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Abstract: This study summarizes the results obtained from the doping control analysis during the period of the XXVIII summer Olympic Games (30 July–29 August 2004). The analysis of all doping control samples was performed at the Doping Control Laboratory (DCL)—the World Anti-Doping Agency (WADA) Accredited Laboratory of Athens. Three thousand six hundred and seventeen tests were conducted in total throughout the games. In 23 specimens the presence of a prohibited substance was confirmed. Sixteen of those were related to anabolic agents. The screened results were confirmed with various mass spectrometry analytical techniques, such as gas chromatography/high resolution mass spectrometry (GC/HRMS), gas chromatography/mass spectrometry (GC/MS), gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) and liquid chromatography/mass spectrometry (ion trap) (LC/MS). The results of the first time applied screening and confirmatory procedures for the detection of recombinant human growth hormone in serum were also presented. Besides, 107 therapeutic use exemptions (TUE) were verified for glucocorticosteroid and beta2-agonist use. [Copyright &y& Elsevier]

Abstract: In this paper, a new immunosensor has been proposed based on the receptor protein adsorbed directly on a porous gold film. The film was produced electrochemically on a glassy carbon electrode in 0.08M hydrogen tetrachloroaurate solution containing 0.004M lead acetate with applied potential of −0.5V (versus Ag/AgCl) for 50s. The assay was carried out based on a sandwich procedure. The impedance signals amplified by precipitation of an insoluble product on the electrode showed good linearity with the content of IgG in the range of 0.011–11ngmL−1 with a detection limit of 0.009ngmL−1. The gold film was characterized by scanning electron microscopy and the results showed porous gold nanoclusters were electrochemically deposited on the glassy carbon electrode. [Copyright &y& Elsevier]

Abstract: Synchrotron IR micro-spectroscopy is appropriately suited to the analysis of small particles of archaeological cosmetics. The sample originates from a 33 centuries old Egyptian cosmetic remain. Thanks to the high spectral quality and high lateral resolution achieved by this synchrotron-based microspectroscopic tool, new insights into the composition and spatial location of both organic and mineral components of the sample were obtained. Five different particles were analyzed and delivered similar findings: the core is fat rich, and surrounded with a mineral phase. In two particles, lead palmitate was clearly identified as a major component. Phosgenite (Pb2CO3Cl2), a lead salt synthesized in aqueous solution, was also located in region near the surface of the particles. [Copyright &y& Elsevier]

Abstract: This paper concerns a first attempt of application of multivariate calibration to the field of cultural heritage for the determination of the superficial pigments composition of a painting. For this purpose, 10 mixtures of three organic pigments (Alizarin, Permanent Red and Phtalocyanine Green) selected by an augmented simplex-centroid design were mixed with linseed oil and spread on 10 cotton canvas strips. Each sample was characterised with three genuine replicates of an ATR-IR spectrum. Three calibration models, responding to the relative concentration of each specific pigment in the mixtures, were built with the partial least squares (PLS1) algorithm, using the ATR-IR spectra of the surfaces as predictors. The three mixtures corresponding to the augmentation of the simplex-centroid design were used to validate the model predictive ability which proved to be very satisfactory, with very low root mean squared error of prediction (RMSEP). Finally the models were successfully applied to a real painting, to predict the concentrations of some unknown mixtures of the three studied pigments. This work might have possible applications in the determination of the composition of dyes in real paintings to obtain information on the execution technique and for restoration purposes. [Copyright &y& Elsevier]

Abstract: Chemical warfare agent (CWA) simulants as well as their degradation and hydrolysis products were detected from surfaces using thermal desorption ion mobility spectrometry (TD-IMS). CWA simulant materials that closely mimic the chemical structures of real CWA G/V-type nerve and S-type vesicant simulants were used in this study. Reduced mobility constants (K 0) in air were reported for 20 compounds studied. Spectra for sample materials as low as 1ng deposited on a paper filter were produced for most of the compounds. Detection limits as low as 15pg of sample material with a sensitivity of 3.2×102 ampere per gram (Ag−1) were reported. TD-IMS, which is normally used for the detection of explosives and drugs of abuse, demonstrated the capability of separating and detecting mixtures of CWA simulants, degradation and hydrolysis products from surface samples. TD-IMS demonstrated clear advantages of speed, high throughput and versatility over chromatographic methods of analysis for detecting CWA simulants, degradation and hydrolysis products. Successful development of the technique may lead to a practical and simple sensor for CWA and related compounds that could be installed and used at sensitive locations around the USA and throughout the world. [Copyright &y& Elsevier]

Abstract: Carbamazepine is a poorly soluble drug, with known bioavailability problems related to its polymorphism, and a form (C-monoclinic or form IV) less soluble than the pharmaceutically acceptable (P-monoclinic or form III) can be formed under various conditions, possible to occur during drug formulation. Therefore, quantitative analysis of form IV in form III is important to the drug formulators. In the present study, a fast and simple non-destructive method was developed for quantification of form IV in form III, by using DRIFTS spectral data subjected to the standard normal variate transformation (row centering and scaling) and to the lazy learning algorithm. Fast principal component (fast PCR) and partial least squares (PLS) regression methods of multivariate calibration were also used, which were compared with lazy learning. The lazy learning algorithm was performing better than the fast PCR and PLS methods (root mean squared error of cross-validation 1.318% versus 3.337 and 3.058%, respectively). Even with a small number of calibration samples it gave satisfactory predictive performance (root mean squared error of prediction <2.0% versus >3.3% of fast PCR and >2.6% of PLS), in the concentration range below 30% (w/w) of form IV. This is attributed to the capability of handling non-linearity in the relation of reflectance and concentration as well as to local modeling using a pre-selected number of nearest neighbor concentrations. [Copyright &y& Elsevier]

Abstract: Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Ga, Ge, As, Se and Sb in fly ash samples. The influences of instrument operating conditions and slurry preparation on the ion signals were reported. Pd and ascorbic acid were used as the mixed modifiers to enhance the ion signals. This method has been applied to determine Ga, Ge, As, Se and Sb in NIST SRM 1633a and 1633b coal fly ash reference materials and a fly ash sample collected locally. Since the sensitivities of the elements studied in slurry solution and aqueous solution were different slightly, analyte addition technique was used for the determination of Ga, Ge, As, Se and Sb in these samples. The As and Se analysis results of the reference materials agreed with the certified values. The results for which no certified value was available were also found to be in good agreement between the ETV-ICP-MS results and the reference values. The reference value was obtained by digesting the samples and analyzing the digested sample solutions by pneumatic nebulization Dynamic Reaction Cell™ (DRC) ICP-MS. The method detection limits estimated from analyte addition curves were about 0.23, 0.13, 0.17, 0.25 and 0.11μgg−1 for Ga, Ge, As, Se and Sb, respectively, in original fly ash samples. [Copyright &y& Elsevier]

Abstract: Novel HPLC methods were developed for the analytical and semipreparative resolution of new antidepressant drug mirtazapine enantiomers. At analytical scale, the separation of the mirtazapine enantiomers was investigated using both cellulose and amylose tris(3,5-dimethylphenylcarbamate) (CDMPC and ADMPC) chiral stationary phases under normal-phases and polar organic modes. Good baseline enantioseparation was achieved using cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases under both normal-phases and polar organic modes. Furthermore, the elution order of mirtazapine enantiomic pairs was found reversed by changing the stationary phase from the amylose-based ADMPC–CSPs to its cellulose-based counterpart, CDMPC–CSPs. The validation of the analytical methods including linearity, limit of detection (LOD), limit of quantification (LOQ), recovery and precision, together with the semipreparative resolution of mirtazapine racemate were carried out using cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases and methanol as mobile phase without any basic additives under polar organic mode. At analytical scale, the elution times of both enantiomers were less than 6min at normal temperature and 1.0ml/min, with the separation factor (α) 1.99 and the resolution factor (Rs) 3.56. Then, the analytical methods were scaled up to semipreparative loading to obtain small quantities of both mirtazapine enantiomers. At semipreparative scale, about 16mg/h enantiomers could be isolated and elution times of both enantiomers were less than 10min at 2.0ml/min. To increase the throughput, the technique of boxcar injections was used. One enantiomer ((−)-(R)-mirtazapine) was isolated with purity of >99.9% e.e. and >98.0% yield and another ((+)-(S)-mirtazapine) was isolated with purity of >97.0% e.e. and >99.0% yield. In addition, optical rotation and circular dichroism (CD) spectroscopy of both mirtazapine enantiomers isolated were also investigated. [Copyright &y& Elsevier]

Abstract: Mass spectroscopy with two different ionization techniques, electrospray ionization and atmospheric pressure chemical ionization, optimized for cocaine, was applied to study 170 molecules. For each of the molecules, 429 molecular descriptors were calculated. The aim of this work is, on one hand, to determine whether it is possible to identify which is the better ionization technique, electrospray ionization or atmospheric pressure chemical ionization, to analyse a given molecule, based on the calculated descriptors, and on the other hand to correlate the response of each of the techniques individually with these descriptors. For each molecule, the ratio between the corrected responses of electrospray ionization and atmospheric pressure chemical ionization was used as criterion to decide which ionization technique was the better for the analysis. The chemometrical methods used to explore and model the data were Principal Component Analysis, Projection Pursuit, Classification and Regression Trees, Partial Least Squares and Stepwise Multiple Linear Regression. The results obtained did not allow establishing, based on the calculated molecular descriptors, which is the better ionization technique to analyse a certain molecule for the studied data. [Copyright &y& Elsevier]

Abstract: Express-methods for detection of counterfeit drugs are of vital necessity. Visual control, dissociating tests or simple color reaction tests reveal only very rough forgeries. The feasibility of information-rich NIR-measurements as an analytical method together with multivariate calibration for mathematical data processing for false drugs detection is demonstrated. Also, multivariate hyperspectral image analysis is applied providing additional diagnostic information. Hyperspectral imaging is becoming a useful diagnostic tool for identifying non-homogeneous spatial regions of drug formulation. Two types of drugs are used to demonstrate the applicability of these approaches. [Copyright &y& Elsevier]

Abstract: The application of liquid chromatography–mass spectrometry (LC–MS) was investigated for the analysis of l-5-hydroxytryptophan (5-HTP) in rat serum. The chromatographic elution was carried out using C18 column (YMC, 250mm×2mm, 5μm) with a mobile phase water: acetonitrile (93:7, v/v). Quantitative analysis was performed by negative ion mode using selective ion monitoring (SIM) method with electrospray ionization interface. The serum samples were de-proteinized with acetonitrile. The limit of detection (LOD) and limit of quantification (LOQ) in the serum was found to be 2 and 6ng and calibration curve ranging from 5 to 17ngμl−1 showed to be linear with correlation coefficient 0.994±0.0006. Within-day and day-to-day reproducibility were 0.39–0.44% and 0.66–1.67%, respectively and the recoveries of 5-HTP in the serum were 94.65–95.46%. The method developed was also found to be applicable for the analysis of Griffonia simplicifolia seed extracts and dosage forms with LOD and LOQ, 0.02 and 0.05ng, respectively and linearity range 3–20ngμl−1 with a correlation coefficient of 0.9992±0.0004. The recoveries in the extracts were 97.00–100.20% and %R.S.D. of the intra- and inter-day precision was found to be 0.27–1.29% and 0.35–1.12%. [Copyright &y& Elsevier]

Abstract: A procedure for the determination of three chloroanisoles (2,4,6-trichloro, 2,3,4,6-tetrachloro and pentachloroanisol), as well as their precursor chlorophenols (2,4,6-trichloro, 2,3,4,6-tetrachloro and pentachlorophenol), involved in the presence of cork taint in red wine has been developed. Samples, up to 1l, were concentrated using a 200mg Oasis HLB solid-phase extraction (SPE) cartridge. Chlorophenols were quantitatively eluted from this sorbent with 3ml of methanol. Chloroanisoles were mainly recovered in a second fraction of n-hexane (2ml). Both fractions were combined and mixed with an aqueous solution of sodium bicarbonate and 50μl of acetic anhydride. Chlorophenols were acetylated in the aqueous-methanolic phase and extracted to n-hexane. Chloroanisoles remained unaffected in the n-hexane layer. Both groups of compounds were determined by gas chromatography–tandem mass spectrometry in the same chromatographic analysis. Using a temperature programmable vaporization injector detection limits from 0.2 to 2.4ngl−1, below their sensorial threshold level in red wine, were obtained for all compounds. Average recoveries higher than 80% and acceptable precision were achieved using red wine samples spiked with the analytes at different concentration levels. [Copyright &y& Elsevier]

Abstract: Studies on the luminescence spectra behaviors of seven quinines on solid substrate (SS-RTP) were performed. Experimental conditions, such as heavy atom type, pH and drying time of the sample, etc. on solid substrate room temperature phosphorescence (SS-RTP) or solid substrate delayed fluorescence (SS-DF), were studied in detail. CdCl2 could induce strongest RTP or DF emission of these quinolones. In addition, a comparative study on the spectral behavior of seven quinolones was given, including low temperature phosphorescence (LTP), low temperature fluorescence (LTF) and spectra methioned above. New determination methods for the analysis of seven quinolones by solid substrate room temperature fluorescence (SS-RTF), SS-RTP or SS-DF with filter paper as solid substrate were presented. Analytical characteristics of these methods of seven quinolones were studied. The linear dynamic ranges (LDR), the limit of detection (LOD) and the relative standard deviation (R.S.D.) were valued. Recoveries of seven quinolones in human urine samples were from 98.1% to 104.3%. [Copyright &y& Elsevier]

Abstract: A method for the simultaneous determination of 22 volatile organic compounds (VOCs), methyl-tert-butyl ether (MTBE), 1,4-dioxane, 2-methylisoborneol (2-MIB) and geosmin in water by headspace solid phase microextraction (SPME)-gas chromatography–mass spectrometry (GC–MS) is described. Three types of SPME fibers (carboxen (CAR)/polydimethylsiloxane (PDMS), divinylbenzene (DVB)/PDMS and 100-μm PDMS) were evaluated to achieve the method detection limits and linear range required in Japanese water regulation. A 100-μm PDMS was found to be the best coating to obtain a wide range of linearity for the target compounds in multiple-component system. CAR/PDMS and DVB/PDMS of adsorbent type fibers showed a narrow linear range for 22 VOCs, MTBE and 1,4-dioxane at the μg/l levels due to the limited capacity. The detection limits of this method were 0.01–0.05μg/l for 22 VOCs, 0.01μg/l for MTBE, 1.2μg/l for 1,4-dioxane, 0.6ng/l for 2-MIB and 0.3ng/l for geosmin. The recoveries of 22 VOCs and MTBE from a river water sample spiked at 1μg/l were between 93.7 and 104.0%, with R.S.D. values of between 1.7 and 9.5%. Those of 1,4-dioxane, 2-MIB and geosmin at 5μg/l, 10ng/l and 10ng/l, respectively, were 109.1, 95.9 and 97.4%, with R.S.D. values of 2.0, 5.6 and 1.8%. The method provided linear range from 0.1 to 100μg/l for 21 VOCs and MTBE, 0.1 to 50μg/l for m,p-xylene, 5 to 100μg/l for 1-4dioxane and 1 to 100ng/l for 2-MIB and geosmin. [Copyright &y& Elsevier]

Abstract: Diesel properties determined by ASTM reference methods as cetane index, density, viscosity, distillation temperatures at 50% (T50) and 85% (T85) recovery, and the total sulfur content (%, w/w) were modeled by FTIR-ATR, FTNIR, and FT-Raman spectroscopy using partial last square regression (PLS) and artificial neural network (ANN) spectral analysis. In the PLS models, 45 diesel samples were used in the training group and the other 45 samples were used in the validation. In the ANN analysis a modular feedforward network was used. Sixty diesel samples were used in the neural network training and other 30 samples were used in the validation. Two different ATR configurations were compared in the FTIR, a conventional (ATR1) and an immersion (ATR2) cell. The ATR1 cell presented the best results, with smaller prediction errors (root mean square error of prediction, RMSEP). The comparison of the three PLS models (FTIR-ATR1, FTNIR, and FT-Raman) shows that reasonable values of R 2 and RMSEP were obtained by the FTIR-ATR1 and FTNIR models in the evaluation of density, viscosity, and T50. The PLS/FT-Raman models presented reasonable results only for the T50 property. None of the techniques was able to generate suitable PLS calibration models for the determination of sulfur content. The ANN/FT-Raman models presented the best performances, with all models presenting R 2-values above 85% some of them with RMSEP values significantly smaller than those obtained with FTIR-ATR and FTNIR. The ANN/FT-Raman and ANN/FTIR-ATR1 models were able to estimate the total sulfur content of diesel with 0.01% (w/w) accuracy. [Copyright &y& Elsevier]

Abstract: In this paper, fluorescence correlation spectroscopy (FCS) was applied to measure the size of water-soluble quantum dots (QDs). The measurements were performed on a home-built FCS system based on the Stokes–Einstein equation. The obtained results showed that for bare CdTe QDs the sizes from FCS were larger than the ones from transmission electron microscopy (TEM). The brightness of QDs was also evaluated using FCS technique. It was found that the stability of the surface chemistry of QDs would be significantly improved by capping it with hard-core shell. Our data demonstrated that FCS is a simple, fast, and effective method for characterizing the fluorescent quantum dots, and is especially suitable for determining the fluorescent nanoparticles less than 10nm in water solution. [Copyright &y& Elsevier]

Abstract: Multivariate curve resolution with alternating least squares (MCR-ALS) is successfully applied to UV–vis spectroscopic data of a model system of metal ion/humic acid interactions, namely Al(III)/caffeic acid. MCR-ALS provides resolution into the contributions of the different equilibrium species. Because of rank-deficiency phenomena, the pure spectra and concentration profiles of all species can only be recovered through matrix augmentation. The data set is thus generated coupling three different experiments, two pH-dependent Al(III)/caffeic acid experiments and one acid–base caffeic acid titration. Under these conditions, the rank-deficiency is suppressed in the matrices of analytical interest and the correct number of chemical species can be detected and modelled. Furthermore, local rank information is derived from the application of evolving factor analysis to the full-rank augmented matrices. This approach provides prior knowledge about the complexation mechanism of Al(III) by caffeic acid and enables the characterisation of the different complexed species from spectrophotometric data. [Copyright &y& Elsevier]

Abstract: The functional properties of fats are determined by the distribution pattern of fatty acid residues in their acylglycerols, which may be modified by ester interchange (transesterification). In the margarine industry, the time course of the transesterification of fat blends is monitored by assaying for the amount of the solid fraction at different temperatures (SFC-solid fat content) currently measured by nuclear magnetic resonance (NMR). The aim of this study was to evaluate the feasibility of near infrared spectroscopy (NIRS) to quantify the SFC of different fat blends using NMR data for calibration. SFC values of 128 samples, consisting of different blends of palm stearin, palm kernel oil and concentrates of triglycerides enriched with ω-3 polyunsaturated fatty acids were assayed by NMR prior to (64 samples) and following inorganic (10 samples) or lipase-catalysed transesterification (54 samples). Prior to SFC measurement by NMR, sample preparation takes about 90min. With NIRS technique, a faster determination is achieved since NIR spectra for SFC estimations are directly obtained on the sample at room temperature. High correlations were obtained for cross-validation of the data estimated by NIRS models and NMR for SFC assays at 10°C (R 2 =0.91, RMSECV=2.4), 20°C (R 2 =0.96, RMSECV=1.7), 30°C (R 2 =0.96, RMSECV=1.3) and 35°C (R 2 =0.96, RMSECV=1.3) of the different blends tested. The obtained results show that NIRS is a reliable technique to replace NMR for SFC estimation. [Copyright &y& Elsevier]

Abstract: Ion mobility spectrometry based analysis has been found to provide a powerful and reliable tool as a portable gas detector of different chemical compounds and mixtures. The suitability of the spectrometer in food quality assay was studied in a case study, in which fish quality changes during cold storage were modelled. Hexane extracts of gills of vendace (Coregonus albula L.) were analysed by using ion mobility spectrometry. For reference, microbial counts of gills, ATP-breakdown products (K-value) of fish flesh, electrical properties (Torrymeter scores) of fish skin and sensory evaluation scores were determined. Principal component analysis (PCA) was utilised to create an index for quality by compressing the reference data. Relationship between the quality index and the spectral data were modelled with N-mode partial least squares (PLS). Thus, the ion mobility data have three-dimensional nature, since signals from six channels are recorded simultaneously. Reliability of the predictions and ion mobility measurements was of great interest in the development procedure of this novel analytical method. The multivariate statistical process control (MSPC) charts were used to determine the reliability of the ion mobility measurements. The chemical composition of gill extracts changed during the storage period as indicated by the ion mobility spectrum profiles. The dominant variation in the data was related to the length of storage of fish and to seasonal variation. The results of the case study revealed that the spectrometer, with the analytical method, and with chemometric tools form a promising tool for food quality assays. [Copyright &y& Elsevier]

Abstract: This work reports application of the multivariate curve resolution (MCR) and the two-dimensional correlation spectroscopy (2DCOS) to the study of temperature induced changes of conformational multiequilibria in water. The phenomena were simultaneously monitored by the mid-infrared (MIR) and the near-infrared (NIR) spectra. Ordinary methods of band shape analysis are not sufficient to distinguish sub-bands that can be unambiguously assigned to specifically hydrogen-bonded assembles. To achieve the best possible resolution of the multicomponent water system, the MCR analysis has been performed on an augmented data matrix. The 2DCOS calculations were carried out in hetero-spectral mode. The simultaneous analysis of the intensity changes for bands assigned to the fundamental stretching vibration and vibration that combines the fundamental stretching and bending vibrations of the OH groups pointed out on a two-component structure in terms of Oation manifested by three spectral components that are in a different way involved in hydrogen bond. The use of MCR and 2DCOS for exploring the NIR and MIR spectra of water enabled to postulate one common picture of the temperature-induced structural changes of water that should be very useful in monitoring the conformational transitions of proteins embedded in aqueous environment. [Copyright &y& Elsevier]

Abstract: The presented work is concerned with spectroscopy solutions as means for feedback and feedforward control in the production of wet-processed hardboards. For this purpose online UV–vis–NIR spectroscopy was installed on a full-scale industrial hardboard production to collect spectra from fibre materials, intermediate fibremats and from final hardboards. The acquired spectra were subjected to following chemometric methods: (i) principal component analyses (PCA) to characterise raw materials and process variables; and (ii) partial least square (PLS) regression to investigate the linkages between spectral information and technological data that were determined on the final hardboards. The groupings according to different raw material types, fine and coarse fibre furnish, and the “H-factor” a measure that is indicative for the softening of lignin and the hydrolysis of hemicelluloses, clearly demonstrated that UV–vis–NIR spectroscopy is instrumental in feedback and feedforward control throughout the processing stages. Strong relationships were observed between UV–vis-online-spectra of the fibremats and the water uptake of the corresponding fibreboards. Additional plant trials are needed to investigate further applications that lead a full feedback and feedforward control of industrial manufacturing of wood-based panels. [Copyright &y& Elsevier]

Abstract: In the Italian context, bread wheat flour is commercially classified in different quality categories on the basis of a Synthetic Index of Quality (Indice Sintetico di Qualità, ISQ), which is defined by means of specific parameters, i.e., hectolitric weight, falling number, protein content, alveographic indexes (W, P/L) and farinograph stability. The analyses involved in the determination of these parameters are expensive, time consuming and require specialized personnel, thus there is concern to develop alternative methods to be applied during the commercial transactions, when the products need to be characterized in very short times. For this reason, a fast technique such as an automated classification on the basis of NIR spectra acquired on the wheat flour samples could be a very useful tool. In this work, various wheat flour samples belonging to four different ISQ classes have been analysed by means of NIR spectroscopy, and the obtained spectra have been classified both by SIMCA applied to the signals subjected to different pretreatment methods, and by using a wavelet-based feature selection/classification algorithm, called WPTER. Due to the high overlap of the two intermediate quality classes, it was not possible to classify all the data set signals. However, when considering only the two extreme categories, an acceptable degree of class separation can be gained after feature selection by WPTER. Moreover, this approach allowed us to locate the NIR spectral regions that are mainly involved in the assignment of the wheat flour samples to these two quality categories. [Copyright &y& Elsevier]

Abstract: In this paper, a general methodology to determine non-chromogenic compounds by UV–vis spectrophotometry given the competition of their inclusion complex in cyclodextrins with a structure-alike synthetic standard has been explored. The method was satisfactorily applied to quantify γ-lindane to levels as low as 0.05μgmL−1 in tap water spiked with standard by resolving the UV–vis spectra of the complex of the structure-alike chromogenic standard and HP-γ-cyclodextrin by partial least squares (PLS). [Copyright &y& Elsevier]

Abstract: A new method is described for the concomitant use of the Lu–Hf and Sm–Nd radiogenic isotope systems on the same rock digest. After total spiking with two mixed 176Lu–179Hf and 149Sm–150Nd enriched tracers, the sample is decomposed by fusion with a LiBO2 flux in an induction furnace. Hf is first separated from all matrix elements using U-TEVA Spec extraction chromatography material in 3M HNO3 medium, and obtained in a single step ready for isotope ratio measurements using multiple collector ICP–MS [B. Le Fèvre, C. Pin, Anal. Chem. 73 (2001) 2453]. The rare earth elements (REE) are then separated as a group from the same sample solution by conventional cation-exchange in nitric acid-oxalic acid medium. After evaporation of the REE fraction, Nd, Sm, and Lu are isolated by extraction chromatography using two tandem columns filled with RE Spec and Ln Spec extraction chromatographic materials, respectively. This separation scheme provides fractions of the analytes with excellent recoveries (>90%) and purity, suitable for thermal ionization mass spectrometry, with satisfactory blanks. The potential and present limitations of this method, are exemplified by repeat analyses of several international standard reference materials. [Copyright &y& Elsevier]

Abstract: Fluorescence and mass spectrometric detection schemes are developed and compared for the simultaneous activity determination of two enzymes in solution. As model system, the following reactions are used: The alkaline phosphatase catalyzed reaction with 5-fluorosalicyl phosphate yields the fluorescent 5-fluorosalicylic acid, whereas microperoxidase 11 reacts with 4-(N-methylhydrazino)-7-nitro-2,1,3-benzooxadiazole and H2O2 to the strongly fluorescent 4-(N-methylamino)-7-nitro-2,1,3-benzooxadiazole. As the emission spectra of the fluorescent products as well as the molecular masses of substrates and products do not interfere with each other, is it possible to determine both reactions in parallel with both detection schemes. The measurements resulted in the same limits of detection, limits of quantification and linear ranges of the single/simultaneous enzyme determination for fluorescence and MS detection. While the relative standard deviations were significantly lower in case of fluorescence detection (1.4–3.2%) than in mass spectrometry (5.7–10.1%), the latter proved to be the more versatile approach for multianalyte determination. [Copyright &y& Elsevier]

Abstract: Microwave acid digestion and aqua regia extraction techniques were investigated to obtain a simple, rapid and safe method for the determination of eight trace elements in soil (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn). Soil samples were collected between 6 October and 3 November 2004, air dried, grinded, sieved (<63μm) and subjected to digestion. The digests were subsequently analyzed for metal content by inductively coupled plasma-mass spectrometry (ICP-MS). Various combinations and volumes of hydrofluoric, nitric and hydrochloric acids were evaluated for the microwave acid digestion efficiency. Two certified reference materials (CRM 142, light sandy soil, and CRM 143, over fertilized soil) were used in the comparison of these digestion protocols and good agreement between the two procedures and the certified values was found. The aqua regia microwave acid digestion with a mixture of 2ml of HNO3 and 6ml of HCl produced the fastest, safest and accurate analytical results with a recovery of 91–110% and a precision better than 5% in most cases. Very low limits of detection were obtained, below 0.05μgg−1, for all elements, except for Zn, 2.3μgg−1. A number of agricultural soil samples irrigated by the Tinishu Akaki River (TAR) and its tributaries, Ethiopia, were analyzed. [Copyright &y& Elsevier]

Abstract: Anionic surfactants, sodium dodecyl sulfate (SDS), and di-2-ethylhexyl sodium sulfosuccinate (Aerosol-OT, AOT), were incorporated into a hydrated macroreticular anion-exchanger such as a DEAE- or QAE-Sephadex A-25 gel. The observation of fluorescence spectra of N-phenyl-1-naphthlamine indicated the formation of the surfactant micelles in gels. The hydrophobicity of the micelles corresponded to octanol, tetrahydrofuran, or ethyl acetate. A hydrophobic chelating agent, dithizone (1,5-diphenylthiocarbazone), and its metal chelates were incorporated into the Sephadex gels. The complex formation with dithizone and the subsequent adsorption on Sephadex gels required 10min. The metals collected in gels were desorbed with 8M nitric acid. As a result of 300-fold concentrations, traces of heavy metal ions at ngl−1 levels in river water were successfully determined by graphite-furnace atomic absorption spectrometry. [Copyright &y& Elsevier]

Abstract: Total luminescence and synchronous fluorescence spectroscopies were tested as regards their ability to differentiate edible from lampante virgin olive oils. Total luminescence spectra were recorded by measuring the emission spectra in the range 350–720nm at excitation wavelengths from 320 to 535nm. The synchronous fluorescence spectra of 41 edible and 32 lampante virgin olive oils were acquired by synchronous scanning the excitation and emission monochromator maintained at an offset value of 80nm. Classification of virgin olive oils based on their synchronous fluorescence spectra was performed by hierarchical cluster analysis and principal component analysis using the spectral range of 429–545nm. Principal component analysis provided better discrimination between the two classes, without any classification error, while hierarchical cluster analysis allowed 97.3% correct classification. These results indicate the capability of fluorescence techniques to differentiate virgin olive oils according to their quality. [Copyright &y& Elsevier]

Abstract: A chitosan resin functionalized with 3,4-diamino benzoic acid (CCTS-DBA resin) was newly synthesized by using a cross-linked chitosan (CCTS) as base material. The adsorption behavior of trace amounts of elements on the CCTS-DBA resin was examined by the pretreatment with a mini-column and measurement of the elements by inductively coupled plasma-Mass spectrometry (ICP–MS). Arsenic(V) could be retained on the CCTS-DBA resin at pH 3 as an oxoanion of H2AsO4 −. Selenium(VI) is strongly adsorbed at pH 2 and pH 3 as an oxoanion of SeO4 2−, while selenium(IV) as HSeO3 − is adsorbed on the resin at pH 3. The sorption capacities are 82, 64, and 88mgg−1resin for As(V), Se(IV), and Se(VI), respectively. The effect of common anions and cations on the adsorption of As(V), Se(IV), and Se(VI) were studied; there was no interference from such anionic matrices as chloride, sulfate, phosphate, and nitrate up to 20ppm, as well as from such artificial river water matrices as Na, K, Mg, and Ca after passing samples through the mini-column containing the resin. The CCTS-DBA resin was applied to the collection of arsenic and selenium species in bottled drinking water, tap water, and river water. [Copyright &y& Elsevier]

Abstract: A constrained total-line-shape (CTLS) fitting strategy for organic impurity analysis from 1H NMR spectra was developed and assessed by studying two examples. In general, total-line-shape fitting allows integration of overlapping lines without suffering from baseline artifacts as much as traditional integration methods. It is shown here that the constrained total-line-shape fitting, where the spectral structures of the multiplets to be fitted are taken into account in form of constraints, allows quantification of seriously overlapping lines and when the signals are close to the root of major signals. Also, a method for removal of 13C satellite signals is described. The results indicate that our approach significantly improves the usefulness of qNMR in impurity analysis and that impurity levels of 0.1mol%, which in some cases means down to 0.01wt%, can be easily determined with relative standard error smaller than 10%. [Copyright &y& Elsevier]

Abstract: Ofloxacin is a synthetic fluoroquinolone antibiotic that has been used in the treatment of respiratory tract, urinary tract and tissue-based infections. Methodology for the determination of ofloxacin based on chemiluminescence detection can be divided into: direct oxidation with tris(2,2′-bipyridyl)ruthenium(III) or permanganate; and enhancement of the emission from either the oxidation of sulfite or the reaction between sodium nitrite and hydrogen peroxide. In this paper, we compare the analytical methodology and evaluate the light-producing pathways that have been proposed for these reactions. [Copyright &y& Elsevier]

Abstract: Partial least-squares (PLS) regression was used to generate various models for the determination of both the protein and the ash contents of wheat flours by using spectroscopic data in the mid-infrared region obtained with a horizontal attenuated total reflectance (HATR) accessory. One hundred samples of wheat flour were used as purchased in the market: 55 for constructing the calibration model and 45 as external samples. The protein content varied between 8.85 and 13.23% and the ash content, between 0.330 and 1.287%, as determined by reference methods. Raw spectra and those corrected by multiplicative signal correction (MSC), first and second derivative spectra, were used as data for building the models. Different pre-treatments, such as mean centered and/or variance scaled (VS) methods, were tested and compared. Very good models were built as judged by the correlation coefficients (R 2), root mean square error of calibration (RMSEC), root mean square error of validation (RMSEV) and root mean square error of prediction (RMSEP) that were obtained. Best results were achieved with MSC treated spectra. [Copyright &y& Elsevier]

Abstract: A sensitive liquid chromatographic–electrospray ionization mass spectrometric method was developed and validated for fast determination of telmisartan in human plasma. Plasma of 0.1mL was deprotienated with methanol, centrifugation, evaporation to dryness and dissolving in mobile phase, samples were separated using a Hypersil-Keystone C18 reversed-phase column (150mm×2.1mm i.d., 5μm), together with a mobile phase containing of acetonitrile–10mM ammonium acetate (42:58, v/v), 0.2% acetic acid and was isocratically eluted at a flow rate of 0.2mL/min. Telmisartan and its internal standard, valsartan, were measured by electrospray ion source in positive selective ion monitoring mode. The method demonstrated linearity from 1 to 2000ng/mL (r =0.9988). The limit of quantification for telmisartan in plasma was 1ng/mL with good accuracy and precision. The mean sample extract recovery of the method were higher than 82 and 78% for telmisartan and internal standard (IS), respectively. The within-run and between-run precision ranged from 3.4 to 8.9% and 5.9 to 11.2% (relative standard deviation, R.S.D.), respectively. [Copyright &y& Elsevier]

Abstract: The effect of hydroxypropyl-β-cyclodextrin (HPβCD, β-cyclodextrin (βCD) derivative) was determined on the fluorescence emission spectra of skatole (3-methylindole, MI) and auxin (indole 3-acetic acid, IA). The experiments were conducted at excitation wavelength (λ ex)=280nm, in aqueous solutions at different pH values, with and without HPβCD as receptor. The enhanced fluorescence in the presence of the receptor showed a 1:1 host–guest interaction and the values of the association constants K A were between 100 and 200mol−1 L. The effects of methanol and propanol with and without receptor were also studied. The limit of detection (L D) for the HPβCD enhanced fluorimetric method at pH = 7.00 were 0.279 and 0.765ngmL−1 for MI and IA, respectively. For the determination of indole compounds with closely overlapping spectral bands a zero-crossing first derivative spectrofluorimetric method with or without HPβCD is described. Binary mixtures of MI or IA with melatonin (N-acetyl-5-methoxytryptamine, M) or 5-methoxytryptamine (5-methoxy-3-(2-aminoethyl)indole, 5M) were analysed in the presence of HPβCD. In the absence of receptor, binary mixtures of MI with IA and M with 5M were determined. The matrix effect was evaluated in urine samples by the method of standard addition. Good apparent recoveries were found for each indolic compound by the direct method (98–105% with R.S.D. 0.5–5%) and for mixtures of them by the first derivative method (90–105% with R.S.D. 1–5%) indicating the applicability of them with the advantage of their simplicity, low cost in materials, no time consuming and no requirement of the use of a sophisticate calibration program. [Copyright &y& Elsevier]

Abstract: The on-line column preconcentration technique with inductively coupled plasma optical emission spectroscopy (ICP–OES) has been developed using a cartridge filled with octadecyl silica modified by l-(2-pyridylazo) 2-naphtol (PAN). The aim of this method was to determine some rare earth elements (REEs) (Ce, Dy, La, Sm, and Y) and uranium in water samples. Sample solutions were passed through the C18-modified column. The adsorbed cations were subsequently eluted from the column and transferred into the plasma with nitric acid solution for simultaneous determination of them. Sample pH, amount of PAN as a complexing agent, sampling and eluting flowrates and concentration of the eluent were optimized. Detection limits based on three times of standard deviations of blank by 10 replicates were in the range of 11ngl−1 for Dy to 69ngl−1 for U. Sample throughput was 10 samplesh−1. The proposed method was applied to determine REEs in natural water samples. Recoveries of the REEs from natural water samples were between 95 and 106% with percent relative standard deviation (%R.S.D.) of 1.0–7.9%. [Copyright &y& Elsevier]

Abstract: In the study, we developed a simple, rapid, sensitive, and inexpensive method for determination of the disease biomarkers of acetone, hexanal and heptanal in human blood. For the first time, derivatization of carbonyls with O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine (PFBHA) was combined with headspace single-drop microextractin (HS-SDME) and gas chromatography-mass spectrometry (GC–MS) and applied to the analysis of acetone, hexanal, and heptanal in human blood. At first, acetone, hexanal and heptanal in blood were derivatized with PFBHA and formed oximes in several seconds. Sequentially, the oximes were headspace extracted and concentrated by a microdrop solvent. Finally, the extracted oximes were analyzed by GC–MS. HS-SDME conditions and method validations were studied. Due to needing of only 2μl organic solvent, short extraction time of 8min, and simple operation, derivatization-HS-SDME was shown to be a rapid, simple, and inexpensive technique for analysis of acetone, hexanal, and heptanal in human blood. Moreover, it had low detection limit values from 0.24 to 0.62nM, and good reproducibility (R.S.D. less than 12%). [Copyright &y& Elsevier]

Abstract: Twenty protein α-amino acids have been used to detect adulterations in orange juices from Spanish oranges. An analytical method based on the use of normal-phase liquid chromatography coupled to mass spectrometry has been performed for detection and quantification of these compounds in this complex matrix. MS and MS/MS parameters were optimized and most abundant product ion of each amino acid were selected to be monitorized. Method performance is improved with the use of an Allure Acidix column in which mobile phase composition and flux were optimized. Good separation was achieved using water/acetonitrile (20:80) and water/methanol (10:90) at pH 3, with elution gradient. The method has been used to assess the presence of amino acids in different kinds of orange juice: packing orange juice from both frozen concentrates and recently squeezed oranges, and fresh sweet orange juice hand-squeezed in the laboratory just before the analysis. The differences in composition between the juices and the potential adulteration practices have been evaluated and discussed. [Copyright &y& Elsevier]

Abstract: The interaction and separation of ions with zwitterionic layers are reviewed principally based on a series of the author''s work. An electrostatic model has allowed us to discuss the chromatographic retention of ions on the zwitterionic stationary phase, and has revealed the ionic interaction occurring at the zwitterionic interface. Similar consideration is applicable to the ionic partition into zwitterionic micelles having the spherical dimension. In the electrostatic models, ion association and solvation changes of ions have been assumed to explain the selectivity in ion recognition. Both assumptions are applicable to polarizable large ions, whereas the former cannot account for the results obtained for small and well-hydrated ions (Cl− and Br−). A special X-ray absorption finestructure (XAFS) measurement, which allows selective access to ions interacting with surface monolayers, has been developed, and applied to ions attracted by a zwitterionic monolayer. The X-ray absorption spectra suggest that Zn2+ attracted by the zwitterionic monolayer is still hydrated. In contrast, the direct interaction of Br− has been confirmed, indicating that the electrostatic model involving either ion association or the solvation change of an ion does not properly explain the observed phenomena but both effects should be taken into consideration. [Copyright &y& Elsevier]

Abstract: The distribution of aluminium (Al) species was investigated in the roots of Al-tolerant Chinese cabbage (Brassica rapa L. ssp. pekinensis) by employing fast protein liquid chromatography (FPLC) with inductively coupled plasma optical emission spectrometry (ICP-OES) and electrospray tandem mass spectrometry (ES–MS–MS) detection. The cabbage was exposed to a nutrient solution that contained 10μgcm−3 of Al3+. The results demonstrated that after 24h of exposure, Al was quantitatively taken up by the cabbage and was distributed in different parts of the plant. 36±6% of total Al was located in the roots, while the remaining 64±10% was transferred to the leaves. It was found that in the roots Al was partially present in the root sap (15.5%), while the majority (84.5%) was accumulated in its apoplasmic compartments. It was further demonstrated that the proportion of Al that entered the symplasm formed a complex with organic acid. Speciation analysis by FPLC with ICP-OES detection and ES–MS–MS identification of the binding ligand indicated that Al-citrate complex was the prevailing species in the root sap. The results of the present study showed that both immobilization of Al in the apoplasmic compartments of the roots and transformation of Al3+ to Al-citrate are most likely responsible for the tolerance of Chinese cabbage (B. rapa L. ssp. pekinensis) to the toxic effects of Al3+. [Copyright &y& Elsevier]

Abstract: It has been shown that by using pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS), it is possible to discriminate between a variety of automotive clear coat paints, indistinguishable by Fourier transform infrared spectroscopy (FT-IR). [Copyright &y& Elsevier]

Abstract: We have developed a molecularly imprinted polymer (MIP) using a stable isotope labeled compound as the template molecule and called it the “isotope molecularly imprinted polymer” (IMIP). In this study, bisphenol A (BPA) was used as the model compound. None imprinted polymer (NIP), MIP, dummy molecularly imprinted polymer (DMIP) and IMIP were prepared by the suspension polymerization method using without template, BPA, 4-tert-butylphenol (BP) and bisphenol A-d16 (BPA-d16), respectively. The polymers were subjected to molecularly imprinted solid phase extraction (MI-SPE), and the extracted samples were subjected to liquid chromatography–mass spectrometry (LC–MS). Although the leakage of BPA-d16 from the IMIP was observed and that of BPA was not observed. The selectivity factors of MIP and IMIP for BPA were 4.45 and 4.43, respectively. Therefore, IMIP had the same molecular recognition ability as MIP. When MI-SPE with IMIP was used and followed by LC–MS in the analysis of river water sample, the detection limit of BPA was 1 ppt with high sensitivity. Moreover, the average recovery was higher than 99.8% (R.S.D.: 3.7%) by using bisphenol A-13C12 (BPA-13C12) as the surrogate standard. In addition, the IMIP were employed in MI-SPE of BPA in river water sample by LC–MS. The concentration of BPA in the river water sample was determined to be 32pgml-1. We confirmed that it was possible to measure trace amounts of a target analyte by MI-SPE using IMIP. [Copyright &y& Elsevier]

Abstract: This study evaluates solid-phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) to determine trace levels of bisphenol A in water and leached from plastic containers. The extraction using headspace post-derivatization with bis(trimethylsilyl) trifluoroacetamide (BSTFA), containing 1% trimethylchlorosilane (TMCS) vapor, following SPME was compared with extraction without derivatization. The SPME experimental procedures to extract bisphenol A in water were optimized with a relatively polar polyacrylate (PA)-coated fiber, an extraction time of 50min and desorption at 300°C for 2min. Headspace derivatization following SPME was performed using 7μL of BSTFA with 1% TMCS at 65°C for 30s. The precision was 5.2% without derivatization and 9.0% headspace derivatization. The detection limit was determined to be at the ng/L level. When SPME was used following headspace derivatization, the detection limit was one order of magnitude better than that achieved without derivatization. The results of this study reveal the adequacy of SPME–GC–MS method for analyzing bisphenol A leached from plastic containers. The concentrations of bisphenol A leached from plastic containers into water ranged from 0.7 to 78.5μg/L. [Copyright &y& Elsevier]

Abstract: The use of multivariate calibration methods, principal component regression (PCR) and partial least square (PLS) regression, applied on the raw and first derivative spectra, for the estimation of pyrazinamide (PYZ), isoniazid (INH) and rifampicin (RIF) in antitubercular combination formulation is presented. First derivative spectra were computed using Savitzky–Golay transformation. The three drugs show considerable degree of spectral overlap. The calibration set exhibiting central composite design was used to develop models able to predict the concentration of unknown samples containing three drugs. The calibration model was optimized by an appropriate selection of number of factors and wavelength regions to be used for building data matrix, based on minimization of predicted error sum of square (PRESS) using leave-one-out cross-validation strategy. The calibration model was validated by a separate set of 15 mixture solutions. The PCR and PLS models on the raw and first derivative spectra were statistically compared by ANOVA. All methodologies gave statistically similar results. The methodologies were successfully applied to the simultaneous estimation of PYZ, INH and RIF in pharmaceutical formulation. [Copyright &y& Elsevier]

Abstract: This study concerns with the development and application of a mercury analyzer system capable of quantitative analysis and binding forms of trace mercury in different body tissues of rats after oral intake of cinnabar and HgCl2. The analyzer consists of a temperature programmed thermolysis unit for sample decomposition and mercury release, coupled downstream to an atomic absorption spectrometry for mercury detection. No sample digestion was needed and this greatly simplifies the analytical procedure and minimizes potential sources of contamination. The precision of the method is in general better than 1.4%; the detection limit (3σ) is 6.3ng/g; the recovery based on the analysis of standard reference materials ranges from 93.5 to 107%. The performance of the method has been compared with inductively coupled plasma–mass spectrometry (ICP–MS) technique and excellent agreements were observed between the two methods. The method has been applied to the investigation of the distribution and binding forms of mercury in rats, which had been fed orally with cinnabar and HgCl2. The results obtained show that mercury is mainly accumulated in the tissues of liver and kidney, meanwhile, the mercury levels in different tissues change with the feeding time, dosage and the chemical form of mercury compounds. In addition to total mercury measurements, the mercury thermal release profiles obtained from temperature programmed thermolysis provides mercury binding forms information, and preliminary data suggest the presence of protein/polypeptide-bound Hg compounds in kidney samples of rats. [Copyright &y& Elsevier]

Abstract: A simple, reliable and selective high performance liquid chromatographic method with fluorescence detection at different programmed wavelengths has been developed for the simultaneous analysis of B6 vitamers (pyridoxal 5′-phosphate, 4-pyridoxic acid, pyridoxal, pyridoxine and pyridoxamine) and Vitamin B2 in commercial vitaminized milk and in woman milk. The chromatographic separations were performed on a reversed phase octyl column by using a mobile phase consisting of sodium pentanesulfonate in 1% acetic acid–methanol–tetrahydrofuran under gradient elution conditions. The fluorescence intensity of pyridoxal 5′-phosphate was enhanced by post-column photochemical conversion, giving significantly different fluorescence spectra by a on-line photoreactor switched OFF and ON under irradiation at 254nm. In addition, a simple and rapid method in isocratic conditions without the need of photochemical conversion was proposed for the analysis of Vitamin B6 and Vitamin B2 in pharmaceuticals. Linearity, precision, recovery, selectivity and sensitivity were found satisfactory for each analysed compound. Quantitation limits ranged from 26 to 240fmol. [Copyright &y& Elsevier]

Abstract: This investigation evaluates solid phase microextraction (SPME) combined with liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS) to determine trace levels of amphetamine (AM) and methamphetamine (MA) in serum. Chromatography was performed on a C18 reversed-phase column using a linear gradient of acetonitrile–water as a mobile phase. Using sample extraction by SPME at optimum conditions, analytes were desorbed with static desorption in SPME–HPLC desorption chamber for 1min and then determined with LC–ESI–MS/MS. The detection limits for amphetamine and methamphetamine in serum were 0.3μg/L and 0.04μg/L, respectively. According to the analysis, the linearity range is from 0.5μg/L to 200μg/L with R.S.D. values below 8%. The feasibility of applying the methods to determine amphetamine and methamphetamine in real samples was examined by analyzing serum samples from methamphetamine abused suspects. [Copyright &y& Elsevier]

Abstract: A new infrared (IR) sensing system based on attenuated total reflection (ATR) to determine the levels of glucose in aqueous solutions was developed in this work. To increase the selectivity of the system, we employed glucose oxidase (GOx) to convert glucose into gluconic acid, which was the actual species detected by the IR-ATR sensor. Because gluconic acid is highly polar and was produced generally in low concentrations, the surface of the IR-ATR sensor was modified with cyclodextrin to increase the sensitivity of its detection. As a result, the sensitivity increased roughly by 100 times relative to that of the unmodified ATR. To simplify the detection system, we immobilized GOx onto the surfaces of glass beads and packed them into a column to function as an enzyme reactor. For comparison, GOx was also immobilized onto the internal surface of fused silica tubing. Glucose can be converted to gluconic acid effectively when passed through a flow system and using either packed or open tubular columns. To optimize the performance of the developed system, we investigated the effects of the pH of the sample solutions and the flow rate used to pump glucose through the system. Our results indicate that the optimal pH for the system was ca. 5; a low pH was required for high-efficiency detection of gluconic acid by the CD phase, but it lowered the efficiency of the enzymatic reactions. The flow rate exerted a small influence on the analytical signals over the examined range of flow rates because of the limited rates of the enzymatic reactions. Under the optimal conditions, the linear regression coefficients in the standard curve can be >0.99 for a concentration range of 1–50mM and a detection time of 2min. In addition, our developed system can be regenerated effectively using aqueous solutions at high pH. [Copyright &y& Elsevier]

Abstract: A SIMCA model was developed for classification of C10-bicycloalkanes to assist evaluation of kinetic experiments involving complex mixture of C10-hydrocarbons. The influence of different pre-processing methods, such as square root and cubic root scaling, and transformation methods, including autocorrelation transform and spectral features, on the classification of C10-bicycloalkanes was investigated. While the transformation of mass spectra into spectral features was found essential for modeling of spectra of C10-bicycloalkanes, the intensities scaling was only of little importance for the quality of the SIMCA models. The best SIMCA model was successfully applied in detailed analysis of C10-bicycloalkanes originating from decalin isomerization and contributed to identification of the decalin isomerization mechanism. [Copyright &y& Elsevier]

Abstract: This work presents the archaeometric characterisation of a group of ancient pottery remains discovered during the restoring of the Novalesa Abbey (Susa Valley, Turin, Italy) performed in 2000. The characterisation focuses on the achievement of information about provenance and production process of the samples. Firstly, the data concerning the multi-element characterisation of the samples by inductively coupled plasma–mass spectrometry (ICP–MS) were analysed by chemometric tools (principal component analysis and cluster analysis) in order to obtain information about their similarity and clustering. These information, integrated with the results of micro-Raman spectroscopy analysis of the inclusions shed light on differences in the production process of the samples. [Copyright &y& Elsevier]

Abstract: The application of chemometric tools to analyze multi-way data has become popular, especially for excitation–emission matrix (EEM) fluorescence spectroscopy where PARAFAC often is employed to resolve the pure component profiles of mixtures of fluorophores. There are, however, some features in a typical EEM that do not follow the required low-rank tri-linear structure required for PARAFAC to work optimally. The most significant of these features is the light scatter effects that form diagonal lines in the landscapes. These cannot be modeled by one (or a few) factor(s) in the decomposition step, and has so far been removed by subtracting a standard, inserting missing values, or weighting these areas down. This paper suggests a novel method, which models the first order Rayleigh scatter as a separate set of factor(s) in the decomposition step by shifting the Rayleigh scatter into becoming low-rank bi-linear. This method is easier to implement than current methods and provides good results; both requirements for increasing the use of fluorescence spectroscopy by the non-expert user. [Copyright &y& Elsevier]