The determination of tin,chlorine, and fluorine in six japanese sedimentary standards

Concentrations of tin, chlorine, and fluorine in six new Geological Survey of Japan (GSJ) sedimentary standards are reported. Tin was determined using graphite furnace atomic absorption spectrometry (GFAAS), following a lithium metaborate (LMB) fusion of the rock material. Chlorine and fluorine were determined using ion-selective electrode (ISE) potentiometry following an acid digestion and a LMB fusion, respectively. The methods employed are briefly described and determination limits in the rock of 0.2 g/g for tin, 10 g/g for chlorine, and 100 g/g for fluorine are reported. The precision obtained for the six sedimentary standards, expressed as %relative standard deviation, averaged 5.3% over the range of 2-200 g/g tin, 5.8% over the range of 20–65 g/g chloride, and 1.7% over the range of 100–4500 g/g fluoride, all in the rock. This compares favorably to the precision obtained for international geologic reference materials determined concurrently with the GSJ sedimentary standards. The values of tin, chloride, and fluoride obtained for the international reference materials were in favorable agreement with the recommended literature values.     

Characterization of Dodecanethiol SAM and Multi-Walled Carbon Nanotube Modified Gold Electrodes,and Voltammetric Determination of Prochlorperazine

A multi-walled carbon nanotube and dode-canethiol (DDT) modified gold electrode (i.e. MWNTs/DDT/Au) was prepared and characterized. When the gold electrode was modified with a DDT self-assembled monolayer (SAM) followed by a MWNT film, the electrode area increased by a factor of about 4. At the same time, the blocking action of the DDT SAM with respect to electron transfer disappeared. The conductivity of MWNT wires imbedded in the DDT SAM was thought to account for that. The resultant electrode was more stable than MWNTs/Au and more sensitive than MWNTs/GC. At the MWNTs/DDT/Au, prochlorperazine exhibited two anodic peaks at about 0.69V and 0.88V in pH 5.8 phosphate buffer solution. The peak at about 0.69V was suitable for prochlorperazine determination. After an accumulation time of 180s in an open circuit, the peak current was linear to prochlorperazine concentration over the range of 5×10^–7M–1.5×10^–5M with correlation coefficient of 0.995; the detection limit was 1×10–7M. Compared to DDT/Au, this electrode regenerated easily by repetitive cycling in a blank solution.     

Determination of Promedol (Trimeperidine) and Ketamine in Blood Using Gas Chromatography–Mass Spectrometry

A procedure was developed for the gas-chromatographic determination of promedol (trimeperidine) and ketamine in whole blood with mass-selective detection. The detection limit for trimeperidine and ketamine in blood is 0.05 g/mL. The analytical range is 0.1–5.0 g/mL. The maximum within-series errors in the determination of the studied compounds are no higher than 14.1% for concentrations of 0.10 g/mL and 7.47% for concentrations of 1.0 g/mL. The maximum between-series relative errors are 5.75% for concentrations of 0.10 g/mL and 2.7% for concentrations of 1.0 g/mL. The procedure can be used in toxicological and clinical analyses.     

Gas Chromatographic Determination of Diacetylmorphine with Mass Spectrometric Detection

The possibility of determining diacetylmorphine traces in various matrices by gas chromatography with mass spectrometric detection is demonstrated. Diacetylmorphine can be reliably determined by gas chromatography–mass spectrometry in the range 0.02–7.5 g/mL. A procedure is developed for the quantitative determination of diacetylmorphine and its concomitants, including acetylated opioid derivatives, in forensic samples. The detection limit for diacetylmorphine without preconcentration is 0.01 g/mL. The detection limit in the selective-ion monitoring mode with preconcentration is 1 × 10^–4 g/mL.     

Trace analysis of cationic surfactants in water using HPLC with conductometric detection

Summary A simple and fast determination of trace amounts of commercially used cationic surfactants is described. After extraction from water cationic surfactants are separated by HPLC and detected by conductometry. The detection limit is 3 g/l for distearyldimethylammonium chloride, 16 g/l for ditallowimidazolinium methosulphate, and 6 g/l for dodecylpyridinium chloride.     

Simultaneous determination of copper,mercury and lead by first-order derivative spectrophotometry using dithizone as reagent

A first-order derivative spectrophotometric method has been developed for the simultaneous determination of copper, mercury and lead at g/L levels using dithizone as reagent. The procedure involves the simultaneous extraction of these elements by dithizone in chloroform from weakly alkaline solutions. Linear calibration curves were obtained in the ranges 0.5–10 (Cu), 1–10 (Hg) and 1–10 (Pb) g present in 40 ml of aqueous phase with detection limits of 5 g/L (Cu) and 20 g/L (Hg and Pb). The R.S.D.s for 100 g/L of copper, mercury and lead were 2.5, 2.6 and 3.1% respectively, for 5 determinations. The method is applicable for the determination of copper and lead in marine sediment samples with good precision and accuracy.     

Capillar-Gas-Chromatographie mit ECD- und MS-Detektion zur quantitativen Bestimmung von Pentachlorphenol im menschlichen Plasma und Harn

Zusammenfassung Pentachlorphenol (PCP) wurde im Plasma und Harn mittels Capillar-Gas-Chromatographie und ECD-Detektion erfaßt. Die parallele Analyse mit einem massenselektiven Detektor erbrachte nahezu identische Werte (r=0,9978). Die Nachweisgrenzen lagen bei ca. 5 g PCP/l Harn bzw. ca. 10 g PCP/l Plasma. Die Untersuchung von 27 Personen ohne beruflichen bzw. besonderen usuellen Kontakt mit Pentachlorphenol ergab mediane PCP-Konzentrationen im Plasma von 28 g/l (95.0 Perzentil 149 g/l) bzw. im Harn von 10 g/l (95.0 Perzentil 55 g/l).

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Determination of pentachlorophenol in human plasma and urine samples by capillary gas chromatography with ECD- and MS-detection

Summary Pentachlorophenol (PCP) levels in plasma and urine samples were determined by capillary gaschromatography and EC-detection. The results of the parallel analysis of samples with a selective mass detector correlated well (r=0.9978). The detection limits were around 5 g PCP/l urine and around 10 g PCP/l plasma respectively. A study on 27 persons occupationally not exposed to PCP or without a known special ecological intake of PCP showed median PCP levels of 28 g/l plasma (95.0 percentile: 149 g/l plasma) and 10 g/l urine (95.0 percentile: 55 g/l).

     

Voltammetric determination of trace amounts of mercury with a carbon paste electrode modified with an anion-exchanger

Summary A carbon paste electrode modified with a liquid anion exchanger (Amberlite LA2) was used for the voltammetric determination of mercury(II). Mercury is preconcentrated, as tetrachloromercurate(II), onto the surface of the modified electrode only by the ion-exchange effect of the modifier without application of potential. After exchange of the medium the accumulated amount of mercury(II) is determined by differential pulse anodic stripping voltammetry in a blank electrolyte solution. The response depends on the concentration of mercury in the bulk solution, preconcentration time, and other parameters. The detection limit was 1 g Hg(II)/l when a suitable time for preconcentration was chosen. Preconcentration for 5 min yields a linear calibration graph for concentrations up to 1000 g Hg(II)/l. The effect of other ions on the determination of mercury and the applicability of the method to the analysis of phenylmercury compounds in pharmaceutical preparations were investigated.     

Horseradish peroxidase-based organic-phase enzyme electrode

An organic-phase enzyme electrode (OPEE) based on horseradish peroxidase (HRP) immobilized within Nafion on spectroscopic graphite was investigated in acetonitrile. The amperometric electrode response to hydrogen peroxide and cumene hydroperoxide present was found to be the result of the reduction of oxygen, produced upon enzymatic decomposition of both hydroperoxides (i.e., by the catalase-like activity of HRP). The electrode response was found to depend linearly on the hydroperoxide concentration up to 700 M within the range of potentials from –200 to –400 mV (versus Ag|AgCl). Detection limits of approximately 45 M for H₂O₂ and 100 M for cumene hydroperoxide were determined under the selected experimental conditions. Nernstian dependence (the open circuit voltage of HRP-based electrode versus logarithm of H₂O₂ concentration) was obtained between 0.2 and 2.0 mM, with a slope of approximately 23 mV per logarithmic unit, suggesting a catalase-like, two-electron disproportionation of the substrate in acetonitrile.     

Nuclear interferences of uranium and thorium in a reactor neutron activation analysis determination of cerium using the radionuclides141Ce and143Ce

The interference contributions of uranium and thorium to the determination of cerium based on radionuclides¹⁴¹Ce and¹⁴³Ce produced by irradiation in a reactor core was determined. The values of the interference contributions for¹⁴¹Ce were 0.28±0.01 g Ce/g U and /2.01±0.05/x10^–3 g Ce/g Th, and for¹⁴³Ce 1.33±0.03 g Ce/g U and /9.0±0.2/x10^–3 g Ce/g Th.     

HPLC with electrode array detection

Summary A fast method for the determination of amitrole in drinking and ground water is described. Amitrole is separated from other substances by HPLC. For the determination a highly sensitive coulometric electrode array detector is applied. Tap and well water with concentrations down to 0.1 g amitrole/L can be determined without any enrichment steps. The detection limit of amitrole added to Viennese tap water is 0.05 g/L.     

Analysis of cobalt in plasma by electrothermal atomic absorption spectrometry

Summary A method for the determination of traces of cobalt in plasma is described. The sample is digested in a test tube using a mixture of nitric and perchloric acid. Ammonium-pyrrolidine dithiocarbamate is added as chelating agent, and after pH-adjustment to pH 9±0.1, cobalt is extracted into methyl-isobutyl ketone.Recovery studies using Co-60 showed that losses of cobalt during the procedure, including digestion and extraction are less than 3%. Possible contamination from the steel needle used is tested and discussed. The coefficient of variation for the method is 9.5% at the 0.20 g/l level. A realistic determination limit following this procedure is estimated to be 0.06 g/l. Using this method, the cobalt concentration in plasma from 32 control persons was determined to 0.15 ±0.07 g/l. For 10 refinery workers daily exposed to aerosols of CoCl₂ the determined average was 9.7±7.1 g/l.

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Analyse von Kobalt in Plasma mit Hilfe der elektrothermischen AAS

Zusammenfassung Bei dem beschriebenen Verfahren wird die Probe mit Hilfe von Salpetersäure/Perchlorsäure aufgeschlossen. Als Komplexierungs-Reagens wird Ammonium-pyrrolidindithiocarbamat zugefügt und nach pH-Einstellung auf 9±0,1 wird Co mit Methylisobutylketon extrahiert.Mit Hilfe von Co-60 wurde festgestellt, daß die durch Aufschluß und Extraktion verursachten Verluste weniger als 3% betragen. Eine mögliche Verunreinigung durch die benutzten Stahlnadeln wurde untersucht und diskutiert. Der Variationskoeffizient beträgt 9,5% bei 0,2 g Co/l. Die Bestimmungsgrenze nach diesem Verfahren liegt bei 0,06 g Co/l. Die Kobaltkonzentration im Plasma von 32 Kontrollpersonen wurde zu 0,15±0,07 g Co/l bestimmt. Für 10 Raffineriearbeiter, die täglich CoCl₂-Aerosolen ausgesetzt waren, wurde ein Durchschnitt von 9,7±7,1 g Co/l gefunden.

     

Determination of tetraethyllead and tetramethyllead using high performance liquid chromatography and electrochemical detection

Summary A new method for the separation of tetramethyllead (TML) and tetraethyllead (TEL) was developed using high-performance liquid chromatography. The electrochemical detection was examined with different electrodes. Amperometric and pulse-amperometric techniques were investigated and the optimal working potential for each electrode was determined. Linearity for the glassy carbon electrode was observed between 350 ng and 30 g; the detection limit is 310 ng (TML) resp. 340 ng (TEL). In case of the mercury gold electrode the linearity range was 300 g–3 g and the detection limit 1.5 m (TML) resp. 1.7 g (TEL).     

Determination of selenite,selenate and selenomethionine by ion chromatography,microwave digestion and HGAAS

An on-line system for the simultaneous determination of Se(IV), Se(VI) and selenomethionine (Se-Met) in aqueous samples was developed, consisting of separation by ion chromatography, microwave digestion and detection by hydride generation atomic absorption spectrometry. 8.3 mmol/l Na₂HPO₄ (pH 9.2) was used as mobile phase for the ion chromatography, with a flow-rate of 1.5 ml/min. After the separation the sample was mixed with concentrated KBr-HCl solution and heated with microwave energy to digest Se-Met and reduce Se(VI) to Se(IV). The detection limits were 15 g/l, 12 g/l and 103 g/l for Se(IV), Se(VI) and Se-Met, respectively.     

Determination of bisacodyl and its hydrolysis products in bisacodyl formulations by high-performance liquid chromatography

Summary Bisacodyl, its half-hydrolysed and fullyhydrolysed products can be determined specifically by high-performance liquid chromatography at 254 nm after separation on a C₁₈ reversed-phase column with a mixture of water-acetonitrile-sodium acetate as a mobile phase. Ten different bisacodyl preparations, enteric coated dragees and suppositories, were analysed and found to contain the hydrolysis products in the range of 0.1 to 1.67%. The detection limit was around 7.5 g/ml for hydrolysis products and about 15 g/ml for bisacodyl for an injected volume of 20 l. The coefficients of variation of the method for bisacodyl and hydrolysis products are 1.44 and 2.40%, respectively.

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Bestimmung von Bisacodyl und seinen Hydrolyseprodukten in Bisacodylpräparaten durch HPLC

Zusammenfassung Es wird über eine hochdruckflüssigkeitschromatographische Methode zur Bestimmung von Bisacodyl und seinen beiden Zersetzungsprodukten, der halbverseiften- und der vollverseiften Ester berichtet. Die Bestimmung erfolgte auf einer C₁₈ Reversed-Phase Säule mit dem Fließmittel Wasser-Acetonitril-Natriumacetat bei 254 nm. Zehn bisacodylhaltige Präparate, magensaftresistente Dragees und Zäpfchen, wurden analysiert. Der Gehalt an den beiden Verseifungsprodukten lag zwischen 0,1 und 1,67%. Die Nachweisgrenze beträgt für das Bisacodyl ca. 15 (g/ml und für die beiden Verseifungsprodukte etwa 7,5 g/ml für die eingespritzten Volumina von 20 l. Als relative Standardabweichung der Methode wurde für Bisacodyl und die Hydrolyseprodukte 1,44 bzw. 2,4% ermittelt.

     

Separation and determination of trace amounts of barium as its thenoyltrifluoroacetone complex with dibenzo-18-crown-6 by means of synergistic extraction and flame photometry

Summary A new method for the separation and determination of trace amounts of barium at the ppb-ppm level in water as its thenoyltrifluoroacetone (TTA) complex with dibenzo-18-crown-6 (DB18C6) comprises synergistic extraction and back extraction combined with flame photometry. The effect of various factors (solvent, size of crown ether, reagent concentration, shaking time, preconcentration factor, foreign ions etc.) on the extraction and back extraction of barium has been investigated. The barium TTA chelate in o-dichlorobenzene forms stable adducts with DB18C6 [Ba(TTA)₂ · nDB18C6, n=12]; the stability constants (n) of the adducts determined by means of the curve fitting method are log ₁=3.77 and log ₂=7.91. The content of barium in sodium chloride and sodium nitrate of guaranteed reagent grade was found to be 9.67±0.08 g/g and 7.86±0.09 g/g, respectively.     

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.