Microwave-assisted Natural Deep Eutectic Solvents Pretreatment Followed by Hydrodistillation Coupled with GC-MS for Analysis of Essential Oil from Turmeric (Curcuma longa L.).

In the past decade, natural deep eutectic solvents (NADESs) as green and sustainable extraction solvents with great potential for the efficient extraction of bioactive compounds from the plants are emerging. In this study, a microwave-assisted technology is used to prepare natural deep eutectic solvents. And natural deep eutectic solvents as pretreatment solvents coupled with microwave-assisted hydrodistillation (MAHD) for isolating essential oil (EO) derived from turmeric (Curcuma longa L.) is investigated. To improve the essential oil yield of turmeric (Curcuma longa L.) as a target, various factors affecting extraction efficiency including the type and amount of natural deep eutectic solvents, pretreatment time, pretreatment temperature and hydrodistillation (HD) time are discussed and optimized through central composite design (CCD) of the response surface methodology (RSM). The optimal conditions are as follows: natural deep eutectic solvent composed of choline chloride and oxalic acid (molar ratio with 1:1) as a pretreatment solvent, an amount of 60 g, a pretreatment time of 5 min, a pretreatment temperature of 84 ºC, a hydrodistillation time of 76 min. Under the optimum conditions, the highest essential oil yield of 0.85% is achieved. Additionally, the essential oil is analyzed by using gas chromatography-mass spectrometry (GC-MS), with a total of 49 compounds being identified. Through combining natural deep eutectic solvents with a microwave-assisted hydrodistillation technique, this work provides an eco-friendly extraction way of isolating essential oil, which boosts development in the monitoring other spice quality field.

Dispersive Liquid-Liquid Microextraction Combined with Microwave Demulsification for Determination of FAME Residuals in Biodiesel Wastewater.

Biodiesel consists of various fatty acid methyl esters (FAMEs) that are mainly produced through transesterification of plant oil or animal fat. It is essential for biodiesel to be purified utmostly to meet its product standard before being traded, while the universal purification method has been water washing. However, water washing inevitably causes the residual of FAMEs in wastewater, which represents a loss of industrial profits. For the purpose of determination and monitoring of the FAME profile in wastewater, there is a necessity to develop a fast and reliable approach with small volume of sample in need. Hence, in this study, a combination of dispersive liquid-liquid microextraction (DLLME) and microwave demulsification is applied for the enrichment of residual FAMEs in water, followed by qualitative and quantitative analyses using gas chromatography-mass spectrometry. The results indicate that the optimal extractant in DLLME approach is toluene. And the optimal parameters are 20 mL of water sample, 80 µL of toluene as the extractant, 60 s of ultrasonic irradiation duration, 200 W of microwave power and 2 min of microwave irradiation duration. The standard curves and linear equations obtained with these conditions are used for the quantitative analysis of biodiesel wastewater, which reveals that there was 50.35 mg·L-1 of the total FAME residuals in wastewater. To the best of our knowledge, it is for the first time that the combined technique of DLLME and microwave demulsification is applied in determination of residual FAMEs in water samples. The proposed method corresponds to small volumes of sample and extractant and short analytical period. It also has the potential to be extended to the analysis of other water pollutants.

Attraction of Culex pipiens pallens (Diptera: Culicidae) to Floret Volatiles and Synthetic Blends of Its Nectar Host Plant Abelia chinensis (Rubiales: Caprifoliaceae).

Abelia chinensis R. Br. (Dipsacales: Caprifoliaceae) is one of the preferred nectar host plants for Culex pipiens pallens Coquillett (Diptera: Culicidae). However, the volatile compounds of its flowers that might be involved in directing mosquitoes' orientation to its nectaries remain unknown. In the present study, the volatile compounds released by A. chinensis florets were collected by solid phase microextraction fiber and analyzed by gas chromatography-mass spectrometry system. Based on the major component species in the volatile profile, a synthetic phytochemical blend (Blend B, composed of six compounds at their most attractive concentrations) was formulated, and its attractiveness was tested against the pentane extract of A. chinensis florets at most attractive concentration (Blend A) and a formerly developed synthetic phytochemical blend (Blend C) in the olfactometer, respectively. The results revealed that the volatile profile of A. chinensis florets was mainly composed of aromatic compounds, most of which had been reported to be attractive to other mosquito species. The synthetic Blend B was as attractive as Blend A (10-1-fold of the crude pentane extract) in the olfactometer bioassays, but they were not as attractive as the formerly developed Blend C. The present study indicated that quantitative and qualitative differences in the constituents of phytochemical blends could significantly affect their attractiveness to Cx. pipiens pallens, and the capture efficiency of phytochemical attractants deserves further research before being applied in the field.

Microwave-assisted-demulsification dispersive liquid-liquid microextraction for the determination of triazole fungicides in water by gas chromatography with mass spectrometry.

A novel microwave-assisted-demulsification dispersive liquid-liquid microextraction technique was established for determination of three triazole fungicides in environmental water samples by gas chromatography with mass spectrometry. Importantly, microwave irradiation has been applied in demulsification to achieve the phase separation and enrichment of triazole fungicides in water samples successfully with low-density toluene as extractant. The experimental variables, including microwave power, microwave time, ultrasonic time, type and volume of extraction solvent, and effect of salting out were investigated. Under the optimized conditions, the method showed good linearity for myclobutanil, tebuconazole, and difenoconazole in the range of 1-100 µg/L. The limits of detection and the limits of quantification were within the range of 0.14-0.27 and 0.47-0.90 µg/L, respectively. The suitable enrichment factors for three triazole pesticides were in the range of 425-636. The recoveries were between 89.3 and 108.7%, and the relative standard deviations were from 5.4 to 8.6%. Finally, environmental water samples were used to verify the applicability of the proposed method for analysis of triazole fungicides targets. It can be concluded that the developed microwave-assisted-demulsification dispersive liquid-liquid microextraction gas chromatography with mass spectrometry method was a rapid, efficient, reliable, and environmental friendly way for analysis of triazole fungicides in water.

Microwave-Assisted Simplified Simultaneous Distillation Coupled with Ionic Liquid Pretreatment for the Analysis of Essential Oil in Schisandra sphenanthera.

Simultaneous distillation extraction (SDE) is quite useful for the separation of volatile compounds from an analyte when their contents are quite low. In this study, a simplified SDE approach is applied for the extraction of essential oil from Schisandra sphenanthera, with microwave as heating source, [Bmim][Cl] as the medium for pretreatment, and gas chromatography-mass spectrometry as the analytical approach. Consequently, the improvement resulted from [Bmim][Cl] pretreatment is demonstrated by taking comparison with blank experiments. Totally 61 compounds have been detected in the essential oil obtained by using [Bmim][Cl] pretreatment, while without [Bmim][Cl] pretreatment, only 53 compounds can be detected. Moreover, [Bmim][Cl] pretreatment can also resulted in a higher yield of essential oil. The experimental results demonstrate that the simplified SDE coupled with ionic liquid pretreatment is a feasible approach for the extraction of essential oil from S. sphenanthera with high efficiency as 0.85% of essential oil yield has been obtained, and can be potentially extended to the extraction of essential oil or other target volatile compounds with low content.

Transesterification of soybean oil by using the synergistic microwave-ultrasonic irradiation.

Microwave and ultrasound have been demonstrated to be outstanding process intensification techniques for transesterification of oil. According to their mechanisms, simultaneous effects can surely bring about better enhancement than sole microwave or ultrasound. Therefore, this study aimed to investigate the important factors and their suitable levels in the KOH-catalyzed transesterification of soybean oil with methanol by using synergistic assistance of microwave-ultrasound (CAMU). The feasibility of application of CAMU in transesterification of oil was demonstrated. When the dosage of methanol, soybean oil and KOH were 15.4g, 34.7g (with methanol-to-oil molar ratio of 12:1) and 1g, respectively, and the microwave power, ultrasonic power, ultrasonic mode, reaction temperature and reaction time were 700W, 800W, 1:0, 65°C and 6min, respectively, the transesterification reached 98.0% of yield, being the highest yield among all the results obtained; while by using 600W of microwave plus stirring instead of CAMU, only 57.4% of yield could be obtained. Compared with other reaction techniques, the transesterification by applying novel CAMU was found to have remarkable advantages. Furthermore, by monitoring the variation of real-time temperature and microwave power during transesterification reactions with different microwave operation time and by taking comparison of the corresponding yield, it was demonstrated that the main reason for the acceleration of microwave-assisted transesterification was the polarization and further activation of reactants caused by microwave irradiation, but not the factor of fast heating.

Development of a Microextraction Method Based on Dissolved Carbon Dioxide Flotation after Emulsification for the Determination of Triazole Pesticides Residues in Water Samples by Gas Chromatography-Mass Spectrometry.

A novel dissolved carbon dioxide flotation after emulsification microextraction (DCF-EME) method was proposed for the determination of four triazole pesticides in water samples coupled with gas chromatography-mass spectrometry (GC-MS) in a home-made glass round flask. The DCF-EME method is based on a rapid and simple phase separation of low-density organic solvent (toluene) from the aqueous phase via introducing a saturated NaHCO3 solution into the acidified sample (0.1 mol L-1 HCl); then analytes were extracted in toluene. Various parameters affecting the extraction process were optimized. Under the optimal conditions, the recoveries for four pesticides ranged from 82.8 to 121.2%. Meanwhile the limits of detection were at the range of 0.14 - 1.04 µg L-1, and the preconcentration factors were varied between 342 and 473 for different triazoles. The method is simple, fast and environmentally friendly, being successfully applied for the determination of triazole pesticides in water samples.

Simultaneous determination of sulfonamides and metabolites in manure samples by one-step ultrasound/microwave-assisted solid-liquid-solid dispersive extraction and liquid chromatography-mass spectrometry.

An in-line matrix cleanup method was used for the simultaneous extraction of 15 sulfonamides and two metabolites from manure samples. The ultrasound/microwave-assisted extraction (UMAE) combined with solid-liquid-solid dispersive extraction (SLSDE) procedure provides a simple sample preparation approach for the processing of manure samples, in which the extraction and cleanup are integrated into one step. Ultrasonic irradiation power, extraction temperature, extraction time, and extraction solvent, which could influence the UMAE efficiency, were investigated. C18 was used as the adsorbent to reduce the effects of interfering components during the extraction procedure. The extracts were concentrated, and the analytes were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) without any further cleanup. The isotopically labeled compounds sulfamethoxazole-d 4, sulfamethazine-d 4, sulfamonomethoxine-d 4, and sulfadimethoxine-d 6 were selected as internal standards to minimize the matrix effect in this method. The recoveries of the antibiotics tested ranged from 71 to 118 % at the three spiking levels examined (20, 200, and 500 µg · kg(-1)). The limits of detections were 1.2-3.6 µg · kg(-1) and the limits of quantification were 4.0-12.3 µg · kg(-1) for the sulfonamides and their metabolites. The applicability of the method was demonstrated by analyzing 30 commercial manure samples. The results indicated that UMAE-SLSDE combined with LC-MS/MS is a simple, rapid, and environmentally friendly method for the analysis of sulfonamides and their metabolites in manure, and it could provide the basis for a risk assessment of the antibiotics in agricultural environments.

Effects of acupuncture on Chinese medicine syndromes of vascular dementia.

OBJECTIVE: To study the effects of acupuncture on Chinese medicine syndromes of vascular dementia (VaD). METHODS: Sixty-three VaD patients were divided into three groups. Those willing to be randomized were randomly assigned to receive either acupuncture (random acupuncture group, 24 cases) or rehabilitation training (guided rehabilitation group, 24 cases) for 6 weeks. Those unwilling to be randomized also received acupuncture for 6 weeks (non-random acupuncture group, 19 cases). Patient syndromes and their severity were evaluated before treatment (baseline), at the end of treatment, and at 4-week follow-up after the completion of treatment using a CM scoring system (scale of differentiation of syndromes of vascular dementia, SDSVD). The SDSVD scores of the random and non-random acupuncture groups, and of all patients who received acupuncture (combined acupuncture group, 43 cases), were compared with those in the guided rehabilitation group. RESULTS: In the random, non-random, and combined acupuncture groups, SDSVD scores were significantly reduced at the end of treatment and at follow-up than at baseline. In the guided rehabilitation group, SDSVD scores were similar to baseline scores at the end of treatment and at follow-up. However, there were no significant differences in SDSVD scores among the three groups or between the combined acupuncture group and the guided rehabilitation group at any time points. In the non-random and combined acupuncture groups, SDSVD scores were significantly reduced at the end of treatment than at baseline in patients with hyperactivity of Liver (Gan)-yang or phlegm obstruction of the orifices. CONCLUSIONS: Acupuncture reduced the severity of VaD. The improvement was the greatest in patients undergoing their treatment of choice. Treatments in this study were more effective for excess syndromes, such as Liver-yang hyperactivity or phlegm obstruction of the orifices than deficiency syndromes, such as Kidney (Shen)-essence deficiency.

Effect of acupuncture on hippocampal Ref-1 expression in cerebral multi-infarction rats.

Redox effector factor (Ref-1) is a sensitive marker for oxidative cellular injury. The aim of this study was to investigate the effects of acupuncture on hippocampal Ref-1 expression in cerebral multi-infarction rats. The rats with reference memory impairment were randomly allocated to three groups: impaired group, acupuncture group and placebo acupuncture group. Moreover, normal group and sham-operated group were set as control groups. Morris water maze test showed that cerebral multi-infarction rats did not present significant changes in spatial working memory performance. Further investigation by immunohistochemistry revealed that acupunctural treatment significantly increased the expression of Ref-1 in the hippocampus of the impaired rats. These findings suggested that the spatial working memory was unaffected in the cerebral multi-infarction rats although spatial reference memory deficits were detected in our previous study; in addition, acupuncture could increase the Ref-1 expression, consequently exerting the anti-oxidant effects.

[Study on the mechanism of liesegang pattern development during carbonating of traditional sticky rice-lime mortar].

Liesegang patterns in traditional sticky rice-lime mortar undergoing carbonation were investigated by means of FTIR, XRD and SEM. Results indicate that well-developed Liesegang patterns only occur in the mortar prepared with aged lime and sticky rice. The smaller Ca(OH)2 particle size in aged lime and the control of the sticky rice for the crystallization of calcium carbonate lead to the small pores in this mortar. These small pores can make Ca2+ and CO3(2-) highly supersaturated, which explains the reason why Liesegang pattern developed in the sticky rice-aged lime mortar. The formed metastable aragonite proves that Liesegang pattern could be explained based on the post-nucleation theory.

Determination of perfluorocarboxylic acids in water by ion-pair dispersive liquid-liquid microextraction and gas chromatography-tandem mass spectrometry with injection port derivatization.

A novel technique for derivatization in a gas chromatograph injection port after a one-step extraction of trace perfluorocarboxylic acids (PFCAs) in water with ion pair formation during dispersive liquid-liquid microextraction (DLLME) was investigated. Tetrabutylammonium hydrogen sulfate (TBAHS) was used as the ion pair reagent. PFCA butyl ester derivatives were formed in the GC injection port and then analyzed using gas chromatography coupled to tandem mass spectrometry with negative chemical ionization. According to our analysis, the operative linear range for PFCA detection from 250 pg mL(-1) to 2 µg mL(-1) with a relative standard derivation (RSD) below 13%. Detection limits were achieved at the level of 37-51 pg mL(-1). This method was successfully applied for the analyzing of PFCAs in river water samples from urban and industrial areas without tedious pretreatment. The concentration range over which PFCAs were detected is from 0.6 ng mL(-1) to 604.9 ng mL(-1).

Determination of chlorophenols in landfill leachate using headspace sampling with ionic liquid-coated solid-phase microextraction fibers combined with gas chromatography-mass spectrometry.

A new microextraction technique based on ionic liquid solid-phase microextraction (IL-SPME) was developed for determination of trace chlorophenols (CPs) in landfill leachate. The synthesized ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)MIM][PF(6)]), was coated onto the spent fiber of SPME for extraction of trace CPs. After extraction, the absorbed analytes were desorbed and quantified using gas chromatography-mass spectrometry (GC/MS). The term of the proposed method is as ionic liquid-coated of solid-phase microextraction combined with gas chromatography-mass spectrometry (IL-SPME-GC/MS). No carryover effect was found, and every laboratory-made ionic liquids-coated-fiber could be used for extraction at least eighty times without degradation of efficiency. The chlorophenols studied were 2,4-dichlorophenol (2,4-DP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP). The best results of chlorophenols analysis were obtained with landfill leachate at pH 2, headspace extraction for 4 min, and thermal desorption with the gas chromatograph injector at 240°C for 4 min. Linearity was observed from 0.1 to 1000 µg L(-1) with relative standard deviations (RSD) less than 7% and recoveries were over 87%. The limit of detection (LOD) for pentachlorophenol was 0.008 µg L(-1). The proposed method was tested by analyzing landfill leachate from a sewage farm. The concentrations of chlorophenols were detected to range from 1.1 to 1.4 µg L(-1). The results demonstrate that the IL-SPME-GC/MS method is highly effective in analyzing trace chlorophenols in landfill leachate.

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 (SFE) was investigated for the determination of trace amounts of perfluorocarboxylic acids (PFCAs) 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 µL 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 µm film 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).

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 µL of buffer solution. Under these optimal conditions, the linear range was from 10 ng g(-1) to 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.

Identification of new minor metabolites of penicillin G in human serum by multiple-stage tandem mass spectrometry.

Liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) were applied to characterize drug metabolites. Although these two methods have overcome the identification and structural characterization of metabolites analysis, they remain time-consuming processes. In this study, a novel multiple-stage tandem mass spectrometric method (MS(n) ) was evaluated for identification and characterization of new minor metabolism profiling of penicillin G, one of the ß-lactam antibiotics, in human serum. Seven minor metabolites including five phase I metabolites and two phase II metabolites of penicillin G were identified by using data-dependent LC/MS(n) screening in one chromatographic run. The accuracy masses of seven identified metabolites of penicillin G were also confirmed by mass spectral calibration software (MassWorks™). The proposed data-dependent LC/MS(n) method is a powerful tool to provide large amounts of the necessary structural information to characterize minor metabolite in metabolism profiling.

[Progress of researches on acupuncture manipulation and its quantification].

The acupuncture manipulation is an important factor for achieving a good therapeutic effect in acupuncture practice. The authors review recent studies on acupuncture manipulation and its qualification from (a) differences of the therapeutic effects of acupuncture manipulation, (b) quantification of acupuncture manipulations, and (c) instruments for delivering and sampling the analogued parameters of different acupuncture manipulations, computer analysis software, etc. Most studies revealed that different acupuncture manipulations had different clinical efficacies. Meanwhile, researches on the quantification of acupuncture manipulations and some related instruments also have made a bigger progress. Nevertheless,there still exist many problems, such as difficulties of various acupuncture techniques in unification in clinic, stronger personal subjectivity in performing manipulations, etc. We should overcome these problems and conduct more researches, so as to raise the clinical curative effect further.

Exploring the structural requirements for jasmonates and related compounds as novel plant growth regulators: a current computational perspective.

Jasmonates and related compounds have been highlighted recently in the field of plant physiology and plant molecular biology due to their significant regulatory roles in the signaling pathway for the diverse aspects of plant development and survival. Though a considerable amount of studies concerning their biological effects in different plants have been widely reported, the molecular details of the signaling mechanism are still poorly understood. This review sheds new light on the structural requirements for the bioactivity/property of jasmonic acid derivatives in current computational perspective, which differs from previous research that mainly focus on their biological evaluation, gene and metabolic regulation and the enzymes in their biosynthesis. The computational results may contribute to further understanding the mechanism of drug-receptor interactions in their signaling pathway and designing novel plant growth regulators as high effective ecological pesticides.

Quantitative structure-activity relationship analysis of aryl alkanol piperazine derivatives with antidepressant activities.

Quantitative structure-activity relationship analysis for recently synthesized aryl alkanol piperazine derivatives was studied for their antidepressant activities. The statistically significant 2D-QSAR models (r(2)>0.924, r(-CV)(2)>0.870, r(-pred)(2)>0.890) were developed using genetic function approximation (GFA) when the number of descriptors in equation was set to four, indicating the descriptors of Atype_C_6, Dipole-mag, S_sssCH and Jurs-PNSA-3 mainly influence the 5-hydroxytryptamine (5-HT) reuptake inhibition activity while the descriptors of HOMO, PMI-mag, S_sssN and Shadow-XZ may chiefly control the noradrenaline (NA) reuptake inhibition activity. The results of the 2D-QSAR models were further compared with 3D-QSAR models generated by molecular field analysis (MFA), investigating the substitutional requirements for the favorable receptor-drug interaction and providing useful information in the characterization and differentiation of their binding sites. The results derived may be useful in further designing novel antidepressants prior to synthesis.

Quantitative structure-property relationship studies on amino acid conjugates of jasmonic acid as defense signaling molecules.

Jasmonates and related compounds, including amino acid conjugates of jasmonic acid, have regulatory functions in the signaling pathway for plant developmental processes and responses to the complex equilibrium of biotic and abiotic stress. But the molecular details of the signaling mechanism are still poorly understood. Statistically significant quantitative structure-property relationship models (r(2) > 0.990) constructed by genetic function approximation and molecular field analysis were generated for the purpose of deriving structural requirements for lipophilicity of amino acid conjugates of jasmonic acid. The best models derived in the present study provide some valuable academic information in terms of the 2/3D-descriptors influencing the lipophilicity, which may contribute to further understanding the mechanism of exogenous application of jasmonates in their signaling pathway and designing novel analogs of jasmonic acid as ecological pesticides.