Determination Of Alkaline Earth Metals Research Articles

Determination of labile barium in petroleum-produced formation water using paper-based DGT samplers

A polyacrylamide hydrogel containing the Chelex-100 resin has traditionally been used as the binding agent for the diffusion gradients in thin films (DGT) technique. The Chelex-100 resin, although important for the determination of various transition metals, is unsatisfactory for the determination of alkaline earth metals, particularly Ba. In this paper, a cellulose membrane, treated with phosphate (P81 membrane), was evaluated as a binding agent for DGT devices for the determination of Ba in produced formation water (PFW) samples. In addition, diffusive layers of filter paper (cellulose) were tested to diffuse Ba through the DGT devices. Experiments to evaluate the key variables of the technique (pH, deployment time, and ionic strength/salinity) were performed. The Ba sampled by these DGT devices was measured using inductively coupled plasma optical emission spectrometry. Aiming to generate information (related to bioavailability of Ba) on the reuse of PFW for irrigation, the determination of Ba in onshore and offshore samples was performed. The new approach was effective for determination of Ba in onshore samples. To determine Ba in offshore samples, it was necessary to use an alternative calibration procedure due to the high NaCl concentration in these samples.

Low pressure ion chromatography with a low cost paired emitter–detector diode based detector for the determination of alkaline earth metals in water samples

The use of a low pressure ion chromatograph based upon short (25 mm × 4.6 mm) surfactant coated monolithic columns and a low cost paired emitter–detector diode (PEDD) based detector, for the determination of alkaline earth metals in aqueous matrices is presented. The system was applied to the separation of magnesium, calcium, strontium and barium in less than 7 min using a 0.15 M KCl mobile phase at pH 3, with post-column reaction detection at 570 nm using o-cresolphthalein complexone. A comparison of the performance of the PEDD detector with a standard laboratory absorbance detector is shown, with limits of detection for magnesium and calcium using the low cost PEDD detector equal to 0.16 and 0.23 mg L −1, respectively. Finally, the developed system was used for the determination of calcium and magnesium in a commercial spring water sample.

Use of graph theory for evaluating the selectivity of flow-injection analysis based on displacement reactions: Determination of alkaline-earth metals in water-ammonia media

A theory was developed for quantitatively evaluating the selectivity in the determination of metals by the flow-injection technique with spectrophotometric detection. The theory was applied to flow-injection analysis based on the ability of alkaline-earth metals to displace copper(II) ions in the Cu(II)-EDTA-4-(2′-pyridylazo)resorcinol system in water-ammonia solutions. The feasibility of the theory was demonstrated. It was shown how the theory could be used for the selection of justified conditions in the determination of Ca, Sr, and Ba and for the evaluation of the selectivity of the determination. Practical examples of the determination of Ca confirm the usefulness of the approach developed.

Determination of aluminium in natural waters by single-column ion chromatography with indirect UV detection

The selective, sensitive and rapid determination of Al was achieved using ion-exchange separation and indirect UV detection. A solution of Ce salt was used as the eluent. The parameters influencing the shape of the Al peak, the selectivity of Al separation and sensitivity of its determination were studied. The separation of Al on chemically modified and on silica gel-based dynamically coated sorbents was achieved. With direction injection the detection limit under the optimum conditions was 50 ng/ml. The time of analysis was about 6 min. The use of a simple preconcentration procedure permitted the detection limit to be decreased. Preconcentration of Al was performed on a complexing sorbent with iminodiacetate functional groups. The technique presented was applied to the determination of Al in natural and tap waters. The technique also provides the determination of alkaline earth metals along with Al.

Kinetics and equilibria of the Zn-EDTA-PAR postcolumn reaction detection system for the determination of alkaline earth metals

Zn-EDTA-PAR is the archetypical displacement reagent for the postcolumn detection of metals in ion chromatography. However, only a superficial understanding of the mechanism of this system exists. The displacement reaction of the Zn-EDTA-PAR reagent was investigated using stopped and continuous flow methods. The kinetics and sensitivity of the Zn-EDTA-PAR reagent are strongly dependent upon the nature and the concentration of the auxiliary complexing agent. Ethylenediamine was more effective than ammonia for the dertermination of alkaline earth metals, both in terms of reaction kinetics (t 1/2 of 0.7 s for ethylenediamine vs 3.6 s for NH 3 for Mg 2+ ) and sensitivity (2-9 fold improvement)

Determination of alkaline earth metals in offshore oil-well brines using high-performance chelation ion chromatography

High-performance chelation ion chromatography (HPCIC) using chelating-dye impregnated resin has been developed as a novel technique for the quantitative determination of alkaline earth metals in oil-well brines. Detection limits of 1 mg dm–3 for barium in samples containing over 1600 mg dm–3 of calcium and up to 3% of sodium have been achieved. Three brine samples were investigated and levels of Ba2+, Si2+, Mg2+ and Ca2+ were determined in each. The results compared well with inductively coupled plasma optical emission spectrometry (ICP-OES).

Determination of Alkaline Earth Metals in Japanese Rain and Snow by ICP Emission Spectrometry

Abstract Alkaline earth metals such as magnesium, calcium, strontium and barium were easily determined in rain and snow samples by a sequential ICP emission spectrometry, when appropriate instrumental conditions and solution matrices were chosen. In this study, 1 N HNO3 solution was used, without any preconcentration or separation, in a regular determination mode by a sequential ICP emission spectro-photometer. The amount of monthly deposition of magnesium, calcium, strontium and barium was determined at 11 stations in Japan in 1984 and 1985. The seasonal variation of Sr(excess) was served as a good index for the characterization of Japanese rain, evaluating the contribution rate of sea salt.

Determination of alkaline-earth metals in foetus bones by inductively-coupled plasma atomic-emission spectrometry

Alkaline-earth metals in human bone samples have been determined simultaneously by inductively-coupled plasma atomic-emission spectrometry (ICP—AES). Results obtained by atomic-absorption spectrometry for Mg, Sr and Ba, and complexometry for Ca, have been compared with those by ICP—AES for a laboratory-control bone sample. Accuracy and precision were examined by analysing the IAEA animal bone standard (H-5). Agreement with the certified values to within 5% was obtained. The concentrations of the elements in foetal bone have also been determined.

Determination of alkaline-earth metals in samples containing a large excess of alkali by ion chromatography

Determination of alkaline-earth metals in samples containing a large excess of alkali by ion chromatography

Determination of Potassium, Sodium, Calcium, and Magnesium in Natural Waters by Ion Chromatography

AbstractSimultaneous determination of alkali and alkaline earth metals in water samples is needed. Studies to evaluate the Dionex Model 10 Ion Chromatograph (IC) for simultaneous determination of K and Na or Ca and Mg in diverse types of natural waters, including soil extracts, showed that the results by the IC method closely agreed with those obtained by flame photometry for K and Na and by atomic absorption spectrophotometry for K, Na, Ca, and Mg. The IC method is based on separation of the monovalent and divalent cations by a separator column containing a low‐capacity sulfonated divinylbenzene polystyrene copolymer, cation‐exchange resin in the H↓ form and on converting the various metal ions to their corresponding hydroxides by a suppressor column containing a high‐capacity, anion‐exchange resin in the OH− form. The eluent used for determination of alkali metals was 5 mM HCl, and a solution containing 2.5 mM HCl + 2.5 mMm‐phenylenediamine dihydrochloride was used for determination of alkaline earth metals. Electrical conductivity is used as the mode of detection. The method is precise, accurate, and can detect as little as 0.1 mg L−1 of K, Na, Ca, or Mg in water samples. The coefficient of variation values ranged from 1.3 to 5.0% for K, from 0.63 to 9.1% for Na, from 1.9 to 3.5% for Ca, and from 0 to 2.4% for Mg. With the IC method, K and Na or Ca and Mg can be determined simultaneously in 2 mL of water in approximately 7 min. A single operator can perform about 40 analyses of alkali or alkaline earth metals in a normal working day. Successive analyses of waters containing high concentrations of metals (e.g., Fe) may lead to loss of resolution of alkali metals, but this can be restored by washing the separator column with 3 M HCl saturated with EDTA.

Ion chromatographic determination of alkaline earth metals and some heavy metals

The method is described for ion chromatographic determination of Ba, Ca, Cd, Cu, Mn, Ni, Sr, Pb and Zn. Ethylenediammonium chloride or tartrate solutions are used as eluents with a suppressor column. The detection limits for the listed elements are (in μg l−1): Ba 1.4, Ca 0.045, Cd 0.6, Cu 0.3, Mn 0.8, Ni 0.5, Pb 6.3, Sr 0.3, Zn 1.2. Relative standard deviations are 0.015–0.050 ar the 20 mg l−1 level (n = 5, p = 0.95). Interferences are considered.

Determination of alkaline earth metals by ion-exchange chromatography with spectrophotometric detection

Determination of alkaline earth metals by ion-exchange chromatography with spectrophotometric detection

Application of displacement reactions in flame photometry—II: Emission flame photometric determination of alkaline earth metals in the presence of interfering anions

For the emission flame photometric determination of strontium and barium in the presence of interfering ions such as phosphate, sulphate, arsenate and oxalate, calibration or simple standard addition methods cannot be used. Greatly reduced errors can be achieved by dividing the sample solution into four equal parts and adding to each certain known amounts of two metal ions. One of these is identical to the determinand ( e.g., strontium or barium) the other has similar characteristics to it ( e.g., calcium). The amounts of these metals are chosen so that the total (molar) concentration of these should be identical in all solutions, but the ratio of the concentrations of the two metals should be different. The emission of the determinand metal must be measured, and a standard addition plot produced. The amount of determinand present in the sample can be obtained from the intersection of the emission vs. concentration line with the concentration axis.

Photometric titration of metal ions, based on ultraviolet absorption by a lead(II) complex. I

A method is described for the complexometric determination of alkaline earth metals with EDTA and EGTA by means of photometric end-point indication at 242 nm, using lead(II) as indicator ion. Determinations of 10−5M solutions of calcium and barium appeared to be possible with good accuracy.

The mechanisms of interference effects and their elimination in the determination of alkaline earth metals by flame photometry

The depressing effect of aluminum on the signal of alkali earth metals in an acetylene-air flame with a spray chamber and the various possibilities of eliminating this interference were investigated. The importance of processes taking part in the crystalline aerosol particles before volatilization, as revealed by flame profiles is emphasized, and appropriate mechanisms for the depressing effect and its elimination are suggested.

The spectrophotometric determination of alkaline earth metals after separation by paper chromatography

The spectrophotometric titration of magnesium, calcium, strontium, and barium, in the visible and ultra-violet regions of the spectrum, has been investigated and a method is presented for the determination of small amounts of these elements by spectrophotometric titration using Eriochrome Black T as indicator, after separation by paper chromatography and removal from the paper with dilute hydrochloric acid. The minimum amount of each cation determined was 0.5 μ M and the procedure was applied successfully to the analysis of a dolomite, a strontianite, and a barytocalcite. Die spektrophotometrische Titrage des Magnesiums, Calciums, Strontiums und Baryums wird auf sichtbarem und ultra-violettem Gebiet untersucht, und ein Verfahren für die Bestimmung geringer Mengen dieser Elemente durch spektrometrische Titrage nach papier-chromatographischer Trennung wird beschrieben. Der Minimalbetrag jedes Kations belauft sich auf 0,5 μ M und das Verfahren wurde zur Analyse von Dolomit, Strontianit und Barytocalzit erfolgreich benutzt. Après examen du titrage spectrophotométrique du magnésium, du calcium, du strontium et du baryum dans les régions visibles et ultra-violettes du spectre, on présente une méthode pour effectuer le dosage de petites quantités de ces éléments par titrage spectrophotométrique, utilisant comme indicateur le noir ériochrome T, après séparation chromatographique sur papier et déplacement par l'acide chlorhydrique dilué. La quantité minimum dosée de chaque cation a été 0,5 μ M . On a appliqué avec succès ce processus à l'analyse d'une dolomie, d'une strontianite et d'une barytocalcite.

A gas volumetric apparatus for the determination of milligram quantities of alkaline earth metals

An apparatus for the determination of alkaline earth metals dissolved in or mixed with a salt by measurement of the equivalent volume of hydrogen evolved on dissolution in water is described. An accuracy of better than 1% is claimed.