pair formed between BF4− and R (1×10−4molL−1R) is carried out by dispersive liquid–liquid microextraction using 0.5mL of amyl acetate (as extraction solvent), tetrachloromethane (as auxiliary solvent) and acetonitrile (as dispersive solvent) in a ratio of 1:1:2. The absorbance of the coloured extracts obeys Beer's law in the range 0.22–18.7mgL−1 of B(III) at 553nm wavelength. The limit of detection calculated from a blank test (n=10) based on 3s is 0.015mgL−1 of B(III). The method was applied to the determination of boron in mineral waters.

Spectrophotometric determination of boron based on charge transfer reaction

Boron determination by a charge transfer spectophotometric method is described. Accompanied the reaction, a charge transfer complex can be formed by lysine with sodium 1, 2-naphthoquinone-4-sulfonate and boron in alkaline solution (pH 12.00). Subsequently, a new reaction mechanism has been proposed and discussed. The absorbance at the maximal absorption wavelength is 574 nm and boron concentration agrees well with Beer's law in a range of 2.16–43.24 μg mL −1. The linear regression equation is A = −0.01867 + 0.01326 C (μg mL −1), with a linearly correlation coefficient of 0.9935. The relative standard deviation (R.S.D.) of eleven parallel determinations is 2.1% with a detection limit (3 σ/ k) of 2.00 μg mL −1. The recovery ranges from 96.4% to 104.5% with the satisfactory results. This method has been successfully applied to determine boron in pharmaceutical samples directly.

Positive Thermal Ionization Mass Spectrometric Analysis of Boron Isotope on River/Rain Water with Low Content and Rich Organic Matter

A method for separation and isotopic determination of boron with low content and rich organic matter in the river/rain water samples was developed. Samples were concentrated by ion exchange Amberlite IRA-743 resin. The concentrated solution was subsequently micro-sublimated for 12 h to eliminate the organic matters. Then the boron isotope ratio was determined by measuring positive Cs(2)BO(2)(+) thermal ions. The average recovery was between 97. 5% and 101. 2%. The results that were determined by positive thermal ionization mass spectrometry were closed to those by MC-ICP-MS. The precision of isotopic measurement for boron in river/rain water was better than 0. 05 parts per thousand. The results demonstrated that this method was extremely effective for elimination organic matter interference during boron isotopic analysis with low sample size, high precision and accuracy.

Flow Injection Fluorometric Determination of Boron in Steel with 2,3-Dihydroxynaphthalene Using Methanol as a Carrier Liquid

The size of the blank value is enumerated in one of the factor that influence the detection limit in the fluorescence determination method. The blank value in this case is brought about by excess reagent. Therefore, the some methods for removing the excess reagent were studied under the conditions of the stability of boron-complex. To remove the influence of excess reagent, the solvent–extraction method etc. is used beside a method of changing the pH. This study attempted a fluorescence determination of boron by flow injection analysis using the methanol as a carrier liquid. As a result, the amount of reagent decreased down to 1/15 compared to that of conventional method, because of decreasing the amount of water in the sample solution.The water in the sample solution suppressed the reaction between boron and 2,3-dihydroxynaphthalene (2,3-DHN). Therefore, the decrease of water tolerates the low concentration of 2,3-DHN. Under the optimum conditions, a calibration curve was drawn, which was linear over the range of 0 to 120 ppb. The relative standard deviation at 20 ppb B was 0.9% (n=6). For the determination of a trace amount of boron in steels, the on-line separation/preconcentration of boron from iron matrix (500 ppm) was performed by using resin (Amberlite IRA 743). The limit of B determination was 0.8 ppb (1.5 ppm in steels). The determination results for boron in standard steel materials showed good agreement with the certified values.

New Device of Continuous Flow System for Determination of Boron in Steel by Using Both Methods of Chemiluminescent Detection and Continuous Sample Flow Injection

For easy, rapid and economical analysis of steel sample, a continuous flow system was developed by both methods of chemiluminescence (CL) detection and continuous sample flow injection. The system was consisted of 4 channels and analytical time required was less than 30 sec and RSD was less than 2.8 % in 5 repeated runs by using the boron standard solution. Lower detection limit and range of determination were 3x10 -7 M and from 1.0x10 -6 M to 9.6x10 -4 M, respectively. Selectivity of the proposed system was good and interference by another foreign compounds such as AlCl3 and Ni(NO3)2 was negligible small in 1000 times higher concentration of their compounds to boron. In some real steel sample analyses, their determined values agreed with their certified ones, and then the reliabilities were less than 4.4 % in terms of relative error in 3 repeated tests. Additionally, concerning the background CL determination for real steel sample, the D-sorbitol solution should be changed to the purified water, since residual acid after the steel sample preparation might be existed in the system. Also, the steel sample solution should be adjusted to the higher pH than 4.

Estimation of uncertainty in measurement of boron in Zr–Nb alloy samples by BF4 − ion selective electrode

Boron doped zirconium–niobium alloy is employed for neutron reactivity control in advanced nuclear reactors. An accurate knowledge of the boron content and uncertainty associated with the measurement result is essential for reactivity calculations. In view of the refractory nature of the alloy, boron determination in these matrices is a challenging task for analytical chemists. Also due to non-availability of matrix-matched reference materials, direct solid analysis cannot be resorted to. With this in view, a simple and sensitive method based on potentiometric determination of boron as tetrafluoroborate with tetrafluoroborate ion selective electrode has been developed. After dissolving the sample, boron was quantitatively converted to BF4 − with the addition of HF. Potential response was measured with Orion 9305 BN BF4 − ion selective electrode. The response of the ion selective electrode was Nernstian in the range of 0.1–100.0 μg/g of boron in the solution. The method has been validated by two independent methods namely spectrophotometry and inductively coupled plasma-atomic emission spectrometry (ICP-AES). All identifiable sources of uncertainties in the methodology have been individually assessed. The combined uncertainty is calculated employing uncertainty propagation law. The expanded relative uncertainty in the measurement (coverage factor 2) is 6.50%.

Boron determination in a multi element national water monitoring program: the absence of legal limits

Directive 98/83/EC concerning the drinking water quality and Directive 80/777/EC for Natural Mineral Water demand strict control and monitoring for the presence of metals. The State General Laboratory as the official control laboratory (Accredited by ISO 17025:2005) implements a national monitoring program in order to ensure that the drinking and natural mineral water quality satisfy the requirements of the respective Directives. The National Monitoring program covers mainly metals such as Pb, Cd, Cr, Ni, As, Se, Sb, Hg, Mn, Cu, Fe, Al and B in water supplied for human consumption either by distribution networks, vending machines, mobile water containers, ground water intended for human consumption as well as bottled water. The determination of metals in water by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) is a technique that successfully meets the requirements of the above Directives as it is a very powerful tool for the measurement of metals at very low concentrations with high accuracy and precision. The results obtained indicate that metal concentrations in drinking and bottled water examined were by far, below the acceptable legal limits and even below the relevant detection limits. However, in samples of bottled natural mineral water, high boron concentration were determined and risk assessment was performed due to the absence of relevant legal limits. The present paper demonstrates the steps undertaken by the General Water Analysis Laboratory of the SGL for the validated method used by ICP-MS in the determination of trace metals including boron in drinking and bottled water.

Electrochemical Determination of Boric Acid Using the Boric Acid–Tiron Complexation System

AbstractFor monitoring the boron concentration in reverse osmosis (RO) water produced by desalination plants, a voltammetric determination method for the amount of electrochemically inactive boron has been developed by using the complexation with 4,5‐dihydroxybenzene‐1,3‐disulfonic acid (Tiron). Cyclic voltammetric measurements showed the oxidation peak of boric acid–Tiron 1 : 1 complex at 920 mV. This peak was successfully applied to the determination of boron in RO water with the LOD of 0.1 mg B dm−3 by using differential pulse voltammetry. The redox and acid–dissociation behaviors of Tiron and its boron complex are found to depend on the properties of pH buffer reagent.