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1.
Sci Total Environ ; 926: 171850, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38521255

RESUMEN

Agriculture is expanding rapidly across the tropics. While cultivation can boost socioeconomic conditions and food security, it also threatens native ecosystems. Oil palm (Elaeis guineensis), which is grown pantropically, is the most productive vegetable oil crop worldwide. The impacts of oil palm cultivation have been studied extensively in Southeast Asia and - to a lesser extent - in Latin America but, in comparison, very little is known about its impacts in Africa: oil palm's native range, and where cultivation is expanding rapidly. In this paper, we introduce a large-scale research programme - the Sustainable Oil Palm in West Africa (SOPWA) Project - that is evaluating the relative ecological impacts of oil palm cultivation under traditional (i.e., by local people) and industrial (i.e., by a large-scale corporation) management in Liberia. Our paper is twofold in focus. First, we use systematic mapping to appraise the literature on oil palm research in an African context, assessing the geographic and disciplinary focus of existing research. We found 757 publications occurring in 36 African countries. Studies tended to focus on the impacts of palm oil consumption on human health and wellbeing. We found no research that has evaluated the whole-ecosystem (i.e., multiple taxa and ecosystem functions) impacts of oil palm cultivation in Africa, a knowledge gap which the SOPWA Project directly addresses. Second, we describe the SOPWA Project's study design and-using canopy cover, ground vegetation cover, and soil temperature data as a case study-demonstrate its utility for assessing differences between areas of rainforest and oil palm agriculture. We outline the socioecological data collected by the SOPWA Project to date and describe the potential for future research, to encourage new collaborations and additional similar projects of its kind in West Africa. Increased research in Africa is needed urgently to understand the combined ecological and sociocultural impacts of oil palm and other agriculture in this unique region. This will help to ensure long-term sustainability of the oil palm industry-and, indeed, all tropical agricultural activity-in Africa.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Humanos , Aceites de Plantas , Agricultura , África Occidental
2.
ACS ES T Water ; 2(2): 357-366, 2022 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-35647583

RESUMEN

Wildfires have destroyed multiple residential communities in California in recent years. After fires in 2017 and 2018, high concentrations of benzene and other volatile organic compounds (VOCs) were found in public drinking water systems in fire-affected areas. The sources of the contamination and appropriate remediation have been urgent matters for investigation. This study characterizes target and non-target VOCs and semi volatile organic compounds (SVOCs) in water from a highly contaminated service line after the 2018 Camp Fire (Paradise, CA). Ninety-five organic compounds were identified or tentatively identified in the service line. Laboratory combustion experiments with drinking water pipes made of polyvinyl chloride (PVC), cross-linked polyethylene (PEX) and high-density polyethylene (HDPE) and a review of the literature were used to evaluate potential sources of the detected chemicals. Among the service line contaminants were thirty-two compounds associated with PVC pyrolysis and twenty-eight organic compounds also associated with the pyrolysis of polyethylene. The service line sample also contained fifty-five compounds associated with uncontrolled burning of biomass and waste materials. The findings support hypotheses that wildfires can contaminate drinking water systems both by thermal damage to plastic pipes and intrusion of smoke. Residual chlorine disinfectant in the water system modifies the contaminant distribution observed.

3.
J Microbiol Methods ; 184: 106206, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33766607

RESUMEN

Droplet digital polymerase chain reaction (ddPCR) was evaluated for the detection of fecal indicator bacteria (FIB), Enterococcus spp., in San Diego County beach water samples collected under diverse conditions, from multiple pollution sources, as part of regulatory monitoring activities over 20 months. Two US EPA-approved methods, qPCR (EPA 1609.1) and Enterolert (SM9230D), were used as reference comparator methods. A total of 361 samples were assayed by both ddPCR and qPCR and yielded an acceptable Index of Agreement (IA) of 0.89, based on EPA Site-Specific analysis guidelines. A Pearson's correlation coefficient of r = 0.87 (p < 0.001), further indicated a strong relationship between the methods results. From the 361 samples, 185 split samples with ddPCR and Enterolert values within the limits of quantification, were used as a 'training' data set to derive an intrinsic copy number equation (ICE) for scaling ddPCR gene copy number to Enterolert most probable number (MPN). Of the 1993 samples that comprised the complete 'test' data set assayed by ddPCR and Enterolert, 1086 generated results that fell within the limits of quantification for Enterolert and yielded an overall IA of 0.64. Re-analysis using median as a measure of central tendency to account for significant skewing of Enterolert data yielded an IA of 0.72. Beach grouping-specific IA values ranged from 0.63 to 0.93. Pearson's correlation coefficient, r, ranged from 0.13 to 0.94 within beach groupings and generated a combined value of 0.60 for all groupings. Using the ICE, a ddPCR advisory threshold of 1413 DNA copy number/100 mL was empirically determined to be the equivalent to the California Enterolert beach action threshold of 104 MPN/100 mL, based on comparison with all 1993 paired ddPCR and Enterolert results. Using the 1413 DNA copy number/100 mL as a beach action threshold for ddPCR resulted in a 90.4% agreement with Enterolert (6.0% false negative and 3.7% false positive). Together these findings support the conclusion that ddPCR readouts align closely with Enterolert MPN for identifying FIB exceedance levels of Enterococcus spp. in coastal waters of San Diego, CA.


Asunto(s)
Bacterias/genética , Bacterias/aislamiento & purificación , Monitoreo del Ambiente/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Agua de Mar/microbiología , Bacterias/crecimiento & desarrollo , Heces/microbiología , Humanos , Agua de Mar/química , Estados Unidos , United States Environmental Protection Agency , Contaminación del Agua/análisis , Calidad del Agua
5.
JFMS Open Rep ; 5(1): 2055116919830214, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30800413

RESUMEN

CASE SUMMARY: A 3-year-old spayed female domestic shorthair cat developed a fever 1 week after starting the anticonvulsant phenobarbital. A diagnostic work-up for seizures and subsequent onset of fever of unknown origin, consisting of MRI of the brain, cerebrospinal fluid analysis and infectious disease testing, was unremarkable. The cat was switched from phenobarbital onto pregabalin with complete resolution of the fever within 24 h, consistent with a drug-induced fever following phenobarbital administration. RELEVANCE AND NOVEL INFORMATION: While anticonvulsant hypersensitivities have been reported and studied in veterinary medicine, phenobarbital-induced fever outside of the context of systemic clinical signs has not been documented in the veterinary scientific literature. Drug-induced fever secondary to anticonvulsants should be considered in patients that develop a fever after starting anticonvulsant therapy with an unrewarding diagnostic work-up for fever of unknown origin.

6.
Chemosphere ; 158: 171-6, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27262687

RESUMEN

Purge and trap sample introduction (PTI) has been the premier sampling and preconcentration technique for gas chromatographic determination of volatile organic compounds (VOCs) in drinking water for almost 50 years. PTI affords sub parts-per-billion (ppb) detection limits for purgeable VOCs including fixed gases and higher boiling hydrocarbons and halocarbons. In this study the coupling of solid phase extraction (SPE) to PTI was investigated as a means to substantially increase enrichment and lower detection limits for the emerging contaminant, 1,2,3-trichloropropane (TCP). Water samples (500 mL) were dechlorinated, preserved with a biocide, and spiked with the isotope labeled internal standard, d5-TCP. The entire 500 mL sample was extracted with activated carbon or carbon molecular sieve SPE cartridges, and then eluted with dichloromethane -- excess solvent was removed in a nitrogen evaporator and diethylene glycol "keeper" remaining was dispersed in 5 mL of water for PTI GC-MS analysis. The experimental Method Detection Limit (MDL) for TCP was 0.11 ng/L (ppt) and accuracy was 95-103% in sub-ppt determinations. Groundwater samples including impaired California sources and treated water (n = 21) were analyzed with results ranging from below the method reporting limit (0.30 ng/L) to > 250 ng/L. Coupling of SPE with PTI may provide similar reductions in detection limits for other VOCs with appropriate physical-chemical properties.


Asunto(s)
Cromatografía de Gases y Espectrometría de Masas , Propano/análogos & derivados , Extracción en Fase Sólida , Contaminantes Químicos del Agua/análisis , Calibración , California , Carbono/química , Cromatografía de Gases , Cromatografía Liquida , Desinfectantes/química , Agua Subterránea , Halogenación , Hidrocarburos/análisis , Hidrocarburos Clorados/análisis , Isótopos/análisis , Límite de Detección , Propano/análisis , Reproducibilidad de los Resultados , Solventes , Compuestos Orgánicos Volátiles/análisis , Agua/química
7.
J Occup Rehabil ; 24(2): 213-9, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23929501

RESUMEN

INTRODUCTION: The purpose of this study is to examine the possible interactions of predictor variables pertaining to perceived disability claims contained in a large governmental database. Specifically, it is a retrospective analysis of US Equal Employment Opportunity Commission (EEOC) data for the entire population of workplace discrimination claims based on the "regarded as disabled" prong of the Americans with Disabilities Act (ADA) definition of disability. METHODS: The study utilized records extracted from a "master database" of over two million charges of workplace discrimination in the Integrated Mission System of the EEOC. This database includes all ADA-related discrimination allegations filed from July 26, 1992 through December 31, 2008. Chi squared automatic interaction detection (CHAID) was employed to analyze interaction effects of relevant variables, such as issue (grievance) and industry type. The research question addressed by CHAID is: What combination of factors are associated with merit outcomes for people making ADA EEOC allegations who are "regarded as" having disabilities? RESULTS: The CHAID analysis shows how merit outcome is predicted by the interaction of relevant variables. Issue was found to be the most prominent variable in determining merit outcome, followed by industry type, but the picture is made more complex by qualifications regarding age and race data. Although discharge was the most frequent grievance among charging parties in the perceived disability group, its merit outcome was significantly less than that for the leading factor of hiring.


Asunto(s)
Árboles de Decisión , Personas con Discapacidad/estadística & datos numéricos , Industrias/estadística & datos numéricos , Prejuicio/estadística & datos numéricos , Adulto , Distribución de Chi-Cuadrado , Bases de Datos Factuales , Personas con Discapacidad/legislación & jurisprudencia , Empleo/legislación & jurisprudencia , Empleo/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Selección de Personal/estadística & datos numéricos , Reorganización del Personal/estadística & datos numéricos , Prejuicio/legislación & jurisprudencia , Estudios Retrospectivos , Estados Unidos , Lugar de Trabajo/legislación & jurisprudencia , Lugar de Trabajo/estadística & datos numéricos
8.
J Am Anim Hosp Assoc ; 49(5): 325-8, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23535756

RESUMEN

Pyrethroids are popular for use in companion animals due to their relatively low mammalian toxicity and efficacy against arthropods. Nonetheless, pyrethroid intoxication has been reported in cats and dogs, and cats appear to be more susceptible due to difficulty in biotransformation and excretion of pyrethroids. Pyrethroid intoxications are generally due to either the improper use or accidental ingestion of approved products. Methocarbamol, given as intermittent injections, is a common first-line treatment choice for the tremors associated with pyrethroid intoxication. Two cats and one dog were treated with a methocarbamol continuous rate infusion (CRI) for pyrethroid intoxication. Clinical signs of toxicity resolved within a few hr in all three cases, with no adverse drug effects. A methocarbamol CRI can be considered in animals presenting with pyrethroid intoxication.


Asunto(s)
Enfermedades de los Gatos/tratamiento farmacológico , Enfermedades de los Perros/tratamiento farmacológico , Sobredosis de Droga/veterinaria , Metocarbamol/uso terapéutico , Relajantes Musculares Centrales/uso terapéutico , Piretrinas/envenenamiento , Animales , Enfermedades de los Gatos/inducido químicamente , Gatos , Enfermedades de los Perros/inducido químicamente , Perros , Sobredosis de Droga/tratamiento farmacológico , Femenino , Insecticidas/envenenamiento , Masculino , Resultado del Tratamiento
9.
J Am Anim Hosp Assoc ; 49(2): 122-7, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23325599

RESUMEN

A 13 mo old spayed female mixed-breed dog presented in a nonambulatory state that was attributed to severe myoclonus secondary to distemper. The authors hypothesized that mitigating the myoclonus would help the dog become ambulatory and expedite convalescence. They injected the severely affected muscles with botulinum toxin on two separate occasions over a period of 18 days. Those injections reduced the myoclonus, helping the dog become ambulatory and attaining a comfortable, functional state.


Asunto(s)
Toxinas Botulínicas/uso terapéutico , Enfermedades de los Perros/tratamiento farmacológico , Mioclonía/veterinaria , Animales , Moquillo/complicaciones , Perros , Femenino , Mioclonía/tratamiento farmacológico , Mioclonía/etiología , Resultado del Tratamiento
10.
Analyst ; 138(4): 1038-47, 2013 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-23248816

RESUMEN

The mass-to-structure or MTS Search Engine is an Access 2010 database containing theoretical molecular mass information for 19,438 compounds assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. This database, which contains no experimental mass spectral data, was developed as an aid to identification of compounds in atmospheric pressure ionization (API)-LC-MS. This paper describes a powerful upgrade to this database, a fully integrated utility for filtering or ranking candidates based on isotope ratios and patterns. The new MTS Search Engine is applied here to the identification of volatile and semivolatile compounds including pesticides, nitrosoamines and other pollutants. Methane and isobutane chemical ionization (CI) GC-MS spectra were obtained from unit mass resolution mass spectrometers to determine MH(+) masses and isotope ratios. Isotopes were measured accurately with errors of <4% and <6%, respectively, for A + 1 and A + 2 peaks. Deconvolution of interfering isotope clusters (e.g., M(+) and [M - H](+)) was required for accurate determination of the A + 1 isotope in halogenated compounds. Integrating the isotope data greatly improved the speed and accuracy of the database identifications. The database accurately identified unknowns from isobutane CI spectra in 100% of cases where as many as 40 candidates satisfied the mass tolerance. The paper describes the development and basic operation of the new MTS Search Engine and details performance testing with over 50 model compounds.


Asunto(s)
Bases de Datos Factuales , Cromatografía de Gases y Espectrometría de Masas/métodos , Isótopos/química , Motor de Búsqueda/métodos , Volatilización
11.
Biochemistry ; 48(43): 10308-20, 2009 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-19795834

RESUMEN

The streptococcal coaggregation regulator (ScaR) of Streptococcus gordonii is a manganese-dependent transcriptional regulator. When intracellular manganese concentrations become elevated, ScaR represses transcription of the scaCBA operon, which encodes a manganese uptake transporter. A member of the DtxR/MntR family of metalloregulators, ScaR shares sequence similarity with other family members, and many metal-binding residues are conserved. Here, we show that ScaR is an active dimer, with two dimers binding the 46 base pair scaC operator. Each ScaR subunit binds two manganese ions, and the protein is activated by a variety of other metal ions, including Cd(2+), Co(2+), and Ni(2+) but not Zn(2+). The crystal structure of apo-ScaR reveals a tertiary and quaternary structure similar to its homologue, the iron-responsive regulator DtxR. While each DtxR subunit binds a metal ion in two sites, labeled primary and ancillary, crystal structures of ScaR determined in the presence of Cd(2+) and Zn(2+) show only a single occupied metal-binding site that is novel to ScaR. The site analogous to the primary site in DtxR is unoccupied, and the ancillary site is absent from ScaR. Instead, metal ions bind to ScaR at a site labeled "secondary", which is composed of Glu80, Cys123, His125, and Asp160 and lies roughly 5 A away from where the ancillary site would be predicted to exist. This difference suggests that ScaR and its closely related homologues are activated by a mechanism distinct from that of either DtxR or MntR.


Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Manganeso/farmacología , Streptococcus/metabolismo , Secuencia de Aminoácidos , Cadmio/farmacología , Cromatografía en Gel , Cobalto/farmacología , Cristalografía por Rayos X , ADN/metabolismo , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/genética , Datos de Secuencia Molecular , Níquel/farmacología , Unión Proteica/efectos de los fármacos , Multimerización de Proteína , Homología de Secuencia de Aminoácido , Ultracentrifugación , Zinc/farmacología
12.
Anal Chem ; 81(10): 4153-60, 2009 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-19374427

RESUMEN

This study examines the effects of electrolytes on microcystin (MC) electrospray ionization (ESI) mass spectrometry and quantitative LC-MS-MS. Sodium replacement ions (SRI) are prominent in MC ESI spectra in protic solvents such as HPLC grade methanol. In a methanol-water-0.006% acetic acid (v/v) gradient, envelopes with up to 11 SRI were apparent in both the +1 and +2 charge states with structures [M + Na(x) - (x-1)H](+) and [M + Na(x) - (x-2)H](+2). The m/z 135 product ion, [Ø-CH(2)-CH=O-CH(3)](+), widely used in tandem LC-MS-MS determination of MC, is a low collision energy fragment of many doubly charged MC precursor ions (e.g., [M+Na+H](+2), [M+Na+NH(4)](+2), M+Na+H+CH(3)OH](+2), [M+2H](+2)). These phenomena impair congener-specific LC-MS-MS detection of MC and degrade quantitative accuracy and precision. Pulse addition experiments established that ammonium formate (AF) strongly suppresses SRI in both +1 and +2 charge states and enhances MH(+) and MNH(4)(+) adducts in neutral MC. Addition of the buffer either post-column or by incorporation in the mobile phase increases specificity for all of the MC which were determined as the MNH(4)(+) > MH(+) and MH(+) > [MH - 134](+) transitions for neutral MC (MCLA, MCLF, MCLW) and [M+2H](+2) > 135(+) and [M+2H](+2) > [M+2H - 135](+) transitions for arginine-containing MC (MCLR, MCYR, MCRR). These findings shed light on mechanisms of electrolyte-induced ionization suppression, and demonstrate beneficial use of a buffer electrolyte for improved specificity and analytical ruggedness in quantitative LC-MS-MS.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Formiatos/química , Microcistinas/análisis , Sodio/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Amoníaco/química , Iones/química
13.
Anal Chem ; 80(20): 7765-77, 2008 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-18811180

RESUMEN

This study evaluates a new model for identifying unknown compounds in atmospheric pressure ionization mass spectrometry based on a mass-to-structure (MTS) paradigm. In this method, rudimentary ESI spectrum interpretation is required to recognize key spectral features such as MH (+), MNa (+), and MNH 4 (+), which lead to the unknown's monoisotopic mass. The unknown's mass is associated directly with known organic compounds using an Access 2003 database containing records of 19,438 substances assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. A user-defined mass tolerance (+/-0.001-0.5 Da) is set according to the instrument mass accuracyunit mass resolution data require a wide mass tolerance ( approximately 0.5 Da) while tolerances for accurate mass data can be as narrow as +/-0.001 Da. Candidate structures retrieved with the MTS Search Engine appear in a report window providing formulas, mass error, and Internet links. This paper provides examples of structure elucidation with 15 organic compounds based on ESI mass spectra from both unit mass resolution (e.g., quadrupole ion trap and triple-stage quadrupole) and accurate mass instruments (e.g., TOF and Q-TOF). Orthogonal information (e.g., isotope ratios and fragmentation data) is complementary and useful for ranking candidates and confirming assignments. The MTS Search Engine identifies unknowns quickly and efficiently, and supplements existing interpretation schemes for unknown identification.


Asunto(s)
Presión Atmosférica , Técnicas de Química Analítica/métodos , Bases de Datos Factuales , Compuestos Orgánicos/análisis , Espectrometría de Masa por Ionización de Electrospray
14.
Rapid Commun Mass Spectrom ; 22(17): 2613-20, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18666199

RESUMEN

The direct determination of dialkyl phosphates (DAPs) in water by strong anion-exchange (SAX) liquid chromatography/atmospheric pressure chemical ionization (APCI) mass spectrometry was investigated. The SAX high-performance liquid chromatography (HPLC) column was eluted with methanol/water gradients containing ammonium formate (AF) separating the DAPs which included six dimethyl- and diethyl-substituted phosphates, thiophosphates, and dithiophosphates. The high buffer concentrations required for separation were compatible with -ve APCI, but in +ve APCI the DAPs were unstable giving anomalous ions such as [M+15]+ and [M+29]+. These ions are believed to result from ion molecule reactions with CH3OH2+ in the plasma. DAPs are very stable in -ve APCI being detected as abundant [M-H](-) ions, even with 200 mM AF. At higher AF concentration formate clusters ([M+45](-) and [M+91](-)) were seen. Fragmentation by collision-activated dissociation (CAD) was more efficient for deprotonated ethyl-substituted DAPs which lost ethylene followed by ethanol. APCI instrument detection limits were in the low ng/mL range and the response was highly linear. Isotope dilution quantitation using d10-diethyl dithiophosphate (DEDTP) as an internal standard produced an instrument detection limit of 2 ng DEDTP/mL and method detection limit (MDL) of 9.3 ng/mL with accuracy of 99% (spike concentration, 25 ng/mL). DAP mixtures required storage in cold, dry conditions and alcohol solvents should be avoided because of solvolysis reactions.


Asunto(s)
Insecticidas/análisis , Compuestos Organofosforados/análisis , Espectrometría de Masa por Ionización de Electrospray/métodos , Presión Atmosférica , Cromatografía Líquida de Alta Presión , Espectrometría de Masa por Ionización de Electrospray/instrumentación
15.
Analyst ; 127(10): 1370-4, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12430612

RESUMEN

Rotenone and piperonyl butoxide (PBO) mixtures, so-called "synergized" rotenone, are invaluable in fisheries management where they are used to protect the habitat of endangered, native species and promote desirable gamefish populations. Continued use of synergized rotenone is threatened by inadequate control of persistence in surface water, especially where drinking water supplies are impacted. The photochemical kinetics of these chemicals were studied in the laboratory with a goal to better understand their fate in natural water. Disappearance quantum yields (phi) were determined in polychromatic light from fluorescent lamps emitting maximally at 350 nm. Rotenone, PBO and trifluralin, an actinometer, were irradiated as aqueous solutions at 25 or 50 microg L(-1) and the piscicides were determined by electrospray-liquid chromatography-mass spectrometry (ESI-LC-MS). In the photoreactor rotenone and PBO photodegraded with first-order half-lives of 500 and 220 min, respectively, and corresponding quantum yields of 0.00015 and 0.034. Rotenone absorbs sunlight strongly, while PRO does not. Differences in spectal overlap tended to counteract the disparities in phi and, in general, mathematical modeling indicates moderately rapid direct photolysis rates for both substances in surface water.


Asunto(s)
Insecticidas/análisis , Butóxido de Piperonilo/análisis , Venenos/análisis , Rotenona/análisis , Contaminantes Químicos del Agua/análisis , Fotoquímica/métodos , Rayos Ultravioleta
16.
J Agric Food Chem ; 50(7): 1852-8, 2002 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-11902923

RESUMEN

This paper describes atmospheric pressure ionization (API) LC-MS-MS determination of urushiols, 3-n-alkenyl- and -alkyl-substituted catechols responsible for poison oak dermatitis. Urushiol was isolated from Western poison oak according to the method of Elsohly et al. (1) (J. Nat. Prod. 1982, 45, 532-538)-the purified preparation contained C(17)- and C(15)-substituted urushiols with zero, one, two, and three double bonds as determined from GC-MS analysis of trimethylsilyl derivatives. Urushiol mixtures were separated on a C(18) reversed phase HPLC column with a methanol-water gradient with urushiols eluting in 100% methanol. Atmospheric pressure chemical ionization (APCI) produced primarily [M - H](-) and MH(+) molecule ions. Electrospray ionization (ESI) yielded [M - H](-) and adduct ions including [M + Cl](-). Daughter ions of [M - H](-) included quinoid radical anions ([M - H - H(2)](-) and m/z 122(-)) and a benzofuran phenate (m/z 135(-)). A suite of hydrocarbon fragments were produced by collision-induced dissociation of MH(+) directly or via an intermediate [MH - H(2)O](+) daughter ion. Six urushiol congeners, one not previously reported in poison oak, were determined by negative ion API-LC-MS-MS with detection limits of approximately 8 pg/microL (ESI) and approximately 800 pg/microL (APCI). API-LC-MS-MS was used to determine urushiol in surface wipes, air samples, and plant materials.


Asunto(s)
Catecoles/análisis , Cromatografía Liquida/métodos , Espectrometría de Masas/métodos , Toxicodendron/química , Presión Atmosférica , Cromatografía Líquida de Alta Presión , Cromatografía de Gases y Espectrometría de Masas , Extractos Vegetales/química , Espectrometría de Masa por Ionización de Electrospray , Compuestos de Trimetilsililo/química
17.
Carib Med J ; 31-32: 60-3, 1969-1970.
Artículo en Inglés | MedCarib | ID: med-4096
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