A new type of instrument that called the rapid determination of carbon dioxide combining power without mercury is proposed. The performance of the instrument in accordance to the requirements in ISO15189 of laboratory accreditation has been evaluated. The results showed that, this instrument is safe, pollution-free, accurate and practical.
Carbon Dioxide ; analysis ; Clinical Chemistry Tests ; instrumentation ; Equipment Design

Homoacetogens are a group of microorganisms with application potential to produce chemicals and biofuels by the bioconversion of synthesis gas. In this study, we collected waste activated sludge samples to screen homoacetogens by Hungate anaerobic technique, and studied the effect of pH on acetate and alcohol production from H2/CO2 gas. The mixed culture contained Clostridium ljungdahlii, Lysinibacillus fusiformis and Bacillus cereus. Acetate concentration achieved 31.69 mmol/L when the initial pH was 7. The mixed culture containing homoacetogen could converting H2/CO2 to acetate, which provides an efficient microbial resource for the bioconversion of synthesis gas.
Acetates ; chemistry ; Bacteria ; classification ; Biofuels ; Carbon Dioxide ; Hydrogen ; Sewage ; microbiology

OBJECTIVETo develop a green and rapid method for extraction of lobetyolin from C. pilosula.

METHODExtraction of lobetyolin from C. pilosula with supercritical carbon dioxide in the presence of ethanol was studied. The effects of pressure, temperature, volume of cosolvent and extraction time on efficiency and their interactive relationships were discussed, based on central composite design and response surface methodology (RSM).

RESULTThe key effect factor was volume of cosolvent. The extraction yield of lobetyolin was 0.078 6 mg x g(-1) when C. pilosula (40-60 mesh) was extracted at 30 MPa, 60 degrees C and 2 L x min(-1) (as CO2 in normal pressure and temperature) for 100 minutes with supercritical CO2 and 1 mL x min(-1) ethanol as dynamic cosolvent.

CONCLUSIONThis result is better than that obtained from traditional method. Therefore, the optimized process is valuable for extraction of lobetyolin from C. pilosula.

Carbon Dioxide ; chemistry ; Chemical Fractionation ; methods ; Codonopsis ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Ethanol ; chemistry ; Polyacetylenes ; chemistry

In order to optimize extraction process conditions of tannins from Geranium orientali-tibeticum by supercritical CO2, the content of tannins was determined by phosphomolybdium tungsten acid-casein reaction, with extraction pressure, extraction temper- ature and extraction time as factors, the content of tannins from extract of G. orientali-tibeticum as index, technology conditions were optimized by orthogonal test. Optimum technology conditions were as follows: extraction pressure was 25 MPa, extraction temperature was 50 °C, extracted 1.5 h. The content of tannins in extract was 12.91 mg x g(-1), extract rate was 3.67%. The method established could be used for assay the contents of tannin in G. orientali-tibeticum. The circulated extraction was an effective extraction process that was stable and feasible, and that provides a way of the extraction process conditions of tannin from G. orientali-tibeticum.
Carbon Dioxide ; chemistry ; Chemical Fractionation ; methods ; Drugs, Chinese Herbal ; chemistry ; Geranium ; chemistry ; Tannins ; isolation & purification

Most main oilfields in China have already entered a "double high" development stage (high water cut, high recovery degree). To further enhance oil recovery in reservoirs after polymer flooding (RAPFs), an efficient activator formulation for promoting metabolism of endogenous microorganism was studied by aerogenic experiments, physical simulation experiments, electron microscopy scanning and pyrophosphate sequencing. Results show that the activator could activate the endogenous microorganisms in the injected water and make the pressurized gas reach 2 MPa after 60 d static culture of the activator in a high pressure vessel. The oil recovery efficiency of natural core physical simulation flooding can be improved by more than 3.0% (OOIP) in RAPFs when injected 0.35 PV activator with 1.8% mass concentration, and a lot of growth and reproduction of activated endogenous microorganism in the core was observed by electron microscopy scanning. Field trial with 1 injector and 4 producers was carried out in the east of south II block of Sa Nan in December 2011. By monitoring four effective production wells, changes of carbon isotope δ13C (PDB) content of methane and carbon dioxide were -45 per thousand to -54 per thousand and 7 per thousand to 12 per thousand. Compared with east II of Sa Nan block, the oil amount increased by 35.9%, water cut stabled at 94%. The incremental oil was 5 957 t during the three and a half years, which provides an alternative approach for further improving oil recovery in similar reservoirs.
Carbon Dioxide ; chemistry ; Carbon Isotopes ; analysis ; China ; Diphosphates ; chemistry ; Methane ; chemistry ; Oil and Gas Fields ; microbiology ; Polymers ; Water ; Water Microbiology

The effects of pretreatment of supercritical carbon dioxide (SC-CO2) on the supramolecular structure of cellulose and the cellulase catalyzed reaction were investigated. The cellulase activity was not affected when it was treated with SC-CO2 at 10MPa and at 50 degrees C for 30 min. But when the cellulase was treated by SC-CO2 in the presence of cellulose, the catalytic activity of the cellulase was lost. The cellulose pretreated with or without cellulase under the same SC-CO2 condition was then hydrolyzed with tresh crude cellulase. The final reducing sugar yield from the hydrolysis of the cellulose pretreated with cellulase was higher than that of the cellulose pretreated without cellulase. It was also found that the improvement of the enzymolysis had a direct relevance with the amount of cellulase used during the SC-CO2 pretreatment. The moisture content of cellulose before SC-CO2 pretreatment had an obvious influence on the subsequent enzymolysis. When the moisture content of cellulose was 60% (W/W), the reducing sugar yield was higher than when the moisture content was over 100% (W/W). The FT-IR spectra showed that the structure of the cellulose pretreated with cellulase under the SC-CO2 condition was different from that of the cellulose pretreated without cellulase. In the presence of the enzyme, the strength of the hydrogen bonds and the I beta phase at 710cm(-1) in the crystalline cellulose was weakened. These results suggest that the change in the cellulose structure induced by the SC-CO2 treatment favous the subsequent enzymolysis.
Carbon Dioxide ; chemistry ; Cellulase ; chemistry ; metabolism ; Chromatography, Supercritical Fluid ; methods ; Spectroscopy, Fourier Transform Infrared

Type, mode of affiliating, mechanism of action of entrainer in Supercritical CO2 on extraction of Chinese traditional and herbal drugs were briefly reviewed. Application of entrainer in Supercritical CO2 on extraction of flavones, terpenes, sterols, and saponins in Chinese traditional and herbal drugs were recommended in particular. Some problems and directions in research of entrainer in Supercritical CO2 on extraction of Chinese traditional and herbal drugs were shown in this paper.
Carbon Dioxide ; chemistry ; Chromatography, Supercritical Fluid ; methods ; Drugs, Chinese Herbal ; chemistry

In order to improve its dispersion condition in dental composite resin and enhance its interaction with the matrix, single-walled carbon nanotubes(SWNTs) were refluxed and oxidized, then treated by APTE. Their outer surface were coated by nano-SiO2 particles using sol-gel process, then further treated by organosilanes ATES. IR and TEM were used to analyze modification results. TEM pictures showed nano-particles were on the surface of SWNTs; IR showed characteristic adsorbing bands of SiO2. Composite resin specimen with modified SWNTs was prepared and examined by TEM. SWNTs were detected in composite resin matrix among other inorganic fillers.
Composite Resins ; chemistry ; Dental Materials ; chemistry ; Humans ; Nanotubes, Carbon ; chemistry ; Resin Cements ; chemistry ; Silicon Dioxide ; chemistry ; Surface Properties ; Tensile Strength

BACKGROUNDSevoflurane is currently used as a volatile inhalation anesthetic with many clinical advantages. A representative degradation product, compound A, was quantitatively measured to investigate whether there are different reactions between two kinds of water content sevoflurane formulations with different carbon dioxide (CO2) absorbents.

METHODSA closed-circle breathe bag with the Dräger Fabius GS anesthesia apparatus was used as an artificial rubber lung. The experiments were grouped according to different sevoflurane formulations: group A: higher-water sevoflurane (Ultane); group B: lower-water sevoflurane (Sevoness). During the experiment, CO2 (200 ml/min) was continually perfused to keep the end-tidal pressure of CO2 (P(ET)CO2) at 35 - 45 mmHg. The artificial ventilation was set to 6 L/min, and the breathing rate at 12 breaths/min. The circuit was operated with constant fresh gas flow rate (1 L/min) and the sevoflurane concentration was kept at 1.0 minimum alveolar concentration (MAC) for 240 minutes. At 0, 10, 20, 30, 60, 90, 120, 180 and 240 minutes, gas was collected from the Y-piece. Gas chromatography/mass spectrometry (GC/MS) was used to quantify the major degradation product, compound A, with different water content sevoflurane. PETCO2 and sevoflurane concentration, and the temperature of the canister were continuously monitored during the experiment.

RESULTSThere were no significant differences in P(ET)CO2 and sevoflurane concentrations between the two groups. Drägersorb 800 plus produced the highest concentrations of compound A compared with other sodalimes, and Sevoness in Drägersorb 800 plus generated more compound A than Ultane (P < 0.05). There were significant differences in the peak and average compound A concentrations between Ultane and Sevoness with Drägersorb 800 plus (P < 0.05), while the compound A concentration produced by Sodasorb grase and sofonolime in the two groups showed no significant difference (P > 0.05). In the same group, the peak and average of compound A concentration produced by Sodasorb grase and sofonolime showed significant difference with Drägersorb 800 plus (P < 0.05).

CONCLUSIONThe water content of sevoflurane and potassium hydroxide in CO2 absorbent can influence compound A production.

Absorption ; Carbon Dioxide ; chemistry ; Ethers ; chemistry ; Gas Chromatography-Mass Spectrometry ; methods ; Hydrocarbons, Fluorinated ; chemistry ; Methyl Ethers ; chemistry

OBJECTIVETo optimize the extraction condtions in the modification of Rhizoma Cyperi, which had been extracted by the technique of supercritical CO2 extraction.

METHODThe semi-bionic extraction (SBE) conditions were optimized through homogeneous design while the extracts (< or = 1 000), the total area of HPLC and dry extracts were adopted as markers.

RESULTThe optimized SBE extraction conditions are the following: pH in first extraction was adjusted to 2.005 3. And then pH in second and third extraction adjusted to 6.508 2 and 8.945 6, time of the whole extracted process was 3.912 7 h.

CONCLUSIONCombine the faction of production,we make sure the conclusion is pH in first extraction was 2.00, pH in second and third extraction adjusted to 6.50 and 9.00, duration of run was 2.0 h, 1.0 h and 1.0 h, respectively.

Carbon Dioxide ; chemistry ; Chromatography, Supercritical Fluid ; methods ; Cyperus ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Hydrogen-Ion Concentration ; Rhizome ; chemistry