An investigation of concentration variations of trace elements during storage of natural water samples

Contamination and adsorption of trace elements during storage of natural water samples in polyethylene containers have been studied. Variations of concentrations of 29 elements in pH=1.5 natural water samples stored in polyethylene bottles for 15 and 30 days respectively were determined by the method of freeze-drying preconcentration and NAA. The percentage adsorption loss of radioactive indicators⁶⁰Co,¹²⁴Sb,⁶⁵Zn,⁷⁵Se,¹³⁴Cs and⁴⁶Sc in the pH=1.5–8.0 reservoir water, tap water and distilled water stored for 1–2 months were also determined. The optimized storage condition for natural water is obtained.     

Flow-injection determination of trace amounts of dopamine by chemiluminescence detection

A flow-injection analysis (FIA) for the determination of dopamine has been developed. The method is based on the inhibition effect of dopamine on the iron(II)-induced chemiluminescence (CL) of 10,10'-dimethyl-9,9'-biacridinium dinitrate (lucigenin). The presence of a non-ionic surfactant, polyoxyethylene (23) lauryl ether (Brij 35), caused an increase in the inhibition effect. The present method allows the determination of dopamine over the range 1x10(-8)-2x10(-7) mol dm(-3). The relative standard deviation was 0.7% for eight determinations of 6x10(-8) mol dm(-3) dopamine. The detection limit (S/N=3) was 2x10(-9) mol dm(-3) with the sampling rate of 40 samples h(-1). The effect of other catecholamines and compounds of similar structure on the lucigenin CL reaction was studied: quinone, hydroquinone, norepinephrine, pyrocatechol and l-dopa suppressed the CL intensity.     

偶合化学发光法测定环境水样中的痕量亚硝酸根

将亚硝酸盐在酸性条件下氧化亚铁氰化钾为铁氰化钾的反应 ,和尿酸 铁氰化钾 鲁米诺化学发光反应偶合一起 ,建立了一种间接测定亚硝酸根离子的新方法。讨论了酸度、反应物浓度、干扰离子等因素的影响。方法的检出限为5 .0× 1 0 - 1 1 g/mL ,对环境水样样品进行了平行测定 (n =1 1 ) ,其相对标准偏差为1 .8%～ 3 2 % ,线性范围为 1 .0× 1 0 - 9g/mL～ 1 .0× 1 0 - 5g/mL ,回收率为 94.3%～ 1 0 5 3%。     

Separation of trace elements from natural water and waste water

Summary Methods of discrimination between different chemical forms of trace elements in natural waters and for their separation are discussed and results given for their application to Rhine water. Various methods of trace element separation are presented: separation from sea-water by adsorption on activated carbon in presence of complexing agents, separation from mineral waters by use of the chelating cellulose exchanger Hyphan, separation of actinide elements by co-precipitation with barium sulphate, co-precipitation from waste water with hydrous ferric oxide and with ferric phosphate.

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Trennung von Spurenelementen aus natürlichem Wasser und Abwässern

Zusammenfassung Methoden der Unterscheidung verschiedener chemischer Formen der Spurenelemente in natürlichen Wässern und ihre Trennung werden diskutiert und für Rheinwasser angewendet. Folgende Ergebnisse von Spurenelement-Trennungen werden beschrieben: Abtrennung aus Meerwasser durch Adsorption an Aktivkohle in Gegenwart von Komplexbildnern, Abtrennung aus Mineralwässern unter Verwendung des chelatbildenden Zelluloseaustauschers Hyphan, Abtrennung der Actinidenelemente M^IV durch Mitfällung mit Bariumsulfat, Mitfällung mit Eisenhydroxid und Eisenphosphat aus Abwasser.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

流动注射化学发光法测定水样中痕量锡

在HCl介质中,KMnO4 甲醛 Sn(Ⅱ)为强化学发光体系,利用流动注射和巯基棉分离技术建立了测定锡的新方法,探讨了发光反应的机理。方法的线性范围为0.1～30μg L,检出限为0.04μg L,对1.0μg L的Sn(Ⅱ)标准溶液连续11次测定的相对标准偏差为2.1%。方法已用于环境水样中痕量锡的测定。     

Determination of trace elements in water by non-destructive neutron activation

A systematic study was undertaken in order to find out which of the most relevant elements can be determined in water under normal conditions by non-destructive neutron activation simultaneously using a suitable monostandard method. Standardized water samples as well as natural water of different kind were used, brought to dryness by freeze-drying and irradiated in quartz at a neutron flux of 10¹⁴ cm⁻² s⁻¹ for 1 day. The trace element content in quartz ampoules of different origin was determined separately. The following elements are discussed in detail including possible interferences: As, Au, Br, Ca, Cd, Co, Cr, Cu, Eu, Fe, Hg, K, La, Mo, Na, Ni, Sb, Sc, Se, U, Zn. Presented at the Euroanalysis II Conference, Budapest, 25–30. Aug. 1975.     

Determination of trace elements in biological materials using tetramethylammonium hydroxide for sample preparation

A method to prepare milk powder, bovine liver and bovine muscle samples for analysis by electrothermal atomic absorption spectrometry (ETAAS) is proposed. Samples are mixed with a small amount of tetramethylammonium hydroxide (TMAH) and a stable and homogeneous slurry is produced in ca. 2 h with heating at 60–70 °C. After such sample preparation and dilution with water, trace elements are determined in certified reference materials. Pyrolysis and atomisation temperatures are optimised for each element, and several modifiers are investigated. External calibration is used for every analyte. Limits of detection (LODs), precision and accuracy are reported for Cd, Pb, Ni, Cr, Cu and Ag and compared with those obtained after conventional acid digestion. The main advantages of the proposed method are the simplicity of sample preparation and the longer lifetime of the graphite tube.     

Factorial analysis of a chemiluminescence system for bromate detection in water

A chemiluminescent flow system for bromate detection, based on the reaction of bromate with sulphite in acid medium and using the steroid hydrocortisone as sensitiser, was studied. A factorial analysis strategy for the study of the effect on the system response of the experimental factors, flow rates of two pumps (Q₁ — acid sulphite plus hydrocortisone aqueous solution; Q₂ — carrier, water), sample injection volume (V_L), reactor volume (V_R), sulphite concentration (C_S), hydrocortisone concentration (C_H) and acid concentration (C_A), was used. Screening analysis of the system performance was made using Plackett Burman designs. The system optimisation procedure was achieved by three levels three factors full factorial designs. V_L and C_H are the most significant factors — a quadratic C_H term was also observed to be significant. The optimised system responded linearly (logarithm of the detector signal as function of the logarithm of the bromate concentration) in the concentration range between 3.6×10⁻⁷ and 5.0×10⁻⁴ M with a limit of detection of about 8.0×10⁻⁸ M (about 10 microg/l). An analysis of some interfering ions was made and it was suggested that bromide and chloride begin to quench chemiluminescence when they are in a 10-fold excess relatively to bromate concentration.     

Multielement-standards for determination of trace elements in water by neutron activation

Summary For the determination of trace elements in water by neutron activation (NAA) two multielement-standards on the basis of calcium carbonate were prepared by freeze-drying from solutions after addition of calcium carbonate. Homogeneity was certified by NAA, and the content was tested by atomic absorption (AAS), NAA and X-ray fluorescence analysis (XFA). The multielement-standards were applied for trace element determination in standardized water samples and in Rhine water. Comparison with a monoelement-standard (iron) and with AAS showed good agreement of the results.

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Multielement-Standards für die Bestimmung von Spurenelementen in Wasser durch Neutronenaktivierung

Zusammenfassung Zwei Multielement-Standards auf Basis von Calciumcarbonat wurden durch Gefriertrocknung von Lösungen nach Zusatz von CaCO₃ hergestellt. Die Homogenität wurde durch NAA bewiesen und der Gehalt durch AAS, NAA und Röntgenfluorescenz geprüft. Die Standards wurden für die Spurenelementbestimmung in standardisierten Wasserproben und in Rheinwasser angewendet. Vergleiche mit einem Monoelement-Standard (Eisen) und der AAS zeigten gute Übereinstimmung der Ergebnisse.

     

Estimation of trace elements in water matrix from photon attenuation coefficients

The method of elemental analysis based on the measurement of attenuation coefficient has been used to estimate the impurity introduced in a water matrix using a scintillation detector with a single channel analyser. For a 2% change in the mass attenuation coefficient the minimum detectable fractions of impurities were estimated to be of the order of 625–1250 μg/g for uranium and thorium compounds at photon energies 32.1 and 59.5 keV.     

Determination of trace elements in surface water by neutron activation analysis

In order to assure the public health, simple and relibable analytical methods must be established for effective surveillance of polluted surface water. Since the pollutants in surface water are usually found at ultratrace levels, preconcentration is generally required to ensure the quality of the analytical results. An analytical procedure consisting of preconcentration using hydrous magnesium oxide followed by neutron activation analysis has been proposed and applied to the determinations of trace elements in surface water.     

Preconcentration of trace elements from natural water with palladium precipitation

Palladium salts can be used as a coprecipitation carrier for the preconcentration of trace elements from natural water prior to their measurement by atomic spectrometry (AAS). The palladium is subsequently reduced by the introduction of hydrogen gas into the sample solution. The procedure is applied to the determination of Cu, Pb and Cd in seawater (enrichment factor 50) and synthetic water samples. Operating conditions have been optimized for the analysis of real samples. With the technique established an enrichment factor (500 fold) is feasible in synthetic samples. The recoveries of Cu, Cd and Pb from seawater are 95, 103 and 100%, respectively. This simple and rapid method can be applied in a wide pH-range and with complex matrices.     

Minimization of sample volume with air-segmented sample injection and the simultaneous determination of trace elements by ICP-MS.

The application of inductively coupled plasma mass spectrometry (ICP-MS) to forensic chemistry was studied. The developed method, air-segmented sample injection (ASSI) coupled with ICP-MS, allowed the determination of about 25 elements at the sub-ppb level with only 0.2 ml of a sample solution. The optimum sample flow rate was found to be 0.4 ml min(-1), along with a sample suction time of 30 s. The proposed method was validated by determining trace elements in river-water certified reference material (SLRS-4) issued by National Research Council Canada. The analytical results of the proposed method were in good agreement with the certified values. This method was successfully applied to a human hair sample, the volume of which was 3 ml.     

Preconcentration of trace elements from natural water with palladium precipitation

Palladium salts can be used as a coprecipitation carrier for the preconcentration of trace elements from natural water prior to their measurement by atomic spectrometry (AAS). The palladium is subsequently reduced by the introduction of hydrogen gas into the sample solution. The procedure is applied to the determination of Cu, Pb and Cd in seawater (enrichment factor 50) and synthetic water samples. Operating conditions have been optimized for the analysis of real samples. With the technique established an enrichment factor (500 fold) is feasible in synthetic samples. The recoveries of Cu, Cd and Pb from seawater are 95, 103 and 100%, respectively. This simple and rapid method can be applied in a wide pH-range and with complex matrices.     

A simple flow-injection chemiluminescence method for the determination of trace pentavalent vanadium in water samples

A simple method for rapid determination of trace pentavalent vanadium in natural water was presented by flow-injection chemiluminescence (CL). Through water injection, luminol and potassium permanganate were eluted from the anion exchange column to generate the CL, which was enhanced in the presence of V(V). Under the optimum conditions, the increased CL intensity was linear with V(V) concentration in the range from 0.1 to 100?ng?mL^?1. The limit of detection was 50?pg?mL^?1 (3σ) and the relative standard deviation (RSD) was 2.24% (n?=?5) for a 1.0?ng?mL^?1?V(V). At a flow rate of 2.0?mL?min^?1, one cycle of analysis could be performed in 0.5?min with a RSD of less than 3.0%. The proposed method was successfully applied to the determination of vanadium in natural water.     

Determination of trace elements in water by radioisotope alpha-particle induced X-ray emission

An X-ray spectrometric system including²¹⁰Po -particle sources for excitation and a Si(Li) detector has been applied to determine the concentrations of trace elements in water samples. Thin targets were prepared by the evaporation of a known volume of water deposited on a Mylar backing. The system was calibrated using the internal standard method. Relative sensitivities were measured for 16 elements detected by their K, L and M X-rays. The results are compared with theoretical calculations. The minimum detection limits from 0.01 to 0.07 g/ml were obtained for 2000 s analysis time.     

Composition and origin of trace elements in fog water studied by INAA

Characterization of dilute solution of gamma-irradiated polymethyl methacrylate (PMMA) in acetone has been carried out. The polymer sample in form of natural beads was administered a gamma-ray dose of 30 kGy by a cobalt-60 radiationsource. Various types of viscosities, viscosity average molecular weight, shape and size of irradiated PMMA and its two fractions were calculated. The results were compared with those for unirradiated PMMA. Degradation of PMMA as a result of irradiation has been observed.     

Determination of concentration distribution of trace elements near the detection limit

The results of a numerical simulation, performed to check the validity of a method developed for reconstruction of concentration distributions truncated by the detection limit, are reported in the context of trace element analysis in biomedical samples by total-reflection X-ray fluorescence. This method, by correcting a distribution over the whole range of concentrations in a population of samples, restores a number of measurements reporting results below the detection limit. We show by Monte Carlo simulations, assuming lognormal distributions to describe both the concentrations measured as well as the detection limits in the biomedical samples, that the method developed is accurate to within 5% for most typical situations. Moreover, we demonstrate that the factor limiting the accuracy of the correction is the number of measurements, not the correction procedure itself. We have found in simulations that the reconstruction of a concentration distribution, for a typical population size of N=100, is possible when the concentrations are measured only in 20–30% of samples. On the other hand, we show that by ignoring the truncation of a concentration distribution by the detection limit, the results can be systematically biased by as much as 50%. The method developed is applied to the analysis of trace elements in human breast tissue samples by total-reflection X-ray fluorescence (TXRF). The results are also discussed in terms of the size of the population studied.     

Determination of trace elements in sea water by inductively-coupled plasma emission spectrometry

Pb, Zn, Cd, Ni, Mn, Fe, V and Cu in sea water are determined by extraction of their complexes with sodium diethyldithiocarbamate into chloroform, decomposition of the chelates and inductively-coupled plasma emission spectrometry. When 1-l water samples are used, the lowest determinable concentrations are: 0.063 μg Mn l^-1, 0.13 μg Zn l^-1, 0.25 μg Cd l^-1, 0.25 μg Fe l^-1, 0.38 μg V l^-1, 0.5 μg Ni l^-1, 0.5 μg Cu l^-1, and 2.5 μg Pb l^-1. Above these levels, the relative standard deviations are better than 12% for the complete procedure.