Search

Abstract: Laser desorption ionization mass spectrometry (LDI-MS) was performed on selected azaborolinyl zirconium complexes in order to study them as potential industrial polyolefin catalyst compounds. UV–vis absorption data in conjunction with negative and positive ionization analyses revealed the mechanistic workings of the compounds when such single-site catalysts function in olefin polymerization reactions. Results presented highlight the many benefits of LDI-MS in the study of single-site zirconium azaborolinyl catalyst complexes including minimal sample preparation, the absence of matrix/pH/solvation effects, a lower degree of fragmentation as compared to EI ionization, high sensitivity and the ability to observe interesting and unique gas phase chemistry including ring slippage, and distinctive metal coordination and oxidation states. The extreme lability of the chlorine ligands was apparent, as well as the reactivity of the resulting zirconium metal center as demonstrated by the appearance of numerous similar four-coordinate zirconium species along with di-chloro-bridged dimers. LDI-MS permits analysis at low molecular weights, improving spectral characterization of these zirconium complexes. [Copyright &y& Elsevier]

Abstract: This study addresses the necessity to provide fast assessment of pesticide coverage on plants, which is required for saving the expensive compounds and for protecting the environment against overdosing. The feasibility of applying several optical methods for direct detection of the pesticides on plants has been investigated. In order to overcome the matrix effect, which is related to plant fluorescence emission and to physiological spectral interferences, we suggest the application of a fluorescent labeling agent, in form of nano- and micro-crystallites. The coverage assessment is based on the spectral effects related to the interaction of these crystallites with the pesticides. Among the studied features are the fluorescence quenching/enhancement, spectral shifts and fluorescence lifetimes. It has been found that these spectral features are adequate for mapping the pesticides on plant surfaces, and assessing their coverage. Direct charge-coupled-device (CCD) fluorescence imaging was found as a low-cost adequate method, while Fourier transform spectral imaging provided more specific and accurate results. [Copyright &y& Elsevier]

Abstract: A novel and sensitive cloud point extraction procedure for the determination of trace amounts of malachite green by spectrophotometry was developed. Malachite green was extracted at pH 2.5 mediated by micelles of nonionic surfactant Triton X-100. The extracted surfactant-rich phase was diluted with ethanol and its absorbance was measured at 630nm. The effect of different variables such as pH, Triton X-100 concentration, cloud point temperature and time and diverse ions was investigated and optimum conditions were established. The calibration graph was linear in the range of 4–500ngmL−1 of malachite green in the initial solution with r =0.9996 (n =10). Detection limit based on three times the standard deviation of the blank (3Sb) was 1.2ngmL−1 and the relative standard deviation (R.S.D.) for 20 and 300ngmL−1 of malachite green was 1.48 and 1.13% (n =8), respectively. The method was applied to the determination of malachite green in different fish farming and river water samples. [Copyright &y& Elsevier]

Abstract: The interaction of brilliant red X-3B (BRX) with bovine serum albumin (BSA) in three pH media has been characterized by the spectral correction technique. The binding number maximum of BRX was determined to be 102 at pH 2.03, 82 at pH 3.25 and 38 at pH 4.35 and the binding mechanism was analyzed in detail. The effects of ionic strength from 0 to 1molL−1 and temperature from 20 to 70°C on the binding were investigated. The results showed that the interaction of BRX with BSA responded to the Langmuir adsorption isothermal model and the binding constant was determined. From the correlation between the binding number and the number of basic amino acid residues, the ion-pair attraction induced the union of non-covalent bonds including H-bond, van der Waals force and hydrophobic bond and the binding model was illustrated. The binding of BRX to BSA has resulted in change of the BSA conformation confirmed by means of circular dichroism. Using this interaction at pH 2.03, a sensitive method named the absorbance ratio difference spectrometry was established and applied to the protein assay and the limit of detection of protein was only 6μgL−1. Two samples were determined and the results were in agreement with those obtained by the classical coomassie brilliant blue colorimetry. [Copyright &y& Elsevier]

Abstract: In this work, the lightfastness of wool textile samples, dyed with madder and its principal components alizarin and purpurin, was investigated using two complementary experimental techniques: absorption and emission UV-vis spectroscopy and chromatography (HPLC-PDA). Spectroscopic techniques were used to follow the time course of ageing, whereas chromatography was applied to determine relative compositional changes that occurred after exposure of wool dyed samples to natural and artificial ageing. The results from the two techniques integrate well each other and provide complementary and useful indications about the sensitivity of the dyed textiles to ageing, showing that purpurin is the principal component responsible for the spectral and chromatic properties of madder as well as for its degradation. The fading of both the fibre and dye is reduced in the presence of alum and in the absence of oxygen. The multi-analytical approach used highlights the potential of the UV-vis spectroscopy for the investigation of dyes on textiles. The great sensitivity of the spectrofluorimetry makes this technique particularly promising for a non-destructive study of dyes on works of art. [Copyright &y& Elsevier]

Abstract: An autonomous multi-parameter flow-through CO2 system has been developed to simultaneously measure surface seawater pH, carbon dioxide fugacity (fCO2), and total dissolved inorganic carbon (DIC). All three measurements are based on spectrophotometric determinations of solution pH at multiple wavelengths using sulfonephthalein indicators. The pH optical cell is machined from a PEEK polymer rod bearing a bore-hole with an optical pathlength of ∼15cm. The fCO2 optical cell consists of Teflon AF 2400 (DuPont) capillary tubing sealed within the bore-hole of a PEEK rod. This Teflon AF tubing is filled with a standard indicator solution with a fixed total alkalinity, and forms a liquid core waveguide (LCW). The LCW functions as both a long pathlength (∼15cm) optical cell and a membrane that equilibrates the internal standard solution with external seawater. fCO2 is then determined by measuring the pH of the internal solution. DIC is measured by determining the pH of standard internal solutions in equilibrium with seawater that has been acidified to convert all forms of DIC to CO2. The system runs repetitive measurement cycles with a sampling frequency of ∼7 samples (21 measurements) per hour. The system was used for underway measurements of sea surface pH, fCO2, and DIC during the CLIVAR/CO2 A16S cruise in the South Atlantic Ocean in 2005. The field precisions were evaluated to be 0.0008 units for pH, 0.9μatm for fCO2, and 2.4μmolkg−1 for DIC. These field precisions are close to those obtained in the laboratory. Direct comparison of our measurements and measurements obtained using established standard methods revealed that the system achieved field agreements of 0.0012±0.0042units for pH, 1.0±2.5μatm for fCO2, and 2.2±6.0μmolkg−1 for DIC. This system integrates spectrophotometric measurements of multiple CO2 parameters into a single package suitable for observations of both seawater and freshwater. [Copyright &y& Elsevier]

Abstract: It was found that oxolinic acid (OA) at high concentration can self-assemble into nano- to micro- meter scale OA aggregates in Tris–HCl (pH 7.48) buffer solution. The nanoparticles of OA were adopted as fluorescence probes in the quantitative analysis of proteins. Under optimum conditions, the fluorescence quenching extent of nanometer scale OA aggregates was in proportion to the concentration of albumins in the range of 3.0×10−8 to 3.0×10−5 gmL−1 for bovine serum albumin (BSA) and 8.0×10−8 to 8.0×10−6 gmL−1 for human serum albumin (HSA). The detection limits (S/N=3) were 3.4×10−9 gmL−1 for BSA, and 2.6×10−8 gmL−1 for HSA, respectively. Samples were satisfactorily determined. The interaction mechanism of the system was studied using fluorescence, UV–vis, resonance light scattering (RLS) and transmission electron microscope (TEM) technology, etc., indicating that the nonluminescent complex was formed between serum albumin molecular and OA, to disaggregate the self-association of OA, which resulted in the dominated static fluorescence quenching in the system. [Copyright &y& Elsevier]

Abstract: A novel detection method for organophosphate neurotoxins has been described, based on the fluorescence quenching of a Coumarin derivative. These dyes are similar in structure to some organophosphates (OPs), and they fluoresce in the blue–green region of the spectra. This methodology has been utilized for the detection of organophosphates whose hydrolysis product is p-nitrophenol by using an enzyme, organophosphorus hydrolase (OPH). Coumarin1 in the presence of p-nitrophenol results in a quenching of fluorescence, providing a direct measure of the concentration of p-nitrophenol present in the sample. The decrease in fluorescence intensity is proportional to the paraoxon concentration in the range of 7.0×10−7–1.7×10−4 M. The specificity of this sensing application for p-nitrophenyl substituent OPs has also been demonstrated. OPs are a class of synthetic organic pesticides which generally have a short residual life and can cause numerous acute and chronic health effects. They have been an integral part of the agricultural industry for the past several decades due to their target specificities and selectable toxicities. The toxic nature of these compounds can be attributed to the species–specific inhibition of acetylcholinesterase (AChE), an important enzyme responsible for the regeneration of neural synaptic function. In addition to their wide agricultural and urban usage, they have also been exploited for the development of neurological chemical warfare agents. Currently available technologies for OP detection include sol–gel thin films, screen printed electrodes, acoustic patterning, gas chromatography–mass spectrometry, and various other intricate techniques that have limited field applicabilities. This optically-based approach promises much simpler and more direct detection capabilities. [Copyright &y& Elsevier]

Abstract: On-line near infrared spectroscopy was used to determine the water content in a continuous conversion reactor. The NIR predictions were incorporated into the distributed control system (DCS) which then controlled the addition of water to the reactor. The conversion reaction utilizes methanol, water, sodium carbonate and a reactant. Control of the water content is important for a number of reasons. At elevated water levels, a competing hydrolysis reaction increases along with the product solubility in the mother liquor leading to product losses. At reduced water levels, the product becomes anhydrous and the reaction mixture becomes gelatinous, necessitating a shutdown of the reactor for cleaning. The previous procedure for monitoring water was to remove a sample once per hour, transfer the sample to the laboratory, and run a Karl Fisher assay. Upon obtaining results from the lab, an operator would manually adjust the water inlet valve to the reactor. NIR spectroscopy in an on-line mode allows spectra to be collected every 200s markedly increasing the frequency of results. A partial least squares model was constructed, validated and successfully implemented to predict the water content of the reactor. Further, by feeding the results to the process DCS, water additions to the reactor were fully automated. The increased frequency of sampling by NIR led to an improvement in the control of the water content and decreased the normal amount of equipment downtime. These factors improved process stability and recovery thereby generating an estimated $500,000 in savings over the course of the campaign. [Copyright &y& Elsevier]

Abstract: Particle swarm optimization (PSO) combined with alternating least squares (ALS) is introduced to self-modeling curve resolution (SMCR) in this study for effective initial estimate. The proposed method aims to search concentration profiles or pure spectra which give the best resolution result by PSO. SMCR sometimes yields insufficient resolution results by getting trapped in a local minimum with poor initial estimates. The proposed method enables to reduce an undesirable effect of the local minimum in SMCR due to the advantages of PSO. Moreover, a new criterion based on global phase angle is also proposed for more effective performance of SMCR. It takes full advantage of data structure, that is to say, a sequential change with respect to a perturbation can be considered in SMCR with the criterion. To demonstrate its potential, SMCR by PSO is applied to concentration-dependent near-infrared (NIR) spectra of mixture solutions of oleic acid (OA) and ethanol. Its curve resolution performances are compared with SMCR with evolving factor analysis (EFA). The results show that SMCR by PSO yields significantly better curve resolution performances than those by EFA. It is revealed that SMCR by PSO is less sensitive to a local minimum in SMCR and it can be a new effective tool for curve resolution analysis. [Copyright &y& Elsevier]

Abstract: The amounts of drug and excipient were predicted from ATR-FTIR spectra using two multi-way modelling techniques, parallel factor analysis (PARAFAC) and multi-linear partial least squares (N-PLS). Data matrices consisted of dissolved and undissolved parallel samples having different drug content and spectra, which were collected at axially cut surface of the flat-faced matrix tablets. Spectra were recorded comprehensively at different points on the axially cut surface of the tablet. The sample drug concentrations varied between 2 and 16% v/v. The multi-way methods together with ATR-FTIR spectra seemed to represent an applicable method for the determination of drug and excipient distribution in a tablet during the release process. The N-PLS calibration method was more robust for accurate quantification of the amount of components in the sample whereas the PARAFAC model provided approximate relative amounts of components. [Copyright &y& Elsevier]

Abstract: The transesterification of vegetable oils, animal fats or waste oils with an alcohol (such as methanol) in the presence of a homogeneous catalyst (sodium hydroxide or methoxyde) is commonly used to produce biodiesel. The quality control of the final product is an important issue and near infrared (NIR) spectroscopy recently appears as an appealing alternative to the conventional analytical methods. The use of NIR spectroscopy for this purpose first involves the development of calibration models to relate the near infrared spectrum of biodiesel with the analytical data. The type of pre-processing technique applied to the data prior to the development of calibration may greatly influence the performance of the model. This work analyses the effect of some commonly used pre-processing techniques applied prior to partial least squares (PLS) and principal components regressions (PCR) in the quality of the calibration models developed to relate the near infrared spectrum of biodiesel and its content of methanol and water. The results confirm the importance of testing various pre-processing techniques. For the water content, the smaller validation and prediction errors were obtained by a combination of a second order Savitsky–Golay derivative followed by mean centring prior to PLS and PCR, whereas for methanol calibration the best results were obtained with a first order Savitsky–Golay derivative plus mean centring followed by the orthogonal signal correction. [Copyright &y& Elsevier]

Abstract: The scale-up of batch kinetic models was studied by examining the kinetic fitting results of batch esterification reactions completed in 75mL and 5L reactors. Different temperatures, amounts of catalysts, and amounts of initial starting reagents were used to completely characterize the reaction. A custom written Matlab toolbox called GUIPRO was used to fit first-principles kinetic models directly to in-line NIR and Raman spectroscopic data. Second-order kinetic models provided calibration-free estimates of kinetic and thermodynamic reaction parameters, time dependent concentration profiles, and pure component spectra of reagents and product. The estimated kinetic and thermodynamic parameters showed good agreement between small-scale and large-scale reactions. The accuracy of pure component spectra estimates was validated by comparison to collected NIR and Raman pure component spectra. The model estimated product concentrations were also validated by comparison to concentrations measured by off-line GC analysis. Based on the good agreement between kinetic and thermodynamic parameters and comparison between actual and estimated concentration and spectral profiles, it was concluded that the scale-up of batch kinetic models was successful. [Copyright &y& Elsevier]

Abstract: A rapid analytical method for quantifying 17 ginsenosides in rat urine by ultra performance liquid chromatography (UPLC) coupled to electrospray ionization mass spectrometry (ESI-MS) is described. All analytes were extracted by solid-phase extraction optimized to obtain good recovery and quantified using digoxin as an internal standard. ESI-MS was optimized for different cone voltages at positive ionization mode to allow simultaneous analysis of all analytes in a relatively short time. Qualitative methodological considerations, including the linear range, precision, limit of quantification, limit of detection, recovery and sensitivity are also provided. [Copyright &y& Elsevier]

Abstract: A method that use kernel independent component analysis (KICA) and support vector regression (SVR) was proposed for estimation of source ultraviolet (UV) spectra profiles and simultaneous determination of polycomponents in mixtures. In KICA–SVR procedure, the UV source spectra profiles were estimated using KICA, then the mixing matrix of the components were calculated using the estimated sources, and the calibration model was build using SVR based on the calculated mixing matrix. A simulated UV dataset of three-component mixtures was used to test the ability of KICA for estimating source spectra profiles from spectra data of mixtures. It was found that KICA has the potential power to estimate pure UV spectra profiles, and correlation coefficient of estimated sources correspond to the real adopted ones are better compared with that by FastICA and Infomax ICA. An UV dataset of polycomponent vitamin B was processed using the proposed KICA-SVR method. The results show that the estimated source spectra profiles are correlative with the real UV spectra of the components and chemically interpretable, and accurate results were obtained. [Copyright &y& Elsevier]

Abstract: A new method is presented for the identification of oligosaccharides obtained by enzymatic digestion of hyaluronan (HA) with bacterial hyaluronidase (E.C. 4.2.2.1, from Streptomyces hyalurolyticus) using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOFMS). Mixtures containing HA oligosaccharides of tetrasaccharide (4-mer)–34-mer were analyzed using this method. The carboxyl groups of the glucuronate residues in the prepared HA oligomers, were modified as the acidic form (dium salts (rganic ammonium salts, or methylesters before MALDI-TOFMS measurement. Among these samples, the methylester form of glucuronate residues in HA oligosaccharides, prepared by methylation using trimethylsilyl diazomethane, afforded high sensitivity for spectra. This simple modification method for carboxyl group methylation of acidic polysaccharides [Hirano et al., Carbohydr. Res., 340, (2005) 2297–2304] provides samples suitable for MALDI-TOF mass spectrometric analysis throughout a significantly enhanced range of masses. [Copyright &y& Elsevier]

Abstract: It has been made a critical evaluation of the application of near infrared Fourier transform-Raman spectroscopy for the simultaneous determination of the most important nutritional parameters such as energetic value, carbohydrate, protein and fat contents of infant formula and powdered milk samples based on the use of partial least squares (PLS) regression analysis. A highly heterogeneous population of 23 samples, covering a wide range of infant food formula and powdered milk, were obtained from the Spanish market. Raman spectra, obtained by excitation with a Nd:YAG laser at 1064nm, show no disturbing fluorescence effects; therefore sample spectra can be recorded without any previous preparation step. After correcting the spectra, hierarchical cluster analysis was performed in order to select a representative calibration set and the corresponding validation sample set. Different PLS models and several spectral windows were tested in order to evaluate their prediction capabilities for the validation set. Considering a calibration set comprised of three replicate spectra of 15 samples and a validation data set of eight samples, the procedure developed provided figures of merit which complied with the statutory values declared by the United States Food and Drug Administration (US FDA). [Copyright &y& Elsevier]

Abstract: The pharmaceutical industry faces increasing regulatory pressure to optimize quality control. Content uniformity is a basic release test for solid dosage forms. To accelerate test throughput and comply with the Food and Drug Administration''s process analytical technology initiative, attention is increasingly turning to nondestructive spectroscopic techniques, notably near-infrared (NIR) spectroscopy (NIRS). However, validation of NIRS using requisite linearity and standard error of prediction (SEP) criteria remains a challenge. This study applied wavelet transformation of the NIR spectra of a commercial tablet to build a model using conventional partial least squares (PLS) regression and an artificial neural network (ANN). Wavelet coefficients in the PLS and ANN models reduced SEP by up to 60% compared to PLS models using mathematical spectra pretreatment. ANN modeling yielded high-linearity calibration and a correlation coefficient exceeding 0.996. [Copyright &y& Elsevier]

Abstract: A high quality anodic aluminum oxide (AAO) template with ordered apertures about 50–80nm was fabricated by anodizing aluminum in electrolytes through a two-step method, and silver nanowires with diameters from 40nm to 70nm were prepared on this AAO template by magnetron sputtering. On the glass covered with silver nanowires, high quality surface enhanced Raman scattering (SERS) spectra of sudan II (C18H16N2O) with enhancement factors of 105 were obtained. And comparison of SERS spectra on silver nanowires with the SERS spectra of silver colloids indicates that main enhanced mode is lightning rod effect of nanorods on the Sudan II/silver nanowires system. [Copyright &y& Elsevier]

Abstract: This article aims to provide the basic information necessary to afford the discrimination of artistic prints based on chemical information. The presence of original and non-original prints in the art market is a real problem, especially for contemporary artists. Most of the non-original elements can be distinguished on the basis of their stylistics and printing characteristics, but sometimes this information is not enough. To facilitate discrimination in these cases, we propose to add, to the previously indicated aspects, the chemical information of the materials involved in the production of the original series (inks, paper and pencil). Comparison of the composition of any element with that established for the original series will permit the attribution of any doubtful element. This article is focused on the evaluation of this approach by determining the chemical composition of contemporary black printing inks by infrared spectroscopy and by searching, on the basis of the information obtained, for criteria capable to discriminate between prints made of different inks. The success of the approach with this set of inks could easily be extended to the study of colour inks. The study also includes the characterization and discrimination of black pigments because they are the most characteristic component of these inks and because this information can also be useful for other artistic studies. The procedure proposed permits the analysis of inks with minimum deterioration of the artwork. Results indicate the capability of the approach because, following the procedure, it is possible to distinguish between black pigments attending to the presence of hydroxyapatite, silicate and some other specific bands, whereas black inks can be discriminated by paying attention to the inclusion in their composition of such pigments as bone black, Prussian blue, mars brown or other specific bands. Scanning electron microscopy analyses have corroborated the results obtained. [Copyright &y& Elsevier]

Abstract: Recent studies have evaluated the capability of plastic scintillation (PS) as an alternative to liquid scintillation (LS) in radionuclide activity determination without mixed waste production. In order to complete the comparison, we now assess the extent to which PS can be used to quantify mixtures of radionuclides and the influence of the diameter of the plastic scintillation beads in detection efficiency. The results show that the detection efficiency decreases and the spectrum shrink to lower energies when the size of the plastic scintillation beads increases, and that the lower the energy of the beta particle, the greater the variation takes place. Similar behaviour has been observed for beta–gamma and alpha emitters. Two scenarios for the quantification of mixtures are considered, one including two radionuclides (14C and 60Co) whose spectra do not overlap significantly, and the other including two radionuclides (137Cs and 90Sr/90Y), where the spectra of one the isotopes is totally overlapped by the other The calculation has been performed by using the conventional window selection procedure and a new approach in which the selected windows correspond to those with lower quantification errors. Relative errors obtained using the proposed approach (less than 10%) are lower than those of the conventional procedure, even when a radionuclide is completely overlapped, except for those samples with extreme activity ratios that were not included in the window optimization process. [Copyright &y& Elsevier]

Abstract: Autocorrelation infrared (ACIR) analysis is based upon the application of the autocorrelation function to standard Fourier transform infrared (FTIR) transmission spectra. We present a rigorous examination of the effect of experimental parameters such as dilution ratio, spectral resolution, grinding time and pressing conditions upon the ACIR analysis of haematite. Results were found to vary by less than 4.5% irrespective of sample preparation, instrumental and data collection parameters. For a series of perovskite samples, the relationship between the measured effective linewidth and material composition appears to be reproducible, even though the absolute magnitudes of Δcorr values do not. Our results further indicate that the ACIR technique is indeed valid for comparative analysis of synthetic sample sequences that vary slightly in composition or structural state, provided that primary spectra are all recorded by the same instrument. [Copyright &y& Elsevier]

Abstract: A rapid and highly sensitive trace analysis technique for determining malachite green (MG) in a polydimethylsiloxane (PDMS) microfluidic sensor was investigated using surface-enhanced Raman spectroscopy (SERS). A zigzag-shaped PDMS microfluidic channel was fabricated for efficient mixing between MG analytes and aggregated silver colloids. Under the optimal condition of flow velocity, MG molecules were effectively adsorbed onto silver nanoparticles while flowing along the upper and lower zigzag-shaped PDMS channel. A quantitative analysis of MG was performed based on the measured peak height at 1615cm−1 in its SERS spectrum. The limit of detection, using the SERS microfluidic sensor, was found to be below the 1–2ppb level and this low detection limit is comparable to the result of the LC-Mass detection method. In the present study, we introduce a new conceptual detection technology, using a SERS microfluidic sensor, for the highly sensitive trace analysis of MG in water. [Copyright &y& Elsevier]

Abstract: An alternative fast and non-destructive validated Raman spectroscopic analytical procedure, requiring no sample preparation, was compared with the industrially applied HPLC reference method (Pfizer Manufacturing Belgium) for the quantitative determination of medroxyprogesterone acetate (MPA) in DepoProvera® suspensions (150mgmL−1, Pfizer). The Raman calibration model was developed by plotting the peak intensity of the baseline-corrected and normalized spectral band (corrected by external standard measurements) between 1595 and 1620cm−1 against known MPA concentrations in standards. At this band, no spectral interferences from the suspension medium are observed. The most suitable model for the calibration data (straight line or higher order polynomial) was determined by evaluating the fit and predictive properties of the models. In a second step, the developed Raman spectroscopic analytical method was validated by calculating the accuracy profile on the basis of the analysis results of validation samples. Furthermore, based on the data of the accuracy profile, the measurement uncertainty was determined. Finally, as the aim of the alternative method is to replace the destructive, time-consuming HPLC method, requiring sample preparation, it needs to be demonstrated that the new Raman method performs at least as good as the HPLC method. Therefore, the performance (precision and bias) of both methods was compared. A second order polynomial calibration curve through the calibration data supplies the best predictive properties and gives an acceptable fit. From the accuracy profile, it was concluded that at the target concentration (150mgmL−1), 95 out 100 future routine measurements will be included within the acceptance limits (5%). Comparison of the alternative method with the reference method at the target concentration indicates that the Raman method performs at least as good as the HPLC method for precision (repeatability and intermediate precision) and bias. The fast and non-destructive Raman method hence provides an alternative for the destructive and time-consuming HPLC procedure. [Copyright &y& Elsevier]

Abstract: Developing a simple and fast method to analyze possibly adulterated synthetic drugs in suspected herbal medicines (HM) is both methodologically and commercially significant. This paper constructs a new approach named local straight-line screening (LSLS), to the solution of the problem, after carefully observing the characteristics of the spectral line shapes. LSLS can be applied to both the qualitative and quantitative analysis of suspected HM, based solely on infrared spectrum of the possible synthetic drug and the suspected HM without any sample pretreatment. The concept and the application of the method are exemplified by analysis of sibutramine hydrochloride (SH), an anti-obesity medicine, adulterated in some commercially available HM-based diet pills, and compared with MSFDSS, and SNICA methods. The results show that, despite highly overlapping spectra and unresolved data, it is possible with LSLS to obtain an accurate discrimination and determination of SH in the HM-based diet pills. This allows the method to be potentially used in the primary screening of other synthetic drugs suspiciously adulterated in HM, with high rapidity, accuracy and cost-effectiveness. [Copyright &y& Elsevier]

Abstract: Many studies have reported the use of near infrared (NIR) spectroscopy to characterize wines or to predict wine chemical composition. However, little is known about the effect of variation in temperature on the NIR spectrum of wine and the subsequent effect on the performance of calibrations used to measure chemical composition. Several parameters influence the spectra of organic molecules in the NIR region, with temperature being one of the most important factors affecting the vibration intensity and frequency of molecular bonds. Wine is a complex mixture of chemical components (e.g. water, sugars, organic acids, and ethanol), and a simple ethanol and water model solution cannot be used to study the possible effects of temperature variations in the NIR spectrum of wine. Ten red and 10 white wines were scanned in triplicate at six different temperatures (25°C, 30°C, 35°C, 40°C, 45°C and 50°C) in the visible (vis) and NIR regions (400–2500nm) in a monochromator instrument in transmission mode (1mm path length). Principal component analysis (PCA) and partial least squares (PLS) regression models were developed using full cross validation (leave-one-out). These models were used to interpret the spectra and to develop calibrations for alcohol, sugars (glucose+fructose) and pH at different temperatures. The results showed that differences in the spectra around 970nm and 1400nm, related to O were observed for both varieties. Additionally an effect of temperature on the vis region of red wine spectra was observed. The standard error of cross validation (SECV) achieved for the PLS calibration models tended to inverse as the temperature increased. The practical implication of this study it is recommended that the temperature of scanning for wine analysis using a 1mm path length cuvette should be between 30°C and 35°C. [Copyright &y& Elsevier]

Abstract: This paper proposes a method for determination of chemical oxygen demand (COD) in domestic wastewater. The proposed method is based on near-infrared reflectance (NIRR) measurements of seston collected from wastewater samples by filtration. The analysis does not require any special reagent, catalyst or solvent. Inherent baseline and noise features present in NIRR spectra are removed by a Savitzky–Golay derivative procedure followed by wavelet denoising. The resulting wavelet approximation coefficients are used for partial-least-squares modelling and subsequent prediction of COD values in new samples. The model is calibrated by using COD values obtained according to the American Public Health Association (APHA) reference method. The proposed method is applied to effluent samples from the anaerobic ponds of the Mangabeira municipal wastewater treatment plant in the city of João Pessoa (Paraíba, Brazil). By comparing the NIRR prediction results with the APHA reference values, a root-mean-square error of prediction (RMSEP) of 19mgO2 L−1 and a correlation of 0.97 were obtained. Such results are deemed adequate in view of the joint estimate of the standard error of the reference method, which was calculated as 21mgO2 L−1. [Copyright &y& Elsevier]

Abstract: Dithizone-impregnated admicelles were prepared by mixing silica particles with dithizone and cetyltrimethylammonium chloride in 0.1molL−1 aqueous ammonia. The resulting admicelles were added to 1000mL of sample solution and dispersed by stirring for 15min. Traces of Ni(II), Cu(II), Ga(III), Cd(II), Pb(II) and Bi(III) in the solution were simultaneously incorporated into the admicelles at pH 7.5–9. With the aid of a rising stream of numerous tiny bubbles, the admicelles were floated on the solution surface and collected in a small sampling vessel by suction. The metals were desorbed from the admicelles with dilute nitric acid and determined by inductively coupled plasma-mass spectrometry. The proposed method offered a 100-fold multielement preconcentration and it was applicable to the analysis of river and pond waters. [Copyright &y& Elsevier]

Abstract: 27Al NMR spectroscopy is a power tool for investigation of the aluminate species existing in both aqueous and non-aqueous solutions. Aluminum-27 nuclear magnetic resonance (NMR) spectroscopy also can be used to determine thermodynamic properties of complexes in the solution. In this report, 27Al NMR spectroscopy was used to characterize species present in alkaline alcoholic aluminate solutions. (2-Hydroxyethyl)trimethylammonium (2-EHTMA) hydroxide was used as base. In solution of CH3OH and H2O in a mole ratio of 64:1 it was possible to detect five signals by aluminum-27 NMR, indicating formation of [Al(OH)4−n (CH3OH) n ](n−1)+ (n =0,1, 2, 3 and 4) species. Aluminum-27 NMR spectroscopy has also used for investigation of the species present in the ethanolic 2-HETMA aluminate solutions. The equilibrium constants for the formation of aluminate complexes were also determined for both methanolic and ethanolic aluminate solutions. Aluminum-27 NMR spectra of propanolic and butanolic 2-HETMA aluminate solutions were also studied. [Copyright &y& Elsevier]

Abstract: The use of gestagens in animal fattening is prohibited within the European Union. Recently, the use of spectrometric methods for the detection and confirmation of banned substances was made obligatory. Therefore, conventional high-performance liquid chromatographic (HPLC) methods have been superseded. It has been possible to couple a previously described HPLC method for the determination of acetyl-gestagens in kidney fat to tandem mass spectrometry (LC-MS/MS). The decision limits CCα and the detection capability CCβ are found to be below the minimum required performance limit (MRPL) established for medroxyprogesterone acetate (MPA) at 1μgkg−1. The calculated values for CCα are as follows: megestrol acetate (MGA)—0.15μgkg−1, melengesterol acetate (MLA)—0.15μgkg−1, chlormadinone acetate (CMA)—0.37μgkg−1 and for medroxyprogesterone acetate (MPA)—0.24μgkg−1. The CCβ values for these compounds have been determined as 0.19, 0.19, 0.47 and 0.32μgkg−1, respectively. [Copyright &y& Elsevier]

Abstract: In animal production, it is consolidated the synthesis and the illegal use of growth promoters of new generation, able to skip routine screening and confirmatory analysis. In this work it is reported the nuclear magnetic resonance (NMR) and the mass spectrometry identification of a probable new adrenergic drug found in a feed premix. The substance was selectively purified on alpha 1 acid glycoprotein affinity columns; then its structure was first achieved by recording the 13C NMR spectrum that gave the total number of carbons of the molecule, successively sorted by DEPT experiments into quaternary, CH, CH2, and CH3 groups. However, the complete assignments of all resonances were derived from the bi-dimensional analysis and the crucial indications from the 1H–13C reverse experiments. Further characterisation was performed by atmospheric pressure chemical ionisation both in positive and negative ion mode, matching the molecular ion and the fragmentation pattern with those of most recently described new adrenergic agonists. After the loss of a ter-butylic group, the structure shows an internal symmetry along with the presence of Chlorine clusters. The proposed formula of the compound, the 8,8′-diamino-9,9′-dichloro-1-terbutyl-1,1′,4,4-tetrahydro-5H,5′H-2,2′-bi-1-benzazepine-5,5′-dione, partially resembles that of Zilpaterol for the presence of a heterocyclic ring; Further work is in progress to characterise the structure–activity relationship. [Copyright &y& Elsevier]

Abstract: In this study, we explore Raman spectra of bacteria for their biochemical information. Therefore, a database of biomolecules was used and several approaches were applied such as the study of difference spectra, the calculation dot products, the usage of coefficients obtained from an EMSC procedure and the application of 2D correlation spectroscopy. These methods were applied on a dataset containing Raman spectra of Cupriavidus metallidurans LMG 1195 in five stages of its growth, aiming to extract information about the evolution of cell components during growth. EMSC coefficients seemed to be most promising for tracking metabolic products and the results were often confirmed by difference spectra or by 2D correlation spectroscopy. [Copyright &y& Elsevier]

Abstract: Multivariate curve resolution with alternating least squares (MCR-ALS) is applied for the first time to the simultaneous analysis of electrochemical and spectroscopic data. Then, a data analysis is done with augmented matrices constituted by Differential Pulse Polarography and Circular Dichroism data submatrices. The use of proper, and different for each submatrix, constrains in the iterative ALS optimization allows to obtain chemically meaningful results constituted by a common matrix containing the concentration profiles, and two matrices with the pure electrochemical and spectroscopic signals. MCR-ALS is applied to the study of the complexation of Cd by Cys-Gly, a glutathione-fragment of great interest for understanding metal-phytochelatins complexation. [Copyright &y& Elsevier]

Abstract: This study deals with an automated data analysis strategy to pinpoint potential unknown compounds in full scan mass spectrometry (MS) experiments. Three examples of an untargeted metabolomics approach to contaminant analysis are given. By comparing a plant-oil based hormone cocktail to 90 plant oil samples ca. 25 compounds specific to the hormone cocktail could be detected. Five of these compounds were confirmed as steroid hormones. A comparison of a drink water sample from a farm to distillated water showed the presence of contaminants specific to this drink water sample. A grass sample, which was known to give a false positive result in a DR-CALUX bioassay, was unexpectedly shown to contain an abnormal level of chrysene, which was obviously not eliminated during clean-up. [Copyright &y& Elsevier]

Abstract: The applicability of the headspace coupled to mass spectrometry for evaluation of the sensory quality of virgin olive oil samples is presented. The volatiles of the oil are directly transferred from the sample vial to the detector without chromatographic separation. The mass spectrum obtained can be considered as a fingerprint of the oil sample and can be used for classification purposes. After a training step with samples previously qualified following the official method, a classification model was created using the supervised technique soft independent modeling of class analogy (SIMCA). Eight negative (rancid, winey-vinegary, muddy sediment, hay-wood, vegetable water, earthy, fusty and musty-humidity) and three principal positive attributes (fruity, bitter and pungent) have been included in this study. With them, a classification model consisting of two main classes (extra- and lampante-virgin olive oil) was constructed. In addition, the unsupervised technique cluster analysis permited the discrimination among oils with different negative attributes. The proposed procedure has been applied to the classification of commercial samples (as extra- or lampante-virgin olive oils) and the results were compared with those provided by the expert''s panel with acceptable correlation. [Copyright &y& Elsevier]

Abstract: Hemoglobin-based oxygen carriers (HBOCs) are blood substitutes based on hemoglobin of either bovine or human origin and they can potentially be misused in elite sports to improve endurance performance. Recently, three methods have been proposed in doping control analysis to allow HBOCs screening and identification by application of electrophoresis, size-exclusion chromatography coupled with HPLC and LC coupled with tandem mass spectrometry (LC/MSMS). In view of the Athens 2004 Olympic Games, modifications were introduced in order to increase the specificity of these methods. The sample preparation protocols of the electrophoretic and SEC–HPLC methods were modified with the introduction of sequential ultra filtration steps to remove all heme containing material below 100kDa, thus leaving only HBOCs material for analysis. Furthermore, a modification of the LC/MSMS methodology was introduced to allow full scan MS–MS spectra of peptide segments arising from the tryptic digestion of bovine HBOCs. These relatively simple methodological modifications have major impact, as far as time and cost effectiveness is concerned in doping control procedures, because they provide a useful tool in order to identify which suspect samples from the initial visual screening are due to hemolysis and exclude them from further analysis. [Copyright &y& Elsevier]

Abstract: Accurate bacterial identification is important in diagnosing disease and in microbial forensics. Coxiella burnetii, a highly infective microorganism causative of the human disease Q fever, is now considered a U.S. category B potential bioterrorism agent. We report here an approach for the confirmatory identification of C. burnetii at the strain level which involves the combined use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and supervised pattern recognition via Partial Least Squares-Discriminant Analysis (PLS-DA). C. burnetii isolates investigated in this study included the following prototype strains from different geographical and/or historical origins and with different antigenic properties: Nine Mile I, Australian QD, M44, KAV, PAV, Henzerling, and Ohio. After culture and purification following standard protocols, linear MALDI-TOF mass spectra of pure bacterial cultures were acquired in positive ion mode. Mass spectral data were normalized, baseline-corrected, denoised, binarized and modeled by PLS-DA under crossvalidation conditions. Robustness with respect to uncontrolled variations in the sample preparation and MALDI analysis protocol was assessed by repeating the experiment on five different days spanning a period of 6 months. The method was validated by the prediction of unknown C. burnetii samples in an independent test set with 100% sensitivity and specificity for five out of six strain classes. [Copyright &y& Elsevier]

Abstract: Cylindrospermopsin (CYN) was determined by liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) using 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) as the internal standard. In the selected ion monitoring of LC/ESI-MS, m/z 414 for CYN and 237 for HEPES were monitored using the negative mode; the retention times of CYN and HEPES were 12.41 and 14.21min, respectively. CYN was determined from peak area ratios of m/z 414/237. By the treatment of an anion exchange cartridge using a buffer at pH 10.5, CYN was isolated and condensed. No interfering peak was observed. Linearity of this method was observed at the range of 0.10–31.12ng. Total coefficients of variation were 5.1 and 2.9% at 104 and 1038μgCYNL−1. The quantitative limit at a signal-to-noise (S/N) ratio of 10 was 0.16ng. CYN concentration in natural waters is low. CYN in waters should be condensed for determination. This method including the treatment for isolation and condensation of CYN is useful for determination of CYN in environmental and/or drinking waters. [Copyright &y& Elsevier]

Abstract: This paper presents the development of a new, rapid and precise analytical method for submicrogram levels of nitrate (NO3 −) in environmental samples like soil, dry deposit samples, and coarse and fine aerosol particles. The determination of submicrogram levels of nitrate is based on the selection of a quantitative analytical peak at 1385cm−1 among the three observed vibrational peaks and preparing calibration curves using different known concentrations of nitrate by diffuse reflectance Fourier transform infra red spectrometric (DRIFTS) technique. Pre-weighed and ground infrared (IR) grade KBr was used as substrate over which remarkably wide range of known concentration of nitrate was sprayed and dried. The dried sample was analyzed by DRIFTS and absorbance was measured. Eight calibration curves for four different concentration ranges of nitrate for absorbance as well as peak area were prepared for samples containing lower and relatively higher values of nitrate. The relative standard deviation (n =8) for the nitrate concentration ranges, 0.05–40, 0.05–1.5, 1.5–25, 5–40μg/0.1gKBr were in the range 1.6–2.3% for the above calibration curves. The limit of detection (LOD) of the method is 0.07μgg−1 NO3 −. The F- and t-tests were performed to check the analytical quality assurance test. The noteworthy feature of the reported method is the noninterference of any of the associated cations. The results were compared with that of ion-chromatographic method with high degree of acceptability. The method can be applied in wide concentration ranges. The method is reagent less, nondestructive, very fast, repeatable, and accurate and has high sample throughput value. [Copyright &y& Elsevier]

Abstract: Direct orthogonal signal correction (DOSC) is applied to correct for major variance sources such as temperature effects, time influences and instrumental differences in near infrared (NIR) data. The samples analysed are creams containing different concentrations of an active drug. The final aim is to classify the samples according to their concentration of active compound. Having performed DOSC on the data, it is not necessary anymore to apply sophisticated chemometric techniques to correct for temperature or time effects and to attribute the samples to their respective concentration classes. Moreover, the application of DOSC on the NIR spectra recorded on two different instruments shows that this method can be considered as a valuable alternative for the standardisation in classification applications. Since the applied algorithm tends to overfit, in a second part of this paper, a comparison is made with an algorithm designed by Westerhuis, which should overcome this problem. Although the calibration set results show that the overfitting has been partially corrected for by the latter algorithm, the test set results did not improve significantly. [Copyright &y& Elsevier]

Abstract: The objective of this study was to investigate intrinsic fluorophores of thick albumen and egg yolk in order to assess egg freshness during storage at a temperature of 12.2°C and 87% relative humidity (RH). A total of 126 intact brown-shelled eggs of the same flock (29 weeks of age) were stored for 1, 6, 8, 12, 15, 20, 22, 26, 29, 33, 40, 47 and 55 days. The emission fluorescence spectra of aromatic amino acids and nucleic acids (AAA+NA) (excitation: 250nm; emission: 280–450nm), fluorescent Maillard reaction products (FMRP) (excitation: 360nm; emission: 380–580nm) and the excitation spectra of vitamin A (emission: 410nm; excitation: 270–350nm) were scanned on thick albumen and egg yolk. Among the intrinsic fluorophores, only the principal component analysis (PCA) applied on the vitamin A fluorescence spectra allowed a good identification of eggs as a function of their storage time. Factorial discriminant analysis (FDA) was then applied on the first five principal components (PCs) of the PCA applied on each spectral data set. Regarding AAA+NA recorded on thick albumen, correct classification of 69.4% and 63.9% was observed for the calibration and validation sets, respectively. Quite similar results were obtained on AAA+NA scanned on egg yolks. The best results were obtained with vitamin A fluorescence spectra since 97.7% and 85.7% of the calibration and validation sets was obtained, respectively. These results showed that vitamin A fluorescence spectra provide useful fingerprints, mainly allow the identification of eggs during storage and could be considered as a powerful intrinsic probe for the evaluation of egg freshness. [Copyright &y& Elsevier]

Abstract: This work describes the utilization of the focused microwave-assisted micellar extraction in combination with the solid-phase microextraction (SPME) to determine chlorophenols in wood samples. The influence of the nature of the surfactant in the extraction process, the optimization of the variables of the focused-microwave system, and the effect of the ageing time of the samples in the extraction efficiency of the method, have been assessed in this study. The overall method using the non-ionic surfactant POLE as extracting medium allows us to determine chlorophenols in wood samples achieving an average extraction efficiency of 104.1%, limits of detection ranging from 2 to 120ngg−1, and intermediate precision values ranging between 3.5 and 13.2%. The proposed method is also characterized by short analysis times (around 5min for the microwaves extraction step) and by avoiding the use of organic solvents. [Copyright &y& Elsevier]

Abstract: Near infrared spectroscopy (NIRS) was used in combination with partial least squares (PLS) calibration to determine low concentrated analytes. The effect of the orthogonal signal correction (OSC) and net analyte signal (NAS) pretreatments on the models obtained at concentrations of analyte near its detection limit was studied. Both pretreatments were found to accurately resolve the analyte signal and allow the construction of PLS models from a reduced number of factors; however, they provided no substantial advantage in terms of %RSE for the prediction samples. Multiple methodologies for the estimation of detection limits could be found in the bibliography. Nevertheless, detection limits were determined by a multivariate method based on the sample-specific standard error for PLS regression, and compared with the univariate method endorsed by ISO 11483. The two methods gave similar results, both being effective for the intended purpose of estimating detection limits for PLS models. Although OSC and NAS allow isolating the analyte signal from the matrix signal, they provide no substantial improvement in terms of detection limits. The proposed method was used to the determine 2-ethylhexanol at concentrations from 20 to 1600ppm in an industrial ester. The detection limit obtained, round 100ppm, testifies to the ability of NIR spectroscopy to detect low concentrated analytes. [Copyright &y& Elsevier]

Abstract: Laser-induced breakdown spectroscopy (LIBS), combined with a flow-injection system, is demonstrated to analyze liquid droplets of aluminum salt, as generated with an electrospray ionization device. The spray needle also serves as the anode, through which the analyte solution is spread toward the other metal base as the cathode. Along the passage of the FI manifold, the Al-sample loading speed is controlled at 0.15mLmin−1, restricted to the small diameter of the spray needle, and the loading volume amounts to 0.1mL. The metal ion is retained in a cation-exchange resin microcolumn immobilized with Chromotrope 2B chelating agent, followed by elution with a 0.5M HCl solution into LIBS. Upon laser irradiation at the preconcentrated liquid droplets, the time-resolved laser-induced breakdown (LIB) emission and plasma-induced current signals are acquired concurrently on a single-shot basis. The area under the LIB/current distribution increases in linear proportion as the concentration of the sample solution increases. The detection limit thus obtained can reach 1.5mgL−1, about an order of magnitude lower than those achieved previously using single-laser ablation without involvement of preconcentration. The linear dynamic range is more than two orders of magnitude. [Copyright &y& Elsevier]

Abstract: An attenuated total reflectance Fourier transform infrared spectroscopy technique has been developed utilizing an oxide coated internal reflection element to quantitatively evaluate the concentrations of three inorganic oxoanions, arsenate, sulfate, and selenate, at environmentally significant levels. Two iron oxide coatings, goethite and an iron sol–gel, were used and compared to an uncoated internal reflection element which typically has a limit of detection around 1.0mM. The goethite coating improved the limits of detection by factors of 45.6 and 137.0 for arsenate and sulfate as compared to an uncoated cell. The iron sol coating improved the limits of detection by factors of 481.2, 156.2, and 114.0 for arsenate, sulfate, and selenate, respectively. [Copyright &y& Elsevier]

Abstract: Bile acid-based polymers are promising new materials for biomedical applications. The determination of their molar mass, as for other novel polymers, has been difficult, due to the lack of suitable standards for size exclusion chromatography (SEC). In order to solve this problem, a family of main-chain bile acid-based oligo-esters has been synthesized by acyclic diene metathesis to be used as analogues in such analysis. These oligomers have been characterized by SEC, MALDI-TOF mass spectrometry and NMR spectroscopy. The results show that SEC with polystyrene standards tends to overestimate the molar mass of these materials and that a correction factor between 0.50 and 0.60 should be used for more accuracy. [Copyright &y& Elsevier]

Abstract: Transparent, pyridine-functionalized sol–gel monoliths have been formed and their use in Cr(VI) sensing applications is demonstrated. The monoliths were immersed in acidic Cr(VI)-containing solutions, and the Cr(VI) uptake was monitored using UV–vis and atomic absorption spectroscopies. At concentrations at the ppm level, the monoliths exhibit a yellow color change characteristic of Cr(VI) uptake, and this can be measured by monitoring the absorption change at about 350nm using UV–vis spectroscopy. Concentrations at the ppb level are below the limit of detection using this wavelength of 350nm for measurement. However, by adding a diphenylcarbazide solution to monoliths that have been previously immersed in ppb-level Cr(VI) solutions, a distinct color change takes place within the gels that can be measured at about 540nm using UV–vis spectroscopy. Concentrations as low as 10ppb Cr(VI) can be measured using this method. The monoliths can then be regenerated for subsequent sensing cycles by thorough washing with 6.0M HCl. The factors affecting monolith uptake of Cr(VI) have been explored. In addition, the gels have been characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) measurements. [Copyright &y& Elsevier]

Abstract: The aim of this study was to evaluate the performance characteristics of the recently developed super elastic solid-phase microextraction (SPME) fibers. The fiber needle, plunger and fiber core are manufactured with a special type of flexible alloy that exhibits excellent shape memory and tensile strength. This material makes the assemblies more robust, permitting several hundreds of analyses in a sequence, which is one of the ways to improve the robustness and sample throughput of automated SPME methods. The design and size of the needle utilized in the new fiber assemblies is discussed here, as well as the use of a septum-free injector replacement and a low-volume direct injection glass liner placed in the GC inlet. Deionized water and pump oil samples spiked with target volatile compounds (McReynold''s probes and toluene) were used for the purposes of the presented study. A fully automated SPME sample preparation technique was combined with the GC–TOFMS system for the chromatographic separation and identification/quantification of the target analytes. [Copyright &y& Elsevier]

Abstract: Molecularly imprinted polymers capable of sensing organophosphorous compounds by luminescence have been prepared by reversible addition fragmentation chain transfer (RAFT) polymerization. The polymer contained a dithiobenzoate substituted tris(β-diketonate) europium(III) complex which served as a polymerization substrate and as a luminescent binding site for pinacolyl methylphosphonate (PMP), the hydrolysis product of the nerve agent Soman. The resultant polymer allowed quantitation of PMP in the low ppb range with minimal interference from similar compounds. Polymers were characterized by luminescence spectroscopy and scanning electron microscopy. [Copyright &y& Elsevier]

Abstract: The compatibility Teflon-AF 2400 liquid core optical fibre with resonance Raman spectroscopy (RRS-LCOF) was used to detect aqueous biomolecules. The maximum sensitivity enhancement factor for concentrations greater than the detection limit in a conventional cell was 10, and detection limit reduction of about 1000-fold have been achieved for the measurement of aqueous absorbing sample using Teflon-AF 2400 fibre Raman cell compared to the conventional cell. We were able to collect spectra of 2.5×10−9 and 2.5×10−10 M aqueous β-carotene using 16.2mW of laser power and 10s integration time. This volume of a 2.5×10−10 M aqueous solution corresponds to only 1.5fmol or 830fg of β-carotene. The results of this preliminary study indicate that RRS-LCOF has potential in bioanalytical and biomedical applications. [Copyright &y& Elsevier]