Multielement neutron-activation analysis of plants and fertilizers

The report considers the results of the development of the automated technique for simultaneous, multielement activation analysis of plants and fertilizers for the macronutrient elements N, P, K, Ca, Mg, Cl, and Si. On the basis of analytical procedures, algorithms and software developed, the first automatic (computer based) installation for multielement analyses of plants and fertilizers has been completed and is in routine use in the agrochemical and plant breeding research program at Soviet Union. The proposed technique together with the full automatic real time process of measurement and processing of data by computer, provides a throughput of 250–500 samples (1250–2500 elements determinations) per 8-hour shift, with the accuracy of ±3% for N and ±5–10% for P, K, Mg, Cl and ±15% for Ca.     

Multielement trace analysis of solid and liquid samples by X-ray fluorescence

Summary The use of energy-dispersive multielement X-ray analysis is described and the radionuclides¹⁰⁹Cd and²⁴¹Am and X-ray tubes combined with secondary targets are compared as X-ray sources. Solid powdered samples of infinite thickness are used without further treatment. Calibration standards are prepared from silica gel, and correction factors are derived from the peak heights of Compton scattering. Results for various geological samples and for dust samples are presented. Liquid samples are treated by means of a column or a filter with chelating groups bound to cellulose. A thin layer of the cellulose powder or the filter is analysed with the aid of calibration graphs. Results of multielement trace analysis of standardized water, river water and sea-water are presented and discussed.

---

Zusammenfassung Die Anordnung für die energie-dispersive Multielement-Röntgenfluores-zenzanalyse einerseits mit Hilfe von Radionukliden (¹⁰⁹Cd und²⁴¹Am), andrerseits mit Röntgenröhren in Verbindung mit Sekundärtargets als Röntgenquellen wird beschrieben und verglichen. Feste Proben unendlicher Dicke werden in Pulverform ohne weitere Vorbehandlung verwendet. Die Eichung erfolgt mit Standardpräparaten, die aus Silicagel hergestellt werden und unter Anwendung eines Korrekturfaktors, der aus der Höhe der Peaks der Compton-Streuung abgeleitet wird. Ergebnisse für verschiedene geologische Proben und für Staub werden vorgelegt. Flüssige Proben werden mit einer Säulenmethode oder einer Filtermethode behandelt, wobei chelatbildende Gruppen auf Cellulose verwendet werden. Die dünne Schicht des Cellulosepulvers oder das Filter werden mit Hilfe von Eichkurven analysiert. Ergebnisse der Multielement-Spurenanalyse von standardisiertem Wasser, Leitungswasser, Flußwasser und Meerwasser werden vorgelegt und diskutiert.

---

---

Presented at the International Symposium on Microchemical Techniques, May 23–27, 1977, Davos, Switzerland.     

Determination of palladium in biological samples by neutron-activation analysis

Summary A neutron-activation method for determination of nanogram levels of palladium in biological samples is described. It is based on radiochemical separation of 13.5-hr¹⁰⁹Pd by solvent extraction of its dimethylglyoximate complex into chloroform from the acid solution obtained by wet ashing of the irradiated sample. The effect of the acidity of the aqueous phase on the extraction coefficient was also investigated by radiotracer experiments. Results are reported for biological standard reference materials and a few environmental samples.

---

Bestimmung von Palladium in biologischen Proben durch Neutronen-Aktivierung

Zusammenfassung Eine Neutronen-Aktivierungsmethode zur Bestimmung von Nano-grammengen Palladium in biologischen Proben wurde beschrieben. Sie beruht auf der radiochemischen Trennung des¹⁰⁹Pd durch Extraktion seines Dimethylglyoxim-Komplexes mit Chloroform aus der sauren, durch nasse Veraschung gewonnenen Lösung der bestrahlten Probe. Der Einfluß der Acidität der wäßrigen Phase auf den Extraktionskoeffizienten wurde ebenfalls durch Radiotracer-Versuche geprüft. Untersuchungsergebnisse für biologische Standardproben und einige Milieuproben wurden mitgeteilt.

---

---

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

Determination of trace contaminants in hydrogenation catalysts by neutron-activation analysis

A neutron-activation method has been developed for the determination of the active constituents and contaminants in hydrogenation catalysts. The active constituents of palladium and nickel catalysts (Pd and Ni) and Zn and Co contaminants present in small amount were determined by a direct instrumental method. A NaI(Tl) scintillator and a Ge(Li) semiconductor connected to a multichannel analyser were used for the measurements. A computer was used to evaluate the γ-spectra. Contaminants present in small amount were also determined by means of a radiochemical separation method based on heterogeneous isotopic exchange on mercury(II) sulphide and zinc sulphide precipitates.     

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%。     

Trace analysis of isothiazolinones in water samples by large-volume direct injection liquid chromatography tandem mass spectrometry

Isothiazolinones are used as preservatives, biocides and disinfectants in a variety of industrial and domestic applications. Some of the isothiazolinones are difficult to isolate from water due their high polarity. A sensitive and selective analytical method was developed and optimized for the determination of sub-μg/L levels of three isothiazolinones in water samples. Three isothiazolinones are described in this paper: 2-methyl-3-isothiazolinone, 5-chloro-2-methyl-3-isothiazolinone and 4,5-dichloro-2-methyl-3-isothiazolinone. The analytical method involves a robust large-volume direct on-column loop injection of 2 mL on an Aqua ODS HPLC column and tandem MS detection (HPLC–MS/MS). After filtration, samples are directly injected without further pretreatment. Detection limits of the individual target compounds were between 0.03 and 0.1 μg/L employing Multi-Reaction Monitoring (MRM) mass spectrometry. Based on the constant ratio of two selected product-ions together with the retention time, the identification is very selective and quantification is reliable. The method was successfully applied to real samples of membrane flushings, drinking water, surface waters and waste water. Additional investigations showed the instability of the isothiazolinones in river- and waste water. Preservation of river water and waste water samples with sodium azide (NaN₃) promotes the stability of the isothiazolines in solution. In membrane flushings, waste water, surface waters and drinking water, levels of the three isothiazolinones were all below the limit of detection. In effluents of households containing washings from normal shampoo use, isothiazolinones could be detected.     

Multielement trace analysis of high purity aluminium by neutron activation

Instrumental neutron activation analysis was applied to multielement trace analysis of high purity aluminium samples. In order to reduce the production of²⁴Na from the matrix, samples were activated by thermal neutron flux of high cadmium ratio. Detection limits of various impurity elements were evaluated. So called “five nine” class standard aluminium samples were analyzed and concentrations of various impurity elements were determined. The analytical results obtained on zone refined aluminium samples showed that zone refining is effective against many elements, such as Na, Cr, Fe, Co, Cu, Ga, As, Br, Ba, La, Ce, Sm, Yb, Lu, Hf, W, Th and U, but not very effective against the element Sc.     

Multielement determination in water by instrumental neutron activation analysis

Instrumental neutron activation analysis /INAA/ technique has been applied to a water sample to determine the elemental concentrations. The sample was irradiated with a neutron flux of 1.2×10¹² n cm^–2 s^–1 for two different periods followed by counting at three different decay times, using two coaxial type high-resolution Ge/Li/ detectors. The dominant elements determined in the water sample are Ca, Cl, Na, Mg, and K present in ppm-level while Co, I, Mn, Sm, and Sb are present in smaller amounts, approximately on the average 0.01 ppm. Only traces of other elements such as the rare-earth elements, Ag, As, Ba, Cu, Cd, Fe, Sr, W, Zn, seem to be present in the water sample.     

Multielement determination in river water by neutron activation analysis

Concentrations of Al, Br, Ca, Ce, Co, Cr, Eu, Fe, Hf, La, Lu, Mg, Mn, Na, Rb, Sc, Sm, Sr, Tb, Th, Ti, V, Yb, Zn, and Zr have been measured in Tigris and Euphrates river water, using neutron activation analysis in combination with preconcentration technique. River water samples were preconcentrated by evaporation at 70°C under atmospheric pressure. The samples with standard reference materials were irradiated with a neutron flux of 2.3·10¹³ n·cm^–2·s^–1.     

Determination of trace elements in iron by neutron-activation techniques

A systematic analytical procedure for the determination of some trace impurities in iron matrices was developed by employing both direct and destructive neutron-activation techniques. Irradiations in fast neutron fluxes, selective activation by epithermal neutrons and coincidence γ-spectrometry measurements were used in some cases, in order to improve the sensitivity for non-destructive analysis; for destructive methods, radiochemical separations based on ion exchange and solvent extraction were applied. Procedures are described, and some results of the determination of low concentrations of Al, Mn, Ti, V (non-destructive), P, S, Zn (destructive) and As, Co, Cr, Cu, Mo, Ni, Sc, W (both methods) in iron are reported and discussed.     

Multielement trace analysis by atomic absorption spectrometry and neutron activation analysis in biological matrices

According to calculations of NIX and others, the formation of superheavy elements might occur in heavy-ion reaction systems such as the one under investigation in the present work i.e.,²³⁸U+^63,65Cu at 9.6 MeV/nucleon. Since previous experiments have indicated that upper limits to the production cross-section for superheavy elements are extremely low, we have carried out two rather long irradiations of 27 hrs and 42 hrs, respectively, at the University of Manchester LINAC. The first run has already been reported on in the literature. In the case of the second run, after chemical separation into HgS, CdS, and La(OH)₃ fractions, the samples were assayed simultaneously and continuously over a period of 6 months for alpha-and spontaneous-fission activity, using Si surface-barrier detector. Each sample was at the same time mounted on mice, for the purpose of scanning for fission tracks at a later date. No indications from the data have so far been found that superheavy elements were produced.     

Instrumental method for the determination of trace elements in water samples by neutron activation analysis

Thermal neutron activation analysis and a large-volume high-resolution Ge(Li) gammaray spectrometer, connected on-line to a DEC PDP 8/L computer, have been used to measure the concentrations of Na, Sc, Cr, Fe, Co, Ni, Zn, As, Se, Br, Rb, Ag, Sb, Cs, W and Hg in some Italian subsurface water samples. The instrumental method requires neither a chemical separation technique nor a pre- or post-concentration of the trace elements to be detected. As a consequence, this method eliminates many inherent errors associated with chemical determinations. The technique is sensitive, precise and particularly suitable for routine analysis of many trace elements at both natural and pollution levels in water samples. The interferences due to fast neutron (n, p) and (n, α) reactions are not appreciable, with the only exception of the⁵⁴Fe(n, p)⁵⁴Mn and⁵⁸Ni(n, p)⁵⁸Co reactions. Losses of volatile, elements, e. g. As, Br and Hg, during irradiation proved to be negligible.     

Preconcentration techniques for inorganic trace analysis

Summary In inorganic trace analysis, concentration of desired trace elements is frequently required prior to the instrumental determination to lower the detection limits, improve the precision and accuracy of analytical results, and to widen the scope of the determination techniques. This paper surveys the present status and future prospects of preconcentration techniques. Here, emphasis is placed on control of contamination and losses of trace elements, preconcentration from large volumes of aqueous solutions, microscale preconcentration techniques for high-purity solid microsamples, and preconcentration techniques for trace element speciation in natural waters. Continuous-flow coprecipitation-flotation and other techniques which have been developed in the author's laboratory in recent years are given as examples.

---

Anreicherungsverfahren für die anorganische Spurenanalyse

Zusammenfassung In der anorganischen Spurenanalyse ist vor der instrumenteilen Bestimmung oft eine Anreicherung der zu bestimmenden Spurenelemente erforderlich. Hierdurch kann man das Nachweisvermögen sowie die Präzision und die Richtigkeit verbessern und den Anwendungsbereich der Methode erweitern. Es werden in der vorliegenden Arbeit Entwicklungsstand und Entwicklungstendenzen bei Anreicherungstechniken behandelt. Probleme betreffend Kontamination, Verluste von Spurenelementen, Anreicherung aus großen Volumina wäßriger Lösungen, Mikromethoden für Anreicherung im Fall von Mikromengen fester Reinststoffe und Anreicherungsverfahren bei Speziesbestimmungen in natürlichen Gewässern werden diskutiert. Als Beispiele werden auch kontinuierliche Mitfällungs- und Flotationsverfahren sowie andere Techniken, die im Laboratorium des Autors ausgearbeitet wurden, behandelt.

     

GC analysis of trichloroacetic acid in water samples by large-volume injection and thermal decarboxylation in a programmed-temperature vaporizer

Summary AGC method has been developed for the analysis of tricholoroacetic acid (TCA) in water samples. It entails large-volume injection (LVI) and programmed-temperature vaporization (PTV) of water samples, thermal decarboxylation of TCA to chloroform in the injector, and GC-ECD analysis of the decarboxylation product. Conditions such as final injector temperature, splitless time, and injection volume were optimized. The limit of detection is approximately 0.1 μg L⁻¹ Several real samples were analyzed. The method presented is an easy means of determination of TCA and eliminates sample-preparation steps such as extraction and derivatization.     

Semipermeable ion-exchange membranes as a preconcentration matrix for trace analysis by electrochemical and neutron-activation techniques

Ion-exchange membranes were used in conjunction with neutron-activation analysis and anodic stripping voltammetry for the determination of certain trace metal ions. The various parameters which govern the applicability, limitations and sensitivity of the methods were investigated. A new membrane "barrier" electrode assembly was introduced and found to be useful for the anodic stripping determination of trace metal ions in the presence of surface active materials.     

Rapid trace analysis of alachlor in water and vegetable samples

The use of a rapid and specific (cross-reactivity<4%) enzyme-linked immunosorbent assay (ELISA) for the determination of alachlor residues in water and vegetable samples is addressed. The analytical method consists of a fast extraction procedure followed by an optimised ELISA. The detection limit was 0.44 microg l(-1), with a linear range from 0.89 to 143.2 microg l(-1). For alachlor extraction from water samples, different solid-phase cartridges (C, Ph, C8 and C2) were assayed using MeOH as eluent. Extracts were diluted (1:4) with distilled water before ELISA. This procedure gave recoveries close to 100% with RSDs<14%. For vegetable samples, alachlor was extracted directly with MeOH and the extracts diluted 1:40 (v/v) with saline buffer prior to ELISA. The results obtained by the proposed procedure correlate well with the reference method (multiresidue extraction-GC-MS) for vegetable samples (r>0.85).     

Analysis of inorganic species in environmental samples by capillary electrophoresis

The use of capillary electrophoresis for the determination of inorganic species in environmental samples is reviewed. Topics covered include the separation of inorganic anions, inorganic cations, transition metal cations and organometals in different environmental matrices, such as atmospheric deposition, atmospheric aerosols, gases, natural waters, waste waters, soil, sediment and marine biological samples. Cited literature is gathered according to the type of matrix, so that the focus is on the discussion of matrix effects rather than on the method development for a single class of compounds. For each matrix, surveyed methods are tabulated in order to assist the method selection. Innovative applications of capillary electrophoresis to advanced environmental research are also emphasised.     

Non-destructive elemental analysis of large meteorite samples by prompt gamma-ray neutron activation analysis with the internal mono-standard method

Prompt gamma-ray neutron activation analysis (PGNAA) using the internal mono-standard method was tested for its applicability to analyzing large solid samples including irregularly shaped meteorite samples. For evaluating the accuracy and precision of the method, large quantities of the Geological Survey of Japan standardized rock powders (JB-1a, JG-1a, and JP-1) were analyzed and 12 elements (B, Na, Mg, Al, Cl, K, Ca, Ti, Mn, Fe, Sm, and Gd) were determined by using Si as an internal standard element. Analytical results were mostly in agreement with literature values within 10 %. The precision of the method was also shown to be within 10 % (1σ) for most of these elements. The analytical procedure was then applied to four stony meteorites (Allende, Kimble County, Leedey, Lake Labyrinth) and four iron meteorites (Canyon Diablo, Toluca (Mexico), Toluca (Xiquipilco), Squaw Creek) consisting of large chunks or single slabs. For stony meteorites, major elements (Mg, Al, Si, S, Ca, and Ni), minor elements (Na and Mn) and trace element (B, Cl, K, Ti, Co, and Sm) were determined with adequate accuracy. For iron meteorites, results for the Co and Ni mass fractions determined are all consistent with corresponding literature values. After the analysis, it was confirmed that the residual radioactivity remaining in the sample after PGNAA was very low and decreased down to the background level. This study shows that PGNAA with the internal mono-standard method is highly practical for determining the elemental composition of large, irregularly shaped solid samples including meteorites.