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Plasma deposition of conjugated polymer films under atmospheric pressure is described. Three thiophene derivatives (thiophene, 3‐methylthiophene, and 3,4‐ethylenedioxythiophene) are used as monomers. The plasma depositions with the various precursors are compared using analytical techniques such as X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, UV‐vis spectroscopy, and resistance measurements. Good results are obtained with pulsed plasma depositions of poly(3,4‐ethylenedioxythiophene). Conductivities of up to 1 × 10—2S cm–1are measured.

A fast liquid chromatographic method with tandem diode array-fluorescence detection for the simultaneous determination of in total 17 opium alkaloids and opioids is presented. Blank blood and urine samples (1 ml) were spiked with different concentrations of a standard mixture, as well as with the internal standard, butorphanol (2000 ng/ml). After solid-phase extraction, based on weak cation exchange (Bond Elut CBA SPE columns), the extracts were examined by HPLC-DAD-FL. By using a "high-speed" phenyl column (53×7.0 mm I.D., particle size 3 μm) eluted with a gradient system (A: water-methanol (90:10, v/v), B: methanol, both containing 25 m M triethylammoniumformate (pH A =4.5)) all compounds could be baseline separated within 12 min. The method was validated and its applicability was demonstrated by the analysis of real-time forensic cases.

In order to control the quality of platinum, palladium and rhodium determinations in road dust, the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission has started a project, the final aim of which is to certify a road dust reference material for its contents of platinum group elements. The first part of this project consisted of an interlaboratory study, which aimed to test the feasibility of the preparation of a candidate road dust reference material and to detect and remove most of the pitfalls observed in platinum, palladium and rhodium determinations. This paper presents the main results of this interlaboratory study carried out prior to the certification campaign. The concordance of the data obtained by the participating laboratories for the three elements was considered to reflect the state-of-the-art and was encouraging enough to decide on the organization of a certification campaign to be conducted during the year 2000. The progress made with respect to the analytical state-of-the-art for these elements will be of great benefit to the quality of measurements carried out in environmental monitoring in this particular field.

The application of Raman spectroscopy to the examination of ancient art and the identification of mineral pigments used in antiquity has been demonstrated successfully hitherto. However, the examination of modern objects of art is hampered by the absence of a spectral library database of relatively modern organic pigments and dyestuffs, of which there are a large number. Azo pigments provide an example historically of a class of synthetic organic pigments which have been adopted by artists. The Raman spectra of 21 azo pigments were analysed and a protocol was established for their identification. Using this database, two azo pigments from 1 µg samples of 20th century paintings attributed to Picasso and Appel were characterized. Copyright © 2000 John Wiley & Sons, Ltd.

During the last decade the Laboratory of Analytical Chemistry assisted in the certification of 31 environmental and food reference materials issued by the BCR (Bureau of Reference Materials of the European Communities). The efforts spent can be translated into the following statistics: the 10 most frequently certified elements assisted by the Gent Laboratory are As, Cd, Co, Cu, Fe, Hg, Mn, Pb, Se and Zn. They cover 70% of the certification work. The Gent Laboratory cooperated in 74% of the latter. There are 21 more major and trace elements certified, some in a single product only. Activation analysis was the main analytical technique applied by the Gent Laboratory. In many instances radiochemical separations were involved.

An instrumental neutron activation analysis with Ge(Li) -spectrometry and computer-assisted data reduction, has been developed for the determination of more than 20 elements in different liquid fuels. Organo-metallic standard solutions were mixed to obtain suitable standards. Two neutron irradiations and 4 -spectrometric measurements are required for each sample. Corrections were taken into account for a few spectrometric and nuclear interferences. The overall standard deviation for nearly all elements is mainly determined by counting statistics. The following elements can be determined : Na, Al, S, Cl, K, Sc, V, Cr, Fe, Co, Ni, Cu, Zn, As, Se, Br and La whereas the concentration of the following elements are mostly near the limit of detection: Mg, Mo, Sb, Ba, Th and Hg.

A reduction-aeration method is optimized for the analysis of mercury at the ng.I-1-level in drinking-water. The parameters investigated are: the aeration time, the flow rate of the aeration-gas, the type of gas distributor, the amount of reductant and the mercury concentration. To improve the sensitivity, the mercury aerated is preconcentrated on a gold-coated quartz-sand absorber which is analysed by thermal desorption and CVAAS. In this way, the interference by water vapour is avoided and the calibration is simplified.

In a shooting range the metal concentrations in the air during the firing were measured. Stationary sampling at three different locations was performed, size-segregated samples were taken and in order to measure the personal exposure, a personal sampler was carried by an instructor. With the bullets used lead, barium and antimony were the primary metal pollutants. During the shooting the TLV is significantly exceeded for lead.

Cold-vapour atomic absorption spectrophotometry (CVAAS) was used to determine mercury concentrations in sea water from the British Channel and the North Sea. Experiments were carried out to study the stability of the samples during storage and to investigate contamination from the Niskin-satnplers used. Mercury concentrations ranged from 0.28 to 1.5 ng.l-1 for Atlantic and for North Sea water. Somewhat higher values (up to 3.7 ng.l-1) were found in coastal areas. There was also a significant input from the rivers Scheldt and Thames.

200 kg graues Gußeisen mit Zusätzen von Sb, As, Bi und Pb wurden in Form von 80 Stangen hergestellt, die in Scheiben zerschnitten wurden (Durchmesser 32 mm, Dicke 10 mm). Homogenitätstests innerhalb und zwischen den Scheiben von derselben und von verschiedenen Stangen zeigten, daß die Inhomogenität für Sb bzw. Pb weniger als 1,0 bzw. 1.5% betrug. Durch elektrothermische AAS sowie durch Neutronenaktivierungsanalyse oder radiochemische Protonenaktivierungsanalyse wurden die folgenden Werte zertifiziert (95% Vertrauensintervall): 263,5 ± 4,4 ppm Sb, 347,1 ± 5,8 ppm As, 33,6 ± 0,8 ppm Bi und 296 ± 16 ppm Pb. Die Referenzmaterialien stehen Interessenten zur Verfügung.

an automated vacuum extraction line for the production of pure CO2-gas from carbonates is described. The method includes the hydrolysis of carbonates (white marbles) with phosphoric acid, in less than five hours, with a subsequent total extraction time (for a batch of ten samples) of less than two and a half hours. With the new method, good precision and accuracy are obtained. Kinetic isotope fractionation effects are eliminated when a reaction time of more than three hours is used. The relative importance of the different sources of variance, i.e. sample extraction and mass spectrometric measurement, is estimated. It is also demonstrated that the variance due to sample extraction is sample specific and more important for δ18O than for δ13C. Memory effects, expressed as the contribution (in %) of the previous sample to the sample under consideration, are calculated for δ13C (0.28%) and for δ18O (0.52%). These results show that memory effects do not influence the results of two subsequently processed samples.

The determination of bromine in human serum by inductively coupled plasma-mass spectrometry (ICP-MS) is discussed. Sample preparation was kept as limited as possible: serum samples were only diluted with nitric acid (five- or ten-fold). Indium was added as internal standard. In order to avoid overlap of 40Ar 40Ar with

A method for the determination of thallium in solid environmental samples is developed. After destruction of the sample, TI(III) is extracted from 0.5 M hydrobromic acid solution into diisopropyl-ether. the organic phase is evaporated and the residue taken up in a mixture of sulfuric and nitric acids. Measurements are carried out with an atomic absorption spectrometer with Zeeman background corrector. the accuracy of the method is tested by analysis of certified reference materials and the method is applied to fly ash and emitted particulate matter from a municipal refuse incinerator and to soil samples.

An 18-sec neutron irradiation of fluorine, scandium selenium and silver produces the following short-lived isotopes:20F (11.1 S),46mSC(18.7 s), 77mSe (17.7 s), ll0Ag(24.6 s) and 179mHf (18.7 s). A 20-sec Ge(Li) count after a 10-sec decay period allows the simultaneous detection of these five isotopes in aerosols. Errors due to fast decay during the counting are minimized by the use of a dead-time stabilizer. The high initial counting rates due to energetic beta rays of short-lived isotopes are reduced by the use of absorbers. Fluorine is also determined, using the threshold reaction 19F(n, p) 19O(26.9 s). The interference due to (N, γ) reactions on other impurities in the collected aerosol is reduced by a 30-sec irradiation under cadmiumaover, and a 30-sec count after a 25-scc decay period. The activation of silver and hafnium is enhanced also by an irradiation under cadmium owing to their important resonance peaks. The technique is applied to the analysis of aerosols sampled in Belgium, at urban, industrial and background stations.

In the framework of an international certification campaign, organized by the European Commission, inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) was used for the determination of Cu in two groundwater candidate reference materials. No sample pre-treatment other than addition of (i) a⁶⁵Cu-enriched tracer (for isotope dilution purposes) and (ii) an internal standard (to accurately correct for the blank) was carried out. As a result of the presence of molecular ions of the same nominal mass as the analyte nuclides of interest, especially for the water showing the lowest Cu content, a double focusing sector field instrument, operated at a higher resolution setting (R=3000), was used in order to avoid biased isotope ratios and hence erroneous results. Despite the relatively low level of Cu (about 2.5 μg l⁻¹) in one of the materials involved, the results obtained by ICP-IDMS are in excellent agreement with those obtained by other techniques in operation at other laboratories.

Results of a systematic study concerning non-spectral interferences observed with a commercially available high resolution ICP-mass spectrometer are reported and compared to observations made with a quadrupole-based instrument. In general, matrix effects were observed to be to a large extent comparable for both instruments used. In all cases, the matrix-induced signal suppression or enhancement was seen to depend in a regular way on the mass number of the nuclides monitored. In most cases, the ionization potential of the nuclides has little or no influence on the extent of suppression or enhancement. For As, Se and Te, the introduction of 2.5% ethanol, 0.5 mol/l H 2SO 4, or to a lesser extent 0.5 mol/l H 3PO 4, leads to an exceptional increase in the signal intensity for both instruments. Registration of signal behaviour plots (signal intensity as a function of the nebulizer gas flow rate) in different matrices revealed that both the height of the plot and the optimum nebulizer gas flow rate are a function of the matrix composition. Finally, no indication was found that the acceleration of the extracted ions over 8000 V with the high resolution instrument would lead to an alleviation of space charge effects when compared to a quadrupole-based ICP-mass spectrometer.

A description is given of the experimental arrangement for thermospray nebulization of discrete liquid samples (100 µl) into an inductively coupled plasma-mass spectrometer (ICP-MS). The determination of ultratrace levels of platinum in environmental and biological materials is described. This method comprises an off-line sample enrichment by adsorptive chromatography, elution with ethanol and subsequent analysis of the evaporated eluate. The quantification of the concentration was performed with isotope dilution. The recovery, precision, accuracy and detection limit of the method are discussed.

A commercially available graphite furnace was modified in order to use it as an electrothermal vaporization device for solid sample analysis with an inductively coupled plasma atomic emission spectrometer. An evaluation of two different ETV systems has been made. This paper mainly describes the different aspects which must be taken into account when coupling an ETV system to an ICP. Cu was chosen as an element easy to determine and Cd and Pb as elements with more difficulties. From the optimization it was found that the transport efficiency for Cd in solution and solid is different, whereas for Cu and Pb the efficiencies are in good agreement for both sample types. Calibration with solids and liquids was attempted for Cu. The paper gives preliminary results on the determination of Cu in solid reference materials. In some cases (e.g. Pb) a background correction based on a linear interpolation seemed not satisfactory. Detection limits and limits of determination for Cu, Cd and Pb in different solid samples are given.

Recent trends of radiochemical and instrumental neutron activation analysis are discussed. Novel developments include the application of cyclic and pulsed activation, better energy resolution with hyperpure germanium detectors, and use of pulse processing systems allowing extremely high count rates of very short-lived isotopes. Further development is anticipated in the field of speciation in biological and environmental studies. Radiochemical methods have led to accurate determinations at the ng/g level. A promising future is expected for neutron activation techniques.

Abstract: A novel method for the determination of lead in copper by proton, activation analysis has been developed. The bismuth activity formed was, separated from the matrix activity by anion exchange chromatography. Special attention was paid to possible systematic errors. The method was applied to BCR reference materials and yields a precision, of 2–3% at the mgrg/g concentration level.

Abstract: A procedure for the determination of nickel in copper by proton activation analysis has been developed. The57Ni activity induced was separated from the zinc and copper activity formed out of the copper matrix by anion exchange. Pure nickel was used as a standard. This method yields a reproducibility of 4% at the mgrg·g–1 level. The detection limit is 0.03 mgrg·g–1.

Abstract: In the workplace of an iron foundry total and respirable suspended particulate matter was daily collected with a network of stationary filtration systems, with Andersen cascade impactors and with personal samplers. The performances of the different sampling systems are evaluated. All samples were analysed by instrumental neutron activation analysis. More than 30 elements were determined. The composition of the particulate samples is compared to that of the major emission sources. For visualising and interpretation of the data computer programs for contour plotting, classification and clustering of the elements and the samples are applied. On the basis of their distribution and particle size the elements can be divided in a number of groups, for which easily determined elements are proposed as indicator elements. The results allow an estimate of the impact of the major emission sources on the air quality in the entire workroom. Suggestions for representative sampling techniques and locations are made.

Abstract: A method is described for the determination of Au, Pt, Pd, Ag and Ir in two atmospheric aerosol samples, namely in Ghent and in the Milanese intercomparison sample. After neutron irradiation the samples are fused with Na2O2. Gold is extracted with ethylacetate, Pt precipitated as (NH4)2PtCl6 Pd as dimethylglyoximate, Ag as chloride and Ir separated by anion-exchange adsorption and batch extraction. Ge(Li) gamma-spectrometry is applied for all determinations. The concentrations in ng·g−1 in the samples are respectively: Au: 49 and 3000; Pt: below 100 for both samples; Pd: 7 and 28; Ag: 6000 and 14 000; Ir: 2.5 and 1.3.

Abstract: Owing to the high ratio of resonance integral to thermal neutron activation cross-section of238U, a 5 min epithermal neutron irradiation under cadmium shielding, followed by measurement of the 74 keV photopeak of239U with a high resolution low-energy photon Ge(Li) detector, allows the fast determination of uranium in aerosols collected on a Whatman 41 cellulose filter. Uranium blanks of the cellulose filter paper require correction and limit the sensitivity. Simultaneously the concentrations of the elements cobalt, bromine, antimony and indium can be determined. In Belgium, the uranium concentrations of the aerosols were found to be constant and comparable to the uranium contents of rocks.

Cut-over area and boundary placement accuracies from analogue SPOT Panchromatic (PLA) and Multispectral (MLA) Linear Array images were determined for forest cut-overs typical of the Canadian Prairies. Cut-overs were mapped using a Procom-2 to optically project images on to a photogrammetrically-produced planimetric base map. Overall area accuracies for the SPOT PLA and MLA images were 90-7 per cent, and 89-6 per cent, respectively. The influence of increasing accuracy with increasing cut-over size must be considered, however, when interpreting these figures. Proportional regression models were fit to improve the estimates of cut-over areas. On average, boundary placement errors were 24 m for the SPOT PLA, and 26 m for the SPOT MLA. These errors were influenced by the 25 times enlargement factor encountered in the optical projection, and the scale of the base map itself. The base map scale of 1:20 000 was a limiting factor in this study as both plotting errors and pen line widths contributed to existing map errors. Under the forest conditions evaluated, SPOT images offered an approximate five to one cost savings in data acquisition, and are more efficient to interpret and map in comparison to conventional air photos.

The present note deals with the optimization of the combustion of organic materials to CO2 in Pyrex and quartz tubes. The influence of temperature and oxidant on the combustion yield was investigated. Different physical forms of CuO and a CuO/MnO2-mixture were used as oxidants. Possible isotopic effects during combustion were tested by gas isotope ratio mass spectrometry (GIRMS) of the CO2. Excellent results were obtained for combustion in Pyrex at 530 °C using CuO rods mixed with 20% MnO2 as oxidant. The stable isotope results for CO2 prepared with this method were accurate and showed a very good precision of 0.030 %. Applications for which quantitative combustion is a necessity, we suggest the use of CuO powder (< 100 m) as oxidant and a combustion temperature of 850 °C.

This study describes the determination of Cd, Cr, Cu, Ni and Zn in a sample of city waste incinerator ash distributed in 1983 by the European Community Bureau for Reference Materials (sample BCR No. 176) for certification. The sample treatment and the analysis procedure are discussed. The results obtained are evaluated and compared with the values which were later certified.

This paper describes the determination of Co in two samples of high purity Ni by means of ion-exchange in combination with Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and by means of Graphite Furnace - Atomic Absorption Spectrometry (GF-AAS). These samples were both Nickel metal of 99.75%. nominal purity of which one was in the form of a 0.1 mm thick foil and the other a 0.5 mm diameter wire. The Co content in these; samples was determined in the process of a certification campaign and these samples are intended to serve as reference material for Reactor Neutron Dosimetry. The sample treatment and the detection of Co both via ICP-AES and GF-AAS are discussed. The values obtained for both Nickel samples are in accordance with the later certified value.

In the frame of a certification campaign organised by BCR (Bureau Communautaire de Référence, Commission of the European Communities, Brussels), Al, Ca, Cl, Fe, Mg, Mn and Na were determined in two candidate reference materials, low mineral content fresh water CRM 398 and high mineral content fresh water CRM 399. The concentration of the elements ranged from 30 ng/g (for Mn) to 80 g/g (for Ca). Metals present at relatively high concentrations were determined under operating conditions of non-optimal sensitivity, but with no loss in precision. The accuracy and precision of the results obtained by ICP-MS were checked by comparing with other analytical techniques and laboratories. The agreement was excellent. This study showed that ICP-MS not only yields excellent results for interference-free elements at trace levels, but is also competitive for less ideal elements e.g. Ca, Fe and Cl.

A volatilization method was developed for the determination of trace impurities (Al, Cd, Cu, Fe, Mg and Pb) in high-purity gallium. The gallium matrix is converted into gallium trichloride and volatilized at 120–165°C by gaseous hydrogen chloride. The impurities in the residue are dissolved in 0.25 M nitric acid and determined by electrothermal atomization atomic absorption spectrometry. The limits of detection for the impurities are in the range 1.5–11 ng g−1. The recoveries of impurities lie in the range 92–105%. The results obtained by the volatilization method are compared with those obtained by solvent extraction and are in satisfactory agreement. An advantage of the volatilization method is that the risks of contamination are reduced.

Antimony is determined in cast irons by wavelength-dispersive x-ray fluorescence spectrometry. Excitation and detection conditions are evaluated for the three most intense x-rays of antimony, i.e., the Kα, Lαand Lβlines. Standard samples were obtained by precise determination of the antimony content of some specimen cast irons by neutron activation analysis. Calibration graphs are linear from 0 to 200 mg kg−1. The precision of the determination by means of the most sensitive Sb Lαline, using a chromium tube and a 5-min measuring time, ranges from 6% for samples containing 20 mg kg−1antimony, to 1% for samples containing 200 mg kg−1.

The development and improvement of a gas chromatography inductively coupled plasma mass spectrometry system, GC-ICP-MS, is described. The GC and ICP-MS are coupled with a heated stainless steel transfer line. Xe, present in the GC carrier gas, is used to facilitate the nebuliser gas flow rate setting and the positioning of the torch. Alkyltin compounds are separated by GC using a 30 m capillary column within 9 min. The necessity of applying double internal standardisation (use of Bu 3PeSn and Xe gas as internal standards) is shown. The repeatabilities at 50 µg/l concentration for both retention time and peak are better than 0.25% and 5%, respectively. The detection limits for alkyltin compounds are better than those of existing methods and range between 15 and 35 fg Sn. Finally, GC-ICP-MS is applied to the determination of mono-, di- and tributyltin in some harbour waters, after extraction and Grignard derivation with PrMgCl. Concentrations between 1 and 20 ng/l are found.

Abstract: In the14C-dating by accelerator mass spectrometry (AMS) iron and copper oxide are used during sample preparation. In an investigation on the origin of the14C-blank, which in practice determines the dating limit of AMS, the carbon contamination was measured in both reagents by deuteron activation analysis via the12C(d,n)13N reaction. A first batch of iron was analysed radiochemically and a carbon concentration of 37.6 mgrg/g was found with a standard deviation of 2.7 mgrg/g (3 analyses). In a second batch of iron concentrations between 66 and 150 mgrg/g were found for 6 instrumental analyses, suggesting an inhomogeneous distribution of carbon. The carbon content in copper oxide was 17.8 (3.5) mgrg/g for 3 instrumental analyses, but preference should be given to a radiochemical analysis. These figures indicate that the carbon impurities found in iron and copper oxide are possible causes of the14C-blank. However, a final conclusion can only be drawn if the14C concentration of the contaminating carbon and the amount of carbon released during sample preparation are known.

Abstract: NAA and ICP-MS are both highly sensitive methods for multi-element trace-and ultra-trace element determination. A comparison between analytical figures of merit of both methods is made. Both methods have specific advantages that put them beyond competition for certain applications. It is concluded that ICP-MS can replace NAA for many routine analyses. NAA remains essential as a highly reliable and accurate reference method.

Abstract: A method for the determination of copper in zinc by proton activation analysis using the63Cu(p, n)63Zn reaction has been developed.63Zn has to be separated chemically from gallium and copper activities formed out of the zinc matrix and from indium activity formed out of cadnium impurity. Gallium radionuclides are retained on a cation exchanger in chloride medium and the residual activity is extracted in di-isopropyl ether. Copper and indium are subsequently extracted with cupferron in chloroform. The method was applied to BCR reference materials with a copper concentration at the mgrg.g–1 level. The detection limit amounts to 0.5 mgrg.g–1.

Summary The necessity to prepare thin-film standards for use in XRF analysis of thin samples, and the requirements they must meet, are outlined. A method for the preparation of multielement standards by formation of a polymer film from a water-soluble polymer solution containing the elements concerned and a short-lived radioactive tracer is presented. Experimental results illustrating the homogeneity and accuracy of such standards are given. Precautions to take and pitfalls to avoid in the preparation of such standards are discussed and illustrated.