Short Pretreatment Time Research Articles

Microwave-associated ZnCl2 pretreatment followed by enzymatic hydrolysis for high-efficiency production of nanocellulose from Eucalyptus dissolving pulp

Herein, we developed a novel microwave-associated ZnCl2 pretreatment followed by enzymatic hydrolysis for high-efficiency and environmentally friendly production of nanocellulose. With a short pretreatment time (60 s), nanocellulose was yielded with a high overall yield of 87.99 % from Eucalyptus Dissolving Pulp (EDP). Characterization analysis revealed that microwave-associated ZnCl2 pretreatment can efficiently swollen the structure of EDP, and after enzymatic hydrolysis, the nanocellulose in spherical shape was formed with abundant functional groups, low crystalline index, and poor thermal stability. By Energy Dispersive X-Ray Spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS) analysis, approximately 20 wt% of zinc distributed on the surface and in the interior of cellulose, that may lead to the low Zeta potential of the nanocellulose and the formation of nanospheres. Furthermore, through optimization of the pretreatment process, it was feasible to increase the solid concentration of EDP to 3 wt% while concurrently reducing the ZnCl2 concentration to 0.1 mol (ZnCl2·9H2O). Under this condition, ultrafine cellulose nanocrystals (CNC) and cellulose nanofiber (CNF)/CNC blend were produced with an outstanding yield of 93.3 %. Moreover, the recyclability of ZnCl2 post-pretreatment was demonstrated, as ZnCl2 could be efficiently reused for subsequent pretreatment cycles. Notably, even after five cycles of recycling, the nanocellulose yield remained consistently above 90 %. Overall, this study highlights the viability and sustainability of microwave-assisted ZnCl2 pretreatment for efficient nanocellulose production, offering a sustainable and cost-effective route for industrial-scale applications.

Characterization of volatile components of microwave dried perilla leaves using GC–MS and E-nose

Different pretreatments followed by the drying process could affect the volatile compounds of dried perilla leaves. This study investigated the discrepancies in the volatile profiles of perilla leaves after ultrasonic pretreatment for 1 min and 3 min and drying at 50 °C, 60 °C, 70 °C respectively using gas chromatography–mass spectrometry (GC–MS) and an electronic nose (E-nose). Perilla leaves are rich in high nutritional value substances and unique aroma components. The results showed significant differences in the aroma characteristics of perilla leaves under different treatment conditions. 70 main volatile compounds were identified and separated into 9 classes. Perilla ketone and beta-caryophyllene were abundant in all samples and could be the key aroma compounds of perilla leaves. Most volatile flavor substances could be better retained under the conditions of lower drying temperature and shorter pretreatment time. Principal component analysis (PCA) of GC–MS and E-nose showed that there were obvious differences between the samples under different treatment conditions. In addition, a correlation analysis was also conducted on the main volatile compounds detected by GC–MS and E-nose, which further explained the differences among samples owing to the various drying conditions.

Hexafluoroisopropanol-based supramolecular solvent for liquid phase microextraction of triazole fungicides in drinking water and beverages

A new supramolecular solvent (SUPRAS) was synthesized using hexafluoroisopropanol (HFIP) as hydrogen bond donor and undecanol as hydrogen bond acceptor. Then SUPRAS was used as extraction solvent to enrich triazole fungicides in drinking water and beverages by liquid phase microextraction (LPME). Additionally, several variables that influence extraction efficiency were optimized, and the significant factors were investigated by Box-Behnken design. At optimum condition, the method shows desirable precision (RSDs less than 19.4%) and acceptable recovery (63.4%-112.1%). The low limits of detection and limits of quantitation of this method were found to be in the range of 1.0–5.0 μg/L and 5.0–20 μg/L, respectively. Compared with other analytical techniques, the method demonstrated comparable sensitivity, consumed less extractant (750 μL) and a shorter pre-treatment time (10 min). The formation mechanism of SUPRAS was investigated by density functional theory. The proposed methodology was green, sensitive, time-saving and successfully applied to determine triazole fungicides in drinking water and beverages, making it an alternative technique for the analysis of trace analytes with satisfactory sensitivity.

The design of a high-voltage pulsed electric field (hpef) device for non-liquid materials based on microcontroller

High-voltage pulsed electric field (HPEF) is one of the technologies applied in the food industry with the principle of non-heat treatment with a short pre-treatment time and no pollution is produced. The main benefit of this tool is to kill microbes in the food industry. In addition to non-thermal sterilization, HPEF can also be used for electroporation. Cell electroporation is the application of an electric voltage to the cell. The cells are damaged (broken/porous) without destroying the bioactive components present in the cells. Previous studies have shown that materials treated with HPEF increase the yield when distilled. It can occur due to the electroporation process, namely the breakdown of the oil cell network, so that the distillation process is efficient (can reduce distillation time and increase the quantity of oil). The care box is designed with dimensions of 60cm x 40cm x 30cm which is made of acrylic material. The electrodes used a 60cm x 40cm plate mounted on a linear drive to adjust the treatment distance. HPEF uses a 15kV neon sign transformer. The transformer input frequency setting is set with a dimmer. A microcontroller is installed to adjust the shock period on the electrodes. Based on trials, the device can be used for various solid materials with different volumes.

Effects of lauromacrogol injection under contrast-enhanced ultrasound guidance on cesarean scar pregnancy: a prospective cohort study.

Compared with the current commonly used pretreatment approaches, the therapeutic effect of contrast-enhanced ultrasound-guided sclerotherapy with lauromacrogol injection (CEUSL) on cesarean scar pregnancy (CSP) is not clear. This study aimed to investigate the clinical efficacy and safety of CEUSL compared with gelatin sponge uterine artery embolization (UAE) and UAE combined with methotrexate (UAEM) in the pretreatment of CSP to prevent massive bleeding during subsequent curettage. Sixty-four patients were divided into the CEUSL (n=20), UAE (n=22), and UAEM (n=22) groups. All patients with CSP underwent curettage and hysteroscopy after CEUSL, UAE, or UAEM pretreatment. The efficacy and safety indicators after pretreatment were analyzed. Time for pretreatment [95% confidence interval (CI): 31.92-39.28] and hospitalization cost (95% CI: 7,852.32-9,063.23) were significantly decreased in the CEUSL group compared with that in the UAE (95% CI: 53.55-59.99% and 95% CI: 12,901.42-15,166.63, respectively) and the UAEM group (95% CI: 52.90-58.83 and 95% CI: 11,324.66-13,302.69, respectively; P<0.001). The beta human chorionic gonadotropin (β-hCG) percentage decrease 24 hours later and the hospital stay were significantly decreased in the CEUSL group (95% CI: 0.65-0.70 and 95% CI: 3.32-4.58 days, respectively) compared with those in the UAE (95% CI: 0.67-0.74 and 95% CI: 4.06-5.84, respectively) or UAEM (95% CI: 0.62-0.68 and 95% CI: 4.12-5.88, respectively) groups (P<0.05). After pretreatment, there were significantly fewer patients (P<0.05) with fever (95% CI: -0.52 to -0.093), pelvic pain (95% CI: -0.427 to -0.018), increased white blood cell count (95% CI: -0.359 to 0.040), and hypersensitive C-reactive protein (hs-CRP) elevation (95% CI: -0.572 to -0.118) in the CEUSL group than in the UAE or UAEM groups. At follow-up, all patients resumed normal menstruation, with no residual gestational sac on ultrasound imaging or sequel. The pretreatment procedures were all technically successful, with good outcomes in different pretreatment procedures. Compared with UAE with or without methotrexate, CEUSL may be as effective and safe for pretreatment of CSP, with fewer adverse effects and shorter pretreatment time and hospital stay.

Enhanced adipic acid production from sugarcane bagasse by a rapid room temperature pretreatment

Adipic acid is an important precursor for manufacturing Nylon-66, and various efficient renewable routes for adipic acid from lignocellulosic biomass are being explored. To effectively valorize biomass into adipic acid, a novel aqueous solution NaOH/ChCl:TH/water (6:24:160, wt/wt/wt) was firstly applied to pretreat sugarcane bagasse (SCB) at a room temperature (25 °C) for a short pretreatment time (1 min) for improving its saccharification efficiency. A deep eutectic solvent ChCl:TH was synthesized by mixing choline chloride (ChCl) and thiourea (TH). The cellulose structure changes of SCB were characterized by FTIR, XRD, SEM, TEM and LSCM. Composition analysis and reducing sugar yield were used to evaluate pretreatment efficiency. Hydrolysis for 72 h, the yields of reducing sugars and glucose from 40 g/L NaOH/ChCl:TH-SCB with complexed cellulases were obtained at 90.2 % and 94.1 %, respectively. Finally, the obtained SCB-hydrolysate was used for adipic acid production by E. coli MG1655 K12. Glucose in SCB-hydrolysate was consumed within 72 h, with a productivity of 0.39 g adipic acid/g glucose, accounting for 72.2 % of the theoretical yield. Further discovery, xylose in SCB-hydrolysate was also consumed for adipic acid fermentation, which contributed to an increase in adipic acid production. In view of transcriptome data, most of the genes involved in carbohydrate metabolism were most significantly up-regulated, which was conductive to improve the yield of adipic acid using biomass-hydrolysate as carbon source. Therefore, the NaOH/ChCl:TH-SCB hydrolysates were a better carbon source for adipic acid fermentation compared to commercial glucose. Obviously, this established rapid room temperature pretreatment with NaOH/ChCl:TH was proven to be effective for enhancing saccharification efficiency of SCB, and the hydrolysates had excellent adipic acid fermentability.

Facile Cloud Point Extraction for the Separation and Determination of Phenolic Acids from Dandelion.

It is significantly crucial to develop a robust pretreatment for the quantitative analysis of herbs. However, the traditional strategies are time-consuming, tedious, and not eco-friendly. In this work, cloud point extraction (CPE) is engineered for the simultaneous separation and enrichment of ferulic acid (FA), chlorogenic acid (CLA), and caffeic acid (CA) from dandelion prior to its determination by high-performance liquid chromatography (HPLC). A famous nonionic surfactant of Triton X-114 was selected as an extractant of CPE, and parameters affecting the extraction, such as surfactant concentration, salt content, pH value, temperature, and incubation time, were investigated carefully. Furthermore, the well-designed CPE with ultrasonic assistance combined with HPLC was developed for the detection of the target analytes in dandelion. The established method having a good linearity in the range of 0.15–26.2 mg L–1 with R2 more than 0.9979 and the spiked recoveries ranging from 81 to 96% was applied to test real samples of dandelion. The contents of CA in samples were consistent with those assayed by the method (Chinese Pharmacopoeia 2015). The proposed method afforded good analytical performances, shorter pretreatment time (65 min), and less organic solvent consumption (less than 1.0 mL). It was proved that the developed method presented a facile, inexpensive, efficient, and environment-friendly pretreatment and can be used for the quantitative analysis of CLA, CA, and FA in dandelion. As expected, the proposed method would be a promising potential for the quality analysis of herbal medicines.

Novel Single-step Pretreatment of Steam Explosion and Choline Chloride to De-lignify Corn Stover for Enhancing Enzymatic Edibility

It is important to develop efficient and economically feasible pretreatment methods for lignocellulosic biomass, to increase annual biomass production. A number of pretreatment methods were introduced to promote subsequent enzymatic hydrolysis of biomass for green energy processes. Pretreatment with steam explosion removes the only xylan at high severity but increases lignin content. In this study, corn stover soaked in choline chloride solution before the steam explosion is economically feasible as it reduced cost. Enzymatic hydrolysis of de-lignified corn stover is enhanced by combinatorial pretreatments of steam explosion and choline chloride. Corn stover pretreated with choline chloride at the ratio of 1:2.2 (w/w), 1.0 MPa, 184 °C, for 15 min efficiently expelled 84.7% lignin and 78.9% xylan. The residual solid comprised of 74.59% glucan and 7.51% xylan was changed to 84.2% glucose and 78.3% xylose with enzyme stacking of 10FPU/g. This single-step pretreatment had ∼ 4.5 and 6.4 times higher glucose yield than SE-pretreated and untreated corn stover, respectively. Furthermore, SEM, XRD and FTIR indicated the porosity, crystalline changes, methoxy bond-cleavage respectively due to the lignin and hemicellulose expulsion. Thus, the released acetic acid during this process introduced this novel strategy, which significantly builds the viability of biomass in short pretreatment time.

361 Porcine in vitro degradation and fermentation characteristics of heat pretreated corn whole stillage

Abstract Pre-treatment of whole stillage (WS; slurry material that is dried into DDGS) with heat can improve digestibility of the resulting DDGS by pigs. A study was conducted to identify optimal conditions (time and temperature) for heat pre-treatment of corn WS. Six samples of WS from different sources were divided into 13 sub-samples to give a total of 78 sub-samples. Thirteen treatments were applied to 13 sub-samples from each source (1 sub-sample/treatment). The treatments were untreated WS, and WS that was pre-treated (70 psi) for 10, 20, or 30 minutes and at 100, 120, 140, or 160 °C in a 3 × 4 factorial arrangement. Sub-samples were subjected to in vitro digestion with porcine pepsin and pancreatin, followed by in vitro fermentation for 72 h. Accumulated gas production was recorded and modeled to estimate kinetics of gas production. Volatile fatty acids (VFA) concentration in fermented solutions was also measured. Pre-treatment time and temperature did not interact on in vitro digestibility of DM (IVDDM), and total gas and VFA production. Pre-treatment time did not affect total gas and VFA production. The IVDDM for untreated WS was 73.4%. An increase in pre-treatment temperature from 100 to 160 °C resulted in linear and quadratic increase in IVDDM by 11%. Response surface analysis indicated that maximum IVDDM resulted from relatively long pre-treatment times (20–30 mins) and highest pre-treatment temperature. An increase in pre-treatment temperature from 100 to 160 °C resulted in linear increase in total gas production by 13%; maximum total gas production resulted from relatively short pre-treatment times (10–20 mins) and highest pre-treatment temperature. Total VFA production was unaffected by pre-treatment time. In conclusion, in vitro digestibility and fermentability of WS was improved by heat pre-treatment. Optimal conditions for pre-treatment of WS for combined improved digestibility and fermentability were 160 °C and 20 mins.

Characterization of Total-Phosphorus (TP) Pretreatment Microfluidic Chip Based on a Thermally Enhanced Photocatalyst for Portable Analysis of Eutrophication.

To minimize conventional total-phosphorus (TP) analysis systems, TP pretreatment microfluidic chip is proposed and characterized in this paper. Phosphorus (P) is one of the most important elements in ecosystem but it causes the eutrophication due to its overdose. TP analysis systems are increasingly receiving attention as a means to prevent eutrophication. Even though conventional TP analysis systems have high accuracy and sensitivity, they are not frequently utilized outside the laboratory because of their bulky size, complicated pretreatment processes, long response times, and high cost. Thus, there is a growing need to develop portable TP analysis systems. The microfluidic chip in this study is proposed with the aim of simplifying and minimizing TP analysis by replacing the conventional pretreatment process with a new method employing a thermally enhanced photocatalytic reaction that can be applied directly to a microfluidic chip of small size. The fabricated TP pretreatment microfluidic chip with thermally enhanced photocatalyst (TiO2) was optimized compared to the conventional pretreatment equipment (autoclave). The optimum pretreatment conditions using the proposed chip were pretreatment time of 10 min and temperature of 75 °C. The optimized pretreatment process using the proposed microfluidic chip showed similar performance to the conventional pretreatment method, even with shorter pretreatment time. The shorter pretreatment time and small size are advantages that enable the TP analysis system to be minimized. Therefore, the proposed TP pretreatment microfluidic chip based on thermally enhanced photocatalytic reaction in this study will be utilized to develop a portable TP analysis system.

Dimensional stability improvement of corn stalk biocomposites using two-part lignin-derived binder optimized with response surface methodology

To strengthen the dimensional stability of enzymatically treated corn stalk (ECS) biocomposites, hybrid modified lignosulfonate (HML) was used as a binder to fabricate reinforced ECS/HML composites with evaluation by response surface methodology. The effects of the preparation treatment on the enzymatic conditions, as well as the modified lignosulfonate dosage on the physicomechanical properties of the ECS/HML composites, were all evaluated. The optimum preparation parameters were determined via the Box-Behnken experimental design. High mass concentrations of laccase-vanillin and an appropriate modified lignosulfonate dosage for a relatively short enzymatic pretreatment time led to reduced residual stresses and improved dimensional properties. The optimum conditions that minimized thickness swelling (TS) and water adsorption (WA) without significantly compromising the biocomposite mechanical properties were determined to be 25 g/L laccase-vanillin, 118.8 min enzymatic pre-treatment time, and 15 wt% modified lignosulfonate. The ECS/HML composites that were treated under the optimal conditions resulted in an approximate 42% reduction in the dimensional properties without any significant decline in mechanical properties when compared to ECS panels. Unlike the loose structure of ECS biocomposites, the ECS/HML composites had a laminar shape with firm morphology.

Compositional changes of rice straw fibers after pretreatment with diluted acetic acid: Towards enhanced biomethane production

In the present study, diluted acetic acid was used for the pretreatment of rice straw in order to improve its bioconversion into biomethane. After pretreatment with 2% acetic acid for 24 h, cellulose and hemicellulose significantly reduced by 8.9% and 18.1%, respectively. The degradation of cellulose and hemicellulose resulted in significant increase of relative lignin ratio by 14.9%. Cumulative biomethane production after 28 days of anaerobic digestion of straw pretreated with 2%, 4% and 6% for 24 h was 24.3%, 15.2%, and 18.1%, respectively, higher than the untreated sample. Longer pretreatment for 36 and 48 h showed the same trend with relatively low biomethane yield. Thus, 24 h pretreatment with 2% acetic acid improved biomethanation over other pretreatments. Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed the partial degradation of rice straw and modification of lignin structure by un-bonding the ether chain within lignin molecules as a result of pretreatment. Pretreatment with 2% acetic acid for 24 h resulted in the maximum biomethane energy yield of 6.29 MJ kg−1 dry straw, 47.3% energy conversion efficiency and the maximum net profit of US$ 106.4 ton−1 dry straw. In conclusion, application of 2% acetic acid for 24 h is a promising approach for high lignocellulose degradation efficiency at mild conditions due to the relatively short pretreatment time and enhanced biomethanation.

Gasification of lignocellulosic biomass pretreated by anaerobic digestion (AD) process: An experimental study

Biomass gasification was subject to poor quality of gas with low heating value and high tar concentration. Anaerobic digestion (AD) was a biological process resulting in lignin enrichment and structure change of biomass which were beneficial to further gasification. Without going into any economic details, downdraft fixed bed gasification of corn straw (CS) pretreated by AD process was thus proposed and performed in our lab. The properties of CS and the pretreated CS (ADCS) were comparatively analyzed, and the influence of AD pretreatment with different retention time (7 d, 14 d, 21 d, 28 d) on gasification under 600 °C–800 °C was investigated. The results indicated that by degrading holocellulose, AD pretreatment enhanced the gasification property of CS with enriched lignin and catalytic elements (P/Ca/Fe/Al), and the destroyed structure with increased surface area for reactants transfer. Lower heating value (LHV) and cold gas efficiency (CGE) increased with AD pretreatment retention time and topped at 14 d, and then slightly decreased. Compared with CS, the values of LHV and CGE derived from short pretreatment time (7–14 d) increased by 0.76–0.82 MJ/Nm3 and 8.7–10.69% at 600 °C, 1.21–1.3 MJ/Nm3 and 11.71–13.18% at 700 °C, and 0.54–0.86 MJ/Nm3 and 5.49–8.06% at 800 °C, respectively. Under the optimum pretreatment time 14 d and gasification temperature 800 °C, the LHV and CGE were 6.83 MJ/Nm3 and 73.62%. Tar content of ADCS decreased with pretreatment retention time and gasification temperature. Under 800 °C, with extension of pretreatment retention time, the tar content decreased by 30 wt%, 35 wt%, 45 wt% and 56 wt%. The results seemed to be interesting and valuable in promoting biomass gasification.

Pretreatment of wheat straw with ligninolytic fungi for increased biogas productivity

Biogas production from the agriculture waste biomass is a sustainable approach to managing the energy demand in the future. To do so, pretreatment is needed to remove lignin from the agribiomass to make it easily digestible substrate for the fermentative organisms. The current study was carried out to screen the most effective lignin-degrading fungal culture from their natural habitat. Pretreatment with robust ligninolytic fungi could be an efficient and economical method to degrade lignin. The presence of lignin in lignocellulosic biomass is the rate-limiting factor which reduces the biogas production. So, the best fungal strains were selected based on maximal Azure B dye decolorization. The strains were actively producing lignin peroxidases and laccases and decreased 48.2% of lignin from the wheat straw (WS) within 7 days of batch incubation. The scanning electron micrograph demonstrated visible degradation only in the fungi-treated wheat straw. The ligninolytic fungal culture pretreatment of WS enhanced the biogas yield five times compared with the untreated WS sample. Notably, these fast-acting lignin-degrading fungi gave a biogas yield with a short pretreatment time and additionally reduced the lag phase during the anaerobic digestion process. These findings showed that pretreatment with natural ligninolytic fungi could be considered as a less expensive method. The treatment is also effective in increasing the digestibility of lignocellulosic biomass and suitable for biogas production.

Effective tuning guanidinium ionic liquid as greener solvent for fast and sensitive determination of auxin herbicides

Auxin herbicides have attracted continuously increasing attention because of their frequently application worldwide, slow degradation rates and potential toxicity to human beings. It is urgent to develop a fast and practical method to monitor them in environmental samples. Ionic liquids (ILs) are not intrinsically “green” and most of them are as toxic as other solvents. Therefore, tuning for maximizing advantageous properties of ILs and minimizing side effects are crucial steps. In this work, guanidinium IL was applied to preconcentrate and clean up ultra-trace auxin herbicides via designable binding sites. The structurally optimized IL had improved pretreatment performance and was significantly less cytotoxic than imidazolium IL toward human keratinocytes. For further improving the sensitivity of detection, we quantified the concentration of herbicides by a fast and mild fluorescence derivatization. Under optimized pretreatment conditions, high recoveries in real water samples (above 80%), short pretreatment time (<3 min for microextraction; 8 min for derivatization) and extremely low limit of detection values (3.90–12.40 ng L−1) were achieved. The proposed method was successfully applied to the analysis of real water samples.

Trajectory Balancing: A General Reweighting Approach to Causal Inference With Time-Series Cross-Sectional Data

We introduce balancing, a general reweighting approach to causal inference with time-series cross-sectional (TSCS) data. We focus on settings in which one or more units is exposed to treatment at a given time, while a set of control units remain untreated throughout a time window of interest. First, we show that many commonly used TSCS methods imply an assumption that a unit's non-treatment potential outcomes in the post-treatment period are linear in that unit's pre-treatment outcomes as well as time-invariant covariates. Under this assumption, we introduce the mean balancing method that reweights the control units such that the averages of the pre-treatment outcomes and covariates are approximately equal between the treatment and (reweighted) control groups. Second, we relax the linearity assumption and propose the kernel balancing method that seeks an approximate balance on a kernel-based feature expansion of the pre-treatment outcomes and covariates. The resulting approach inherits the property of handling time-vary confounders as in synthetic control and latent factor models, but has the advantages of: (1) improving feasibility and stability with reduced user discretion compared to existing approaches; (2) accommodating both short and long pre-treatment time periods with many or few treated units; and (3) achieving balance on the high-order trajectory of pre-treatment outcomes rather than their simple average at each time period. We illustrate this method with simulations and two empirical examples.

Wheat Straw Bio-refining Part II: Optimization of Alkali Pre-treatment Method with Microwave Radiation for Fermentable Sugars Separation

Background: The potential of microwave-assisted heating for enhancing the alkaline pretreatment of lignocellulosic waste is highlighted in this work. Objective: To maximize separation of fermentable sugars from wheat straw. Methods: Wheat straw hydrolysis assisted by microwave was carried out by setting up a statistical experimental design method and further investigating the main process parameters, namely: temperature (°C), microwave power (W), NaOH concentration (M) and wheat straw pre-treatment time (min) towards maximization of fermentable sugars extraction from wheat straw. The reducing sugars yield (response) of the alkaline pre-treated and microwaved wheat straw in lab scale provided data for building a predictive model which reflected interactions, significance and impact of the process parameters (factors) on the wheat straw hydrolysis yield. Results: SEM and FTIR images of untreated and alkaline pre-treated wheat straw were studied for investigating the morphological changes of wheat straw surface quality and structure resulting from the microwave and/or alkaline pre-treatment. In addition reducing sugars yield of 87%wt. from wheat straw pre-treated at 180°C, 550W microwave power, 0.65M of NaOH for 25min was achieved. This result was significantly higher compared to the one from the straw which was only hydrolysed enzymatically (30 %wt). Conclusion: It was found that shorter pre-treatment times were obtained at higher temperatures, alkali concentration and moderate microwave power levels. The results obtained were further optimized and indicated that the microwave-assisted alkaline pre-treatment of wheat straw technique is an attractive pre-treatment method which reduces the wheat straw pre-treatment time and enhances the hydrolysis yield.

Analysis of trace microcystins in vegetables using matrix solid-phase dispersion followed by high performance liquid chromatography triple-quadrupole mass spectrometry detection

A selective and sensitive method for the simultaneous determination of five common microcystins (MC-LR, -RR, -YR, -LW, -LF) in various vegetables was established using Matrix Solid-Phase Dispersion (MSPD) followed by high performance liquid chromatography-mass spectrometry detection. To optimize the pretreatment procedure for extracting the microcystins from three vegetable matrices (tomato, cucumber and spinacia, which represented different colors), Box-Behnken design was employed to optimize the main factors affecting the extraction efficiency, including sample/dispersant mass ratio, as well as the proportion mixture dispersant and the volumes of solvent. Based on the optimum conditions, the intra-day and inter-day variability for each microcystins in all vegetable samples were less than 8.6%, with the recoveries ranging from 71.9% to 96.5%. The limits of detection and quantitation of the method were 13.0μg/kg (dw) and 43.0μg/kg (dw), respectively. The established method was successfully applied to the analysis of MCs in vegetable samples which were collected by Lake Taihu. The procedure promising to be relative small sample size and short pretreatment time for the assay that can be used for monitoring MCs concentrations in vegetables.

Fabric Sol–gel Phase Sorptive Extraction Technique: A Review

Since the introduction in 2014 of fabric phase sorptive extraction (FPSE) as a sample preparation technique, it has attracted the attention of many scientists working in the field of separation science. This novel sorbent extraction technique has successfully utilized the benefits of sol–gel derived hybrid sorbents and a plethora of fabric substrates, resulting in a highly efficient, sensitive and green sample pretreatment methodology. The proposed procedure is an easy and efficient pathway to extract target analytes from different matrices providing inherent advantages such as high sample loading capacity and short pretreatment time. The present review mainly focuses on the background and sol–gel chemistry for the preparation of new fabric sorbents as well as on the applications of FPSE for extracting target analytes, from the time that it was first introduced. New modes of FPSE including stir FPSE, stir-bar FPSE, dynamic FPSE, and automated on-line FPSE are also highlighted and commented upon in detail. FPSE has been effectively applied for the determination of various organic and inorganic analytes in different types of environmental and biological samples in high throughput analytical, environmental, and toxicological laboratories.

Oxidative Depolymerization of Lignin Using a Novel Polyoxometalate-Protic Ionic Liquid System

Oxidative depolymerization of lignin obtained from pine and willow can be achieved in a novel system encompassing the ionic liquid (IL) 1-butylimidazolium hydrogensulfate coupled with a vanadium based polyoxometalate (POM) under oxygen rich conditions. Along with an array of phenols and functionalized aromatics, vanillin and syringaldehyde were the main products extracted from the IL. The overall yield of aldehyde products were shown to be higher on lignin samples obtained with shorter pretreatment times, with vanillin being the exclusive aldehyde product obtained from pine. In the presence of molecular oxygen, the highest yield of aldehyde products was obtained when 5 wt % of the POM relative to the IL was employed and constituted the major product in the extracted oils. This system succeeds in exploiting the ability of ILs to depolymerize lignin and the remarkable properties of the POM to oxidize the lignin fragments into useful platform chemicals.