Chemometrics-enhanced fiber optic Raman detection, discrimination and quantification of chemical agents simulants concealed in commercial bottles

Chemical sensing of common microorganisms found in biopharmaceutical industries using MIR laser spectroscopy and multivariate analysis

Mid-infrared laser spectroscopy was used to investigate common bacteria encountered in biopharmaceutical industries. The study involved the detection of bacteria using quantum cascade laser spectroscopy coupled to a grazing angle probe (QCL-GAP). Substrates similar to surfaces commonly used in biopharmaceutical industries were used as support media for the samples. Reflectance measurements were assisted by Multivariate Analysis (MVA) to assemble a powerful spectroscopic technique with classification and identification resources. The species analyzed, Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus, were used to challenge the technique's capability to discriminate from microorganisms of the same family. Principal Components Analysis and Partial Least Squares-Discriminant Analysis differentiated between the bacterial species, using QCL-GAP-MVA as the reference. Spectral differences in the bacterial membrane were used to determine if these microorganisms were present in the samples analyzed. Results herein provided effective discrimination for the bacteria under study with high sensitivity and specificity.

Detection Papers with Metal Complexes with Triphenylmethane Dyes for the Detection of G-Series Nerve Agents (Sarin, Soman, Cyclosarin) in the Liquid Phase

The paper presents the results of the study of the possibilities of using color metal complexes to detect the presence of chemical warfare agents (CWA) in liquid or aerosol form. Aluminon/Fe3+ and Eriochrome Cyanine R/Cu2+ coordination complexes and their ability to detect CWA in liquid phase are discussed. Detection systems have been demonstrated on instances of simple detection papers exposed to drops of real CWAs. Detection papers showed a positive response to G-series nerve agents and vesicant lewisite. Other liquid CWA do not interfere and the systems are also resistant to common organic solvents and a wide range of industrial chemicals.

Analysis of the Precursors, Simulants and Degradation Products of Chemical Warfare Agents

Recent advances in analysis of precursors, simulants and degradation products of chemical warfare agents (CWA) are reviewed. Fast and reliable analysis of precursors, simulants and CWA degradation products is extremely important at a time, when more and more terrorist groups and radical non-state organizations use or plan to use chemical weapons to achieve their own psychological, political and military goals. The review covers the open source literature analysis after the time, when the chemical weapons convention had come into force (1997). The authors stated that during last 15 years increased number of laboratories are focused not only on trace analysis of CWA (mostly nerve and blister agents) in environmental and biological samples, but the growing number of research are devoted to instrumental analysis of precursors and degradation products of these substances. The identification of low-level concentration of CWA degradation products is often more important and difficult than the original CWA, because of lower level of concentration and a very large number of compounds present in environmental and biological samples. Many of them are hydrolysis products and are present in samples in the ionic form. For this reason, two or three instrumental methods are used to perform a reliable analysis of these substances.

A hybrid LIBS-Raman system combined with chemometrics: an efficient tool for plastic identification and sorting

Classification of plastics is of great importance in the recycling industry as the littering of plastic wastes increases day by day as a result of its extensive use. In this paper, we demonstrate the efficacy of a combined laser-induced breakdown spectroscopy (LIBS)-Raman system for the rapid identification and classification of post-consumer plastics. The atomic information and molecular information of polyethylene terephthalate, polyethylene, polypropylene, and polystyrene were studied using plasma emission spectra and scattered signal obtained in the LIBS and Raman technique, respectively. The collected spectral features of the samples were analyzed using statistical tools (principal component analysis, Mahalanobis distance) to categorize the plastics. The analyses of the data clearly show that elemental information and molecular information obtained from these techniques are efficient for classification of plastics. In addition, the molecular information collected via Raman spectroscopy exhibits clearly distinct features for the transparent plastics (100% discrimination), whereas the LIBS technique shows better spectral feature differences for the colored samples. The study shows that the information obtained from these complementary techniques allows the complete classification of the plastic samples, irrespective of the color or additives. This work further throws some light on the fact that the potential limitations of any of these techniques for sample identification can be overcome by the complementarity of these two techniques. Graphical Abstract ᅟ.