Rapid determination of halogens in milk by instrumental neutron activation analysis

The absolute concentrations of iodine, bromine and chlorine in milk, have been determined by epithermal neutron activation followed by high resolution gamma-ray spectrometry. Two kinds of milk commonly consumed in Israel have been investigated. The concentration of iodine, bromine and chlorine were found to be 0.18–0.30 g/ml, 2.02–2.85 g/ml and 0.65 mg/ml, respectively. The method is fast, selective, accurate and highly sensitive.     

Chlorine and bromine contents in tobacco and tobacco smoke

The chlorine and bromine contents in tobacco and tobacco smoke in both the particulate and gaseous phases were studied by neutronactivation analysis. Methyl chloride and methyl bromide concentrations were measured in the gaseous phase by gas-liquid chromatography — mass spectrometry. The chlorine and bromine contents in nine brands of cigarettes were on the average as follows: Tobacco—6600 ppm chlorine and 110 ppm bromine. Cigarette smoke, particulate phase—68 g chlorine and 1 g bromine per cigarette. Cigarette smoke, gaseous phase—90 g chlorine and 5 g bromine per cigarette. In the gaseous phase methyl chloride accounted for 60% of the total chlorine and methyl bromine for 80% of the total bromine.     

Spurenbestimmung von organisch gebundenem Schwefel und Chlor in kleinen Probenmengen

Summary A rather simple device is described for mineralizing organic liquids for the determination of sulfur, chlorine, and other halogenides. The detection of the mineralization products of these elements, e.g. chloric acid or sulfuric acid, is done by ion chromatography with high-sensitive suppressor technique. For the determination in the g/g-range samples of 0.1 to 1 ml are required. Detection limits are lower than 1 g/g.     

Analysis of organobromine compounds and HBr in motor car exhaust gases with a GC/microwave plasma system

Summary In this investigation an analytical procedure for the determination of different organobromine compounds in motor car exhaust gases is developed in order to obtain a total balance of these compounds in this type of exhaust gas. For this purpose, adsorption sampling on Tenax GC combined with thermal desorption and a fast cold trap injection into the GC column system is used. A special capillary cold trap/thermodesorption system for a fast injection within 1 s is developed. The chromatographically separated fractions are identified by their retention times and elementspecific detection with a microwave plasma detector. Methyl bromide, 1,2-dibromoethane, and vinyl bromide are analysed in exhaust gases in cases where the gasoline contains 1,2-dibromoethane as an additive (leaded gasoline). The analysed bromine contents, which correspond to these organobromine compounds, are in the range of 90–190 g/m³, 15–85 g/m³, and 5–20 g/m³, respectively. The portion of the organobromine compounds is 22–44% of the total bromine which is emitted by the exhaust gases. The other portion contains mainly inorganic particulate bromide, which can be separated by filters. The concentration of the organobromine compounds decreases with increasing motor temperature. After conversion into 2-bromocyclohexanol and after gas chromatographic separation HBr is detected to be 5.8 g bromine per m³ exhaust gas, which corresponds to approximately 1% of the total bromine emission. 1,2-Dichloroethane is analysed in the range of 5–35 g Cl/m³, whereas the concentration of tetraalkyl lead in the exhaust gases is less than the detection limit of 6.7 g Pb/m³. The average bromine/lead ratio found in the filterable portion of the exhaust gases is 0.30 (by weight); the same ratio calculated for total bromine emission including the organobromine compounds is 0.47. Compared with the bromine/ lead ratio in gasoline of 0.39 this means that at least 17% of the total lead in the gasoline is not directly emitted with the motor car exhaust gases.

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Analyse von bromorganischen Verbindungen und HBr in Autoabgasen mit einem GC/Mikrowellenplasma-System

     

Landolt-Reaktionen auf „Chlorgrundlage“ und ihre Anwendung zum Nachweis und zur Bestimmung katalytisch wirkender Spurenelemente. I

Zusammenfassung Gemische aus Ascorbinsäure, Hydrazin oder Zinn(II)-chlorid mit sauren, Chlorat und Chlorid enthaltenden Lösungen reagieren nach Art der bekannten Landolt-Reaktion unter Chlorausscheidung, die sich mit o-Tolidin indizieren läßt. Die Reaktion wird von Vanadin(V), Eisen(III) oder Osmium(VIII) katalysiert. Auf dieser Grundlage lassen sich diese Elemente sowohl chronometrisch wie auch mit Hilfe der Simultan-komparationsmethode bestimmen. Die Nachweisgrenzen liegen bei 0,1g V, 0,3g Fe bzw. 0,1g Os. Die Arbeitsvorschrift für die Analyse im Konzentrationsbereich 1 bis 10g/5 ml wird angegeben. Der relative Fehler bei der Simultankomparationsmethode liegt innerhalb 2%. Der Einfluß fremder Ionen wurde untersucht.

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Summary Mixtures of ascorbic acid, hydrazine or tin(II) chloride react with solutions containing acids, chlorate and chloride in accord with the familiar Landolt reaction, with liberation of chlorine. The latter can be detected witho-tolidine. The reaction is catalyzed by vanadium(V), iron(III) or osmium(VIII). On the basis of this behavior, it is possible to determine these elements chronometrically and also with the aid of the simultaneous comparation method. The detection limits are 0.1g V, 0.3g Fe, or 0.1g Os. The working directions are given for the analysis in the concentration range from 1 to 10g/5 ml. The relative error in the simultaneous comparation method is within 2%. The influence of foreign ions was studied.

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Résumé Les mélanges d'acide ascorbique, d'hydrazine ou de chlorure d'étain-II avec des solutions acides contenant chlorate et chlorure réagissent suivant la réaction bien connue de Landolt avec libération de chlore mis en évidence par l'o-tolidine. La réaction est catalysée par le vanadium-V, le fer-III ou l'osmium-VIII. Sur ce principe, on peut doser ces éléments aussi bien par chronométrie que par la méthode de comparaison simultanée. Les limites de dilution se situent à 0,1g V, 0,3g Fe ou 0,1g Os. On indique le mode opératoire de l'analyse dans le domaine de concentration de 1 à 10g/5 ml. L'erreur relative pour la méthode de comparaison simultanée est inférieure à 2%. On a étudié l'influence des ions étrangers.

     

Separation of linear gramicidins using carbon dioxide-containing mobile phases

Packed-column supercritical-fluid chromatography (pSFC) is presented as a novel method for separating and analyzing gramicidin samples. By use of methanol-modified carbon dioxide as a mobile phase the pentadecapeptides gramicidin A (gA), gramicidin B (gB), and gramicidin C (gC) are readily separated and eluted from a PRP-1 poly(styrene–divinylbenzene) column. Although optimum separation conditions are typically achieved near a column temperature of 40°C, a column pressure of 11 MPa, and 30% methanol modifier, pressure and modifier gradients around these values are also found to improve the overall separation time. Measurements indicate that the mobile phase solubility of gramicidin under these conditions is 5.0±0.4 g mL^–1. Collection of individual peaks during chromatography achieved analytical-scale isolation of 2 g refined gC from 20 g injected gramicidin D. Further, supercritical-fluid extraction of 200 g gramicidin D from a Chromosorb 102 support packed into the vessel produced 57 g gA in 90% purity. The results establish that carbon dioxide-based mobile phases can be successfully used for the separation of individual gramicidin species.     

Determination of ochratoxin A in Portuguese rice samples by high performance liquid chromatography with fluorescence detection

A sensitive and accurate analytical method for the determination of ochratoxin A (OTA) in rice, based on extraction with phosphate-buffered saline/methanol, an immunoaffinity column (IAC) for clean-up, and high performance liquid chromatography with fluorescence detection (HPLC-FD), is described. The limit of quantification of the proposed method was 0.05 g kg^–1. Recovery of OTA from rice samples spiked at 0.05 g kg^–1 was 92%, with a within-day RSD of 5.4%. The proposed method was applied to 42 rice samples from Portugal and the presence of OTA was found in six samples at concentrations ranging from 0.09 to 3.52 g kg^–1. The identification of OTA was confirmed by methyl ester derivatization and then HPLC analysis. The daily intake of OTA by the Portuguese population was also estimated.     

Elements in car and truck tires and their volatilization upon incineration

The trace metal loading of used car and truck tires and the fractions of the metals volatilized upon incineration of the tire were determined. INAA was chosen due to its multielement analysis capability and its low detection limit for many elements. A high purity planar germanium detector was used. Among the elements measured were, Al (4–150 g/g), Ti (41–730 g/g), V (0.04–0.4g/g), Mg (>80–580 g/g), Zn (1–2.2%) as typical concentrations; also some amounts of antimony, bromine and arsenic have been found. Major differences in elemental concentrations have been observed between the tread and the wall of a tire, and also between different brands.     

Non-catalyzed oscillation reaction in the aniline-KBrO3?H2SO4 system. II. Reaction products and their oscillating behavior

By means of thin-layer and gas chromatography the reaction products have been determined in the oscillation system of aniline, KBrO₃ and H₂SO₄. These products include: 2-bromoaniline, 4-bromoaniline, 2,4-dibromoaniline, 2,4,6-tribromoaniline, 1,4-benzoquinone, 2-bromo-1,4-benzoquinone, 2,6-dibromo-1,4-benzoquinone and a brominated oxidation product. The brominated aniline derivatives do not exhibit an oscillating behavior, and the addition of these substances to an oscillating mixture damps the course of other oscillations.

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, KBrO₃ H₂SO₄. : 2-, 4-, 2,4-, 2,4,6-, 1,4-, 2--1,4-, 2,6--1,4- . , , , .

     

Photometrische Bestimmung von kleinen Mengen Bromid und Chlorid, einzeln und nebeneinander, in wasserl?slichen Substanzen

Zusammenfassung Ein Verfahren wurde ausgearbeitet, das die Bestimmung kleiner Mengen von Bromiden und Chloriden, einzeln und nebeneinander, in wasserlöslichen Substanzen ermöglicht. Bromid- und Chloridionen werden durch Kaliumpermanganat in verschiedenen sauren Lösungen zu Brom bzw. Chlor oxydiert, die mit o-Tolidin ein gelbes Oxydationsprodukt bilden. Die Extinktion dieser Gelbfärbung wird photometrisch gemessen und die entsprechenden Bromid- und Chloridmengen an Eichgeraden ermittelt. 10 bis 100 g Bromid und Chlorid können mit einer Genauigkeit von ± 3% und l bis 10 g Chlorid mit einer Genauigkeit von ± 10% bestimmt werden.

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Photometric determination of small amounts of bromide and chloride, separately and in presence of each other, in water-soluble substances

Bromide and chloride iones are oxidized by potassium permanganate in solutions of different acidity to bromine and chlorine, respectively, which form with o-tolidine a yellow oxidation product. The absorbance of this coloration is measured by photometry and the corresponding amounts of bromide and chloride are find out by calibration curves. 10 to 100 g of bromide and chloride can be determined with an accuracy of ± 3% and 1 to 10 g of chloride with an accuracy of ± 10%.

     

Determination of phosphorus,sulfur and chlorine in high-purity aluminium

Multi-step procedures for the determination of phosphorus, sulfur and chlorine are described and tested against established methods and on reference materials. Phosphorus is separated as hydrogen phosphide, extracted as phosphomolybdic acid, reduced to molydenum blue and measured photometrically (detection limit 0.05 g/g). Sulfur is separated after reduction as hydrogen sulfide or by means of pyrohydrolysis and measured by ICP-OES (detection limit 0.1 g/g). Chloride can be measured by ion chromatography after pyrohydrolytic separation (detection limit 0.1 g/g). The determination of sulfur was also successfully tested on copper and steel samples.Dedicated to Professor Günther Tölg on the occasion of his 60th birthday     

Bestimmung von Argon neben Stickstoff und Sauerstoff in pulvermetallurgisch hergestellten Werkstoffen mit einem modifizierten Tr?gergas-Hei?extraktionsger?t

Summary The modification of a commercial carrier-gas fusion instrument for the simultaneous determination of argon is described. In order to separate argon from nitrogen, a gas-chromatographic column with molecular sieve was incorporated between the absorption traps for H₂O and CO₂ and the thermal conductivity detector. A computing integrator was used for the evaluation of the detector signals. The calibration was done by introduction of defined volumes of dry air into the carrier-gas line. The conditions for the liberation of argon from samples of ODS-alloys and the separation from the other extracted gases were optimized. Results of analysis of powders and compact samples were compared with the results obtained by means of a vacuum-fusion instrument. In the concentration range 25 to 50 g/g argon the relative standard deviations were 1.5 to 3% (six determinations). With powders of 3 to 5 g/g relative standard deviations of about 8% were achieved. The limit of detection for 1 g samples was found to be ca. 0.5 g/g.     

Anwendung der Ringofenmethode zum Nachweis einiger Heteroelemente in organischen Verbindungen

Zusammenfassung Ein schnelles und einfaches Mikroverfahren zum Nachweis einiger Heteroatome organischer Verbindungen wurde entwickelt. Nach Aufschluß mit metallischem Kalium werden die entstehenden Ionen mit der Ringofenmethode getrennt und mit empfindlichen Reaktionen nachgewiesen. Nachweisgrenze: 0,5 bis 1g Stickstoff, 1 bis 2g Schwefel, 2 bis 3g Jod, 4 bis 5g Brom, 5 bis 10g Chlor in 0,5 bis 1 mg Einwaage.

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Summary A rapid and simple micromethod was developed for the detection of several hetero-elements in organic compounds. After breaking down the sample with metallic potassium, the resulting ions are separated by the ring oven method and detected by means of sensitive reagents. Detection limits: 0.5 to 1g nitrogen, 1 to 2g sulfur, 2 to 3g iodine, 4 to 5g bromine, 5 to 10g chlorine in samples weighing 0.5 to 1 mg.

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Résumé On a découvert un procédé à l'échelle micro, simple et rapide, pour rechercher certains hétéroéléments dans les composés organiques. Après mise en solution par le potassium métallique, on sépare les ions formés suivant la méthode du four annulaire et l'on effectue la recherche au moyen de réactions sensibles. Limite de dilution: 0,5 à 1g d'azote, 1 àg de soufre, 2 àg d'iode, 5 à 10g de chlore sur 0,5 à 1 mg de prise d'essai.

     

Determination of nitrate in natural waters by flow-injection analysis

Summary Nitrate was determined in natural water samples by flow-injection spectrophotometry. It was reduced to nitrite with copperized cadmium and the nitrite thus produced reacted with p-aminoacetophenone and m-phenylenediamine. The limit of detection was about 1.5 g l^–1 for sample injections of 650 l. The sampling rate was about 40 samples h^–1 and the relative standard deviation was above 1% for 0.1–0.3 mg l^–1 nitratenitrogen. Nitrite present in the sample was determined separately and subtracted.

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Nitratbestimmung in natürlichen Wässern mit Hilfe der Fließinjektions-Analyse

Zusammenfassung Nitrat wird bei dieser Methode mit Hilfe einer Cu/Cd-Reduktionssäule zu Nitrit reduziert, das mit p-Aminoacetophenon und m-Phenylendiamin zur Reaktion gebracht wird. Die gebildete Verbindung wird spektral-photometrisch gemessen. Die Nachweisgrenze beträgt etwa 1,5 g/l bei injizierten Probevolumina von 650 l. Der Probendurchsatz beträgt 40/h. Die relative Standardabweichung liegt über 1% bei 0,1–0,3 mg/l Nitrat-Stickstoff. Vorhandenes Nitrit wird gesondert bestimmt und abgezogen.

     

Production of certified reference material

Summary Carbon has been determined in 31 European reference steels in the range of 11–2561 g/g C, using an absolute calibration method.High-purity calcium carbonate was used as the calibration material and weighing was carried out by means of a balance with extremely small weighing error. Both synthetic calibration samples and test samples were processed alternatingly under identical conditions, and the analyses were completed in the shortest possible time.In 28 of the cases examined, results were lower than the certificate values, by an average of 27 g/g. The interval of uncertainty of the accuracy was 6 g/g (probability 99%).

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Herstellung zertifizierter ReferenzmaterialienGenaue Bestimmung von Kohlenstoff in Stählen im Bereich von 11–2561g/g

Zusammenfassung Die Kohlenstoffgehalte von 31 europäischen zertifizierten Referenzstählen im Arbeitsbereich von 11–2561 g/g Kohlenstoff wurden durch absolute Eichung überprüft.Die hinreichende Reinheit des Eichmittels Calciumcarbonat wurde sichergestellt und ein Wägesystem mit einem hinreichend kleinen Wägefehler benutzt.Das gleiche Verhalten von synthetischen Eichproben und Analysenproben im Analysenprozeß wurde hergestellt und beide Probearten wechselweise unter konstanten Systembedingungen innerhalb kürzester Zeitspanne untersucht. In 28 der untersuchten Fällen wurden im Mittel um 27 ppm tiefere Werte gefunden als in den Zertifikaten angegeben. Das Unsicherheitsintervall der Richtigkeit der gefundenen Werte lag mit einer Wahrscheinlichkeit von 99% im Mittel bei 6 g/g.

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Abbreviations CRM Certified reference material - ppm g/g The author thanks Mr. E. Weichert for his excellent direction of the practical work.     

Application of high resolution ICP-spectrometry to the determination of B,Be, Co,Mo and Sn in soils and similar matrices

The most sensitive emission lines for the elements B, Be, Co and Mo are strongly influenced by disturbing emission lines of Fe using normal optical resolution. The advantages of high resolution, applying the new ICP-spectrometer JY 38 Plus (Jobin-Yvon, France) with the 2400 lines/mm grating measuring in the 1st and 2nd order will be discussed. Beside the concentrations in soils, sediments and sludges, applying aqua regia and HF decomposition methods, the detection limits in these matrices will be given. The possibilities of ICP-spectrometry for the determination of the above-mentioned elements are shown at the examples of SRMs (standard reference materials). The materials used here were three soils and three sludges from the BCR (Community Bureau of Reference, European Communities) and one sediment from NBS (National Bureau of Standards, USA). For example, the most sensitive and normally used line for the determination of boron at 249.7733 nm cannot be used in case of this type of matrix due to normally high Fe-concentrations and due to a strong Fe-interference. Therefore, it is necessary to use the line at 249.6778 nm, where an interference-free measurement can be achieved in case of high optical resolution. The measured B-contents in these samples are in the range of 20 to 60 g/g, for Co in the 10 g/g region, for Be well below 1 g/g, for Sn between 3 and 400 g/g. Mo was only detectable in the sludge samples (limit of determination 0.5 g/g).Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Determination of pentachlorophenol residues in wine and corks by solvent extraction methodology and specific gas chromatography detection

Summary A gas chromatographic methodology with selective detection is presented for the analysis in wines and corks of pentachlorophenol residues, which are suspected to be the most likely precursors of some off-flavours described in several wine samples. After derivatisation, pentachlorophenol acetate residues were monitored by electrolytic conductivity detection and/or mass spectrometric detection in the selective ion mode at m/z 264 and 266. Recoveries varied from 80 to 96% for wine samples fortified with 5 to 100 g l^–1 and from 83 to 91% for corks (fortified at 25 to 100 g kg^–1). The proposed methodology allowed for a determination limit of g l^–1 for wine and 10 g kg^–1 for corks.     

Determination of cadmium in tobacco smoke and zinc in tap water by solvent extraction flame atomic absorption spectrometry

Procedures are described for the determination of cadmium in tobacco smoke and zinc in tap water by flame atomic absorption spectrometry after chelation with benzyl 2-pyridyl ketone 2-pyridylhydrazone and extraction with isobutyl methyl ketone. Calibration graphs in the organic layer were linear up to 1.3 g/ml, with sensitivities of 80 ng/ml (Zn) and 71ng/ml (Cd), and limits of detection of 49 ng/ml for zinc and 38 ng/ml for cadmium. RSD values were 2.9% at 0.42 g/ml (Cd) and 4.7% at 0.17 g/ml (Zn).     

Fallout analysis of atmospheric water precipitations

Summary A rapid ion-exchange method for the determination of ¹³⁷Cs, ⁸⁹Sr, and ⁹⁰Sr in rain-, snow-, cistern-, and soft surface-waters is presented. The sorption of 2–30 l samples with a calcium content up to 300 mg is carried out on a specially shaped column filled with Dowex 50, X-8 or Dowex 50 W, X-8. Radiocaesium is washed from the column with 0,6 M ammonium glycolate/0.2 M NaCl, pH 5, radio-strontium with 1.0 M ammonium glycolate/0.3 M NaCl, pH 5. After their isolation from the respective eluates the radio-nuclides are counted on a low-background beta-counter: ¹³⁷Cs as Cs-dipicrylaminate, ⁸⁹Sr/⁹⁰Sr as SrCO₃, and ⁹⁰Y as Y₂O₃ in cases of indirect ⁹⁰Sr determination. The mean chemical recoveries of added carriers amount to 85% for caesium, 95% for strontium and 95% for yttrium. At levels of a few picocuries, in parallel determinations, the deviations of the results for ¹³⁷Cs and ⁹⁰Sr from respective mean values generally do not exceed ±5%. With a 30 l sample the limit of detection amounts to 0.006 Ci/l for ¹³⁷Cs and 0.005 Ci/l for ⁹⁰Sr.

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Zusammenfassung Für die Bestimmung von ¹³⁷Cs, ⁸⁹Sr und ⁹⁰Sr in Regen-, Schnee-, Zisternen- und weichem Oberflächenwasser wird eine schnelle Ionenaustausch-methode vorgeschlagen. Die Sorption von 2–30 l Wasserproben mit einem Calciumgehalt bis zu 300 mg wird mit einer besonders gestalteten, mit Dowex 50, X-8 oder Dowex 50 W, X-8, gefüllten Säule durchgeführt. Aus der Kolonne werden Radio-Caesium mit 0,6 M Ammoniumglykolat/ 0,2 M NaCl, pH 5 und Radio-Strontium mit 1,0 M Ammoniumglykolat/ 0,3 M NaCl, pH 5 eluiert. Nach ihrer Isolierung aus den entsprechenden Eluatsfraktionen werden die Radio-Nuklide in einem Beta-Antikoinzidenzzähler gemessen: ¹³⁷Cs als Cs-Dipikrylaminat, ⁸⁹Sr/⁹⁰Sr als SrCO₃, und ⁹⁰Y als Y₂O₃ im Fall der indirekten ⁹⁰Sr-Bestimmung. Die durchschnittliche Rückgewinnung der zugesetzten Träger beträgt 85% für Caesium, 95% für Strontium und 95% für Yttrium. In Parallelbestimmungen überschreiten bei Gehalten von einigen Ci/l die Abweichungen der ¹³⁷Cs- und ⁹⁰Sr-Werte von den entsprechenden Mittelwerten im allgemein nicht ±5%. Bei Anwendung einer 30 l-Wasserprobe beträgt die untere Nachweisgrenze 0,006 Ci/l für ¹³⁷Cs und 0,005 gmCi/l für ⁹⁰Sr.

     

Galvanostatic Coulometric Determination of Salicylic Acid and Some of Its Derivatives Using Electrogenerated Halogens

Reactions of electrogenerated bromine and chlorine with salicylic acid and some of its derivatives were studied. Procedures for the galvanostatic coulometric determination of 2.4 to 19.2 g/mL of salicylic, acetylsalicylic, para-aminosalicylic acids and mesalazine in model solutions and medicinal preparations with electrogenerated halogens were developed (RSD varied from 1 to 5%). The end-point of coulometric titration was determined amperometrically with two polarized platinum electrodes.