Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + ethanol using response surface methodology.

Malaria is a high priority life-threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin-based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC-CO2 ) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9-30 MPa), temperature (33-67°C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO2 extraction conditions were found to be 30 MPa and 33°C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 ± 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC-CO2 and Soxhlet extractions. Results indicated that SC-CO2 and SC-CO2 +ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products.

Automotive Wastes.

A review of the literature from 2014 related to automotive wastes is presented. Topics include solid wastes from autobodies and tires as well as vehicle emissions to soil and air as a result of the use of conventional and alternative fuels. Potential toxicological and health risks related to automotive wastes are also discussed.

Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater.

Hydrocarbon-contaminated soil and groundwater at oil and gas production sites may be additionally impacted by salts due to release of produced waters. However, little is known about the effect of salt on the in-situ biodegradation of hydrocarbons by terrestrial microbes, especially at low temperatures. To study this effect, we prepared a groundwater-soil slurry from two sites in Canada: a former flare pit site contaminated with flare pit residue (Site A), and a natural gas processing facility contaminated with natural gas condensate (Site B). The slurry with its indigenous microbes was amended with radiolabeled hydrocarbons dissolved in free product plus nutrients and/or NaCl, and incubated in aerobic biometer flasks with gyrotory shaking at either 25 or 10 degrees C for up to 5 weeks. Cumulative production of (14)CO(2) was measured and the lag time, rate and extent of mineralization were calculated. For Site A, concentrations of NaCl >or=1% (w/v) delayed the onset of mineralization of both (14)C-hexadecane and (14)C-phenanthrene under nutrient-amended conditions, but once biodegradation began the degradation rates were similar over the range of salt concentrations tested (0-5% NaCl). For Site B, increasing concentrations of NaCl >or=1% (w/v) increased the lag time and decreased the rate and extent of mineralization of aliphatic and aromatic substrates. Of particular interest is the observation that low concentrations of salt (

Detecting naphthenic acids in waters by gas chromatography-mass spectrometry.

Naphthenic acids (general formula C(n)H(2n+Z)O(2)) are water-soluble, toxic compounds found in petroleum and bitumen. Some of the current methods for detecting these acids in waters depend on measuring the presence of the carboxylic acid functional group, and therefore many of these methods also detect naturally occurring carboxylic acids that are not naphthenic acids. We report a procedure that includes liquid-liquid extraction, cleanup, and derivatization to form t-butyldimethylsilyl esters prior to gas chromatography-mass spectrometry (GC-MS) analysis. Using low- and high-resolution MS to detect the ion C(15)H(27)O(2)Si(+) (nominal m/z=267) is an excellent indicator of the presence of naphthenic acids at concentrations > or =10microgL(-1).