A Glycoprotein-Based Surface-Enhanced Raman Spectroscopy-Lateral Flow Assay Method for Abrin and Ricin Detection.

Abrin and ricin, both type II ribosome-inactivating proteins, are toxins of significant concern and are under international restriction by the Chemical Weapons Convention and the Biological and Toxin Weapons Convention. The development of a rapid and sensitive detection method for these toxins is of the utmost importance for the first emergency response. Emerging rapid detection techniques, such as surface-enhanced Raman spectroscopy (SERS) and lateral flow assay (LFA), have garnered attention due to their high sensitivity, good selectivity, ease of operation, low cost, and disposability. In this work, we generated stable and high-affinity nanotags, via an efficient freezing method, to serve as the capture module for SERS-LFA. We then constructed a sandwich-style lateral flow test strip using a pair of glycoproteins, asialofetuin and concanavalin A, as the core affinity recognition molecules, capable of trace measurement for both abrin and ricin. The limit of detection for abrin and ricin was 0.1 and 0.3 ng/mL, respectively. This method was applied to analyze eight spiked white powder samples, one juice sample, and three actual botanic samples, aligning well with cytotoxicity assay outcomes. It demonstrated good inter-batch and intra-batch reproducibility among the test strips, and the detection could be completed within 15 min, indicating the suitability of this SERS-LFA method for the on-site rapid detection of abrin and ricin toxins.

Ultrathin WO3 Nanosheets/Pd with Strong Metal-Support Interactions for Highly Sensitive and Selective Detection of Mustard-Gas Simulants.

Exposure to mustard gas can cause damage or death to human beings, depending on the concentration and duration. Thus, developing high-performance mustard-gas sensors is highly needed for early warning. Herein, ultrathin WO3 nanosheet-supported Pd nanoparticles hybrids (WO3 NSs/Pd) are prepared as chemiresistive sulfur mustard simulant (e.g., 2-chloroethyl ethyl sulfide, 2-CEES) gas sensors. As a result, the optimal WO3 NSs/Pd-2 (2 wt % of Pd)-based sensor exhibits a high response of 8.5 and a rapid response/recovery time of 9/92 s toward 700 ppb 2-CEES at 260 °C. The detection limit could be as low as 15 ppb with a response of 1.4. Moreover, WO3 NSs/Pd-2 shows good repeatability, 30-day operating stability, and good selectivity. In WO3 NSs/Pd-2, ultrathin WO3 NSs are rich in oxygen vacancies, offer more sites to adsorb oxygen species, and make their size close to or even within the thickness of the so-called electron depletion layer, thus inducing a large resistance change (response). Moreover, strong metal-support interactions (SMSIs) between WO3 NSs and Pd nanoparticles enhance the catalytic redox reaction performance, thereby achieving a superior sensing performance toward 2-CEES. These findings in this work provide a new approach to optimize the sensing performance of a chemiresistive sensor by constructing SMSIs in ultrathin metal oxides.

Visual detection and discrimination of nerve and blood agents using a dual-site fluorescent probe in living cells and mice.

Of all chemical warfare agents (CWAs), only nerve and blood agents cause massive mortality at low concentrations. To better detect and discriminate nerve and blood agents, a reliable detection method is desirable. We report a series of fluorescent probes for nerve and blood agent detection. Among the tested probes, SR-Pip detected nerve and blood agents quickly (within 10 s for nerve agents and 1 min for blood agents). SR-Pip coupled with nerve agent produced a weak orange fluorescence with good sensitivity [limit of detection (LOD)= 5.5 µM]. Upon reaction with blood agent, the fluorescence of SR-Pip changed from orange fluorescence to blue fluorescence with detection limits as low as 9.6 nM. This probe effectively visualised different concentrations of nerve agents in living cells and mice. A portable test kit using SR-Pip instantly detected nerve and blood agents. To the best of our knowledge, SR-Pip is the first fluorescent probe for nerve and blood agent detection.

Biomarker profiling in plants to distinguish between exposure to chlorine gas and bleach using LC-HRMS/MS and chemometrics.

Since its first employment in World War I, chlorine gas has often been used as chemical warfare agent. Unfortunately, after suspected release, it is difficult to prove the use of chlorine as a chemical weapon and unambiguous verification is still challenging. Furthermore, similar evidence can be found for exposure to chlorine gas and other, less harmful chlorinating agents. Therefore, the current study aims to use untargeted high resolution mass spectrometric analysis of chlorinated biomarkers together with machine learning techniques to be able to differentiate between exposure of plants to various chlorinating agents. Green spire (Euonymus japonicus), stinging nettle (Urtica dioica), and feathergrass (Stipa tenuifolia) were exposed to 1000 and 7500 ppm chlorine gas and household bleach, pool bleach, and concentrated sodium hypochlorite. After sample preparation and digestion, the samples were analyzed by liquid chromatography high resolution tandem mass spectrometry (LC-HRMS/MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). More than 150 chlorinated compounds including plant fatty acids, proteins, and DNA adducts were tentatively identified. Principal component analysis (PCA) and linear discriminant analysis (LDA) showed clear discrimination between chlorine gas and bleach exposure and grouping of the samples according to chlorine concentration and type of bleach. The identity of a set of novel biomarkers was confirmed using commercially available or synthetic reference standards. Chlorodopamine, dichlorodopamine, and trichlorodopamine were identified as specific markers for chlorine gas exposure. Fenclonine (Cl-Phe), 3-chlorotyrosine (Cl-Tyr), 3,5-dichlorotyrosine (di-Cl-Tyr), and 5-chlorocytosine (Cl-Cyt) were more abundantly present in plants after chlorine contact. In contrast, the DNA adduct 2-amino-6-chloropurine (Cl-Ade) was identified in both types of samples at a similar level. None of these chlorinated biomarkers were observed in untreated samples. The DNA adducts Cl-Cyt and Cl-Ade could clearly be identified even three months after the actual exposure. This study demonstrates the feasibility of forensic biomarker profiling in plants to distinguish between exposure to chlorine gas and bleach.

Chromogenic Detection of the Organophosphorus Nerve Agent Simulant DCP Mediated by Rhodium(II,II) Paddlewheel Complexes.

Organophosphorus nerve agents (OPNAs) pose a great threat to humanity. Possessing extreme toxicity, rapid lethality, and an unassuming appearance, these chemical warfare agents must be quickly and selectively identified so that treatment can be administered to those affected. Chromogenic detection is the most convenient form of OPNA detection, but current methods suffer from false positives. Here, nitrogenous base adducts of dirhodium(II,II) acetate were synthesized and used as chromogenic detectors of diethyl chlorophosphate (DCP), an OPNA simulant. UV-vis spectrophotometry was used to evaluate the sensitivity and selectivity of the complexes in the detection of DCP. Visual limits of detection (LOD) for DCP were as low as 1.5 mM DCP, while UV-vis-based LODs were as low as 0.113 µM. The dirhodium(II,II) complexes were also tested with several potential interferents, none of which produced a visual color change that could be mistaken for OPNA response. Ultimately, the Rh2(OAc)4(1,8-diazabicyclo[5.4.0]undec-7-ene)2 complex showed the best combination of detection capability and interferent resistance. These results, when taken together, show that dirhodium(II,II) paddlewheel complexes with nitrogenous base adducts can produce instant, selective, and sensitive detection of DCP. It is our aim to further explore and apply this new motif to produce even more capable OPNA sensors.

Use of carbonyldiimidazole as a derivatization agent for the detection of pinacolyl alcohol, a forensic marker for Soman, by EI-GC-MS and LC-HRMS in official OPCW proficiency test matrices.

Pinacolyl alcohol (PA), a key forensic marker for the nerve agent Soman (GD), is a particularly difficult analyte to detect by various analytical methods. In this work, we have explored the reaction between PA and 1,1'-carbonyldiimidazole (CDI) to yield pinacolyl 1H-imidazole-1-carboxylate (PIC), a product that can be conveniently detected by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Regarding its GC-MS profile, this new carbamate derivative of PA possesses favorable chromatographic features such as a sharp peak and a longer retention time (RT = 16.62 min) relative to PA (broad peak and short retention time, RT = 4.1 min). The derivative can also be detected by LC-HRMS, providing an avenue for the analysis of this chemical using this technique where PA is virtually undetectable unless present in large concentrations. From a forensic science standpoint, detection of this low molecular weight alcohol signals the past or latent presence of the nerve agent Soman (GD) in a given matrix (i.e., environmental or biological). The efficiency of the protocol was tested separately in the analysis and detection of PA by EI-GC-MS and LC-HRMS when present at a 10 µg/mL in a soil matrix featured in the 44th PT and in a glycerol-rich liquid matrix featured in the 48th Official Organization for the Prohibition of Chemical Weapons (OPCW) Proficiency Test when present at a 5 µg/mL concentration. In both scenarios, PA was successfully transformed into PIC, establishing the protocol as an additional tool for the analysis of this unnatural and unique nerve agent marker by GC-MS and LC-HRMS.

Highly specific and sensitive chromo-fluorogenic detection of sarin, tabun, and mustard gas stimulants: a multianalyte recognition approach.

Nerve agents are the most notorious substances, which can be fatal to an individual because they block the activity of acetylcholinesterase. Fighting against unpredictable terrorist assaults and wars requires the simple and quick detection of chemical warfare agent vapor. In the present contribution, we have introduced a rhodamine-based chemosensor, BDHA, for the detection of nerve gas-mimicking agents diethylchlorophosphate (DCP) and diethylcyanophosphonate (DCNP) and mustard gas-mimicking agent 2-chloroethyl ethyl sulfide (CEES), both in the liquid and vapor phase. Probe BDHA provides the ability for detection by the naked eye in terms of colorimetric and fluorometric changes. It has been revealed that the interaction between nerve agents mimics and probe BDHA facilitates spirolactam ring opening due to the phosphorylation process. Thus, the highly fluorescent and colored species developed while probe BDHA is colorless and non-fluorescent due to the intramolecular spirolactam ring. Moreover, probe BDHA can effectively recognize DCP, DCNP, and CEES in the µM range despite many toxic analytes and could be identified based on the response times and quantum yield values. Inexpensive, easily carried paper strips-based test kits were developed for the quick, on-location solid and vapor phase detection of these mustard gas imitating agents (CEES) and nerve gas mimicking agents (DCP and DCNP) without needing expensive equipment or skilled personnel. More remarkably, the test strips' color and fluorescence can be rapidly restored, exposing them to triethyl amine (TEA) for cyclic use, suggesting a potential application in the real-time identification of chemical warfare agents. To accomplish the on-location application of BDHA, we have experimented with soil samples to find traces of DCP. Therefore, the chromo-fluorogenic probe BDHA is a promising, instantaneous, and on-the-spot monitoring tool for the selective detection of DCP, DCNP, and CEES in the presence of others.

Recent advances in sensing toxic nerve agents through DMMP model simulant using diverse nanomaterials-based chemical sensors.

Recent terrorist assaults have demonstrated the need for the exploration and design of sustainable and stable chemical sensors with quick reaction times combined with great sensitivity. Among several classes of chemical warfare agents, nerve agents have been proven to be the most hazardous. Even short-term exposure to them can result in severe toxic effects. Human beings inadvertently face the after-effects of these chemicals even several years after these chemicals were used. Due to the extreme toxicity and difficulty in handling, dimethyl methylphosphonate (DMMP), a simulant of nerve agents with much lesser toxicity, is frequently used in laboratories as a substitute. Having a chemical structure almost identical to those of nerve agents, DMMP can mimic the properties of nerve agents. Through this paper, authors have attempted to introduce the evolution of several chemical sensors used to detect DMMP in recent years, including field-effect transistors, chemicapacitors, chemiresistors, and mass-sensitive sensors. A detailed discussion of the role of nanomaterials as chemical sensors in the detection of DMMP has been the main focus of the work through a comprehensive overview of the research on gas sensors that have been reported making use of the properties of a wide range of nanomaterials.

Powders to Thin Films: Advances in Conjugated Microporous Polymer Chemical Sensors.

Chemical sensing of harmful species released either from natural or anthropogenic activities is critical to ensuring human safety and health. Over the last decade, conjugated microporous polymers (CMPs) have been proven to be potential sensor materials with the possibility of realizing sensing devices for practical applications. CMPs found to be unique among other porous materials such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) due to their high chemical/thermal stability, high surface area, microporosity, efficient host-guest interactions with the analyte, efficient exciton migration along the π-conjugated chains, and tailorable structure to target specific analytes. Several CMP-based optical, electrochemical, colorimetric, and ratiometric sensors with excellent selectivity and sensing performance were reported. This review comprehensively discusses the advances in CMP chemical sensors (powders and thin films) in the detection of nitroaromatic explosives, chemical warfare agents, anions, metal ions, biomolecules, iodine, and volatile organic compounds (VOCs), with simultaneous delineation of design strategy principles guiding the selectivity and sensitivity of CMP. Preceding this, various photophysical mechanisms responsible for chemical sensing are discussed in detail for convenience. Finally, future challenges to be addressed in the field of CMP chemical sensors are discussed.

The prediction of hydrolysis and biodegradation of organophosphorus-based chemical warfare agents (G-series and V-series) using toxicology in silico methods.

Nerve agents (G- and V-series) are a group of extremely toxic organophosphorus chemical warfare agents that we have had the opportunity to encounter many times on a massive scale (Matsumoto City, Tokyo subway and Gulf War). The threat of using nerve agents in terrorist attacks or military operations is still present, even with establishing the Chemical Weapons Convention as the legal framework. Understanding their environmental sustainability and health risks is critical to social security. Due to the risk of contact with dangerous nerve agents and animal welfare considerations, in silico methods were used to assess hydrolysis and biodegradation safely. The environmental fate of the examined nerve agents was elucidated using QSAR models. The results indicate that the investigated compounds released into the environment hydrolyse at a different rate, from extremely fast (<1 day) to very slow (over a year); V-agents undergo slower hydrolysis compared to G-agents. V-agents turned out to be relatively challenging to biodegrade, the ultimate biodegradation time frame of which was predicted as weeks to months, while for G-agents, the overwhelming majority was classified as weeks. In silico methods for predicting various parameters are critical to preparing for the forthcoming application of nerve agents.

Gas chromatography tandem mass spectrometric analysis of alkylphosphonofluoridic acids as verification targets of nerve agents.

Alkylphosphonofluoridic Acids (APFA) are the major thermal degradation products of G- and A-series nerve agents and thus play a vital role in the verification analysis of Chemical Weapons Convention. Present study focuses on the development of sample clean-up, derivatization procedures and gas chromatography tandem mass spectrometric analysis of APFA in aqueous samples. APFA were found to be much more delicate than the corresponding alkylphosphonic acids and thus required subtle optimizations. Retention of analytes on silica and polymer-based anion exchangers followed by elution under alkaline conditions yielded best recoveries. Elution under acidic conditions led to partial or complete degradation of the analytes to alkylphosphonic acids. Silylation reactions, particularly with MTBSTFA were found the best in terms of chromatographic responses and resolution of the derivative peaks. Methylations with diazomethane, which requires acidic reaction media, failed to produce desired yields of the derivatives. Under optimized conditions, the analytes produced the recoveries ranging from 76.9 to 94.5% with RSD ≤9.2%. The best LOD's in the tandem mass spectrometric analysis ranged from 13 to 56 ng/ml. The applicability of the method was tested by spiking the analytes in the retained aqueous samples received for the 52nd proficiency test conducted by the Organization for the Prohibition of Chemical Weapons (OPCW).

A highly sensitive fluorescence probe for on-site detection of nerve agent mimic diethylchlorophosphonate DCP.

Nerve agents are the most toxic chemical warfare agents that pose severe threat to human health and public security. In this work, we developed a novel fluorescent probe NZNN based on naphthylimide and o-phenylenediamine to detect nerve agent mimic diethylchlorophosphonate (DCP). DCP underwent a specific nucleophilic reaction with the o-phenylenediamine group of NZNN to produce a significant fluorescence turn-on response with high selectivity, exceptional linearity, bright fluorescence, rapid response (<6 s) and a low detection limit (30.1 nM). Furthermore, a portable sensing device was fabricated for real-time detection of DCP vapor with excellent performance. This portable and sensitive device is favorable for monitoring environmental pollution and defense against chemical warfare agents.

Agresiones realizadas con espráis de defensa personal atendidas en el área de descontaminación química de urgencias. A propósito de 15 casos / Injuries from pepper spray used for self defense: analysis of 15 cases managed in an emergency chemical decontamination area

Evalúan las características epidemiológicas, clínicas, terapéuticas y evolutivas, de las asistencias realizadas en el área de descontaminación química (ADQ) del servicio de urgencias, a consecuencia de un ataque con espráis de defensa personal durante un período de 5 años. Se han incluido 15 pacientes con una edad media de 25 años. Trece fueron hombres y el 53% eran personas no nacidas en España. En todos los casos la agresión con el espray se produjo en el curso de una pelea o con ánimo de robo, sobre todo de madrugada (66,7% de los casos entre las 4:30 y las 6:30 h). En el 60% de las atenciones hubo dos o más personas afectadas de forma simultánea. El ataque se produjo en la vía pública en el 73% de las ocasiones y tardaron una mediana de 30 min en llegar a urgencias. Cara y ojos fueron las zonas más afectadas y los síntomas referidos con mayor frecuencia fueron el picor, irritación, quemazón o dolor. El tratamiento aplicado en el hospital fue inmediato (media de demora: 3 min) y se empleó una solución hipertónica, anfótera y quelante en el 80% de los casos, con notable mejoría sintomática, pasando en la escala visual analógica (EVA) del dolor de una puntuación media de 7,2 al ingreso a 3 a la salida (p = 0,009). El tiempo medio de permanencia en el ADQ fue de 40 min. Once de los casos precisaron además asistencia oftalmológica y tratamiento tópico sintomático. La evolución fue favorable y sin secuelas en todos los casos. Concluimos que el uso de espráis de defensa personal con ánimo de robo o agresión es una realidad en nuestro medio. Las medidas de descontaminación son prioritarias y contribuyen a aliviar los síntomas y evitar secuelas (AU)

We analyzed epidemiologic and clinical characteristics, treatment received, and clinical course in cases of pepper spray injury treated in the chemical decontamination area of an emergency department over a 5-year period. A total of 15 patients with a mean (SD) age of 25 (8.3) years were included. Thirteen were men and 53% were foreign-born. All uses of pepper spray occurred during muggings that to place mainly in the early hours of the morning (66.7% between 4:30 and 6:30 AM). Two or more attackers were injured in 60% of the events. Seventy-three percent of the attacks took place on the street and the median delay in reaching the emergency department was 30 minutes. The face and eyes were usually injured, and symptoms included itching, irritation, burning, and pain. On arrival, the patients were treated immediately (mean delay, 3 minutes) with hypertonic saline, an amphoteric surfactant, and a chelating agent in 80% of the cases, in which improvement was substantial as mean pain scale scores changed from 7.2 on admission to 3 on discharge (P=.009). Patients spent an average of 40 minutes in the treatment area. Eleven patients required further care from an ophthalmologist and topical medication for symptoms. Outcomes were good and there were no complications in any of the cases. We conclude that pepper sprays are being used as an aid to self defense in muggings in our community. Decontamination measures have priority as they alleviate symptoms and prevent long-lasting effects (AU)

PCB contamination in surface sediments in the coastal waters of Costa Rica

This paper describes the initial investigation of PCB concentrations in four geographical regions (three on the Pacific and one in the Caribbean) of coastal Costa Rica: Bahia Culebra, Golfo Dulce, Golfo de Nicoya, and Limón. Overall total concentrations of PCB were low in all areas except around the port of Golfito (Golfo Dulce). Overall average concentration is 2.80 ng/g dw, with a standard deviation of 2.75. The low concentration could be due to lack of contamination or the subsequent degradation in the warm climate, or the low sorptive capacity of the sediment. Further investigation is ongoing

Este articulo describe una investigación sobre las concentraciones de bifenilos policlorados (PCB) en cuatro regiones geográficas (tres en el Pacífico y una en el Caribe) costeras de Costa Rica.: Bahía Culebra, Golfo Dulce, Golfo de Nicoya, y Limón. Las concentraciones totales de PCB fueron bajas en todas las regiones excepto en el puerto de Golfito (Golfo Dulce). Las concentraciones promedio fueron de 2.80 ng /g dw, con una desviación estándar de 2.75. Las bajas concentraciones pueden estar asociadas a: la ausencia de contaminación por PCB, la degradación posterior en éste clima cálido, o la poca capacidad de absorción de los sedimentos

PCB concentrations in sediments from the Gulf of Nicoya estuary, Pacific coast of Costa Rica

Thirty-one sediment samples collected from 1996-2003 from the Gulf of Nicoya estuary on the north- western coast of Costa Rica, have been obtained for PCB analyses. This is part of the first study to evaluate the PCB contamination in coastal Costa Rica.Overall, the concentrations are low, especially when compared to sediments from more temperate climates and/or sediments from more heavily industrialized areas. Values average less than 3 ng/g dw sediment, however, a few samples contained up to 7 ng/g dw sediment. Sediments with the highest concentrations were located in the Punta Morales area, where muds were sampled from among mangrove roots. The Puntarenas samples had surprisingly low PCB concentrations, likely due to their sandy lithology. The congener distribution within the majority of the samples showed signs of either recent sources or lack of degradation. However, a few sites, specifically some of the inter-gulf islands and more remote samples had congener distributions indicative of airborne contaminants and/or degradation. Considering the presence of air-borne PCBs in the Gulf of Papagayo to the north, the lack of airborne PCBs and more varied congener distribution in the Gulf of Nicoya estuary was surprising

Se analizó los bifenilos policlorados (PCB) en 31 muestras de sedimentos colectadas entre 1996 -2003 en el estuario del Golfo de Nicoya, costa noroeste de Costa Rica. Esto es parte de un primer estudio para evaluar la contaminación por PCB en aguas costeras de Costa Rica. En general, las concentraciones fueron bajas especialmente cuando se les compara con sedimentos de climas templados y / o sedimentos de areas altamente industrializadas. Los valores promedio son inferiores a 3 ng / dw (peso seco) de sedimento. Sin embargo, unas pocas muestras contienen hasta 7 ng/ g dw de sedimento. Los sedimentos con las concentraciones más altas están localizados en el area de Punta Morales, en cienos de entre raíces de mangle. Las concentraciones de PCB en Puntarenas fueron sorprendentemente bajas, posiblemente por el tipo arenoso del sustrato. La distribución de congéneres dentro de la mayoría de las muestras muestran señal de una reciente contaminación o carencia de degradación . Sin embargo, en unos pocos sitios, específicamente en las islas internas del Golfo y otras areas más remotas tienen distribuciones de congéneres que indican contaminación por vía aerea y /o degradación. Cuando se considera la presencia de PCB transportados por via aerea en el Golfo de Papagayo al Norte, es sorprendente la ausencia en el Golfo de Nicoya de estos PCB y una distribución más variada de congéneres

PCB contamination in marine sediments from Golfo Dulce, Pacific coast of Costa Rica

Twenty-nine marine sediment samples collected from 1996 through 2002 from the Golfo Dulce embayment of Costa Rica were analyzed for PCB concentrations. The Esquinas River and Rincon Bay in the northern and western part of the gulf had relatively low overall concentrations of PCBs, with no samples having greater than 2.1 µg/g dw sediment. The Port of Golfito had the highest overall concentrations, ranging up to 15.7 µg/g dw sediment. These samples were also dominated by higher chlorinated congeners. Samples from the deeper (>100m) waters in the northern part of the gulf, as well as within the sediment plume from the Rio Coto Colorado had intermediate values. Within the Rio Coto Colorado sediment plume the concentrations did decrease with increasing depth and the congeners showed a shift towards less chlorinated congeners with depth. However, the deep northern basin had some of the highest PCB concentrations and the shift towards less chlorinated congeners was not apparent or significant. Whether the anoxic conditions that exist in the deep waters are capable of initiating dechlorination is still unknown. Overall, the data from Golfo Dulce show moderate PCB contamination, despite the pristine nature of the gulf and surrounding lands

Un total de 29 muestras de sedimentos recolectadas de 1996 a 2002 en el Golfo Dulce, Costa Rica fueron analizadas determinar las concentraciones de bifenilos policlorinados (PCBs). La Bahía de Rincón y el Río Esquinas en la parte noroeste del Golfo tienen concentraciones relativamente bajas de PCBs, con ninguna muestras superando los 2.1 ug/ dw (peso seco) de sedimento. El puerto de Golfito tuvo las mayores concentraciones hasta un máximo de 15.7 ug/g dw de sedimento. Estas muestras también estuvieron dominadas por los congéneres más clorinados. Las muestras de los sedimentos profundos (>100 m ) de las aguas de la parte norte del Golfo, así como las de la estela del Río Coto Colorado, tienen concentraciones intermedias. Dentro de la estela de sedimentos del Río Colorado las concentraciones aumentaron con la profundidad y los congéneres variaron con la profundidad hacia los menos clorinados. Sin embargo, la región profunda tuvo una de las más altas concentraciones de PCBs, pero la tendencia hacia los menos clorinados no fue aparente o significativa. No se conoce si las condiciones anóxicas en las aguas profundas son capaces de iniciar la declorización. En general, las muestras analizadas muestran concentraciones moderadas de PCBs, no obstante las condiciones pristinas del Golfo y su cuenca

Extracción de ricina por procedimientos incluidos en publicaciones paramilitares y manuales relacionados con la red terrorista Al Qaeda / Extraction of ricin by procedures featured on paramilitary publications and manuals related to the Al Qaeda terrorist network

Antecedentes: La ricina es una fitotoxina con actividad citotóxica presente en las semillas de ricino (Ricinus communis L.). Algunas publicaciones paramilitares y manuales relacionados con la red terrorista Al Qaeda explican procedimientos para su extracción a partir de las semillas. Esto ha llevado a la actual preocupación por que esta toxina pueda ser empleada con fines terroristas. Objetivo: Determinar la viabilidad y eficacia de estas técnicas de extracción. Materiales y métodos: A partir de las semillas de Ricinus communis, variedades gibsonii y zanzibariensis, se siguieron dos procedimientos para la extracción de ricina incluidos en estas publicaciones y manuales. El primero de ellos se basa en la eliminación del aceite de la semilla mediante la extracción del mismo con disolventes orgánicos. El segundo consiste en la precipitación de la ricina, a partir del extracto acuoso, por modificación de la fuerza iónica mediante la adición de una sal. La detección cuantitativa de ricina en las muestras fue realizada por enzimoinmunoensayo de captura (ELISAc). Resultados: Los extractos de las semillas obtenidos por el primer procedimiento en las variedades zanzibariensis y gibsonii tenian un contenido en ricina de 0,33 por ciento y 0,01 por ciento (peso/peso), respectivamente. La muestra obtenida por la técnica de precipitación por adición de una sal no contenía ricina. Conclusiones: En este trabajo hemos podido constatar la viabilidad y la eficacia de varias técnicas de extracción para la ricina rápidas, baratas y a partir de productos de fácil adquisición. Su utilización como "arma de destrucción masiva", es decir, con el fin de causar un elevado número de intoxicados, estaría limitada por el bajo contenido en ricina de los extractos obtenidos y por la dificultad de diseminarlos de forma eficaz. Sin embargo, no se puede descartar su uso con fines terroristas selectivos, es decir, limitado a una o varias personas, así como el posible perfeccionamiento de los procedimientos incluidos en estas publicaciones (AU)