Jari N. Cardoso

Composition of higher molecular weight organic matter in smoke aerosol from biomass combustion in Amazonia

Abstract Smoke particulate matter was sampled by high volume filtration from a controlled burn of forest litter in the northern forest reserve of INPA about 70 km north of Manaus, Amazonas. The extract of the filter was separated after methylation into hydrocarbon, ketone, carboxylic acid ester and polar fractions and then analyzed by gas chromatography and gas chromatography-mass spectrometry. The total lipid extract yield was ∼13 mg/m 3 of smoke. The major organic components of the smoke particles were straight-chain aliphatic and triterpenoid compounds from vegetation wax, biopolymers, and gum/resin. Polynuclear aromatic hydrocarbons (PAH) from the combustion process were found at high levels and aromatized derivatives from natural product precursors were also important components. Petroleum hydrocarbons representing urban and vehicular emissions were not detectable. The n -alkanes ranged from C 19 to C 35 , with a carbon number maximum (C max ) at C 29 /C 31 and an odd-to-even carbon predominance > C 25 (CPI 20–35 = 3.6). Terminal olefins ( n -alk-1-enes) were also present and ranged from C 17 to C 35 , with a C max at C 22 and an even-to-odd carboon predominance (CPI 17–35 = 0.8). The n -alkanes are derived mainly from vegetation wax and the alk-1-enes with other oxygenated compounds (e.g., ketones, acids, triterpenoids) are thermal alteration products from gum/resin and biopolymers. These alteration products coupled with the PAH are the tracers for biomass combustion.

An assessment of terrestrial higher molecular weight lipid compounds in aerosol particulate matter over the south atlantic from about 30–70°S

A cruise in the South Atlantic allowed the acquisition of a series of aerosol particle samples (high volume filtering) from Rio de Janeiro (Brazil) south to the Antarctic (Bransfield Strait) and back toward Punta Arenas (Chile). These samples were analyzed for the content and composition of solvent-soluble organic matter (range 55–5670 ng/m3) for a preliminary evaluation of the terrestrial components of this organic matter. Distributions of n-alkanes, n-alkanoic acids and n-alkanols were determined (gas chromatography/mass spectrometry) and compared with analogous information on biological and geological (e.g. petroleum) sources. A preliminary data correlation was also attempted by collection of composited local vegetation wax in one possible aerosol particle source region. The results show a petroleum derived component (unresolved hydrocarbon mixture and n-alkanes with no carbon number predominance) in most samples, notably evident remote from continental areas where the plant wax signature (straight-chain homologs C20) was less concentrated, as contrasted with the marine/microbial input (compounds < C20). A procedure for subtraction of the petroleum component in n-alkane traces, as well as analyses of oxygenated components, permitted resolution of some ambiguities and highlighted the biological fingerprint in all cases. In aerosols close to land, polycyclic biomarkers, indicative of fossil fuel (e.g. 17α(H)-hopanes, etc.) and/or biological input (e.g. cholesterol, etc.) could be recognized. Natural product biomarkers of terrestrial vegetation (e.g. amyrins, oleanolic and ursolic acids) showed a rapid depletion downwind from their source regions.

An assessment of the origin and composition of higher molecular weight organic matter in aerosols over Amazonia

Aerosol samples were taken from a tower in the Ducke Forest Reserve about 30 km northeast of the city of Manaus (state capital of Amazonas) at times with typical agricultural burning. High volume filter samples were acquired from the 32 m and 42 m (top) levels of the tower and also in a clearing near the administration camp. The tree tops in the surrounding forest range from 30–35 m and the general wind direction varied from the north to east. Composited extracts of vegetation, primarily tree leaves, from the vicinity of the sampling site were prepared and sediment from a local river was also taken for comparative analyses. The sample extracts were separated into hydrocarbon, ketone, carboxylic acid ester and polar fractions and then analyzed by gas chromatography and gas chromatography-mass spectrometry. The total lipid extract yields ranged from 1.3 to 3.8 μg/m3 of air, a level typical of other rural and forested areas. The major organic components of the aerosol particles were straight-chain aliphatic compounds from vegetation wax. Polynuclear aromatic hydrocarbons (PAH) from combustion sources were found at trace levels only. All samples had a minor component of petroleum hydrocarbons representing urban and vehicular emissions probably originating from Manaus and transported over longer distances. The n-alkanes ranged from C16 to C35, with a carbon number maximum (Cmax) at C29 and a strong odd-to-even carbon predominance > C23 (CPI23–35 range 1.8-3.5). The odd carbon number n-alkanes > C23 were derived from vascular plant wax and their distribution pattern fits well with that of the wax alkanes extracted from the vegetation in the vicinity upwind from the sampling site. The wax n-alkane distributions of the aerosols did not match those of the local river sediment. The oxygenated components (e.g. n-alkanoic acids, n-alkanols) also reflected an origin from plant waxes.

Even N-Alkane Predominances on the Amazon Shelf and A Northeast Pacific Hydrothermal System

Correspondence to: B.R. T. Simoneit An odd-over-even predominance in the n -alkanes >C23H48 has often been used as a marker for a direct input of terrestrial plant wax into geological and environmental samples [1, 2]. On the other hand, an even-over-odd predominance, although much less common, has been reported more frequently in recent years and seems to be generally associated in recent sediment samples with the occurrence of specific inputs from organisms already containing this predominance, such as bacteria and diatoms [3–5]. Several reports show that bacterially produced n -alkanes ranging from C14H30 to C31H64 with strong maxima at one or two carbon numbers are relatively common [6–11]. Many sources have been attributed to the even n -alkanes predominance found in the geosphere and most of those point to a microbial origin. Actually the origin of this unusual carbon number preference has been interpreted as (a) microbial alteration of algal detritus, (b) reductive processes acting on alkanoic acids or other lipid compounds, and (c) direct microbial input (e.g. [3, 12–19]). This paper reports the predominance of n -alkanes with even carbon numbers in samples of dissolved and particulate matter from the Amazon continental shelf (Fig. 1), where the even n -alkanes are of a microbial origin and from alteration of algal detritus. This is contrasted with examples of sediment samples from a hydrothermal system in Middle Valley, Northeast Pacific Ocean, which contain even n -alkanes as a result of reductive processes occurring during the hydrothermal alteration of immature organic matter [19]. Briefly, the Amazon continental shelf (Fig. 1) is characterized by the interaction of an estuarine like, fresh water-seawater frontal system seaward of the river mouth, with strong rotary tidal currents (north-northwest, southsouthwest) and wind-driven surface currents (northwest, southwest) [20]. Bulk sediment C/N ratios are low (2.5–10) [21], indicating a dominance of soil humus from terrestrial sources with a relatively small component of woody (structured) plant material [22]. The analysis of the dC of bulk organic matter revealed a trend for isotopically heavier values seaward [23]. The details of the extraction, fractionation, and lipid analyses are given elsewhere [24]. Middle Valley, NE Pacific, is a faultbounded, “failed” spreading center with large-scale hydrothermal activity and mineral deposits. Abundant turbidite and hemipelagic sedimentation has filled the graben to depths of up to 1.5 km in the center, with as little as 100 m of deposition at the eastern edge. Hydrothermal mounds rise as topographic features above the valley floor [25, 26]. Efficient fluid circulation results in hydrothermal alteration of the sedimentary organic matter from immature precursors to mature petroleum [19]. Sediments from Middle Valley were sampled on Ocean Drilling Project Leg 139 from Sites 857 and 858 [19]. The detailed experimental procedure is given elsewhere [19].

Characterization of indoor air quality in the cities of sao paulo and rio de janeiro, Brazil.

Levels of several gas- and particle-phase substances present in indoor air in nonindustrial office workplaces and in restaurants was acquired during the Southeastern Brazil lndoor Air Quality Study (SEBIAQS) carried out in the summer of 1993. Simultaneous indoor and outdoor samples collected in 12 sites in the cities of Sao Paulo and Rio de Janeiro and in a rural area were analyzed for inhalable particulate matter (IPM dp < 15 µm), inhalable volatilizable particulate organic carbon, black (soot) carbon, trace metals, UV-RSP (d_(50) < 3.5 µm) as a marker for environmental tobacco smoke (ETS), formaldehyde, acetaldehyde, carbon monoxide, and nicotine. Indoor levels were generally higher. Alcohol-fueled vehicle emissions contributed to indoor acetaldehyde. The major sources of trace elements indoors and outdoors were respectively soil dust and combustion, resuspension, and vehicles. Dry deposition indoors was observed for S (mainly sulfate), AI, Fe, and Mn.

Atmospheric BTX and polyaromatic hydrocarbons in Rio de Janeiro, Brazil

Polycyclic aromatic and monoaromatic (benzene, toluene and xylene, or BTX) hydrocarbons were monitored in Rio de Janeiro, Brazil, during the summer of 1998/1999. The levels of these aromatic chemicals decreased with distance from main roads, indicating mobile sources are the main pollutant emitters in this Latin American city. Benzo[ghi]perylene/indeno[1,2,3-cd]pyrene and benzene/toluene ratios corroborate this idea. However, higher benzene/toluene ratios at one of the major access routes into the city suggest pollutant inputs from a nearby refinery. Literature data were reviewed in order to outline differences and similarities among sources and levels of aromatic pollutants in large urban agglomerations worldwide. Concentrations of benzo[a]pyrene and benzene, which are well-known carcinogenic chemicals, were relatively low in Rio de Janeiro. This fact was attributed to specific atmospheric conditions during the tropical summer and differences in vehicle fuel composition.

Total syntheses of oxygenated brazanquinones via regioselective homologous anionic Fries rearrangement of benzylic O-carbamates

Using new variations of anionic aromatic chemistry, the total synthesis of oxygenated brazanquinones (1a-1c), derived from β-brasan, a natural product isolated from Caesalpina echinata, via carbamates 2a-2c is described.

Diagnostic evidence for the presence of β-agonists using two consecutive derivatization procedures and gas chromatography–mass spectrometric analysis

A GC-MS procedure for the detection of different beta-agonists in urine samples based on two consecutive derivatization steps is described. The derivatization procedure is based on the consecutive formation of cyclic methylboronate derivatives followed by a second derivatization step with MSTFA on the same extract, forming TMS derivatives. Injections in the GC-MS system may be carried out after each one of the derivatization steps, obtaining enough information for unambiguous identification. Limits of detection for the two derivatization steps ranged from 0.5 to 5 ng/ml. This procedure was tested with the beta-agonists bambuterol, clenbuterol, fenoterol, formoterol, salbutamol, salmeterol, alpha-hydroxy-salmeterol and terbutaline.

Aromatic hydrocarbons in the Paraiba Valley oil shale

Abstract Aromatic hydrocarbon fractions extracted from different depths of a core (13.8–47.3 m deep) of the Paraiba Valley oil shale were analysed by computerized high resolution gas chromatography-mass spectrometry. Triterpenes derived from precursors oxygenated at position 3, such as tetracyclic (ring-A degraded) and pentacyclic aromatic ursane, oleanane and lupane derivatives, were amongst the most common components, indicating an important input from higher plants to the sediment. This interpretation is supported by the occurrence of sesquiterpenoids (cadalene, calamenene) in the same sediment samples. On the other hand, hopanoids, notably the tetraaromatic derivative, were also detected attesting to a significant bacterial contribution to the sedimentary biomass. In contrast with the abundance of aromatic structures related to oleanane, ursane and hopane, no skeletons traceable to steroidal precursors could be confirmed, suggesting a small algal input. This study also revealed the presence of two new aromatic biomarkers. One of them is a C24 monoaromatic tetracycle apparently derived (via ring-A degradation) from a triterpenoid with the fernene skeleton; the other compound is a ring-A monoaromatic pentacycle with what appears to be a hopanoid structure.

Mass spectra of triterpenyl alkanoates, novel natural products

A series of high molecular mass pentacyclic terpenoid wax esters in smoke from biomass combustion were characterized by high-temperature, high-resolution gas chromatography–mass spectrometry. Based on their mass spectra, they are interpreted as being a series of triterpenyl fatty acid esters (e.g. α- and β- amyryl palmitate). The carbon chain length of the fatty acids ranges from 5 to 20. This interpretation is supported by retention indeces, molecular ions and typical fragments of pentacyclic triterpenoids. Essentially, the mass spectra are simple and composed of the molecular ion, M-CH3, M-fatty acid and fragments characteristic of the esterified triterpenoid moieties.