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Analytical and Bioanalytical Chemistry (v.385, #6)


Trace-level determination of pharmaceutical residues by LC-MS/MS in natural and treated waters. A pilot-survey study by M. D. Hernando; E. Heath; M. Petrovic; D. Barceló (pp. 985-991).
A pilot-survey study was performed by collecting samples (influent and effluent wastewaters, rivers and tap waters) from different locations in Europe (Spain, Belgium, Germany and Slovenia). A solid-phase extraction (SPE) followed by liquid chromatography–tandem mass spectrometry method was applied for the determination of pharmaceuticals (ibuprofen, naproxen, ketoprofen, diclofenac and clofibric acid). Method detection limits and method quantification limits were at the parts-per-trillion level (7.5–75 ng/L). The recovery rates of the SPE from deionized water and effluent wastewater samples spiked at 100- and 1,000-ng/L levels ranged from 87 to 95%. Identification criteria in compliance with the EU regulation for confirmatory methods of organic residues were applied. A detailed study of signal suppression evaluation for analysis of pharmaceutical residues in effluent wastewaters is presented.

Keywords: Pharmaceuticals; Natural water; Treated water; Liquid chromatography–tandem mass spectrometry


Chemical monitoring and occurrence of alkylphenols, alkylphenol ethoxylates, alcohol ethoxylates, phthalates and benzothiazoles in sewage treatment plants and receiving waters along the Ter River basin (Catalonia, N. E. Spain) by Raquel Céspedes; Sílvia Lacorte; Antonio Ginebreda; Damià Barceló (pp. 992-1000).
This study presents a quantitative estimation of the analysis and fate of several emerging pollutants, some of them endocrine-disrupting compounds, in surface water samples collected at several locations along the Ter River and two of its tributaries. Influent and effluent waters and particulate matter from five sewage treatment plants (STP) that discharge into these rivers were also studied. The target compounds analyzed were: nonylphenol ethoxylates (NPEO), nonylphenol (NP), octylphenol (OP), bisphenol A (BPA), phthalates, alcohol ethoxylates (AEO) and benzothiazoles. Chemical analysis by liquid chromatography–mass spectrometry using an electrospray interface (LC–ESI–MS) revealed the presence of low amounts (between 0.06 and 17.5 μg L−1) of the target compounds NPE1+2O and NP, which were detected in 100% and 84% of the samples respectively. Maximum concentrations occurred in the STPs associated with the municipalities of Vic and Girona. From the fate and behavior data obtained for the various compounds analyzed in the STP influent and effluent, we can conclude that the STPs are effective at removing large amounts (more than 70%) of the compounds studied from the water.

Keywords: Liquid chromatography–mass spectrometry; Surface water; Waste water; Endocrine-disrupting compounds


Evaluation of commercial immunoassays for the detection of estrogens in water by comparison with high-performance liquid chromatography tandem mass spectrometry HPLC–MS/MS (QqQ) by Marinella Farré; Rikke Brix; Marina Kuster; Fernando Rubio; Yasuhiro Goda; María J. López de Alda; Damià Barceló (pp. 1001-1011).
In this work four different commercially available enzyme-linked immunosorbent assays (ELISA) (from Japan EnviroChemicals, Ltd., Tokyo, Japan) were evaluated in terms of performance for the rapid screening of estrogens in different water matrices, including natural and spiked samples from urban wastewater, river water and ground water. All four test kits are based on monoclonal antibodies. The compounds detected by these immunoassays are (1) 17-β-estradiol, (2) estrone, (3) 17-α-ethynyl estradiol and (4) estrogens in general, with high recognition properties for 17-β-estradiol, estrone and estriol. Standards were prepared in water containing 10% (v/v) methanol. The IC 50 (corresponding to the 50% of the effective concentration) values, the dynamic ranges, and the limits of detection of the ELISA kits were 0.060–0.304 μg/L, 0.05–5 μg/L and 0.05 μg/L, respectively. All samples were extracted by solid-phase extraction (SPE) beforehand, and the evaluation was carried out by comparing the results obtained by ELISA with those obtained by HPLC–MS/MS using a triple quadrupole (QqQ) instrument. In addition, two different solid-phase extraction procedures were carried out and compared. Except for moderate overestimation in the results observed with the ELISA kits in the analysis of complex wastewater samples, the results obtained using all of the tested techniques were generally in very good agreement.

Keywords: Immunoassay; ELISA; Estrogens; LC–MS/MS


Evaluating the interactions of vertebrate receptors with persistent pollutants and antifouling pesticides using recombinant yeast assays by Tania-Noelia Noguerol; Susanna Boronat; Marta Casado; Demetrio Raldúa; Damià Barceló; Benjamin Piña (pp. 1012-1019).
The development of in vitro methods for screening potentially harmful biological activities of new compounds is an extremely important way to increase not only their intrinsic environmental safety, but also the public perception of the safety standards associated with them. In this work we use two yeast systems to test the ability of different chemicals to bind and activate two vertebrate receptors which are intimately related to adverse biological effects of pollution in exposed fauna: the estrogen receptor (ER) and the aryl hydrocarbon receptor (AhR). The panel of compounds analysed here includes well-known pollutants, like PCBs, pp′-DDT and hexachlorobenzene, together with the less-known, emerging putative pollutants, such as Sea-Nine, Irgarol and diuron. Results show the ability of some of these compounds to interact with one or both receptors, provide hints about the relationship between structure and activity, and suggest mechanistic explanations for the biological activities already described in whole-animal experiments. In addition, we show that AhR may have an intrinsic ligand promiscuity comparable to that of ER, a feature not fully appreciated in the past due to the technical difficulties involved with testing highly lipophilic substances in yeast-based assays.

Keywords: Endocrine disruption; Estrogens; Dioxin; Nuclear receptors; Dissociation constants


Chemometrical investigation of the presence and distribution of organochlorine and polyaromatic compounds in sediments of the Ebro River Basin by Alícia Navarro; Romà Tauler; Sílvia Lacorte; Damià Barceló (pp. 1020-1030).
A multivariate statistical data analysis, using principal component analysis, of historical data from 1996 to 2003 concerning the concentration of different polycyclic aromatic hydrocarbons and organochlorine compounds in sediment samples from different sampling sites of the Ebro River Basin was performed under the UE funded project AQUATERRA. Three major contamination sources were identified and their composition and distribution profiles were resolved. The first contamination profile was mostly loaded by polycyclic aromatic hydrocarbons, the second contamination profile was loaded by some organochlorine compounds and the third contamination profile was more specifically loaded by naphthalene. Samples from the different geographical regions of the Ebro River Basin were grouped according to the contamination described by these three major profiles.

Keywords: Polycyclic aromatic hydrocarbons; Organochlorine compounds; River sediments; Principal component analysis

Report of the 1st AcadeMiC Summer School for ‘Metrology in Chemistry’, held in Rogaška Slatina, Slovenia (6–9 July 2005) by T. Prohaska; E. Bulska; S. Duta; I. Leito; B. Magnusson; N. Majcen; E. Prichard; P. Robouch; M. Suchanek; P. Taylor; E. Vassileva; W. Wegscheider (pp. 1031-1032).

Resonance Rayleigh scattering spectra of tetracycline antibiotic–Cu(II)–titan yellow systems and their applications in analytical chemistry by Xiaoqin Wei; Zhongfang Liu; Shaopu Liu (pp. 1039-1044).
Tetracycline antibiotics (TCs) such as doxycycline (DOTC), chlortetracycline (CTC), oxytetracycline (OTC), and tetracycline (TC) react with Cu(II) in pH 3.5 BR buffer medium to form 1:1 cationic chelates, which further react with titan yellow to form 2:1 ion association complexes. These result in great enhancement of resonance Rayleigh scattering (RRS) and the appearance of new RRS spectra. The ion association complexes of DOTC, CTC, OTC, and TC have similar spectral characteristics and their maximum RRS wavelengths are all located at 464 nm. The quantitative determination ranges and the detection limits (3σ) of the four TCs are 0.037–4.8 μg mL−1 and 11.2 ng mL−1 for DOTC, 0.041–5.2 μg mL−1 and 12.4 ng mL−1 for CTC, 0.050–4.8 μg mL−1 and 15.1 ng mL−1 for TC, and 0.088–5.0 μg mL−1 and 26.3 ng mL−1 for OTC, respectively. The optimum reaction conditions, the effects of foreign substances, the structure of ternary complexes, and the reaction mechanism are discussed. A sensitive, rapid, and simple RRS method for the determination of DOTC has been developed.

Keywords: Resonance Rayleigh scattering; Tetracycline antibiotics; Cu(II); Titan yellow


Effective PCR detection of animal species in highly processed animal byproducts and compound feeds by Olivier Fumière; Marc Dubois; Vincent Baeten; Christoph von Holst; Gilbert Berben (pp. 1045-1054).
In this paper we present a polymerase chain reaction (PCR)-based method for detecting meat and bone meal (MBM) in compound feedingstuffs. By choosing adequate DNA targets from an appropriate localisation in the genome, the real-time PCR method developed here proved to be robust to severe heat treatment of the MBM, showing high sensitivity in the detection of MBM. The method developed here permits the specific detection of processed pig and cattle materials treated at 134 °C in various feed matrices down to a limit of detection of about 0.1%. This technique has also been successfully applied to well-characterised MBM samples heated to as high as 141 °C, as well as to various blind feed samples with very low MBM contents. Finally, the method also passed several official European ring trials.

Keywords: Feed; Meat and bone meal; (MBM); BSE; Polymerase chain reaction; Real time PCR; Mitochondrial DNA; Species identification; Pig; Cattle


Fast LC separation of a myoglobin digest: a case study using monolithic and particulate RP 18 silica capillary columns by Johan Rozenbrand; Wouter P. van Bennekom; Klaus K. Unger; Gerhardus J. de Jong (pp. 1055-1061).
A method was developed for the fast separation of a myoglobin digest using a monolithic RP 18 silica capillary column of 100 μm I.D. The results were compared with those obtained with a particulate RP 18 silica capillary column of 100 μm I.D. at a flow-rate between 0.6 and 1.2 μl/min. The digest was analyzed at the monolithic column at a flow-rate up to 2.8 μl/min. This high flow-rate could not be applied to the particulate column due to the high back-pressure. When the starting composition of the gradient was changed from 0 to 20% and a gradient steepness of 16%/min was used, the analysis time was less than 4 min. A positive Mascot identification score of 115 was achieved for the MS–MS data. When a lower gradient steepness was employed, the chromatographic resolution and the peak capacity did not increase for most compounds. The intraday repeatability for the retention time of the monolithic column was better than 1.5% at 2.8 μl/min and even less than 0.5% using a flow-rate of 0.6 or 1.0 μl/min. For the particulate column, it was between 0.5 and 1.4% for a flow-rate of 0.6 μl/min, probably due to the high column back-pressure. The interday reproducibility for the retention time of the monolithic column was less than 0.9% using a flow-rate of 1.0 μl/min.

Keywords: Proteomics; Myoglobin digest; Peptides; Monolithic capillary silica columns


HPLC analysis of K-48 concentration in plasma by H. Kalász; M. Y. Hasan; R. Sheen; K. Kuca; G. Petroianu; K. Ludányi; A. Gergely; K. Tekes (pp. 1062-1067).
K-48 is a new oxime-type compound to be used as an enzyme reactivator in the treatment of exposure to organophosphorous compounds. Plasma concentration of K-48 can be determined using reversed-phase HPLC. Analysis using octyl silica stationary phase and ultraviolet-absorbance detection is fast and simple. K-48 displays a relatively high dose-normalized area under the curve as compared to pralidoxime, which might be beneficial for an antidote. After i.m. administration of 50 μmol K-48, the time course of the concentration can be approximated by a straight line between 15 and 120 min meaning the elimination follows zero-order kinetics.

Keywords: Cholinesterase reactivator; HPLC; HPLC-MS; Serum concentration


Study of a toxin–alkaline phosphatase conjugate for the development of an immunosensor for tetrodotoxin determination by D. Neagu; L. Micheli; G. Palleschi (pp. 1068-1074).
This paper describes a direct competitive immunoenzymatic spectrophotometric assay (ELISA) for tetrodotoxin (TTX) determination and the adaptation of this method for use in an electrochemical assay format. The novelty of this work involves the use of the antigen labelled with alkaline phosphatase (AP); this conjugate was prepared in our laboratory as there is no commercially available conjugate of any kind for TTX. The new conjugate was characterized in terms of its affinity for the specific antibody as well as the residual concentration and the residual activity of the enzyme (AP) incorporated as label. The proposed method based on the new conjugate showed satisfactory results for TTX determination: for the spectrophotometric method the dynamic range was 4–15 ng mL−1 with a limit of detection (LOD) of 2 ng mL−1 (R=0.9247), whereas for the electrochemical protocol the dynamic range was 2–50 ng mL−1 and the LOD was1 ng mL−1.

Keywords: Immunoassay/ELISA; Bioanalytical methods; Electroanalytical methods; Toxin–alkaline phosphatase conjugate; Seafood toxin


Determination of evodiamine and rutecarpine in human serum by liquid chromatography–tandem mass spectrometry by Dawei Wen; Chenchen Li; Yuping Liu; Yiping Liao; Huwei Liu (pp. 1075-1081).
Evodiamine and rutecarpine are two kinds of indole alkaloids contained in the fruit of Evodiae fructus, which have been shown to exhibit various bioactivities in humans. A liquid chromatography–tandem mass spectrometric method (LC–MS/MS) was developed for the determination of evodiamine and rutecarpine in human serum. The serum was extracted by solid-phase extraction (SPE) and analyzed using a C18 column and a mobile phase consisting of methanol–water (85:15) solution containing 5 mmol/L ammonium formate at a flow rate of 0.5 mL/min. The mass spectrometer was operated in positive mode, employing the extracted ion chromatogram (EIC) for detection and quantitation of evodiamine (m/z 288) and rutecarpine (m/z 304). Good linear relationships between the peak area and the concentration were obtained in the ranges of 5.2–1040 ng/mL and 10.2–1020 ng/mL, with correlation coefficients (r) of 0.999 and 0.998, for evodiamine and rutecarpine, respectively. The repeatabilities (RSD, n=6) of quantitation for evodiamine and rutecarpine were 2.18–4.00% and 2.99–5.67%, respectively, and the recovery ranged from 90.5% to 98.1%. A comparative study of the different ionization and quantitation modes, including ESI–MS, ESI–MS/MS, APCI–MS and APCI–MS/MS, was also accomplished. The MS/MS fragmentation mechanism of the base peak ([M+H]+, m/z 304) of evodiamine was investigated in order to identify the analytes in more complicated body fluid samples.

Keywords: Evodiamine; Rutecarpine; LC–MS; LC–MS/MS; Serum


Determination of volatile residual solvents in pharmaceutical products by headspace liquid-phase microextraction gas chromatography-flame ionization detector by Xia Wang; Ting Jiang; Jinpeng Yuan; Chuange Cheng; Jianhua Liu; Junbo Shi; Rusong Zhao (pp. 1082-1086).
This paper demonstrates headspace liquid-phase microextraction (HS-LPME) as used for the determination of volatile residual solvents in pharmaceutical products. This method is based on headspace liquid-phase microextraction capillary column gas chromatography. Under optimum conditions, the linerary of the method ranged from 1 to 1,000 mg l−1. The limits of detection are 0.2–2.0 mg l−1 and relative standard deviations (RSD) for most of the volatile solvents were below 10%. This novel method is applied to the analysis of volatile residual solvents in pharmaceutical products with satisfactory results.

Keywords: Volatile residual solvents; HS-LPME; Flame ionization detector; Pharmaceutical products


New interface plate for microspray ionization mass spectrometry by Li Zhou; Lailiang Zhai; Bingfang Yue; Edgar D. Lee; Milton L. Lee (pp. 1087-1091).
A new interface plate was employed in microspray ionization mass spectrometry (μESI-MS) to improve ion transmission from the sprayer into the sampling nozzle of the mass spectrometer at atmospheric pressure. Using a time-of-flight mass spectrometer (TOFMS), a fivefold increase in ion intensity and a sevenfold reduction in method detection limit were observed. The interface plate attenuated the dependence of the ion intensity on the sprayer position. Even when the distance between the sprayer tip and sampling nozzle was 15.0 mm, ion signals were still stronger than when the sprayer tip was positioned 3.0 mm in front of the sampling nozzle with the original interface plate. This enhancement in the performance of μESI-MS was due to the improved shapes of the equipotential lines near the sprayer tip and the long desolvation distance between the sprayer and the sampling nozzle of the MS.

Keywords: Interface plate; Microspray ionization; Time-of-flight; Mass spectrometry; Ion transmission; Detection limit


Slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Cd and Pb in plastics by Po-Chien Li; Shiuh-Jen Jiang (pp. 1092-1097).
Ultrasonic slurry sampling electrothermal vaporization dynamic reaction cell inductively coupled plasma mass spectrometry (USS–ETV–DRC–ICP–MS) for the determination of Cr, Cd and Pb in several plastic samples, using NH4NO3 as the modifier, is described. The influences of the instrumental operating conditions and the slurry preparation technique on the ion signals are investigated. A reduction in the intensity of the background at signals corresponding to chromium masses (arising from matrix elements) was achieved by using NH3 as the reaction cell gas in the DRC. The method was applied to determine Cr, Cd and Pb in two polystyrene (PS) samples and a polyvinyl chloride (PVC) sample using two different calibration methods, namely standard addition and isotope dilution. The results were in good agreement with those for digested samples analyzed by ultrasonic nebulization DRC–ICP–MS. The precision between sample replicates was better than 17% with the USS–ETV–DRC–ICP–MS method. The method detection limits, estimated from standard addition curves, were about 6–9, 1–2 and 8–11 ng g−1 for Cr, Cd and Pb, respectively, in the original plastic samples.

Keywords: Inductively coupled plasma mass spectrometry; Ultrasonic slurry sampling; Electrothermal vaporization; Dynamic reaction cell; Plastics; Cr; Cd; Pb


Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate by Erik H. Larsen; Ryszard Lobinski; Karin Burger-Meÿer; Marianne Hansen; Rafal Ruzik; Lena Mazurowska; Peter Have Rasmussen; Jens J. Sloth; Olga Scholten; Chris Kik (pp. 1098-1108).
The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic enzymes, which ensured liberation of selenium species contained in peptides or proteins. Separate extractions using an aqueous solution of enzyme-deactivating hydroxylamine hydrochloride counteracted the possible degradation of labile selenium species by enzymes (such as alliinase) that occur naturally in garlic. The selenium content in garlic, which was analysed by ICP–MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 μg g−1 (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content in garlic to around one part per thousand. The parallel analysis of the sample extracts by cation exchange and reversed-phase HPLC with ICP–MS detection showed that γ-glutamyl-Se-methyl-selenocysteine amounted to 2/3, whereas methylselenocysteine, selenomethionine and selenate each amounted to a few percent of the total chromatographed selenium in all garlic samples. Se-allyl-selenocysteine and Se-propyl-selenocysteine, which are selenium analogues of biologically active sulfur-containing amino acids known to occur in garlic, were searched for but not detected in any of the extracts. The amendment of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of γ-glutamyl-Se-methyl-selenocysteine and γ-glutamyl-Se-methyl-selenomethionine in isolated chromatographic fractions by quadrupole time-of-flight mass spectrometry.

Keywords: Selenium speciation; Garlic; HPLC–mass spectrometry; Selenium enrichment; Mycorrhiza


Evaluation of extraction/digestion techniques used to determine lead isotopic composition in forest soils by Michael Komárek; Vladislav Chrastný; Vojtěch Ettler; Pavel Tlustoš (pp. 1109-1115).
Lead isotopic studies in soils provide an efficient tool for tracing the sources of lead pollution. Five different extraction/digestion techniques (0.05 M EDTA, 0.5 M HNO3, 2 M HNO3, aqua regia, total digestion) were used for lead isotopic composition (206Pb/207Pb) determination in three forest soil profiles with different kinds of prevailing Pb contamination (unpolluted area, smelting area and vicinity of a motorway). The results obtained showed that all extraction/digestion methods used for the determination of 206Pb/207Pb ratios in surface horizons containing high organic matter contents gave statistically identical values (according to the Tukey test). In mineral soil horizons, differences between the individual extraction/digestion methods could be observed (the lowest 206Pb/207Pb ratios were obtained from EDTA extracts, corresponding to weakly bound anthropogenic lead, and the highest 206Pb/207Pb ratios were obtained from total digestion). The combination of total digestion and EDTA extraction (labile lead fraction) seems to be the optimal combination for 206Pb/207Pb ratio determination and optimal result interpretation.

Keywords: Pb isotopes; 206Pb/207Pb; Forest soil; Extraction procedure; Digestion procedure


Detection of V-type nerve agent degradation products at electrodes modified by PPy/PQQ using CaCl2 as supporting electrolyte by Olga V. Shulga; Christopher Palmer (pp. 1116-1123).
Electrochemical detection without derivatization was used to detect thiol-containing degradation products of V-type nerve agents. Electropolymerization of pyrrole was used for entrapment of the biocatalyst PQQ to produce a sensor. Various parameters which affect the detection processes such as the type of the supporting electrolyte used during electrodeposition and the thickness of the polypyrrole film were examined and optimized. Electocatalytic oxidation of thiols by the PPy/PQQ electrode was strongly affected by the presence of Ca2+ cations during electrodeposition of the PPy/PQQ. Cyclic voltammetry, linear sweep voltammetry and amperometry have been used for electrode characterization. Amperometric detection of the V-type nerve agent thiol degradation products 2-(dimethylamino)ethanethiol (DMAET) and 2-(diethylamino)ethanethiol (DEAET) was performed at 0.38 V. Linear calibration plots were observed for these compounds. The detection limits of 4.5 and 3 μM were obtained for DMAET and DEAET respectively, with sensitivities of 1.18 and 1.37 nA μM−1 cm−2.

Keywords: Chemical warfare agents; Thiols; Pyrroloquinoline quinone; Polypyrrole; Electrodeposition; Amperometry


Acidity constants in different media (I=0 and I=0.1 M KCl) from the uncertainty perspective by Eve Koort; Peter Gans; Koit Herodes; Viljar Pihl; Ivo Leito (pp. 1124-1139).
Procedures for estimating the measurement uncertainty for the acidity constant K a (or the pK a value) in different media (I=0 and I=0.1 mol L−1 KCl), as determined by potentiometric titration, are presented. The uncertainty budgets (the relative contributions of the different input quantities to the uncertainty in the result) of the pK a(I=0) and pK a(I=0.1 mol L−1 KCl) values are compared. Unlike the values themselves, the uncertainties and uncertainty budgets of the values are comparable. The uncertainty estimation procedures are based on mathematical models of pK a measurement and involve the identification and quantification of individual uncertainty sources according to the ISO GUM approach. The mathematical model involves 52 and 48 input parameters for pK a(I=0) and pK a(I=0.1 mol L−1 KCl), respectively. The relative importance of each source of uncertainty is discussed. In both cases, the main contributors to the uncertainty budget are the uncertainty components due to the hydrogen ion concentration/activity measurement, which provide 63.7% (for pK a(I=0)) and 89.3% (for pK a(I=0.1 mol L−1 KCl)) of the uncertainty. The remaining uncertainty contributions arise mostly from the limited purity of the acid. From this work, it is clear that the uncertainties of the pK a(I=0.1 mol L−1 KCl) values tend to be lower than those of the pK a(I=0) values. The main reasons for this are that: (1) the uncertainty due to the residual liquid junction potential is nominally absent in the case of pK a(I=0.1 mol L−1 KCl) due to the similarly high concentrations of background electrolyte in the calibration solutions and measured solution; (2) the electrode system is more stable in solutions containing the 0.1 mol L−1 KCl background electrolyte and so the readings obtained in these solutions are more stable.

Keywords: Dissociation constant; pK a value; Uncertainty; ISO GUM; Potentiometric titration


LIBS for landmine detection and discrimination by Russell S. Harmon; Frank C. DeLucia Jr.; Aaron LaPointe; Raymond J. Winkel Jr.; Andrzej W. Miziolek (pp. 1140-1148).
The concept of utilizing laser-induced breakdown spectroscopy (LIBS) technology for landmine detection and discrimination has been evaluated using both laboratory LIBS and a prototype man-portable LIBS systems. LIBS spectra were collected for a suite of landmine casings, non-mine plastic materials, and ‘clutter-type’ objects likely to be present in the soil of a conflict area or a former conflict area. Landmine casings examined included a broad selection of anti-personnel and anti-tank mines from different countries of manufacture. Other materials analyzed included rocks and soil, metal objects, cellulose materials, and different types of plastics. Two ‘blind’ laboratory tests were conducted in which 100 broadband LIBS spectra were obtained for a mixed suite of landmine casings and clutter objects and compared with a previously-assembled spectral reference library. Using a linear correlation approach, ‘mine/no mine’ determinations were correctly made for more than 90% of the samples in both tests. A similar test using a prototype man-portable LIBS system yielded an analogous result, validating the concept of using LIBS for landmine detection and discrimination.

Keywords: Broadband LIBS; Landmine detection; Laser-induced breakdown spectroscopy


Application of a monolithic silica capillary adsorbent for the preconcentration of airborne trichloroethylene and tetrachloroethylene by Wei Chang; Takashi Korenaga (pp. 1149-1152).
Monolithic silica with a bimodal pore structure was prepared in a fused silica capillary by the sol-gel process and investigated as an adsorbent for the preconcentration of airborne trichloroethylene and tetrachloroethylene. The airborne trichloroethylene and tetrachloroethylene are adsorbed when they flow through the silica capillary column and can be desorbed by liquid hexane followed by GC/MS analysis. The monolithic silica adsorbent is mechanically stable and no frits or other special structures are needed to retain them in place. In addition, owing to the smaller size of the capillary column, only a small volume of desorption solvent is needed. The present investigation demonstrates the satisfactory applicability of monolithic silica as a capillary adsorbent.

Keywords: Monolithic silica; Gas preconcentration; GC/MS
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