Valorization and characterization of bio-oil from Salvadora persica seed for air pollutant adsorption.

Salvadora persica (SP) is an important medicinal plant. Numerous articles have been conducted on the leaf, the roots, and the stem of the plant, but there is little information about the seed. Thus, the present work tries to identify the chemical composition of SP seed bio-oil and investigates its use as an adsorbent for cyclohexane removal. This study extracted bio-oil from seeds using different polar and non-polar organic solvents. Two techniques have been used to determine the chemical composition of the bio-oil extracted: FTIR and GC-MS. Results show that the extracted bio-oil presented 13 new major organic bio-compounds in n-hexane and ethanol SP seed extracts. Moreover, the analytical results showed that the two extracts are complex and contained thiocyanic acid, benzene, 3-pyridine carboxaldehyde, benzyl nitrile, ethyl tridecanoate, ethyl oleate, and dodecanoic acid ethyl ester. Additionally, each technique of analysis showed that the extracted bio-oils from SP seeds are rich in non-polar compounds. Indeed, the major fatty acids obtained are pentadecylic acid, myristic acid, lauric acid, oleic acid, margaric acid, and tricosanoic acid. This work provides guidelines for identifying these compounds, among others, and offers a platform for using SP seeds as a herbal alternative for various chemical, industrial, and medical applications. Furthermore, the capacity of SP extracts for air pollution treatment, namely, the removal of cyclohexane in batch mode, was investigated. Results showed that cyclohexane adsorption could be a chemical process involving both monolayer and multilayer adsorption mechanisms. The pores and the grooves on the surface of the SP bio-oil extract helped in adsorbing the cyclohexane with an outstanding maximum removal capacity of about 674.23 mg/g and 735.75 mg/g, respectively, for the ethanol and hexane SP extracts, which is superior to many other recent adsorbents.

[Preparation and application of graphene oxide functionalized melamine-formaldehyde aerogel coated solid-phase microextraction tube].

Many solid-phase microextraction (SPME) sorbents have been developed from aerogels because of their low densities, large surface areas, and high porosities. Melamine-formaldehyde (MF) aerogel, made from melamine and formaldehyde by a sol-gel reaction, is one of the typical organic aerogels. MF aerogel has better mechanical strength, chemical stability and extraction performance than inorganic aerogels. The performance of the aerogel is limited in some fields, while composite aerogels can meet different requirements such as good mechanical strength and strong adsorption performance. Graphene oxide (GO) is a two-dimensional nanomaterial composed of a single layer of carbon atoms and provides π-π interaction by a large π-electron. In addition, the oxygen-containing groups at the edge of the lamellar structure improve the hydrophilicity of the material and can interact with various compounds. To improve the extraction performance of MF aerogel for polycyclic aromatic hydrocarbons (PAHs), GO/MF aerogels were prepared by functionalizing MF aerogel with GO. In this study, 1.2612 g of melamine and 80 mg of sodium carbonate were dissolved in 30 mL of water, and the mixture was heated to 80 ℃ under stirring. Then, 2.8 mL formaldehyde solution (37%) was slowly added, and a clear solution was obtained gradually. Next, 50 mg of GO powder was ultrasonically dispersed in 10.0 mL of water and evenly mixed with the above solution. After adjusting the pH to 1.5, the sol-gel process was performed for 48 h, then the gel was aged at room temperature for 24 h. The gel was then soaked in ethanol, acetone, and cyclohexane in turn to replace the solvent. Finally, the GO/MF aerogel was obtained by freeze-drying for 24 h. The GO/MF aerogel was characterized by scanning electron microscopy (SEM) and X-ray photoelectric spectroscopy (XPS), confirming that GO was successfully introduced into MF aerogel, while retaining its three-dimensional network and porous structure. GO/MF aerogel was coated onto the surface of a stainless steel wire to be used as sorbent. Four such wires were placed into a polyetheretherketone (PEEK) tube (0.75 mm i. d., 30 cm length) for in-tube (IT) SPME. The tube was combined with a high-performance liquid chromatography (HPLC) unit to construct an IT-SPME-HPLC online system. When the six-way valve was in the Load state, sample solution achieved online enrichment with analytes while it flowed through the extraction tube. After extraction, the valve was turned to the Inject state, and the analytes were eluted into the chromatographic column by the mobile phase at a flow rate of 1.0 mL/min for separation and detection with the detector. Under the same extraction conditions (sampling volume=30 mL, sampling rate=1.00 mL/min, and concentration of polycyclic aromatic hydrocarbons (PAHs, viz. naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorine (Flu), phenanthrene (Phe), anthracene (Ant), fluoranthene (Fla) and pyrene (Pyr))=5.00 µg/L), GO/MF aerogel-based tube was compared with that of MF aerogel-based tube. GO enhanced the enrichment efficiency of MF aerogel towards PAHs from 1.1 to 2.5 times, due to the increased number of adsorption sites and enhanced π-π interaction with PAHs. IT-SPME was affected by the sampling volume, sampling rate, concentration of organic solvent in sample, desorption solvent, desorption rate, and desorption time. To obtain accurate results, the main extraction and desorption conditions (sampling volume, sampling rate, organic solvent concentration, desorption time) were investigated carefully. As the sampling volume in the extraction tube was increased, the extraction efficiency was found to increase gradually until saturation. In this study, the extraction efficiency was investigated for sampling volumes ranging from 30 to 80 mL, and 70 mL was selected as a suitable sampling volume to achieve satisfactory extraction efficiency. The sampling rate affects not only the extraction efficiency, but also the extraction time. When the sample flows through the extraction tube at a low rate, it requires a long test time. Although the increase in sampling rate reduces the extraction time, it often decreases extraction efficiency. In addition, large sampling rate leads to high pressure in the tube, which in turn reduces the service life of the tube. Therefore, the effect of sampling rate (1.25-2.50 mL/min) on extraction efficiency was investigated, and good extraction efficiency and short test time were achieved when the sampling rate was 2 mL/min. High hydrophobic PAHs have poor solubility in water. An appropriate amount of organic solvent in the sample solution can improve the solubility of PAHs to obtain accurate analytical results. However, the extraction efficiency was affected by the added organic solvent. Thus, the effect of volume fraction of methanol (0, 0.5%, 1%, 2%, 3%, and 5%, v/v) on the extraction efficiency was investigated. The sample solution without methanol afforded better extraction efficiency and satisfactory repeatability. After online extraction, the desorption directly affects the desorption efficiency. The peak areas of the eight PAHs were investigated with different desorption times (0.2, 0.4, 0.6, 0.8, 1.0, and 2.0 min), and a desorption time of 2.0 min was required to fully desorb all analytes and reduce their residuals. The IT-SPME-HPLC-DAD method was established under the optimized conditions, and the limits of detection (LODs), linear equations, linear ranges, and correlation coefficients were obtained. The LODs of the eight PAHs were in the range of 0.001-0.005 µg/L, the quantitative ranges of the analytes were 0.003-15.0 µg/L for Fla and Pyr, 0.010-20.0 µg/L for Phe and Ant, and 0.017-20.0 µg/L for Nap, Acy, Ace and Flu, the enrichment factors were in the range of 2029-2875, and the analytical precision was satisfactory (intra-day RSD%≤4.8%, and inter-day RSD≤8.6%). Compared with some reported methods, the method reported herein provided higher sensitivity, wider linear range, and shorter test time. This method was applied to the detection of PAHs in common drinking water, including bottled mineral water and water from drinking fountain. The satisfactory recovery (76.3%-132.8%) obtained proves that the method is suitable for the determination of trace PAHs in real water samples, with high sensitivity, rapid testing, online detection, and good accuracy. The extraction tube also exhibited satisfactory durability and chemical stability.

[Simultaneous determination of seven dimethylcyclosiloxanes in cosmetics of different formulation systems by gel permeation chromatography purification-gas chromatography-tandem mass spectrometry].

At present, the addition of dimethylcyclosiloxanes (DMCs) in cosmetics is being debated and no substantial progress has been made in their safety risk assessment because of the lack of a suitable analytical method. Therefore, it is of theoretical and practical significance to establish a method suitable for the determination of DMCs in cosmetics with different formulation systems. Accordingly, a method based on gel permeation chromatography (GPC) purification combined with gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the determination of seven DMCs in cosmetics. The cosmetic samples were extracted by ethyl acetate-cyclohexane (1∶1, v/v), purified by gel permeation chromatography, separated on a DB-5ms column (30.0 m×0.25 mm×0.25 µm), confirmed and detected by gas chromatography-tandem mass spectrometry in the selected reaction monitoring (SRM) mode, and quantified by the internal standard method with n-hexadecane as the internal standard. Experiments were carried out using n-tetradecane, n-hexadecane, and n-octadecane as the internal standards, and based on the retention time in GPC and GC, n-hexadecane was found to be the suitable choice for further analyses. The extraction efficiency for the target compounds was tested in different solvents such as methanol, n-hexane, acetonitrile, ethyl acetate, and ethyl acetate-cyclohexane (1∶1, v/v). Given the high recovery, ethyl acetate-cyclohexane (1∶1, v/v) was selected as the extraction solvent for analyses. Among the three purification methods (analysis without purification, solid-phase extraction (SPE), and GPC purification), GPC was selected as the best method because of the minimal matrix interference to the target compounds. Under the optimized conditions, the seven DMCs showed good linearities in the range of 0.05-1.0 mg/L. The correlation coefficients (r) were 0.994-0.998, which were greater than the required of the specification (r≥0.990). The limits of detection (LODs, S/N=3) were 0.04-0.08 mg/kg, and the limits of quantification (LOQs, S/N=3) were 0.12-0.24 mg/kg. According to the cosmetic matrix in different formulation systems, standard addition recovery tests at three levels of low, medium, and high were carried out. The average recovery rates of the targets were 85.3%-108.8%. The relative standard deviations (RSDs, n=6) were 3.1%-9.4%. The established method was also employed for the analysis of cosmetics in the market, and octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) were detected at various levels in the cosmetics. The method established in this study has the advantages of operational simplicity, high sensitivity, and good reproducibility, and it allows for the determination of seven DMCs in cosmetics with different formulation systems. The establishment of this method provides a basis for the quality supervision and inspection of DMCs in cosmetics in China, in addition to providing technical support for follow-up health and safety evaluation.

Optimization of microwave assisted extraction of simmondsins and polyphenols from Jojoba (Simmondsia chinensis) seed cake using Box-Behnken statistical design.

A closed-vessel microwave-assisted extraction (MAE) of simmondsins and polyphenols from defatted Jojoba cake using Box-Benkhen design with four independent variables (solvent/cake ratio, ethanol concentration, extraction time and microwave power) was investigated. ANOVA results showed that the obtained models were significant at 95% confidence level. Optimal extraction conditions were found for highest values of microwave power (500 W) and extraction time (15 min) and for moderate values of solvent to cake ratio (41 - 45 mL/g). Optimum simmondsins yield (23.35%) was obtained with pure water as solvent. However, optimum polyphenols yield (2.33%) and ORAC antioxidant activity (656 µmol TE/g) were obtained with 46.79% and 42.04% ethanol in water, respectively. ORAC antioxidant activity was found to be well correlated to polyphenol and simmondsin contents. These results indicate that MAE is an effective technique for recovery of bioactive compounds for food and pharmaceutical industries from Jojoba by-products.

Mass spectrometry imaging as a potential technique for diagnostic of Huanglongbing disease using fast and simple sample preparation.

Huanglongbing (HLB) is a disease of worldwide incidence that affects orange trees, among other commercial varieties, implicating in great losses to the citrus industry. The disease is transmitted through Diaphorina citri vector, which inoculates Candidatus Liberibacter spp. in the plant sap. HLB disease lead to blotchy mottle and fruit deformation, among other characteristic symptoms, which induce fruit drop and affect negatively the juice quality. Nowadays, the disease is controlled by eradication of sick, symptomatic plants, coupled with psyllid control. Polymerase chain reaction (PCR) is the technique most used to diagnose the disease; however, this methodology involves high cost and extensive sample preparation. Mass spectrometry imaging (MSI) technique is a fast and easily handled sample analysis that, in the case of Huanglongbing allows the detection of increased concentration of metabolites associated to the disease, including quinic acid, phenylalanine, nobiletin and sucrose. The metabolites abieta-8,11,13-trien-18-oic acid, suggested by global natural product social molecular networking (GNPS) analysis, and 4-acetyl-1-methylcyclohexene showed a higher distribution in symptomatic leaves and have been directly associated to HLB disease. Desorption electrospray ionization coupled to mass spectrometry imaging (DESI-MSI) allows the rapid and efficient detection of biomarkers in sweet oranges infected with Candidatus Liberibacter asiaticus and can be developed into a real-time, fast-diagnostic technique.

In smell's shadow: Materials and politics at the edge of perception.

This article examines the politics of smell at the edge of perception. In January 2014, the municipal water supply of Charleston, West Virginia was contaminated by an under-characterized chemical, crude MCHM. Even when instrumental measurements no longer detected the chemical, people continued to smell its licorice-like odor. In a space where nothing was certain, smell became the only indicator of potential harm. Officials responded by commissioning state-funded sensory testing of crude MCHM to determine its sensory threshold. Via the critical passage point of sensory science, some instances of embodied attunement were allowed to enter into the evidentiary regimes of perception, while other, similarly trained moments of attunement were excluded from the process. This, I show, produced knowledge about the spilled chemical that maintained the systems that contributed to the spill in the first place. Drawing on new materialist thought, I riff on biology and 'transduce' the ephemeral phenomena of smelling crude MCHM into a new medium: Rather than thinking of smell as a volatile molecular material (an odorant), I show that consideration of smell as a manipulable object that one can imagine as having tangible substance and shape offers a way to experiment with disciplinary forms. I suggest an alternate future, where sensory science acts to record sensory labor that produces facts about collective experience that cannot (easily) travel through current systems, a process that is one possible way of beginning to unravel entrenched systems of toxic harm.

Occurrence of bisphenol A and its alternatives in paired urine and indoor dust from Chinese university students: Implications for human exposure.

Bisphenol analogs (BPs), as the industrial chemicals, are widely used in consumer products. Limited information exists regarding human exposure to BPs in university students in China. In this study, we detected concentrations of seven BPs, namely bisphenol A (BPA), bisphenol AF (BPAF), bisphenol P (BPP), bisphenol AP (BPAP), bisphenol Z (BPZ), bisphenol S (BPS), and bisphenol F (BPF), in paired urine (n = 160) and indoor dust samples (n = 40) from university students in South China. High detection rates and levels (median) was found in BPA in paired urine (99%, 3.57 ng/mL) and indoor dust (80%, 2.98 µg/g) samples, followed by BPS (88%, 0.24 ng/mL; 78%, 0.22 µg/g). These findings suggest that BPA remains the major BPs used in consumer products. A positive relationship between urinary ∑BPs (sum of six BPs) concentration and indoor dust was observed (r = 0.444, p < 0.01), indicated that exposure to non-dietary BPs may also be significant to human exposure. The median EDIurine values (ng/kg bw/day) of ∑BPs in males (119.6) were relatively higher than (p < 0.05) those in females (84.6). By contrast, the median EDIdust of BPs (except for BPAF) in dust form female dormitories were slightly higher than that in dust from male dormitories. Notably, BPF was the most ingested from indoor dust (dormitory dust). This study is the first time to document the occurrence of BPs in paired urine and indoor dust in university students from China.

Occurrence, Distribution and Ecological Risk of Bisphenol Analogues in the Surface Water from a Water Diversion Project in Nanjing, China.

Due to the widespread use of bisphenol analogues (BPs) as alternatives to bisphenol A (BPA), considerable attention for health risk has been shown in aquatic ecosystems. The occurrence and distribution of six BPs were researched in a soluble phase (<10-3 µm), colloidal phase (10-3 µm to 1 µm), and suspended particulate matter (SPM >1 µm) in a water diversion project of Nanjing, China. Except for bisphenol Z, all BPs were detected in two or three phases, where the total concentrations of detected BPs were 161-613 ng/L, 5.19-77.2 ng/L, and 47.5-353 ng/g for the soluble phase, colloidal phase, and SPM, respectively. Among the detected compounds, BPA is still the dominant BPs in the soluble and colloidal phases, which is followed by bisphenol-S , while bisphenol-AF was the major contaminant in SPM, followed by BPA. The mean contribution proportions of colloids were 1-2 orders of magnitude higher than SPM, which suggests that colloids have a clear impact on regulating BPs' environmental behaviors. In terms of spatial distribution, the water diversion project could reduce the pollution levels of BPs, which might further affect the ecological security of the Yangtze River.

Characterization and analysis of estrogenic cyclic phenone metabolites produced in vitro by rainbow trout liver slices using GC-MS, LC-MS and LC-TOF-MS.

Cyclic phenones are chemicals of interest to the USEPA and international organizations due to their potential for endocrine disruption to aquatic and terrestrial species. The metabolic conversion of cyclic phenones by liver hepatocytes and the structure of main metabolites yielded have not been assessed in fish species. As part of a larger project, in this study we investigated the structure of metabolites produced in vitro by rainbow trout (rt) liver slices after exposure to the model cyclic phenones benzophenone (DPK), cyclobutyl phenyl ketone (CBP) and cyclohexyl phenyl ketone (CPK). While only one distinct metabolite was detected for DPK and CBP (benzhydrol and CBPOH, respectively), CPK yielded nine positional isomers (M1-M9) as products. In absence of standards, improved inference of CPK metabolites tentative structures was achieved by combining GC-MS with and without derivatization, LC with tandem MS, LC with high resolution time of flight (TOF) MS and LC fractionation data with CPK phase II conjugative metabolism information. Data supported that CPK is metabolized by phase I oxidation of the cyclohexyl ring and not the phenyl group as predicted by metabolism simulators. CPK metabolites M1 and M2 (MW 186), were proposed to be cyclohexenyl-derivatives. Also, M6-M9 were proposed to be hydroxylated metabolites (MW 204), with the potential for undergoing phase II conjugative metabolism to glucuronides and sulfates. Finally, M3, M4 and M5 were proposed as cyclohexanone-derivatives of CPK (MW 202), resulting from the limited redox-interconversion of their hydroxylated pairs M8, M6 and M7, respectively. Assessment of metabolite role in biological responses associated with endocrine disruption will advance the development of methods for species extrapolation and the understanding of differential sensitivity of species to chemical exposure.

A simple GC-MS method for the determination of diphenylamine, tolylfluanid propargite and phosalone in liver fractions.

In this study, an accurate and robust gas chromatography/mass spectrometry method was developed for quantitative analysis of diphenylamine, tolylfluanid, propargite and phosalone in liver fractions. Different injector parameters were optimized by an experimental design technique (central composite design). An optimal combination of injector temperature (°C), splitless time (min) and overpressure (kPa) values enabled to maximize the chromatographic responses. Sample preparation was based on protein precipitation using trichloroacetic acid followed by liquid-liquid extraction (LLE) of the pesticides with hexane. All compounds and endrin as internal standard were quantified without interference in selected ion monitoring mode. The calibration curves for diphenylamine, tolylfluanid, propargite and phosalone compounds were linear over the concentration range of 0.1 to 25 µM with determination coefficients (R2) higher than 0.999. A lower limit of quantification of 0.1 µM was obtained for all analytes, i.e. 422.5, 868.0, 876.2 and 919.5 µg/kg of liver fraction (hepatocytes) for diphenylamine, tolylfluanid, propargite and phosalone, respectively. All compounds showed extraction recoveries higher than 93%, with a maximum RSD of 3.4%. Intra- and inter-day accuracies varied from 88.4 to 102.9% and, imprecision varied from 1.1 to 6.7%. Stability tests demonstrated that all pesticides were stable in liver extracts during instrumental analysis (20 °C in the autosampler tray for 72 h) following three successive freeze-thaw cycles and, at -20 °C for up to 12 months. This simple and efficient analytical procedure is thus suitable for metabolism studies or for assessing mammals liver contamination.

Photodegradation of cyclohexane and toluene using TiO2/UV/O3 in gas phase.

Volatile organic compounds (VOC) are air pollutants usually found in urban and industrial areas. Heterogeneous photocatalysis is an interesting technique used to degrade these compounds. Several approaches may enhance this process; some studies have shown higher VOC conversions by adding ozone to the experimental system, once ozone increases the number of reactive radicals in the reaction. In this context, this work studied the conversion of cyclohexane and toluene by heterogeneous photocatalysis in gas phase, in the presence of titanium dioxide (TiO2), UV light, and different concentrations of ozone. For fixed space times from 13.1 to 48.8 s, an average increase of 9% was reached in cyclohexane conversion when comparing the system with maximum concentration of ozone (0.8%) and the system without it. In addition, difference of less than 2% in the conversion of cyclohexane with different moisture fractions was observed. Toluene photodegradation was also analyzed in the presence of ozone and although the conversion was only about 40% for the space time of 25 s, this result was maintained during 4 h of experiment, with no catalyst deactivation as usually reported in the literature for aromatic compounds. Based on the results, ozone addition is an advantageous technique to improve the photodegradation of VOC.

The 2014 crude 4-methylcyclohexanemethanol chemical release and birth outcomes in West Virginia.

Approximately 10,000 gallons of crude 4-methylcyclohexanemethanol and propylene glycol phenyl ether were accidentally released into the Elk River upstream from a water treatment facility in West Virginia. The objective of this study was to use logistic and Poisson regression analyses to determine the effect potential exposures had on adverse birth outcomes (birth weight, small for gestational age, and abnormal Apgar score). We adjusted for confounding factors and assessed prevalence of adverse birth outcomes by residential location and timing of the pregnancy. There were no statistically significant interactions between residential location and timing of the pregnancy (range of p values: .157-.806). Changes in the prevalence of birth outcomes were consistent before and after the spill regardless of residential location. There was no evidence of an association between adverse birth outcomes and potential exposure to the released chemicals.

A dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by injector port silylation coupled with gas chromatography-tandem mass spectrometry for the determination of nine bisphenols in bottled carbonated beverages.

In the present study, a method has been efficiently developed for the first time to determine nine bisphenol analogues [bisphenol A (BPA), bisphenol C (BPC), bisphenol AF (BPAF), bisphenol E (BPE), bisphenol F (BPF), bisphenol G (BPG), bisphenol M (BPM), bisphenol S (BPS), and bisphenol Z (BPZ)] together in bottled carbonated beverages (collected from the local market of Lucknow, India) using dispersive liquid-liquid microextraction process. This is based on solidification of floating organic droplet (DLLME-SFO) followed by injector port silylation coupled with gas chromatography-tandem mass spectrometry. The process investigated parameters of DLLME-SFO (including the type of extraction and disperser solvents with their volumes, effect of pH, ionic strength, and the sample volume), factors influencing to injection port derivatization like, collision energy, injector port temperature, derivatizing reagent with sample injection volume, and type of organic solvent. BPA, BPF, BPZ, and BPS were detected in each sample; whereas, other bisphenols were also detected in some carbonated beverage samples. After optimizing the required conditions, good linearity of analytes was achieved in the range of 0.097-100ngmL-1 with coefficients of determination (R2)≥0.995. Intra-day and inter day precision of the method was good, with relative standard deviation (% RSD)≤10.95%. The limits of detection (LOD) and limits of quantification (LOQ) values of all bisphenols were ranged from 0.021 to 0.104ngmL-1 and 0.070 to 0.343ngmL-1, respectively. The recovery of extraction was good (73.15-95.08%) in carbonated beverage samples and good enrichment factors (96.36-117.33) were found. Thus, the developed method of microextraction was highly precise, fast, and reproducible to determine the level of contaminants in bottled carbonated beverages.

Comparative analytical and toxicological assessment of methylcyclohexanemethanol (MCHM) mixtures associated with the Elk River chemical spill.

On January 9, 2014, a chemical mixture containing crude methylcyclohexanemethanol (MCHM) contaminated the water supply of Charleston, West Virginia. Although the mixture was later identified as a mix of crude MCHM and stripped propylene glycol phenyl ethers, initial risk assessment focused on 4-MCHM, the predominant component of crude MCHM. The mixture's exact composition and the toxicity differences between 4-MCHM, crude MCHM, and the tank mixture were unknown. We analyzed the chemical composition of crude MCHM and the tank mixture via GC/MS and, based on identified spectra, found that crude MCHM and the tank mixture differed in chemical composition. To evaluate acute developmental toxicity, zebrafish embryos were exposed to 0, 1, 6.25, 12.5, 25, 50, or 100 parts per million (ppm; mg/L) of 4-MCHM, crude MCHM, or the tank mixture. The percent mortality and percent hatch, larval morphology alterations, and larval visual motor response test were used to establish toxicity profiles for each of the chemicals or mixtures. The acute toxicity differed between 4-MCHM, crude MCHM and the tank mixture with significant differences in survival, hatching, morphology, and locomotion at levels as low as the short-term screening level of 1 ppm, suggesting a need for further research into human health risks. This study is the first to evaluate the developmental toxicity of the tank mixture and highlights that studies evaluating risk should not assume the effects of 4-MCHM or crude MCHM are representative of the Tank 396 mixture.

Kinetic, product, and computational studies of the ultrasonic induced degradation of 4-methylcyclohexanemethanol (MCHM).

A massive spill of 4-methylcyclohexanemethanol (MCHM), a semi-volatile organic compound, contaminated the Elk river and forced the recent closure of tap water for nearly 300,000 residents. Typical water treatment methods are not effective for MCHM remediation, however ultrasonic irradiation leads to its rapid pseudo-first order degradation. The degradation processes were effectively modeled employing heterogeneous kinetic models with the reaction surface corresponding to the gas-liquid interface of the cavitation bubble. The Freundlich model which takes into account non-uniform distribution within the reactive zone showed the strongest correlation to the observed degradation kinetic data with R2 > 0.99. Solute-solute clustering behavior is proposed to explain non-uniform distribution of MCHM. The results indicate the degradation occurs predominantly at the gas-liquid interface as a result of hydroxyl radical reactions and pyrolysis with primary reaction products, (4-methylcyclohexenyl) methanol and 4-methylcyclohexanone. Computational methods using density functional B3YPL/6-311G** calculations with Gaussian 09 provided insight of the hydroxyl radical and pyrolytic degradation pathways for the isomeric and conformational forms of MCHM. Our studies demonstrate that heterogeneous kinetic models and computational methods are important tools for the fundamental understanding and effective application of ultrasonically mediated degradation of MCHM which may be extended to a number of semi-volatile compounds.

Essential oil from leaves of Myrcianthes fragrans (Myrtaceae) from Costa Rica: a new chemotype? / Aceite esencial de las hojas de Myrcianthes fragrans (Myrtaceae) de Costa Rica: ¿Un nuevo quimiotipo?

Myrcianthes is a Myrtaceous genus of flowering plants of about 30 to 40 species, distributed in the American continent. The aim of this work was to study the chemical composition of the foliar essential oil from M. fragrans growing wild in central Costa Rica. The essential oil was obtained through the steam distillation process in a Clevenger type apparatus. The chemical composition of the oil was performed by capillary gas chromatography with a flame detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) using the retention indices on a DB-5 type capillary column in addition to mass spectral fragmentation patterns. A total of 98 compounds were identified, accounting for 98.8% of the total amount of the oil. The major constituents in the leaf oil were (E)-methyl cinnamate (39.6%), limonene (34.6%), α-pinene (6.8%), and linalool (6.8%). This is the first report of (E)-methyl cinnamate occurring in oils of this plant genus. These findings appear to suggest a new chemotype of M. fragrans.

Myrcianthes (Myrtaceae) consta de 30 a 40 especies, distribuidas en el continente americano. El objetivo del presente trabajo consistió en identificar la composición química del aceite esencial contenido en las hojas de M. fragrans, planta que crece en forma silvestre en el Valle Central de Costa Rica. La extracción del aceite se efectuó mediante el método de hidrodestilación usando un equipo de Clevenger modificado. La composición química del aceite se analizó mediante las técnicas de cromatografía gaseoso-líquida con detector de ionización de llama (GC-FID) y de cromatografía gaseoso-líquida acoplada a un detector de masas (GC-MS). Se utilizaron índices de retención obtenidos en una columna capilar tipo DB-5 y se compararon con los patrones de iones de fragmentación de masas. Se identificaron en total 98 compuestos, correspondientes a un 98.8% de los constituyentes totales. Los componentes mayoritarios del aceite resultaron ser (E)-cinamato de metilo (39.6%), limoneno (34.6%), α-pineno (6.8%) y linalol (6.8%). Este es el primer informe de la aparición de (E)-cinamato de metilo en aceite de hojas de este género de plantas. Los datos obtenidos parecen sugerir un nuevo quimiotipo de M. fragrans.

Moscatel vine-shoot extracts as a grapevine biostimulant to enhance wine quality.

Non-aromatic vine-shoot extracts (Airén) has been recently proposed as "viticultural biostimulants" when applied to grapevine. In this paper, the application of extracts from non-toasted (MVS) and toasted (MVSToasted) vine-shoots from the well-known aromatic variety such Moscatel were applied on Airén grapevine leaves, observing an increased for grape yield and wines with a lower alcohol degree. All wines at the end of the alcoholic fermentation were characterized by their fruity and floral descriptors, especially MVS wines; and 4 months later, MSV and MVSToasted wines surprised by their higher spicy notes, which correspond with the highest OAVs values for compounds such as norisoprenoids (ß-damascenone), vanillin derivatives (vanillin, acetovanillone) and volatile phenols (guaiacol, syringol), compared to control wine. Wine phenolic composition was affected positively over all by MVS in case of phenolic acids. These results confirm that Moscatel vine-shoot extracts foliar application into Airén non-aromatic grapevines produce an interesting enhance on wine quality.

Elucidation of Biosynthetic Pathways of Natural Products.

During the last decade, we have revealed biosynthetic pathways responsible for the formation of important and chemically complex natural products isolated from various organisms through genetic manipulation. Detailed in vivo and in vitro characterizations enabled elucidation of unexpected mechanisms of secondary metabolite biosynthesis. This personal account focuses on our recent efforts in identifying the genes responsible for the biosynthesis of spirotryprostatin, aspoquinolone, Sch 210972, pyranonigrin, fumagillin and pseurotin. We exploit heterologous reconstitution of biosynthetic pathways of interest in our study. In particular, extensive involvement of oxidation reactions is discussed. Heterologous hosts employed here are Saccharomyces cerevisiae, Aspergillus nidulans and A. niger that can also be used to prepare biosynthetic intermediates and product analogs by engineering the biosynthetic pathways using the knowledge obtained by detailed characterizations of the enzymes. (998 char.).