Effect of fatty acids on self-assembly of soybean lecithin systems.

With the increasing interest in natural formulations for drug administration and functional foods, it is desirable a good knowledge of the phase behavior of lecithin/fatty acid formulations. Phase structure and properties of ternary lecithin/fatty acids/water systems are studied at 37°C, making emphasis in regions with relatively low water and fatty acid content. The effect of fatty acid saturation degree on the phase microstructure is studied by comparing a fully saturated (palmitic acid, C16:0), monounsaturated (oleic acid, C18:1), and diunsaturated (linoleic acid, C18:2) fatty acids.

Anthropological study of ear tubercles in a Spanish sample.

The ear has been used since the 19th century as a valuable instrument in personal identification. Its special interest is due to the morphological complexity of the structures involved. The aim of the present investigation is to establish the morphological variability of the helix tubercles in a sample of the Spanish European population (303 individuals between 18 and 72 years old).

Micro-injector for capillary electrophoresis.

A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary.

Concurrent determination of anions and cations in consumer fireworks with a portable dual-capillary electrophoresis system.

A new automated portable dual-channel capillary electrophoresis instrument was built and applied to the concurrent determination of cations and anions. The system uses a single buffer and hydrodynamic injection of the sample is performed autonomously. A novel engraved flow-cell interface is used at the injection ends of the capillaries allowing the autonomous operation of the system.

Near infrared spectral imaging for the analysis of dynamite residues on human handprints.

This study examines the utility of near infrared hyperspectral imaging (NIR-HSI) combined with chemometrics for the detection of dynamite residues on human handprints. Polyvinyl sheets containing dynamite residues were then analysed with the NIR-HSI system. A spectral library was developed by using partial least squares-discriminant analysis model (PLS-DA) to detect and classify the pixels contaminated with the dynamite residues.

Detection of residues from explosive manipulation by near infrared hyperspectral imaging: a promising forensic tool.

In this study near infrared hyperspectral imaging (NIR-HSI) is used to provide a fast, non-contact, non-invasive and non-destructive method for the analysis of explosive residues on human handprints. Volunteers manipulated individually each of these explosives and after deposited their handprints on plastic sheets. For this purpose, classical explosives, potentially used as part of improvised explosive devices (IEDs) as ammonium nitrate, blackpowder, single- and double-base smokeless gunpowders and dynamite were studied.

Analysis and differentiation of paper samples by capillary electrophoresis and multivariate analysis.

This work reports an investigation for the analysis of different paper samples using CE with laser-induced detection. Papers from four different manufactures (white-copy paper) and four different paper sources (white and recycled-copy papers, adhesive yellow paper notes and restaurant serviettes) were pulverized by scratching with a surgical scalpel prior to their derivatization with a fluorescent labeling agent, 8-aminopyrene-1,3,6-trisulfonic acid. Methodological conditions were evaluated, specifically the derivatization conditions with the aim to achieve the best S/N signals and the separation conditions in order to obtain optimum values of sensitivity and reproducibility.

Electrophoretic fingerprinting of benzodiazepine tablets in spike drinks.

Over the last few years, there has been an increase in the reports of drug-facilitated crimes. The list of drugs associated with these crimes is extensive and benzodiazepines constitute one of the groups of substances more commonly used. The sedative properties, which characterize benzodiazepines, are enhanced when such drugs are combined with alcohol, being more attractive for committing these types of crimes.

Anions in pre- and post-blast consumer fireworks by capillary electrophoresis.

Consumer fireworks are a heterogeneous group of pyrotechnic items widely used by citizens around the world. There are a wide number of forensic cases related to consumer fireworks that require knowing their chemical composition and variety of designs to conduct accurate and comprehensive analyses. In this research paper, a selection of six consumer firework types (firecracker, rocket, pyrotechnic fountain, pyrotechnic battery, sparkler, and smoke bomb) is physically described and their anionic compositions are determined.

Rapid determination of scopolamine in evidence of recreational and predatory use.

In recent years, scopolamine has become a drug of common use for recreational and predatory purposes and several ways of administration have been devised. A method for the rapid analysis of suspicious samples was developed, using a portable capillary electrophoresis with contactless conductivity detection. The method allows the separation of scopolamine from atropine which has a similar structure and is present along with scopolamine in some samples.

Discrimination of non-explosive and explosive samples through nitrocellulose fingerprints obtained by capillary electrophoresis.

This work is focused on a novel procedure to discriminate nitrocellulose-based samples with non-explosive and explosive properties. The nitrocellulose study has been scarcely approached in the literature due to its special polymeric properties such as its high molar mass and complex chemical and structural characteristics. These properties require the nitrocellulose analysis to be performed by using a few organic solvents and in consequence, they limit the number of adequate analytical techniques for its study.

Determination of ethylene glycol dinitrate in dynamites using HPLC: application to the plastic explosive Goma-2 ECO.

In this study, a sequential extraction method using water and methanol to recover ethylene glycol dinitrate or nitroglycol (EGDN) contained in Goma-2 ECO dynamite was developed. After, an HPLC method was used for the determination of EGDN in the two extracted phases. The analytical method was validated by evaluating its selectivity, sensitivity, linearity, and linear working concentration range, limit of detection and quantitation, precision (as repeatability and intermediate precision), accuracy, and robustness, providing appropriate values (i.

Why is methenamine detected in Goma-2 dynamites originally methenamine free? An interpretation of relevant forensic results.

After the train bombing in Madrid (Spain) on 11 March 2004, methenamine was detected in some of the specimens of Goma-2 ECO dynamite submitted to the forensic laboratories when analyzed by gas chromatography coupled with mass spectrometry detection (GC-MS). Methenamine is synthesized from formaldehyde and ammonia through a condensation reaction. However, neither methenamine nor any of these compounds were used to manufacture Goma-2 ECO dynamite.

New protocol for the isolation of nitrocellulose from gunpowders: utility in their identification.

In this work, a new approach for the isolation of nitrocellulose from smokeless gunpowders has been developed. A multistep solvent extraction method was needed to purify nitrocellulose contained in gunpowders. For single-base or double-base gunpowders six consecutive solvent extractions were selected: three extractions with methanol (to remove nitroglycerin, 2,4-dinitrotoluene, ethyl-centralite, diphenylamine, and diphenylamine derivatives); one extraction with dichloromethane (to remove colorants and plasticizers of organic nature); one extraction with methanol (to facilitate a final polar extraction); and one extraction with water (to remove ionic components) were necessary at 35 degrees C.