Detection Limit Of Boron Research Articles

Assessing boron quantification and depth profiling of different boride materials using ion beams

We assessed the capability to quantify and depth profile boron in different materials by a number of ion beam-based techniques. Specifically, the depth resolution, probing depth, film homogeneity, and detection limit for boron using particle-particle nuclear reaction analysis (resonant and non-resonant mode), elastic backscattering spectrometry, and time-of-flight elastic recoil detection analysis using heavy primary ions were evaluated. Samples consisted of high and low-Z materials implanted by 11B+ at different energies and fluences, Au/BN structures as well as bulk boride targets. Advantages and limitations for the individual techniques for the different sample types are discussed. As an example, while ToF-ERDA allows to efficiently depth profile 10B and 11B individually, limitations in probing depth and depth resolution, as well as quantification are apparent in particular for target materials containing high-Z species. While EBS presents large probing depth (~14 μm), the best detection limit (~0.1 × 1015/cm2) is obtained from resonant-NRA.

Determination of boron in in-house graphite reference material by instrumental charged particle activation analysis

Due to high thermal neutron absorption cross-section, boron (B) content is a binding specification for nuclear grade graphite. Reliable analytical methods are essential to determine boron at trace to ultra-trace levels. Analytical Chemistry Division, Bhabha Atomic Research Centre, India has prepared an in-house graphite reference material (GRM). A Charged particle activation analysis methodology has been developed for quantification of B in graphite matrix. Detection limit for boron using this methodology is 1.4 mg kg−1. This in-house GRM can be used for quantification of B in unknown graphite samples, validating existing analytical methods and for the development of new analytical methods.

The implementation of a DSSSD in the upgraded boron analysis at LIBAF for applications in geochemistry

Interest in high spatial resolution boron analyses from a geochemical perspective is related to the recognition of boron as an important tracer of chemical recycling in the Earth, due to the high solubility of boron in aqueous fluids and silicate melts. Although boron is not a nominal component in common silicates they may still contain significant B-concentrations and hence constitute important boron reservoirs in the deeper parts of the Earth.Boron analyses have been performed at the Lund Ion Beam Analytical Facility for almost 20years. For the analysis the nuclear reaction p+11B is used with beam energy just below 700keV where the reaction has a broad resonance.In this paper we describe an upgrade of the system with a double sided silicon strip detector, which allows for much higher count rates compared to the old annular surface detector based system. A gain close to 20 in the data rate allows for high resolution mapping of boron distributions in crystals. This is illustrated by a number of examples. In addition, the detection limits for boron in geological samples are improved, now around 5ppmw. In this work we address issues with data quality, especially charge normalization, lifetime correction and subtraction of different background components.

Design, construction and characterization of a prompt gamma activation analysis facility at the Oregon State University TRIGA® reactor

A prompt gamma neutron activation analysis facility has been designed, built, and characterized at the Oregon State University TRIGA® reactor. This facility was designed for versatile multi-elemental analyses. The facility utilizes the leakage neutrons originating from beam port #4 of the Oregon State University TRIGA® reactor. The neutrons are collimated through a series of lead and Boral® collimators, and filtered through both a bismuth filter and single-crystal sapphire. Samples are irradiated in a sample chamber outside the biological shielding of the reactor, and the resulting gamma radiation produced from neutron interactions within the sample is monitored using a high-purity germanium detector (HPGe). The thermal and epithermal neutron fluxes were measured using gold-foil irradiations and found to be 2.81 × 107 and 1.70 × 104 cm−2 s−1, respectively. The resulting cadmium ratio was 106. Measured detection limits for boron, chlorine, and potassium in a NIST SRM 1571 orchard leaf were 5.6 × 10−4 mg/g, 8.2 × 10−2 mg/g, and 1.0 mg/g, respectively. Detection limits for additional elements and samples are presented.

Prompt gamma activation analysis of boron in reference materials using diffracted polychromatic neutron beam

Boron concentrations were analyzed for standard reference materials by prompt gamma activation analysis (PGAA). The measurements were performed at the SNU-KAERI PGAA facility installed at Hanaro, the research reactor of Korea Atomic Energy Research Institute (KAERI). The facility uses a diffracted polychromatic beam with a neutron flux of 7.9 × 10 7 n/cm 2 s. Elemental sensitivity for boron was calibrated from the prompt gamma-ray spectra of boric acid samples containing 2–45 μg boron. The sensitivity of 2131 cps/mg-B was obtained from the linearity of the boron peak count rate versus the boron mass. The detection limit for boron was estimated to be 67 ng from an empty sample bag spectrum for a counting time of 10,000 s. The measured boron concentrations for standard reference materials showed good consistency with the certified or information values.

Spectrophotometric Determination of Trace Amounts of Boron in High-Purity Iron and Ferroalloy after Chemical Separation

It is known that impurity elements in steel and other feeds exert an influence on the material characteristics. It is known that boron has a large influence on hardening and brittleness of iron even if a small amount of pole exists, and is requested a accurate quantitative analysis of with good repeatability. Boron is sensitively determined by spectrophotometry after color development with curcumin. However the blank value is high. Therefore, methanol and acids used for the analysis are refined, water is added in addition after color development, and the blank value has been decreased. As a result, the blank value decreased from 0.35 to 0.05 μg and the detection limit of boron became 0.01 ppm. Then, trace amount of boron in high purity electrolysis iron (mairon HP) became 0.24±0.01 ppm by using this method. The separation of B from the matrix is possible hardly receiving the influence of the coexistence element. However, there are little examples of investigation on the recovery of boron by co-precipitation. Si was selected us an element to check the influence in this report. In addition, application of separation procedure to the Fe-Cr-Si alloy was performed. The decrease at the recovery of boron was admitted that the amount of Si in the solution exceeded 25 mg. Then, the Fe-Cr-Si alloy was taken, in which the amount of Si should not exceed 25 mg, and boron in the alloy was determined As a result, it was possible to measure in the change coefficient (C.V) 3.1%.

Analytical challenges of low level boron analysis in biological matrices

Analytical instruments and sample handling procedures have steadily improved during the last decade in pursuit of accurate boron concentrations in biological matrices. Boron values reported at the mg/kg level are now generally reliable; however, μg-B/kg level determinations remain a challenge in many biological matrices. The detection limits for boron by isotope dilution mass spectrometry (IDMS), inductively coupled plasma mass spectroscopy (ICP-MS), neutron activation mass spectrometry (NA-MS), ion-coupled plasma emission spectroscopy (ICP-ES), and prompt gamma activation analysis (PGAA) are usually adequate. Rather, limiting factors include establishing boron-clean laboratory environments, the implementation of appropriate quality control, and foremost, maintaining proper precautions in handling and preparing samples for instrumental analysis. At the μg-B/kg level, particular care is required to prevent boric acid interchange during sample handling and while bringing biological matrices into solution. Specific knowledge of boron's chemical pathway in the laboratory is essential. For example, because boric acid is relatively volatile, it persists as an environmental source of contamination and as a transport mechanism for loss. Although boron concentration levels in purified water start below 1 μg/kg, they can exceed 15 μg/kg before a noticeable change in electrical conductivity is registered. Thus alternative procedures for controlling boron “break-through” are necessary. Likewise, “inert” Teflon containers appear boron free, but they serve as a significant source or repository of boric acid. These examples and others illustrate that despite instrumental values being accurate, serious errors are unwittingly incurred, which can alter the sample before analysis. The need for extraordinary vigilance and innovation throughout the experimental procedure is essential. J. Trace Elem. Exp. Med. 12:205–212, 1999. © 1999 Wiley-Liss, Inc.

Determination of Trace Amounts of Metalloid Elements in High-Purity Iron by Chemical Separation-Spectrophotometry

Boron is sensitively determined by spectrophotometry after color development with curcumin, but, the presence of a large amount of iron interferes with the color development. Therefore, in order to separate boron from the iron, boron is allowed to react with methanol to form trimethyl borate ester which is separated from iron by distillation. The distilled ester is trapped into sodium hydroxide solution. For color development with curcumin, water in the solution must be removed by evaporation. The procedure is time-consuming. In order to shorten the time, an apparatus for the distillation is modified to carry out simultaneously both distillation of the ester and evaporation of water in sodium hydroxide solution which traps it. Hence, the time of these procedures is shortened to 25 min from about 90 min of a conventional procedure. Boron reacted with curcumin is extracted with 4-methyl-2-pentanone. The detection limit of boron in iron corresponds to 0.048 μg/g.

Measurement of boron concentration and isotope ratios in biological samples by inductivey coupled plasma mass spectrometry with direct injection nebulization

A method for the determination of boron in a variety of biological samples is described. Sample material is fused with sodium carbonate and boron is separated from matrix components by using Amberlite IRA-743 boron selective ion-exchange resin. Boron is eluted with 1% HNO 3 and samples are introduced to an inductively coupled plasma mass spectrometer with a direct injection nebulizer. This nebulizer provides a fast sample cleanout of ca. 15 s. The 10B/ 11B ratio is determined with a relative standard deviation (RSD) of 0.4–1.5%, and the detection limit for boron is approximately 1 ng g −1 in these samples. Stable isotope dilution methodology for quantitation of boron shows that: (1) fusion of sample with sodium carbonate avoids volatilization of boron from samples; (2) approximately 80% of submicrogram amounts of boron from samples can be recovered from the resin with insignificant isotopic fractionation; (3) results for biological reference materials are in agreement with certified values; and (4) the boron concentration of pooled human blood plasma is 24 ± 4 μg l −1 (95% confidence interval).

Quantitative analysis of boron in steel by secondary ion mass spectrometry using ion-implanted iron as standard

The trace boron in steels was quantitatively analysed by secondary ion mass spectrometry using ion-implanted iron as standards. The calibration curve obtained ranges from the per cent to the parts per billion level. The detection limit for boron using BO 2 − secondary ions was found to be 50 wt.ppb. The grain boundary segregation and precipitation of boron in steel containing a boron concentration of 10 wt.ppm were observed as BO 2 − secondary ion images. The quantitative analysis of the boron concentration segregated to the grain boundaries was performed by application of the above calibration curve.

BORON ANALYSIS AND MAPPING WITH A WINDOWLESS ENERGY DISPERSIVE DETECTOR

Boron has been detected and mapped in a multiphase metallurgical A windowless energy dispersive detector was used on a scanning electron microscope to analyse the boron containing samples. In order to determine the detection limit for boron, a borosilicate glass was also analyzed.

A Carrier Distillation Method for Estimation of Boron in CaF2

Abstract A carrier distillation method is described for determination of boron in calcium fluoride. The sample is mixed with 5 % copperoxyfluoride containing 200 ppm of gallium. 50 mg of this mixture is loaded in pre-arced U. C. C. 1990 electrode and excited using 15 amp. d. c. arc. The resulting spectra are recorded in the region 2200 to 2850 A employing Hilger large quartz spectrograph. The detection limit for boron is 0.1 ppm and the precision of the method is ± 12%.