A Microwave-Assisted Extraction Method for Determining Hot Water Solubility of Wood

A microwave-assisted extraction method is proposed as an alternative to the conventional method for determining the hot water solubility of wood. In this alternative method, microwave heating substitutes for the boiling water to extract part of the extraneous components as well as starches in wood tissues. Experimental results indicate that 100 mL water can be heated to boiling in only 75 s under the microwave radiation. Hence, only 15-20 min are required to complete the extraction procedure for Liquidambar formosana Hance and Swietenia mahagoni Jacq., 10 min and 5 min for Taiwania cryptomerioides and Cunninghamia lanceolata (Lamb) Hook, respectively. In general, a 15-min microwave heating has the potential to be an alternative to the conventional method, which requires 3 h for the hot water solubility determination

Dispersive resonance bands within the space charge layer of metal- semiconductor junction

Based on measurements of angle resolved photoemission, we report that in the Pb/Ge(111)- \sqrt{3}x\sqrt{3} R30^\circ structure, in addition to three bands resembling Ge heavy hole (HH), light hole (LH), and split off (SO) bulk band edges, a fourth dispersive band resembling the non split off (NSO) band is found near the surface zone center. While three Ge bulk-like bands get distorted due to strong coupling between Pb and Ge, the NSO-like band gets weaker and disappears for larger thickness of Pb, which, when combined with ab initio calculations, indicates its localized nature within space charge layer. Our results are clearly important for designing electronics involved with metal-semiconductor contacts.Comment: 21 pages, 4 figures, Phys. Rev. B 81, 245406 (2010

Determination of cyromazine and melamine in chicken eggs using quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction coupled with liquid chromatography–tandem mass spectrometry

A rapid and sensitive method has been developed for the simultaneous detection of cyromazine and melamine in chicken eggs using the quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The optimal extraction solvent for the liquid–liquid extraction was 5 mL of acetonitrile with a 0.1 M hydrochloric acid aqueous solution (99.5:0.5, v/v). The extract was cleaned with 0.5 g of anhydrous magnesium sulfate and 10 mg of graphitized carbon black. The analysis of cyromazine and melamine was accomplished by combining the use of an anion exchange LC column with tandem mass spectrometry in the positive electrospray ionization mode with selected reaction monitoring mode (SRM). The detection limits were 1.6 ng g−1 for cyromazine and 8 ng g−1 for melamine, and the quantitation limits were 5.5 ng g−1 for cyromazine and 25 ng g−1 for melamine. The recoveries of cyromazine and melamine in the spiked egg samples were 83.2% and 104.6%, respectively, with an relative standard deviation (RSD) of less than 18.1%. The intra-day and inter-day precisions, represented by the RSD, ranged from 1.5% to 8.8% and 6.8% to 14.3%, respectively. The proposed method was tested by analyzing chicken eggs from the markets and from the veterinary medicine laboratory. The concentrations of cyromazine and melamine detected in these samples were in the range of 20–94 ng g−1. The results demonstrated that the QuEChERS method combined with LC–MS/MS is a simple, rapid and inexpensive method for the analysis of cyromazine and melamine in eggs

Gramella planctonica sp. nov., a zeaxanthin-producing bacterium isolated from surface seawater, and emended descriptions of Gramella aestuarii and Gramella echinicola

A Gram-stain negative, strictly aerobic, zeaxanthin-producing, rod-shaped, non-spore-forming bacterial strain which is motile by gliding, designated CC-AMWZ-3(T), was isolated from surface seawater off coastal Kending, Taiwan. Strain CC-AMWZ-3(T) was found to share 93.3 % and 96.0-92.4 % pairwise 16S rRNA gene sequence similarity to Gramella echinicola KMM 6050(T) and other Gramella species, respectively, and formed distinct phyletic lineage during phylogenetic analysis. The major fatty acids were identified as C16:0, iso-C15:0, anteiso-C15:0, C16:1 ω6c and/or C16:1 ω7c and iso-C17:1 ω9c and/or C16:0 10-methyl. Polar lipids were found to include phosphatidylethanolamine, six unidentified lipids and three unidentified aminolipids. The DNA G+C content was determined to be 40.6 mol%. Menaquinone-6 was the sole respiratory quinone identified and triamine-sym-homospermidine was the predominant polyamine. Based on the polyphasic characteristics that are in line with those of Gramella species, in addition to distinguishing phylogenetic and phenotypic features, strain CC-AMWZ-3(T) appears to represent a novel species of the genus Gramella, for which the name Gramella planctonica sp. nov. (type strain CC-AMWZ-3(T) = JCM 18807(T) = BCRC 80553(T)) is proposed. In addition, emended descriptions of the species Gramella aestuarii and Gramella echinicola are also proposed

Headspace solid phase microextraction in-situ supercritical fluid extraction coupled to gas chromatography-tandem mass spectrometry for simultaneous determination of perfluorocarboxylic acids in sediments

Headspace solid phase microextraction (HS-SPME) in-situ supercritical fluid extraction (SEE) was investigated for the determination of trace amounts of perfluorocarboxylic acids (PECAs) in sediments. Quantitation was performed by using gas chromatography coupled to negative chemical ionization-tandem mass spectrometry (GC-NCI-MS/MS). The optimum conditions of HS-SPME following SFE were obtained using 500 mu L n-butanol as a derivatization reagent in supercritical carbon dioxide with static extraction for 10 min, then dynamic extraction for 20 min at 30 MPa and 70 C and simultaneous collected with 100 mu m thickness PDMS fiber. The linear range of proposed method was from 5 to 5000 ng g(-1). with limit of detection ranging from 0.39 to 0.54 ng g(-1) and limit of quantitation ranging from 1.30 to 1.80 ng g(-1). The developed method was successfully applied to analyze PFCAs in sediments from rivers and beach near industrial areas. The concentrations of PFCAs determined are from 282 to 4473 ng g(-1). (C) 2011 Elsevier B.V. All rights reserved

A novel method of ultrasound-assisted dispersive liquid-liquid microextraction coupled to liquid chromatography-mass spectrometry for the determination of trace organoarsenic compounds in edible oil

A novel approach, ultrasound-assisted dispersive liquid-liquid microextraction combined with liquid chromatography-mass spectrometry (UA-DLLME with LC-MS) is demonstrated to be quite useful for the determination of trace amounts of organoarsenic compounds in edible oil. The organoarsenic compounds studied include dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and 3-nitro-4-hydroxyphenyl arsenic acid (Roxarsone). Orthogonal array experimental design (OAD) was utilized to investigate the parameter space of conditions for UA-DLLME. The optimum conditions were found to be 4 min of ultrasonic extraction using 1.25 mL of mixed solvent with 50 mu L of buffer solution. Under these optimal conditions, the linear range was from 10 ng g(-1) tc 500 ng g(-1) for DMA and Roxarsone, from 25 ng g(-1) to 500 ng g(-1) for MMA. Limits of detection of DMA, MMA and Roxarsone were 1.0 ng g(-1), 3.0 ng g(-1) and 5.8 ng g(-1), respectively. The precisions and recoveries also were investigated by spiking 3-level concentrations in edible oil. The recoveries obtained were over 89.9% with relative standard deviation (RSD) of 9.6%. The new approach was utilized to successfully detect trace amounts of organoarsenic compounds in various edible oil samples. (C) 2011 Elsevier B.V. All rights reserved