Determination Of Boron In Waters Research Articles

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.

Determination of boron in water using neutron scattering and transmission, and prompt gamma ray neutron activation analysis methods: A comparative study

The boron concentration in water was determined using neutron scattering and transmission, and prompt gamma ray neutron activation analysis methods. The experimental setup is based on a Pu-Be neutron source, 3He neutron detectors and an NaI(Tl) gamma-ray detector. Water samples of different volumes and known amounts of boron were prepared. Transmitted and scattered neutrons and prompt gamma rays resulting from neutron capture reactions within the samples were simultaneously measured. The sensitivities of the neutron scattering and transmission measurements were determined to be better than those of the prompt gamma ray neutron activation analysis. The neutron scattering measurements were determined to be more sensitive than those of the neutron transmission measurements.

An automatic, vigorous-injection assisted dispersive liquid–liquid microextraction technique for stopped-flow spectrophotometric detection of boron

A novel automatic vigorous-injection assisted dispersive liquid–liquid microextraction procedure based on the use of a modified single-valve sequential injection manifold (SV-SIA) was developed and applied for determination of boron in water samples.The major novelties in the procedure are the achieving of efficient dispersive liquid–liquid microextraction by means of single vigorous-injection (250µL, 900µLs−1) of the extraction solvent (n-amylacetate) into aqueous phase resulting in the effective dispersive mixing without using dispersive solvent and after self-separation of the phases, as well as forwarding of the extraction phase directly to a Z-flow cell (10mm) without the use of a holding coil for stopped-flow spectrophotometric detection. The calibration working range was linear up to 2.43mgL−1 of boron at 426nm wavelength. The limit of detection, calculated as 3s of a blank test (n=10), was found to be 0.003mgL−1, and the relative standard deviation, measured as ten replicable concentrations at 0.41mgL−1 of boron was determined to be 5.6%. The validation of the method was tested using certified reference material.

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.

Determination of boron in water samples at nanograms per cubic decimeter levels by reversed-phase partition high-performance liquid chromatography with precolumn complexation reaction using salicylaldehyde and 1-amino-8-naphthol-3,6-disulfonate

A new method for the highly sensitive and selective determination of boron at nanograms per cubic decimeter levels has been developed based on the derivatization reaction of boron using salicylaldehyde and 1-amino-8-naphtol-3,6-disulfonate with reversed-phase partition high-performance liquid chromatography. A detection limit as low as 2.0 nmol/dm(3) (22 ng/dm(3)) was achieved without any preconcentration. No significant interference was observed in the determination of 16 micromol/dm(3) of boron with the addition of nine metal ions (Al(III), Cu(II), Co(II), Fe(II), Fe(III), Ni(II), Mn(II), V(V), Zn(II)) at concentrations 100 times greater than that of boron without any masking procedure. The proposed method was successfully applied to the determination of boron in river water, tap water, doubly distilled water, and highly purified water.

Voltammetric determination of boron by using Alizarin Red S

A novel voltammetric method for boron determination in ppb level is described. Boron complexes with Alizarin Red S (ARS) and the complex, as well as the free ligand, both adsorbs on a hanging mercury drop electrode. The method is based on the monitoring the anodic peak of the complex at −0.47 V in ammonium acetate–phosphate buffer (pH 7). The maximum peak current was obtained by scanning the potential from −700 mV versus Ag/AgCl to more positive potentials without accumulation in the presence of 1 × 10 −6 mol L −1 of ARS. The instrumental parameters were mainly differential pulse mode with a pulse duration of 0.02 s and a scan rate of 5 mV s −1. The limit of detection based on signal to ratio of 3 was calculated as 15 μg L −1. The calibration plot for boron was linear in the range of 0–500 μg L −1. The interference of various ions was examined and serious interference was observed from antimony(III). The relative standard deviation was found to be 5.1% for the 100 μg L −1 boron level ( n = 10). The method was applied to the determination of boron in water and seawater samples with high boron content. The results obtained from the developed method were compared with Azomethine-H-method and no statistically significant difference was found.

Determination of boron in water and pharmaceuticals by sequential-injection analysis and fluorimetric detection

This work reports the application of a sequential-injection analysis (SIA) method for the determination of boron. The method relies on the enhancement of the fluorescence ( λ ex=313 nm, λ em=360 nm) of chromotropic acid (4,5-dihydroxynaphthalene-2,7-disulphonic acid-CA) as a result of its complexation with boric acid (BA). Individual zones of the sample, the CA solution in a suitable buffer and a NaOH solution were aspirated in the holding coil of the SIA apparatus. As the zones were propelled towards the detector, zone penetration in the sample–CA interfaces occurred resulting in the formation of the strongly fluorescent BA–CA complex. The native fluorescence of the CA was quenched by the alkaline environment established as a result of the mixing at the CA–NaOH interface. The chemical and instrumental parameters affecting the fluorescence intensity were investigated and the influence of potential interferents was investigated. After selecting the most suitable conditions, the calibration plot for boron was linear in the range of 8–350 μg l −1 with a 3 σ limit of detection of 3 μg l −1 and a relative standard deviation of 2.7% at the 90 μg l −1 boron level ( n=8). Finally, the method was applied to the determination of boron in natural waters and pharmaceutical products with revoveries in the range of 96–106%.

Automated method for the determination of boron in water by flow-injection analysis with in-line preconcentration and spectrophotometric detection

A sensitive, automated method for the determination of boron in water samples is described, involving flow injection with on-line ion-exchange preconcentration and spectrophotometric detection of the azomethine-H—boron complex. The method is applicable to various water samples and is free from interferences, even in coloured samples. Detection limits of 5 μg l −1 at 20 samples h −1 and 1 μg l −1 at 10 samples h −1 with relative standard deviations of < 10% at 1–10 μg l −1 and < 5%at 10–200 μg l −1 levels of boron were achieved. The recoveries for spiked natural water samples ranged from 96 to 101%. The method compares favourably with inductively coupled plasma atomic emission spectrometry.

Determination of boron in water by flow injection/inductively coupled plasma emission spectrometry

A method is described involving flow injection and inductively coupled plasma emission spectrometry for the determination of boron (0.5–25 mg l −1) in water at a sampling rate of 320 h −1. An 11-ml capacity cloud chamber, with a tangential aerosol outlet, was used to introduce the nebulized sample to the plasma. The sample volume injected was 300 μl. The relative standard deviation for peak height was 3% for 10 mg l −1 of boron at a carier flow-rate of 3.5 ml min −1. The wash-out between samples was improved by using the 11-ml cloud chamber rather than a conventional 110-ml chamber.

Spectrophotometric determination of boron in water with prior distillation and hydrolysis of the methyl borate

A procedure for the determination of boron in irrigation waters is proposed, involving the prior distillation and hydrolysis of methyl borate and subsequent spectrophotometric determination with azomethine-H. The selectivity is better than that of the direct analysis method.

Determination of boron with chromotropic acid by high-performance liquid chromatography

The determination of boron with chromotropic acid has been studied using high-performance liquid chromatography (HPLC). The anionic complex formed between boric acid and chromotropic acid in an aqueous solution was injected on to an anion-exchange column (TSK gel IC-Anion PW, 5 cm × 4.6 mm i.d.) and detected at 350 nm. The complex formation between boric acid and chromotropic acid was enhanced in the presence of octyltrimethylammonium chloride, resulting in higher sensitivity. The calibration graph was rectilinear up to 1.0 µg of boron. The proposed method was applied satisfactorily to the determination of boron in waters and in commercially available chemicals.

Determination of boron in waters by using methyl borate generation and flame atomic-emission spectrometry

An improved method is proposed for the determination of boron in waters. The esterification reaction between boric acid and methanol in a concentrated sulphuric acid medium and the vaporisation of the methyl borate formed (boiling-point, 68 °C) are used in the determination by boron by measuring the emission of the BO2 radical at 548 nm. This reaction is carried out in a simple and inexpensive generator, designed for this purpose, and the heat developed in it causes the rapid volatilisation of the methyl borate. Thus no collection systems or carrier gas are required. The proposed method gives an improved detection limit and it can be applied to the determination of boron in water samples. It is both rapid and highly selective.

Determination of boron in river water with flameless atomic absorption spectrometry (graphite furnace technique)

A simple and rapid procedure is described for the determination of boron in water using flameless atomic absorption spectrometry. A Ca/Mg solution is added before measurement. The method is suitable for boron concentrations up to 250 μg/l. The mean standard deviation is 6±4 μg/l.

A spectrophotometric method for the determination of boron in water by use of ferroin.

The determination of boron in water by use of ferroin has been studied, and a rapid method developed for the determination of 0·01 to 2·70 mg l–1 of boron. The boron is complexed with salicylate, and the ion-association complex of borodisalicylate with ferroin is extracted into chloroform. The intensity of the resulting colour is observed spectrophotometrically. The effects of ions likely to occur in sewage, river, drinking and sea waters were studied; only copper, zinc, carbonate and anionic detergents interfered significantly. Interference due to copper can be inhibited by the addition of EDTA, that due to zinc by the addition of diammonium hydrogen orthophosphate and that from carbonate by prior neutralisation of the sample. The interference of anionic detergents can be used to determine the concentration of such detergents in the same sample. The application of the method to sewage, sea, drinking and river waters is described.

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.

Determination of Boron in Water, Nutrient Media, and Chlorella Cells

Methods are presented for determining submicrogram amounts of boron in distilled water, nutrient media, and in Chlorella cells Boron is determined colorimetrically as a boron-curcumin complex after the sample is either dried or ashed in the presence of calcium hydroxide Boron is removed from distilled water by passing it through a column of Dowex-1 ion exchange resin in the hydroxl form Ions which interfere with the boron analysis are removed on small columns of Dowex-1 and Dowex-50 in the formate and sodium forms, respectively. Neither of the columns retains boron. Approximately 80% of a 1-μg boron standard added to Chlorella cells is recovered when calcium hydroxide is used to trap the boron during the evaporation and ashing steps Regardless of the amount of boron supplied to Chlorella during its growth, only trace amounts of boron were found in the cells

Determination of boron in waters: Method for direct titration of boric acid

Determination of boron in waters: Method for direct titration of boric acid