A supramolecular solvent‐based dispersive liquid‐liquid microextraction was proposed for the extraction and determination of lignans in Forsythiae Fructus combined with high‐performance liquid ...chromatography. The supramolecular solvent, consisting of tetrabutylammonium bromide and n‐hexanol, was mixed with the sample solution to extract the analytes by a vortex. After accomplishing the extraction, the extraction phase was separated by centrifugation and collected for high‐performance liquid chromatography analysis. In this work, the important extraction variables such as the type and amount of extraction solvent, pH and salt amount in the sample phase, and extraction time were optimized. The synthesis of supramolecular solvent was studied and its microstructure was characterized by transmission electron microscopy. Under the optimal conditions, the analytes’ enrichment factors were between 6 and 170 for the proposed procedure. Satisfactory linear ranges (r ≥ 0.99), detection limits (0.025–0.4 ng/ml), precisions (< 9.2%), and accuracies (recoveries: 96.5%–104.8%) were obtained. The method has been successfully applied to the preconcentration of lignans in Forsythiae Fructus with simple and rapid operation, low cost, and environmental friendliness.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Biochar reduced runoff volumes and ratios of slopping land.•Biochar decreased the concentrations of N and P in the runoff.•Biochar has induced significant reduction of the nutrients losses.•Biochar ...exhibits a risk of increasing sediment loss under tillage conditions.
The effects of biochar on runoff and loss of soil and nutrients in the subtropical regions of China are rarely documented. Two field experiments, an orchard and a cropland field were set up, involving two treatments: biochar (BC) and no-biochar (NBC). The effects of BC on runoff volumes and ratios, sediment yield and the level of nutrient losses were monitored and evaluated over three years (2014–2016). Results showed that the treatment of BC induced a significant reduction in the runoff and nutrients losses. By plotting the data collected for the BC application, we observed that the average annual runoff decreased by 19–28%, whereas the average annual sediment yield by 11%. The cumulative values of total nitrogen (N) and phosphorus (P) losses were also substantially minimized by the BC treatment compared with the NBC one (P<0.05). However, the average annual concentrations of total N and P losses as obtained from the BC plots (16.21mgL−1 and 0.72–0.99mgL−1) were still high, and exceeding the wastewater discharge standard (N: 15mgL−1 and P: 0.5mgL−1). In addition, under tillage conditions, the BC application led to larger sediments yield (6.5gm−2) in contrast with the NBC treatment (5.5gm−2). In general, these findings can suggest that BC exhibits a vital efficiency in the control of soil erosion process, but there is a risk of increasing sediment loss under tillage conditions, which might need to be made up by combined with biological and agronomic managements such as straw mulching or adding polyacrylamide into soil in order to control further soil erosion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A simple and rapid instantaneous nebulization dispersive liquid-phase microextraction method was developed, and combined with high-performance liquid chromatography for determination of the contents ...of seven analytes in traditional Chinese medicines. In this study, using the sprinkler device to achieve instantaneous synchronous dispersion and extraction, only one spray can rapidly achieve the concentration and enrichment of seven kinds of chalcone and isoflavones. The key factors affecting the extraction efficiency were optimized including the type and volume of extractant, the pH and salt concentration of the sample phase, and the number of dispersion. Under the optimal conditions, the enrichment factor of the target analytes ranged from 103.1 to 180.9, with good linearity and correlation coefficients above 0.9970. The limits of detection ranged from 0.02 to 0.15 ng/mL, with good accuracy (recoveries 91.1 to 108.9%) and precision (relative standard deviations 1.5-7.1%). This method has short extraction time (2 s), low organic solvent consumption and high enrichment effect, so it has a wide application prospects.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A three‐phase hollow‐fiber liquid‐phase microextraction based on deep eutectic solvent as acceptor phase was developed and coupled with high‐performance capillary electrophoresis for the simultaneous ...extraction, enrichment, and determination of main active compounds (hesperidin, honokiol, shikonin, magnolol, emodin, and β,β′‐dimethylacrylshikonin) in a traditional Chinese medicinal formula. In this procedure, two hollow fibers, impregnated with n‐heptanol/n‐nonanol (7:3, v/v) mixture in wall pores as the extraction phase and a combination (9:1, v/v) of methyltrioctylammonium chloride/glycerol (1:3, n/n) and methanol in lumen as the acceptor phase, were immersed in the aqueous sample phase. The target analytes in the sample solution were first extracted through the organic phase, and further back‐extracted to the acceptor phase during the stirring process. Important extraction parameters such as types and composition of extraction solvent and deep eutectic solvent, sample phase pH, stirring rate, and extraction time were investigated and optimized. Under the optimal conditions, detection limits were 0.3–0.8 ng/mL with enrichment factors of 6–114 for the analytes and linearities of 0.001–13 μg/mL (r2 ≥ 0.9901). The developed method was successfully applied to the simultaneous extraction and concentration of the main active compounds in a formula of Zi‐Cao‐Cheng‐Qi decoction with the major advantages of convenience, effectiveness, and environmentally friendliness.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•The use of a switchable deep eutectic solvent in homogeneous liquid-liquid microextraction.•The rapid phase transition of the switchable extractant by the addition of an inorganic acid.•The ...characterization of extraction phase by FTIR, NMR and DSC.•Simultaneous preconcentration of six active ingredients from traditional Chinese medicine.
A homogeneous liquid-liquid microextraction (HLLME) was established based on a switchable deep eutectic solvent (DES) for the preconcentration and determination of six flavonoids with different polarity in “Scutellariae Radix” combined with high performance liquid chromatography (HPLC). A switchable DES composed of N,N-dimethylethanolamine (DMEA) and heptanoic acid was used as an extraction solvent in the HLLME method, which was miscible thoroughly with the aqueous sample phase initially, and then underwent rapid phase transition induced by the addition of an inorganic acid. After the extraction, the upper hydrophobic layer was recovered for HPLC analysis. Different experimental parameters were optimized, and the optimal extraction conditions were as follows: the switchable DES extraction phase, 90 µL of DMEA-heptanoic acid (1:1 mole ratio); phase-switching trigger, 100 µL of 5 mol/L HCl; 10% (w/v) of salt concentration in sample phase; extraction time, 0.3 min. Furthermore, the structures of the switchable DES and the upper hydrophobic layer were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and differential scanning calorimetry to illustrate the phase-switching mechanism of the extraction phase during the extraction process. Under the optimized conditions, the enrichment factors for six target analytes were between 0.4 and 104. The calibration curves were linear (r≥0.9866) in the range of 0.033–8.65 mg/L for scutellarin, 0.022–5.77 mg/L for baicalin, 0.0033–0.865 mg/L for scutellarein and wogonoside, and 0.0022–0.577 mg/L for baicalein and wogonin, respectively. Low detection limits (≤8.0 × 10−3 mg/L) and quantification limits (≤2.4 × 10−2 mg/L) as well as good precisions (relative standard deviations lower than 9.2%) and acceptable accuracies (spiked recoveries 89.3–114.4%) were also obtained. The proposed method is a simple, fast, and eco-friendly sample pretreatment method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
As a simple, rapid, green, and highly-efficient sample-preparation technique, liquid-phase microextraction has been successfully coupled with various instrumental analysis methods and widely applied ...to determine target analytes (especially trace or ultratrace) from different natural products. In this review, the study is centered on the up-to-date (2017/2018) applications and progresses of various liquid-phase microextractions, mainly including dispersive liquid-liquid microextraction, floating solidification liquid-phase microextraction, hollow fiber liquid-phase microextraction and electromembrane extraction and other novel procedures in the analysis of the endogenous chemical compositions, such as active, nutritional and toxic components from plants as well as disease marker, hormone, neurotransmitters from animals. Finally, future development and applications of liquid-phase microextraction in complex sample analysis are prospected.
•Applications of LPME in different natural product fields were described and overviewed.•Recent advances of various LPME approaches in natural product analysis were listed.•The trends and perspectives of LPME were proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel three‐phase hollow fiber liquid‐phase microextraction was developed based on reverse micelle as extraction solvent and acceptor phase, and compared with conventional two‐phase hollow fiber ...liquid‐phase microextraction. Both procedures were used in the extraction and concentration of four cinnamic acids (caffeic acid, p‐hydroxycinnamic acid, ferulic acid, and cinnamic acid) in traditional Chinese medicines prior to high‐performance liquid chromatography analysis. Parameters affecting the two procedures were investigated and optimized to obtain the optimum enrichment factors. The mechanism of the developed procedure was explored and elucidated by comparison with conventional two‐phase hollow fiber liquid‐phase microextraction. Under the optimized conditions, the analytes’ enrichment factors were between 50 and 118 for the proposed procedure, and 31–96 for conventional two‐phase mode. Satisfactory linear ranges (r2 ≥ 0.99), detection limits (0.1–0.6 ng/mL), precisions (<9.2%), and accuracies (recoveries: 80–123.1%) were observed for the two procedures. The results showed that the enrichment capacity of the proposed procedure for the cinnamic acids is better than that of conventional two‐phase procedure, and both are eco‐friendly, simple, and effective for the enrichment and detection of cinnamic acids in traditional Chinese medicines.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A sodium dodecyl sulfate sensitized switchable solvent liquid‐phase microextraction method was developed and applied to the preconcentration of active alkaloids in Rhizoma coptidis followed by high ...performance liquid chromatography determination. Before extraction, nonionic triethylamine was converted to its cationic form in the presence of carbon dioxide. Then, the ionic solvent carrying target analytes was once more reverted to its nonionic form by adding sodium hydroxide, as well as phase separation and analytes enrichment were realized simultaneously. Several parameters affecting the approach, such as concentration of sodium dodecyl sulfate, extraction solvent volume, sodium hydroxide concentration, sample phase pH, injection solvent type, and extraction time, were investigated and optimized. The possible microextraction mechanism of double micelle supramolecular inclusion was explored. Under the optimum conditions, the enrichment factors of four protoberberine alkaloids were from 101.8 to 152.0. The linear ranges (with r2 ≥ 0.990) were 0.032–4.23, 0.031–4.33, 0.0026–10.04, and 0.0013–4.13 μg/mL for epiberberine, coptisine, palmatine, and berberine, respectively. The detection limits were in the range of 0.16–0.32 ng/mL. Satisfactory accuracies (recoveries 98.8–104.6%) and precisions (RSDs 1.9–10.9%) were also obtained. The results showed that the approach is rapid, effective, eco‐friendly, and easy‐to‐handle for the enrichment and detection of active alkaloids in Rhizoma coptidis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Development of a switchable deep eutectic solvent-based liquid-phase microextraction.•The phase conversion of a switchable deep eutectic solvent by the addition of a strong acid.•The Fourier ...transform infrared spectrum for characterizing the extraction phase.•Simultaneous preconcentration of active ingredients from traditional Chinese medicine.•Rapidness, convenience and environmental friendliness with high enrichment factors.
A switchable deep eutectic solvent-based liquid-phase microextraction was proposed and applied to the preconcentration and determination of liposoluble quality-markers of diterpenoid quinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in traditional Chinese medicine coupled with high performance liquid chromatography-ultraviolet detection. In the procedure, the hydrophilic deep eutectic solvent of diethanolamine-hexanoic acid (molar ratio 1:1) was prepared and added into the sample phase as an extractant, and a homogeneous solution was formed under slight vortex stirring. After the addition of HCl solution, the deep eutectic solvent miscible with the sample phase was converted to hydrophobic form, and a cloudy solution was generated. Then, the upper hydrophobic layer enriching the target analytes was collected through centrifugation for high performance liquid chromatography analysis. Several critical parameters affecting the extraction performance including the composition and consumption of switchable deep eutectic solvent, the type and amount of acid, salt amount and extraction time were investigated and optimized. Moreover, the structures of the deep eutectic solvent and the recovered hydrophobic layer were both characterized using Fourier transform infrared spectroscopy, further demonstrating the switching mechanism of the extractant during the extraction process. Under the optimal conditions, enrichment factors of diterpenoid quinones ranged from 59 to 274. Good linearities (r≥0.9963), low detection limits (0.5–0.7 ng/mL), satisfactory precisions (relative standard deviations 0.5%-8.6%) and accuracies (recoveries 94.6%-104.6%) were also obtained. Comparing the proposed switchable deep eutectic solvent-based liquid-phase microextraction with other published methods, the characteristics of the procedure were summarized. The developed method was successfully applied for the preconcentration of four liposoluble diterpenoid quinones from a traditional Chinese herbal medicine of Salvia Miltiorrhiza.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Aims
Afforestation is considered as an effective method to restore degraded ecosystem. The effects of afforestation on soil fertility, microbial communities assembly have been broadly studied in the ...whole soil, yet gaps still exist at the aggregate scale.
Methods
In the Danjiangkou Reservoir area, we set up 3 quadrats (20 m × 20 m) for bareland, farmland and woodland, respectively, and separated the collected soil into four aggregate size fractions (<0.25 mm, 0.25–1 mm 1–3 mm and > 3 mm). Soil fertility, enzyme activities, microbial communities composition were determined for all aggregate fractions.
Results
Afforestation promoted soil fertility, enzyme activities and their aggregational differentiation. E.g., invertase activity in woodland was 3.6 times higher than in bareland. Interestingly, the aggregational differentiation of bacterial alpha-diversity (
P
< 0.05) was more sensitive to afforestation than fungal alpha-diversity (
P
> 0.05). Conversely, afforestation caused that more fungal taxa (16 Ascomycota and 3 Basidiomycota taxa) were susceptible to aggregates than bacterial taxa (5 Proteobacteria taxa). In bareland, deterministic process (83.3%) was the decisive factor for bacterial communities, while fungal communities was determined by stochastic (48.5%) and deterministic (51.5%) processes. Afforestation transformed assembly processes, with dispersal limitation (53%) occurring in bacterial communities and variable selection (68.2%) in fungal communities.
Conclusions
Overall, afforestation enhanced soil fertility, enzyme activities and their variation with aggregate. Moreover, responses of fungal and bacterial assembly to afforestation vary at the soil aggregate level. This study demonstrated the importance of soil aggregates in predicting and quantifying the impact of afforestation on soil fertility and microbial communities.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
