Analysis of street cocaine samples in nasal fluid by Raman spectroscopy

The principal objective of this work was to demonstrate the capability of Raman spectroscopy to detectsmall amounts of cocaine in nasal fluid, and to identify the main drug and the most widely used cuttingagents. Initially, standard samples were analysed and sampling conditions were studied by comparingdifferent swabs used for the sample collection. Once the most appropriate swab was selected, whichpermitted a relatively simple detection of the standard cocaine hydrochloride, qualitative analyses of realsamples were carried out. Three street cocaine samples were analysed, and the presence of cuttingsubstances was highlighted by the appearance of different bands not corresponding to the ones of thestandard cocaine. To identify the substances present in each sample, the spectra of the street cocainesamples were collected and compared with a digital library created on purpose with the spectra of themost common cutting agents. In this case, correlation coefficients permitted to recognize the most importantsubstances presumably present in the samples, and gave an estimation of the purity of the cocaine.However, when nasal fluid was present, its strong signal could overlap or interfere with thesmaller signal of the cutting substances, hindering their identification

Spectroscopic trends for the determination of illicit drugs in oral fluid

The present work aims to review all of the articles published so far, focusedon the determination of drugs of abuse in oral fluid. This fluid provides a simpler,faster, and more controllable sampling in comparison with the other biological fluids,such as blood or urine. Actually, the main goal of the researchers is to lower the limitof detection (LOD) to detect quantities of drugs smaller than the cut-off limitsestablished by law for drug controls. Advances in Raman, infrared (IR), and nuclearmagnetic resonance (NMR) spectroscopy applications are discussed. SurfaceenhancedRaman spectroscopy (SERS) has been shown as the most sensitive techniquefor the detection of illicit drugs in oral fluid. The use of IR spectroscopy fordetermining drugs of abuse in oral fluid is growing, although the LODs obtained untilnow do not yet satisfy the necessities in the forensic field. Finally, NMR spectroscopyhas seldom been used to determine drugs in oral fluid. Another future trend seems tobe related with the use of portable instrumentation, which would allow us to performin-situ analysis. This last application seems to be particularly promising to performroadside drug tests and to identify overdose drugs in patients in emergency conditions

Recent advances in polymer-metallic composites for food packaging applications

Background: The use of metallic micro- and/or nanoparticles as inorganic fillers for the improvement of polymer properties is an active trend. This has led to the development of polymer-metallic composites with high potential to be applied in food packaging, due to the enhanced antimicrobial, gas barrier, light-blocking and antioxidant effect in addition to the polymer intrinsic properties. The increasing number of investigations of novel polymer-metallic composites with promising potential and/or already applied as food packaging has raised concern over their efficacy, but also toxicity and environmental impact. Scope and approach: In this review a critical evaluation of current investigations on polymer-metallic composites, as food packaging options, is assessed. This evaluation emphasizes the enhanced properties provided by the metallic fillers onto the polymer packaging itself, and indirectly in food shelf life, safety and quality. Moreover, awareness regarding the toxicity and environmental impact is also evaluated and related to the migration behaviour. Key findings and conclusions: Without question, the addition of these type of fillers has the enormous potential to enhance the package properties and, therefore, the food shelf life. Usually, their addition is made alone or in complementation with other fillers allowing a broad spectrum of enhanced properties in the composite film. Despite the advantages, special attention must be paid to the migration form of the filler, in the ionic or the particulate form, that is related to the toxicity and environmental impact of such materials. In overall, the strengths and weaknesses are critically organized, allowing guidance decisions on the implementation of such materials in food packaging.Diogo Videira-Quintela thanks the University of Alcalá for his PhD scholarship (FPI-UAH). This work was supported by the University of Alcalá [Grant No. CCG2018/EXP-039]; and the Ministry of Science and Innovation of Spain [Grant No. MAT2014-57557-R]

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. Phase determinations are based on a combination of polarized light microscopy and small-angle X-ray scattering measurements. Interestingly, unsaturated (oleic acid and linoleic acid) fatty acid destabilizes the lamellar bilayer. Slight differences are observed between the phase diagrams produced by the unsaturated ones: small lamellar, medium cubic and large hexagonal regions. A narrow isotropic fluid region also appears on the lecithin-fatty acid axis, up to 8. wt% water. In contrast, a marked difference in phase microsctructure was observed between unsaturated and saturated systems in which the cubic and isotropic fluid phases are not formed. These differences are, probably, a consequence of the high Krafft point of the C16 saturated chains that imply rather rigid chains. However, unsaturated fatty acids result in more flexible tails. The frequent presence of, at least, one unsaturated chain in phospholipids makes it very likely a better mixing situation than in the case of more rigid chains. This swelling potential favors the formation of reverse hexagonal, cubic, and micellar phases. Both unsaturated fatty acid systems evolve by aging, with a reduction of the extension of reverse hexagonal phase and migration of the cubic phase to lower fatty acid and water contents. The kinetic stability of the systems seems to be controlled by the unsaturation of fatty acids.Dr. C.A. Godoy is grateful for her scholarship to the Agencia Española de Cooperación Internacional para el Desarrollo (AECID), Universidad de Alcalá and Banco Santander, through the “Becas Miguel de Cervantes Saavedra” Program, and to the Universidad del Valle for the bibliographic resources provided. Jaume Caelles from the SAXS-WAXS service at IQAC is gratefully for performing the measurements. Imma Carrera is acknowledged for sample preparation. Ignacio Jiménez is grateful for helping in graph improvement.Peer reviewe

Antibacterial LDPE films for food packaging application filled with metal-fumed silica dual-side fillers

There is a paramount demand on the enhancement of plastic package properties to reduce food loss and waste. With this awareness, ternary composite films based on low density polyethylene (LDPE) reinforced with silver- (Ag/FS), copper- (Cu/FS) and copper hydroxynitrate-fumed silica (CuHS/FS) micron-sized dual-side fillers, were produced via melt-blending and compression molding techniques. The ternary films exhibited antibacterial activity against the foodborne pathogens Staphylococcus aureus and Salmonella enterica, showing a stronger effect in the LDPE-Cu/FS with a 0.3% and 30.9% survival ratio, followed by LDPE-CuHS/FS films with a 0.4% and 50.7%, respectively. The specific Cu migration presented a maximum value of 1.29 mg/ kg of food simulant, that is within the threshold limit established by current legislation for food contact materials, thus permitting their use as packaging films for acidic, alcoholic, and aqueous foodstuffs. This work presents the relevance of alternative fillers to produce active packaging products.The authors want to acknowledge Maria Eugenia Sotomayor for the "known-how" regarding the melt-blending process, and the EMSUR (Spain) company for the support in the investigation and as the polymer provider. Diogo Videira-Quintela thanks the University of Alcalá for his Ph.D. scholarship (FPI-UAH). This work was supported by the University of Alcalá [Grant No. CCG2018/EXP-039]; and the Ministry of Science and Innovation of Spain [Grant No. MAT2014-57557-R]

Structure and phase equilibria of the soybean lecithin/PEG 40 monostearate/water system

PEG stearates are extensively used as emulsifiers in many lipid-based formulations. However, the scheme of the principles of the lipid-surfactant polymer interactions are still poorly understood and need more studies. A new phase diagram of a lecithin/PEG 40 monostearate/water system at 30 C is reported. First, we have characterized the binary PEG 40 monostearate/water system by the determination of the critical micelle concentration value and the viscous properties. Then, the ternary phase behavior and the influence of phase structure on their macroscopic properties are studied by a combination of different techniques, namely, optical microscopy, small-angle X-ray scattering, differential scanning calorimetry, and rheology. The phase behavior is complex, and some samples evolve even at long times. The single monophasic regions correspond to micellar, swollen lamellar, and lamellar gel phases. The existence of extended areas of phase coexistence (hexagonal, cubic, and lamellar liquid crystalline phases) may be a consequence of the low miscibility of S40P in the lecithin bilayer as well as of the segregation of the phospholipid polydisperse hydrophobic chains. The presence of the PEG 40 monostearate has less effect in the transformation to the cubic phase for lecithin than that found in other systems with simple glycerol-based lipids.The authors are grateful to Professor Michael Gradzielski for contacting Evonic Goldschmidt GmbH, who supplied us the TEGO® Acid S40P reagent. Marta Rodriguez is gratefully acknowledged for preparing the samples for SAXS analysis and Jaume Caelles from the SAXSWAXS service at IQAC for performing the measurements. Professor Pilar Tarazona is gratefully acknowledged for allowing the use of DSC equipment and Dr. Natali Fernandez for training in that technique. G. Zhang grateful for the Erasmus mobility grant, and M. Díaz grateful for her scholarship to the Agencia Española de Cooperación Internacional para el Desarrollo (AECID), Universidad de Alcalá and Banco Santander, through the “Becas Miguel de Cervantes Saavedra” Program. This paper is dedicated to the memory of our dear Prof. Ali Khan, who was a master in phase behavior.Peer reviewe

Chemical classification of new psychoactive substances (NPS)

This work comprehensively reviews some fundamental concepts about drugs, especially focusing on new psychoactive substances (NPS), and their typical classifications based on either their effects (hallucinogens, stimulants or depressants), their origin (natural, synthetic, or semisynthetic), or legal situation (lawful, illicit, or unregulated). These classifications are highly useful in the medicine/legal field, but completely useless for the chemical determination of drugs. Hence, a classification of NPS based on their chemical composition is revised and discussed. This classification seeks to merge those recent and dispersed chemical groupings of NPS found in scientific literature and/or health/drugs reports from World/European/American Institutions facing the illicit use of drugs (WHO, UNODC, EMCDDA, OEDA, DEA, etc.) into a unique general classification, which might be useful for every forensic practitioner/researcher dealing with the identification of new psychoactive substances

Differentiation of blood and environmental interfering stains on substrates by Chemometrics-Assisted ATR FTIR spectroscopy

Blood is the most common and relevant bodily fluid that can be found in crime scenes. It is critical to correctly identify it, and to be able to differentiate it from other substances that may also appear at the crime scene. In this work, several stains of blood, chocolate, ketchup, and tomato sauce on five different substrates (plywood, metal, gauze, denim, and glass) were analysed by ATR FTIR spectroscopy assisted with orthogonal partial least square discriminant analysis (OPLS-DA) models. It was possible to differentiate blood from the environmental interfering substances independently of the substrate they were on, and to differentiate bloodstains according to the substrate they were deposited on. These results represent a proof-of-concept that open new horizons to differentiate bloodstains from other interfering substances on common substrates present in crime scenes

A comprehensive study of protein-mesoporous-macroporous silica interactions by extended canonical variate analysis of Raman spectra

Understanding the protein-support interactions is of major importance when manufacturing bionanomaterials to a certain application. These interactions can be the cause for enhanced properties or denaturation phenomena in the target protein. Raman spectroscopy was applied to a bionanomaterial comprehending the protein beta-galactosidase immobilized by physical adsorption into a mesoporous-macroporous silica material, with a nanoporous network consisting of 9-nm mesopores and 200-nm macropores. Raman spectra of the bionanomaterial evidenced a complex amount of differences related to the Raman shifts, intensities, band enlargement, appearance of new bands, and overlapping, in comparison with the silica support and the protein spectra. To help in the analysis of the Raman spectra and in the inspection of possible protein-support interactions, ECVA (extended canonical variate analysis) was used as a chemometric complementary tool, dividing the spectra into four segments: 1 (3,100 to 2,800 cm(-1)), 2 (1,800 to 1,500 cm(-1)), 3 (1,500 to 1,200 cm(-1)), and 4 (1,200 to 900 cm(-1)). Major alterations in the Amide I band (1,800 to 1,500 cm(-1)) and the amino acid band regions demonstrated possible structure alterations to a non-native form of the protein beta-galactosidase. Also, other minor alterations were observed in other spectral regions (3,100 to 2,800 cm(-1),1,500 to 1,200 cm(-1), and 1,200 to 900 cm(-1)) also representative of protein structure alteration due to protein-support interactions

Classification of Various Marijuana Varieties by Raman Microscopy and Chemometrics

Fernando Ortega Ojeda desarrolló el procedimiento de tratamiento estadístico de datos y supervisó los cálculos multivariantes en The Unscrambler y SIMCA. The Raman analysis of marijuana is challenging because of the sample's easy photo-degradation caused by the laser intensity. In this study, optimization of collection parameters and laser focusing on marijuana trichome heads allowed collecting Raman spectra without damaging the samples. The Raman spectra of Delta9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) standard cannabinoids were compared with Raman spectra of five different types of marijuana: four Sativa varieties (Amnesia Haze, Amnesia Hy-Pro, Original Amnesia, and Y Griega) and one Indica variety (Black Domina). The results verified the presence of several common spectral bands that are useful for marijuana characterization. Results were corroborated by the quantum chemical simulated Raman spectra of their acid-form (tetrahydrocannabinol acid (THCA), cannabidiol acid (CBDA)) and decarboxylated cannabinoids (THC, CBD, and CBN). A chemometrics-assisted method based on Raman microscopy and OPLS-DA offered good classification among the different marijuana varieties allowing identification of the most significant spectral bands.Instituto Universitario de Investigación en Ciencias Policiales (IUICP), Universidad de Alcalá (UAH)