Application of solid-phase microextraction to the determination of polycyclic aromatic sulfur heterocycles in Bohai Sea crude oils.

A simple and rapid solid-phase microextraction approach for the isolation of polycyclic aromatic sulfur heterocycles from the aromatic fraction of crude oil is described. 8-Hydroxyquinoline silica gel impregnated with palladium chloride was used as a sorbent material for extraction. Operational parameters of the extraction solvents have been evaluated and optimized. Benzothiophene, dibenzothiophene, and benzo[b]naphtho[1,2-d]thiophene and their C1-C4 alkyl derivatives were identified and quantified by GC-MS. Under optimum conditions, the limits of detection for benzothiophene, dibenzothiophene, and benzo[b]naphtho[1,2-d]thiophene were 0.277, 0.193, and 0.597 µg/g oil, respectively. The recoveries for the polycyclic aromatic sulfur heterocycles ranged from 81.5 to 92.1%, and the linear dynamic range was from 10 to 1000 ng/mL. The developed methodology was tested in the characterization of crude oil samples collected at the DY, SZ, ZH, and HC petroleum oil fields of the Bohai Sea. The results proved that SPE coupled with GC-MS is a promising tool for the quantitative analysis of polycyclic aromatic sulfur heterocycles in crude oils, especially for oil samples with low concentrations of polycyclic aromatic sulfur heterocycles.

[Synergic effect of marine obligate hydrocarbonoclastic bacteria in oil biodegradation].

OBJECTIVE: In order to study the synergic effect of two marine obligate hydrocarbonoclastic bacteria in the oil biodegradation process. METHODS: We combined the PAHs degrader Marinobacter sp. PY97S with the oil degrader Alcanivorax sp. 22CO-6 and Alcanivorax sp. JZ9B respectively to construct oil-degrading consortia. Multiple methods including weighting method, gas chromatography-flame ionization detection, gas chromatography-mass spectrometry and thin layer chromatography-flame ionization detection were used to analyze and compare the oil degradation rates as well as the chromatographic figures of degraded oil between the pure cultures of obligate hydrocarbonoclastic bacteria and defined consortia. RESULTS: The two consortia, 22CO-6 + PY97S and JZ9B + PY97S, exhibited synergic effects in the oil biodegradation process. The degradation rates of oil by the consortia were increased from 27.81% and 83.52% to 64.03% and 86.89% compared to the pure culture of oil degrader 22CO-6 and JZ9B, respectively. The consortia could degrade aliphatic and aromatic fraction at the same time, including high molecular weight PAHs chrysene and its alkyl derivatives. CONCLUSION: There are obvious synergic effect of Alcanivorax and Marinobacter strains in the oil biodegradation process, which accelerated the oil biodegradation and decomposed thoroughly the more ecotoxic high molecular weight compounds in crude oil.

Biodegradation of crude oil by an Arctic psychrotrophic bacterium Pseudoalteromomas sp. P29.

A psychrotrophic petroleum-degrading bacterium Pseudoalteromonas sp. P29 was isolated from marine sediment, which was collected during 2nd Chinese Arctic Scientific Expedition. The phenotypic character and biodegradation efficiency on mixed oil or vacuum oil were tested at low temperature. The strain Pseudoalteromonas sp. P29 grew in a range of temperature from 5 to 35 degrees C and the optimum temperature was 25 degrees C. Gas chromatography analysis indicated that the strain might preferentially metabolize shorter-chain alkanes. The biodegradation efficiency were nearly 90 and 80%, respectively, after incubation at 5 degrees C for 28 days in the mineral medium supplement with mixed oil or vacuum oil as the sole carbon and energy source. The results showed a possible exploitation of the strain in future biotechnological processes especially in cold contaminated environments.

GC-MS fingerprints for discrimination of Ligusticum chuanxiong from Angelica.

A GC-MS fingerprinting technique based on the essential oil components has been developed for the discrimination of chuanxiong against Chinese Angelica (Angelica sinensis (Oliv.) Diels) or other herbs with similar compositions. The analytical performance of four different extraction methods for the separation of essential oil components have been compared and these include: ultrasound-assisted extraction (UAE), supercritical fluid extraction (SFE), Soxhlet extraction (SHE) and hydro-distillation extraction (HDE). The results showed that UAE was the most effective extraction method, and the operational parameters of UAE were optimized. 3-Butylphthalide, Z-butylidenephthalide, senkyunolide I, senkyunolide H, E-butylidenephthalide, senkyunolide A, neocnidilide, Z-ligustilide and E-ligustilide were tentatively identified in chromatograms of chuanxiong based on their GC-EI-MS data. Similarity coefficient calculations based on correlation methods have been performed on the GC-MS fingerprints. Using an authentic standard Chuanxiong as the reference, the similarity coefficients between the standard and all other chuanxiong samples ranged from 0.90 to 1.0 (with 1.0 being the perfect match), which as a group can be readily separated from the Angelica samples for which the similarity index against the chuanxiong standard ranged from 0.75 to 0.77. Conversely, when an authentic Angelica standard was used as the reference, the respective similarity coefficients fall in the range of 0.70-0.75 and 0.98-1.00 for the chuanxiong and Angelica sample groups. Our results thus demonstrate that the fingerprinting technique developed in the study can indeed discriminate the two herbs with high reliability.

Residues of organochlorine pesticides in near shore waters of LaiZhou Bay and JiaoZhou Bay, Shandong Peninsula, China.

The extent of organochlorine pesticides (OCPs) contamination in coastal waters around LaiZhou Bay and JiaoZhou Bay in Shandong Peninsula, northern China, was investigated. The areas around the two bays are both densely populated, thrive with intensive agriculture and industrial activities. Multi-techniques including GC-MS, GC-muECD coupled with chemical peak confirmation and strict QC procedures were used for the quantitative determination of 15 OCPs including alpha, beta, gamma and delta isomers of hexachlorocyclohexane (HCH), pentachloronitrobenzene (PCNB), heptachlor, aldrin, endosulfan, p,p'-DDE, dieldrin, endrin, p,p'-DDD, o,p'-DDT, p,p'-DDT and methoxychlor. The survey results show that contaminations by OCP residues remain widespread in the areas, but the averaged concentration levels are all below the regulatory limits, e.g., CMC limits (acute criterion values) specified in US Environmental Protection Agency (USEPA) and China national standards. Average concentration of OCPs in water samples were from undetectable to 3.8 ng l(-1) in LaiZhou Bay and from 0.1 to 3.9 ng l(-1) in JiaoZhou Bay, respectively. A comparison between the current and historical data shows a rapidly decreasing trend of OCPs over the past twenty years in the study areas.

[Content of gentiopicroside and loganic acid in Radix gentianae and their fingerprints].

To develop a HPLC-DAD-ESI-TOF/MS analysis method for the determination of gentiopicroside and loganic acid in Radix gentianae samples and for the research of their fingerprints. The samples were extracted using ASE for 10 min under 100 degrees C and 9.65 MPa, and divided into water phase and chloroform phase and analyzed them with HPLC-DAD-ESI-TOF/MS method respectively. Based on this method, the HPLC fingerprints of Radix gentianae were established. Comparing the spectrogram and mass spectrum of the chromatogram peak with the reference value, three compounds in water phase were identified as gentiopicroside, asafetida acid and loganic acid. There is no report of the compounds in chloroform phase. The content of gentiopicroside and loganic acid in samples of different groups were determined, separately. The fingerprints were compared by the software of the similarity evaluation system for chromatographic fingerprint. The water phase fingerprint congruence coefficients of samples from six different areas were above 0.90, however, the chloroform phase fingerprint congruence coefficients were within 0.62 -0.99. This method can be used for determination of potent component in Radix gentianae and its quality control. Radix gentianae from different producing areas have the largest diversities, and the diversities embodied in the content of chloroform phase compounds.

New non-PBDE brominated flame retardants in sediment and plant samples from Jiaozhou Bay wetland.

Seven non-polybrominated diphenyl ethers (non-PBDE) (TBB, TBX, PBT, PBEB, HBB, DBHCTD and BB153) were analyzed in sediment and plant samples which were collected from Xiaojianxi landfill to Dagu river estuary in Jiaozhou Bay wetland. The species of non-PBDE were different in sediment and plant samples with the concentration of 0.41-9.66ngg(-1) and 0.15-1.2ngg(-1), respectively. DBHCTD was the main non-PBDE compared with other target compounds and its concentration was 1.21-9.66ngg(-1)dw. Generally, the concentration of non-PBDE in sediment showed a decreasing tendency while discrete decline in plant has been revealed. Furthermore, DBHCTD, HBB, as well as other BFRs, might have a common BFRs degradation or similar accumulation potential in sediment, as their Pearson relationship p<0.05. Generally, the content of non-PBDE in Jiaozhou Bay wetland was higher than other published research. Therefore, more attention should be paid to non-PBDE on account of their persisting impact on human health and environment.

Cloning and stress-responding expression analysis of malonyl CoA-acyl carrier protein transacylase gene of Nannochloropsis gaditana.

Malonyl CoA-acyl carrier protein transacylase (MCAT, E2.3.1.39) is closely associated with the FASII pathway of fatty acid biosynthesis. However, the information about microalgal MCAT is scarce. In this study, a MCAT gene was isolated from Nannochloropsis gaditana with its deduced protein (NgMCAT) characterized with bioinformatic tools. The abundance of the NgMCAT transcript under different environmental conditions was determined with real-time quantitative PCR. Results showed that the open reading frame (ORF) of NgMCAT was 1059 bp in length, which encoded 352 amino acid residues. The abundance of NgMCAT transcript reached the maximum (5.17-fold) at 6h when sodium nitrate was limited, and reached the maximum (4.25-fold) at 12h at low temperature (15°C). The abundance of NgMCAT transcript fluctuated at high temperature (35°C) when the concentration of nitrate and sodium chloride exceeded 150 mg/L and 62 g/L, respectively. In addition, some components of fatty acid that changed with the expression of NgMCAT were also observed.

Rapid finding and quantification of the major antioxidant in water extracts of three marine drug organisms from China by online HPLC-DAD/MS-DPPH.

A method based on high-performance liquid chromatography (HPLC) with diode array detector coupled with electrospray ionisation-mass spectrometry and an online detection system for radical scavenging was established and used to rapidly find and quantify antioxidant compounds in the water extracts of Hippocampus japonicus Kaup, Hippocampus kuda Bleeker and Syngnathus acus Linnaeus. The online screening results revealed the presence of one major radical scavenging compound identified as hypoxanthine by comparison of mass data and retention time with the standard. Subsequently, the developed HPLC method was applied to quantify hypoxanthine in different H. japonicus, H. kuda and S. acus samples. The results indicated that the developed HPLC method is simple and reliable for the quantification of hypoxanthine with a detection limit at 0.002 µg mL(-1), and a high recovery from 96.3% to 102.1%. This method provides a powerful tool for rapid identification and quantification of free radical scavenging compounds in complex marine natural products.

[Application of accelerated solvent extraction technique for analysis of active components in traditional Chinese medicinal herbs].

The application of accelerated solvent extraction (ASE) technique for the Analysis of active components in traditional Chinese medicinal herbs was introduced by using two kinds of herbs as examples. The conditions including extraction temperature, static extraction time, the ratio of material to solvent and solvent of ASE for extraction of salvianolic acid B in Salvia miltiorrhiza were optimized by orthogonal experiments, and the optimal conditions were obtained. Different extraction methods (ASE, steam distillation, ultrasonic wave and Soxhlet extraction) were used to extract volatile oil in Aucklandia lappa Decne. Results of the comparative experiments indicated that ASE was the most effective method in this case. All the results from these studies demonstrate that ASE is indeed a powerful tool in the preparation of herbal extracts for downstream chromatographic analysis.

Determination of four major saponins in the seeds of Aesculus chinensis Bunge using accelerated solvent extraction followed by high-performance liquid chromatography and electrospray-time of flight mass spectrometry.

A new method based on accelerated solvent extraction (ASE) followed by a reliable high-performance liquid chromatography-diode array detector (HPLC-DAD) and positive ion electrospray-time of flight mass spectrometry (ESI-TOF/MS) analysis has been developed for the characterization and quantification of four major saponins in extracts of the seeds of Aesculus chinensis Bunge (semen aesculi). The saponins escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted from seeds of A. chinesis Bunge via ASE, and the operational parameters of ASE were optimized, such as extraction solvent, extraction temperature, static extraction time and extraction cycles. The optimized procedure employed 70% MeOH as extraction solvent, 120 degrees C of extraction temperature, 7 min of static extraction time, 60% flush volume and the extraction recoveries of the four compounds were nearly to 100% for two cycles. The HPLC conditions are as follows: SinoChrom ODS BP C18 (4.6 mm x 200 mm, 5 microm) column, acetonitrile and 0.10% phosphoric acid solution as mobile phase, flow rate is 1.0 mL min(-1), detection length of UV is 203 nm, injection volume is 10 microL. The results indicated that the developed HPLC method is simple, sensitive and reliable for the determination of four major saponins in seeds of A. chinesis Bunge with a good linearity (r2 > 0.9994), precision (relative standard deviation (R.S.D.) < 1.5%) and the recovery ranges of 95.2-97.3%. The limits of detection (LOD) of the four compounds were in the range of 0.40-0.75 microg mL(-1). This assay can be readily utilized as a quality control method for semen aesculi and other related medicinal plants.