Dispersive Extraction Research Articles

Application of Response Surface Methodology to Design and Optimize Purification of Acetone or Aqueous Acetone Extracts of Hop Cones (Humulus lupulus L.) Using Superparamagnetic Iron Oxide Nanoparticles for Xanthohumol Isolation.

Iron oxide nanoparticles (IONPs) are an ideal sorbent for magnetic dispersion extraction due to their superparamagnetic properties and developed and active surface. This work aims to use IONPs, obtained by chemical co-precipitation, to purify 100% acetone and 50% acetone extracts from hop cones (Humulus lupulus L.) obtained by ultrasonic-assisted solvent extraction. The extracts were purified from bitter acids (i.e., humulones, lupulones) to isolate xanthohumol. The sorption conditions were optimized depending on the composition of the extraction mixture, specifically the mass of IONPs and the time needed to achieve effective sorption using response surface methodology (RSM). An analysis of variance (ANOVA) was performed to assess the adequacy of the developed model, and a good agreement was found between the experimental data and the proposed model. The polynomial equation describing the model is highly significant (p < 0.05), with a precision of Adeq (above 4). This indicates the usefulness of the polynomial regression model for prediction in experimental design. The final products of the purification for 100% acetone extracts and 50% acetone contain 40.58 ± 2.84 µg mL-1 and 57.64 ± 0.83 µg mL-1 of xanthohumol, respectively. The use of 50% acetone extract provides more favorable conditions due to the smaller amount of nanoparticles required for extract purification and a higher recovery of xanthohumol. The development of a reliable multivariate model allowed for the optimization of the extract purification process, resulting in high-purity xanthohumol from natural sources.

A 96-position platform for magnetic sorbent-based dispersive microextraction: Application to the determination of tetrahydrocannabinol and cannabidiol in saliva of cannabis smokers

BackgroundIn order to obtain sustainable analytical methods, it is essential to develop kinetically efficient sample preparation strategies in which equilibria are reached faster, as dispersive extraction techniques. In addition, the higher the reduction in size, the higher number of extraction vessels can be located and thus the higher number of samples can be simultaneously treated. All this increases sample throughput, and contributes to the reduction of chemical waste, and energy and sample consumption. In this sense, multiposition extraction platforms are smart strategies to achieve these goals, but they are scarcely developed for dispersive extraction techniques. ResultsTaking miniaturized stir bar sorptive dispersive microextraction (mSBSDME) as a starting point, a 96-position extraction platform has been developed using a 96-position stirring plate and a tailor-designed 3D-printed support for locating the miniaturized extraction vessels, achieving a high-throughput miniaturized sample preparation strategy. In order to show the applicability of this novel platform, the determination of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in human saliva has been carried out and applied to samples collected after the consumption of marijuana and legal CBD-rich cannabis. Only 100 μL of saliva were needed for the analysis and good analytical features in terms of linearity (at least up to 500 ng mL−1), limits of detection (0.7 and 2.8 ng mL−1 for THC and CBD, respectively), and precision (RSD ≤ 14 %) were achieved. SignificanceThe miniaturization of the vessel allows the use of small volumes of sample (i.e., a few microliters) and the treatment of 96 samples in parallel, being the first proposal for carrying out dispersive sorbent-based microextraction under the concept of 96-well format. Additionally, this new workflow contributes to the development of analytical methods that meet the three pillars of sustainability, i.e., greenness and easily affordable in terms of economics and applicability.

Benzo(b)fluoranthene and benzo(k)fluoranthene removal by microalgae in the presence of triazine herbicides: Matrix solid-phase dispersion and solid-phase extraction (MSPD/SPE) for HPLC-UV analysis of the different culture components

Over the last decade, human activities in the industrial and agricultural sectors have significantly increased the concentration of persistent and harmful pollutants in aquatic ecosystems. The use of microorganisms is a green strategy for the bio-removal of certain contaminants. However, other pollutants in the same ecosystems can reduce their degrading activity and even affect their survival. Therefore, this study aimed to evaluate the efficiency of benzo(b)fluoranthene (BbF) and benzo(k)fluoranthene (BkF) removal by Selenastrum capricornutum in the presence of triazine herbicides, compounds mainly used in broadleaf weeds. The interest of this work focused on identifying in which of the microalgal components the degrading activity is best evidenced and affected. For this purpose, the use of solid-phase extraction (SPE) and matrix solid-phase dispersion (MSPD) extraction procedures and HPLC-UV analysis allowed the BbF and BkF trace quantification in biomass, liquid medium, and cell lysate separately from cultures exposed to these polycyclic aromatic hydrocarbons (PAHs) alone or with herbicides. The recovery percentages were between 78 and 94 %, good linearity (r2 ≈ 0.99), precision values measured as RSD < 15 %, and limits of detection (LOQs) at levels of ng mL−1 and ng mg−1 were obtained. The individual PAH amounts measured in the components of microalgae cultures show similar removal kinetics (removal percentages: 82–89 %). Likewise, the analysis demonstrated that the removal of PAHs is not affected in the presence of triazine herbicides (atrazine and cyanazine) and with similar removal percentages (79–86 %) compared to those cultures exposed to individual PAHs (74–83 %). These results support the possible real-world applications of PAH removal by extracts from S. capricornutum in aquatic environments contaminated with PAHs and near agriculture areas where triazine herbicides are used.

A Novel Green Sample Pretreatment Method Column-Free Matrix Solid-Phase Dispersion Extraction: Application in a High-Performance Liquid Chromatography Experiment for Undergraduate Chemistry

A Novel Green Sample Pretreatment Method Column-Free Matrix Solid-Phase Dispersion Extraction: Application in a High-Performance Liquid Chromatography Experiment for Undergraduate Chemistry

Influence of strong directional sources in ambient seismic imaging using traffic-induced noise

Continuously moving seismic sources, such as vehicles and train cars, play a crucial role as passive sources for nondestructive exploration in urban areas. Seismic interferometry is commonly used in field data acquisition and processing using linear arrays. However, the simultaneous recording of high-energy noise, excited by buildings and factories, cannot be overlooked. We simulate moving-source seismic records with strong noises using orthogonal arrays. When strong noise originates from specific angles, the energy-phase velocity curves of arrays in different directions significantly diverge. We determine that an L-shaped array, formed by orthogonal arrays, can effectively mitigate this effect, yielding more consistent results. Nonetheless, spatial constraints often preclude the deployment of L-shaped arrays. To mitigate this issue, we develop a new parallel observation system. Field tests conducted on a main road validate that the new array is comparable with the L-shaped array in terms of dispersion extraction. Similar to synthetic data, the phase velocity extracted from the linear array field data is found to be unreliable. Drilling data align well with the inversion results of the parallel observation system. Given the challenges of urban traffic-induced signal acquisition, deploying multiazimuth arrays to minimize noise impact is essential. Considering the spatial limitations, the convenient parallel observation system emerges as a good choice.

Miniaturized matrix solid-phase dispersion assisted by deep eutectic solvent for acrylamide determination in bread samples.

Acrylamide determination is important to state its quantity in baked food preventing any potential carcinogenic effects. Matrix solid-phase dispersion (MSPD) extraction is an extraction procedure based on a homogenization phase between a solid sample and a solid dispersing material to break sample increasing analyte extraction yield, often used for acrylamide determination. The addition of a green deep eutectic solvent (DES) during the MSPD homogenization phase improves the analyte extraction, giving the possibility to reduce the amount of organic solvent used. In this work, a miniaturized MSPD extraction assisted by a DES was developed to determine acrylamide in bread, using high-performance liquid chromatography coupled with mass spectrometry detection. The optimized procedure provides 1:1 (w/w) matrix-to-dispersing material ratio, 2mL of methanol as extraction solvent, and 50 μL of choline chloride-glycerol DES added during the homogenization phase. Method validation ensured good results with minimum recoveries of 90%, high precision with a maximum intra-day error of 4%, and inter-day error of 6%. Limit of detection and limit of quantification resulted to be 16μg/kg and 35μg/kg, respectively. This miniaturized extraction procedure represents a good alternative to those reported in the literature, guaranteeing great performance and respecting green chemistry principles.

Magnetic-stirring-enhanced mechanical amorphous dispersion extraction for the hydrophobic phytochemical constituents using an aqueous solution from a medicinal plant

A method involving chitosan-assisted magnetic-stirring-enhanced mechanical amorphous dispersion extraction was developed and utilized to extract hydrophobic anthraquinones from Rhei Radix et Rhizoma prior to ultrahigh performance liquid chromatography analysis. Incorporating natural chitosan as a dispersant facilitated the extraction of hydrophobic anthraquinones using purified water, considerably enhancing the eco-friendliness of the extraction methodology. To optimize extraction efficiency, an extensive evaluation of the crucial parameters influencing rhubarb yield was conducted. Furthermore, a response surface methodology was applied to optimize the extraction conditions. Under these optimized conditions, the method exhibited linearity ranges of 0.1–100 µg/mL, with correlation coefficients between 0.9990 and 0.9998. The method’s intraday (n = 6) and interday (n = 6) precision levels were maintained at ≤3.58%, which was considered to be within acceptable limits. The computed detection and quantification limits were 16.54–24.60 and 54.91–82.04 ng/mL, respectively. Consequently, this optimized method was effectively employed to extract five specific compounds (aloe-emodin, emodin, rhein, chrysophanol, and physcion) from Rhei Radix et Rhizoma, achieving recoveries ranging from 86.43% to 102.75%.

Cucurbit[7]uril-mediated matrix solid phase dispersion extraction strategy combined capillary electrophoresis for detection of biogenic amines in foods

Biogenic amines (BAs) are the vital indicators of food freshness, and monitoring the change of BAs content is quite essential for food safety. Herein, we developed a matrix solid phase dispersion (MSPD) extraction technology based on cucurbit[7]uril (Q[7]) to extract BAs from pork and shrimp. Then, the extracted BAs were analyzed by capillary electrophoresis (CE) with low sample consumption and high analytical efficiency. The factors affecting MSPD extraction were optimized by Plackett-Burman and the Box-Behnken design (BBD). The limits of detection (LODs) were ranging from 0.003 to 0.019 mg kg−1, the recoveries of spiked samples were 80.15 %–110.3 %. The satisfactory accuracy and precision were attributed to the host–guest interaction between Q[7] and BAs. Furthermore, the freshness of pork and shrimp was evaluated by simultaneous determination of four BAs. For its wide linear range, high sensitivity, and cost-effectiveness, the proposed Q[7] mediated MSPD-CE-UV provides meaningful potential prospects in the rapid monitor of food freshness and safety.

Determination of triazole fungicides in soybeans with cobalt-enhanced lanthanide metal chloride anion magnetic deep eutectic solvents in-situ dispersion extraction

In this work, we synthesized a series of magnetic deep eutectic solvents (MDESs) with lanthanide metal chlorides as paramagnetic metal centers and developed a reversed-phase dispersive liquid–liquid microextraction method (DLLME) based on the in-situ dispersion of MDESs for the extraction and preconcentration of triazole fungicides (TFs) from bean samples. Different MDESs were synthesized by combining quaternary ammonium salts, short-chain carboxylic acids, and lanthanide metal chlorides. The dissolution of short-chain carboxylic acids in n-hexane led to the in-situ dispersion of MDESs to replace the toxic dispersant of traditional DLLME species and shorten extraction time. Cobalt powder was added to encapsulate MDESs to enhance the magnetic properties after the extraction and achieve the purpose of easy phase separation. Notably, the highest extraction efficiency of TFs was observed in the MDES formed by tetrabutylammonium bromide, propionic acid, and gadolinium chloride in a ratio of 1:10:0.06. We optimized various parameters that affected the extraction efficiency of the method, including volume of MDES, extraction time, amount of cobalt powder, and volume of elution solvent. Under the optimal conditions, the detection limits (LODs) and quantification limits (LOQs) of the technique varied between 0.097–0.13 ng·g−1 and 0.32–0.43 ng·g−1, respectively. To assess the accuracy, the method was tested with samples spiking at three concentration levels, and the obtained results revealed that the recovery rates varied from 88.97–113.7%. To summarize, this study represents the initial application of in-situ dispersed lanthanide metal chloride anion-MDESs for analyzing bean samples and the proposed DLLME technique is rapid, straightforward, and efficient.

Study of dispersion extraction for optical coherence tomography imaging.

Dispersion mismatch of optical coherence tomography (OCT), caused by inherent dispersion of biological sample, leads to axial resolution degradation and image blurring. However, the dispersion of biological samples may carry characteristic information of itself. Therefore, it is useful and important to extract dispersion as an additional parameter of biological samples. Here, we study and compare five categories of conventional OCT dispersion extraction methods first. The results show that the iterative method has the best accuracy and stability. Furthermore, we propose an improved iterative method, which achieves higher accuracy and stability in simulation compared with conventional methods. Then, the dispersion values of optical glasses are extracted experimentally utilizing the proposed method. The extracted values are consistent well with reference values. Furthermore, we apply the proposed method for extracting the dispersion characteristics of zebrafish eye. With the proposed method, OCT-based analysis of dispersion characteristics could be a powerful tool in clinical practice.

Determination of coumarins in Fructus cnidii by using deep eutectic solvent elution-based carboxymethyl chitosan matrix solid-phase dispersive extraction

Fructus cnidii has been used as a folk medicine for thousands of years. Coumarins are the active compounds behind its therapeutic effect. Thus, the determination of coumarins is necessary for quality evaluation of Fructus cnidii. However, most traditional methods for determining coumarins in natural products are time-consuming, organic solvent-consuming, and are not amenable to the analysis of volatile compounds. Herein, a novel method termed deep eutectic solvent-based carboxymethyl chitosan matrix solid-phase dispersion extraction was proposed and applied to the determination of coumarins in Fructus cnidii, including bergapten, imperatorin, and osthole. For the first time, carboxymethyl chitosan was applied as a dispersant and hexanoic acid-monoethanolamine (a deep eutectic solvent) was used as an eluting solution in the analytical procedure. The deep eutectic solvent dissolved the dispersant (CMC), thereby releasing the analytes and precluding irreversible adsorption. The analytes could be simultaneously concentrated during the elution process. The newly developed method was coupled with HPLC for the determination of coumarins in Fructus cnidii. Several critical parameters affecting the extraction performance, including the molar ratio of the sample to dispersant, grinding time, type of eluting solution, and amount of acid added were investigated. The method was validated by using HPLC. The good linearity (r ≥ 0.9998), a low detection limit, satisfactory precision (intra-day precision is less than 1.88 %, inter-day precision is less than 6.71 %) and accuracy (recovery is 91.3 %-95.0 %) were obtained. Under the optimal conditions, the proposed method had advantages including a simpler extraction process, smaller sample amount (10 mg), less organic reagent (2.4 mL), shorter extraction time (7 min), and no additional concentration process. It is also allowed the analysis of volatile compounds and is environment friendly.

Matrix solid-phase dispersion extraction of organophosphorus flame retardants in soil based on response surface methodology

Organophosphorus flame retardants (OPFRs) are widely used in commercial products owing to their exceptional flame-retarding and plasticizing properties. However, OPFRs are also well recognized as emerging persistent organic pollutants (POPs) because of their environmental persistence, biological concentration, and potential toxicity. Thus, the accurate detection of OPFRs in environmental media is critical for analyzing their fate, transport, and ecological risk. However, very few OPFR detection methods are currently available, and the types of OPFRs detected may vary from site to site. In this study, matrix solid-phase dispersion extraction (MSPD), a simple, rapid, and versatile technique for preparing solid, semisolid, liquid, and viscous samples, was combined for the first time with gas chromatography-tandem mass spectrometry (GC-MS/MS) to analyze 10 OPFRs in soil, namely, tripropyl phosphate (TPrP), tri-n-butyl phosphate (TnBP), tri-iso-butyl phosphate (TiBP), tris(2-chloroisopropyl) phosphate (TCIPP), tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPP), triphenylphosphine oxide (TPPO), and trimethylphenyl phosphate (TCP). The GC-MS/MS system was equipped with a Bruker-5MS capillary column coupled with a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode. Prior to detection, a mixed standard solution was fortified with 10 ng of13C-PCB208 as an internal standard. The optimal conditions under which MSPD could achieve high selectivity for OPFRs were determined. In addition, single-factor analysis was used to examine the influence of the sorbent (i. e., C18, PSA, Florisil, GCB, and multiwalled carbon nanotubes (MWCNTs)) as well as the dosage, type, and volume of the eluent on the extraction efficiency of the method for the 10 OPFRs. When GCB and ethyl acetate were used as the adsorbent and solvent, respectively, during elution, high extraction recoveries for the OPFRs were achieved. Optimization via response surface methodology (RSM) was adopted to further analyze the impact of three key factors, namely, the adsorbent dosage, eluent volume, and grinding time, as well as their interactions, on OPFR recoveries. Under the optimal conditions of 0.3 g of GCB as the adsorbent, 10 mL of ethyl acetate as the eluent, and 5 min of grinding time, the relative average recovery of the OPFRs was 87.5%. Furthermore, the 10 OPFRs showed good linear relationships under five concentration gradients, with correlation coefficients greater than 0.998. The limits of detection (LODs) and quantification (LOQs) were calculated as signal-to-noise ratios (S/N) of 3 and 10, respectively, and found to be in the ranges of 0.006-0.161 and 0.020-0.531 ng/g, respectively. The performance of the proposed method was verified by determining the recoveries and relative standard deviations (RSDs) of the OPFRs in soils spiked at low, medium, and high levels (10, 20, and 100 ng/g, respectively). The recoveries of the OPFRs ranged from 70.4% to 115.4%, with RSDs ranging from 0.7% to 6.7%. Compared with the conventional accelerated solvent extraction (ASE) method, MSPD presents higher efficiency, simpler operation, and less solvent requirements. The developed method was applied to determine OPFRs in soil samples collected from different sites in Suzhou, including an electronics factory, an auto-repair factory, a paddy field, and a school field. The results revealed that the contents of OPFRs in the soils from the electronics and auto-repair factories were significantly higher than those in the soils from the paddy and school fields. The main pollutants in the soil samples collected from the electronics and auto-repair factories were TCIPP, TPPO, TCEP, and TDCPP. Moreover, the contents of these compounds were 5.30, 4.44, 4.54, and 4.20 ng/g, in soils from the electronics factory and 2.70, 3.93, 7.60, and 5.04 ng/g, in soils from the auto-repair factory. To the best of our knowledge, this study is the first to determine high concentrations of TPPO in industrial soils. Thus, the combination of MSPD and GC-MS/MS adopted in this study can provide useful insights into the detection of the 10 OPFRs in soil.

High Frequency Passive Surface Wave Dispersion Extraction by Linear Seismic Array Aligned with Noise Source Azimuth

Due to the uneven spatial and temporal distribution of noise sources, the dispersion data extracted from high-frequency (>1Hz) ambient noise data would be contaminated and biased. Based on the azimuth analysis of the noise sources, we propose a linear array data acquisition strategy that considers the noise source direction to get high quality dispersion data.

Valorization of Defatted Cherry Seed Residues from Liquor Processing by Matrix Solid-Phase Dispersion Extraction: A Sustainable Strategy for Production of Phenolic-Rich Extracts with Antioxidant Potential.

The integrated valorization of food chain waste is one of the most promising alternatives in the transition to a sustainable bioeconomy. Thus, an efficient solid-phase matrix dispersion extraction method, using experimental factorial design and response surface methodology, has been developed and optimized for the recovery of polyphenols from defatted cherry seeds obtained after cherry liquor manufacture and subsequent fatty acid extraction, evaluating the effect of each processing step on the composition and phenolic content of sweet cherry residues. The phenolic extracts before fermentation showed the highest content of total polyphenols (TPC) and flavonoids (TFC) (3 ± 1 mg QE·g-1 and 1.37 ± 0.08 mg GAE·g-1, respectively), while the highest antioxidant capacity was obtained in the defatted seed extracts after both fermentation and distillation. In addition, high-performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (HPLC-ESI-QTOF-MS) was used to determine the phenolic profile. Dihydroxybenzoic acid, neochlorogenic acid, caffeic acid, and quercetin were the main phenolics found, showing differences in concentration between the stages of liquor production. The results underline the prospective of cherry by-products for obtaining phenol-rich bioactive extracts for possible use in different industrial sectors, offering a feasible solution for the cascade valorization of cherry agri-food waste.

A rapid and eco-friendly method for determination of dictamnine, obacunone, and fraxinellone in Cortex Dictamni by LC–MS and matrix solid-phase dispersion extraction

This study develops a rapid and eco-friendly liquid chromatography–mass spectrometry method for determining dictamnine, obacunone, and fraxinellone in Cortex Dictamni. The samples were extracted by matrix solid-phase dispersion extraction with ethanol. The liquid chromatography separation was operated on an Agilent InfinityLab Poroshell 120 EC-C18 column (2.1 mm × 30 mm, 2.7 μm) using 45% ethanol at a 0.3 mL/min flow rate. Mass spectrometry detection was set at positive ion mode, and the selected ion monitoring mode was used to record the target compounds: dictamnine (mass-to-charge ratio 200), obacunone (mass-to-charge ratio 455), and fraxinellone (mass-to-charge ratio 233). The calibration curves exhibited good linearity (R > 0.9994) within the test range. The intra-day precision was 0.601% for dictamnine, 1.03% for obacunone, and 0.898% for fraxinellone. The recoveries were 100% for dictamnine, 101% for obacunone, and 96.2% for fraxinellone. Six samples were analyzed, and they all conformed to the content requirements of the Chinese Pharmacopeia. Notably, the developed method only requires 6.07 mL ethanol and costs 12 min. This study presents a rapid and eco-friendly analytical method for determining three components in Cortex Dictamni, which will help improve the quality evaluation technology of Cortex Dictamni.

Development of a solid-phase dispersive extraction method for molecularly imprinted polymers and LC-MS/MS for analysis of clenbuterol residues in swine livers and kidneys.

Clenbuterol (CLB) is approved as a veterinary drug because of its tracheal smooth muscle and uterine relaxant effects. However, if improperly administered for the purpose of fattening livestock, CLB can remain in the organs, which may pose a health hazard to humans. We aimed to examine the combination of molecularly imprinted polymer (MIP) and solid-phase dispersive extraction (SPDE) as a pretreatment method for swine liver and kidney, which contain more coexisting impurities than muscle tissue, and attempted to construct an analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Swine livers and kidneys were homogenized and extracted using liquid-liquid partitioning with an ethyl acetate/n-hexane mixture (1:1), followed by SPDE using an MIP gel, and measured using LC-MS/MS. For LC-MS/MS, either an absolute calibration method or isotope dilution mass spectrometry (IDMS) was used. For method validation, a recovery test (additive concentrations: 0.05 and 0.5 ng/g) was conducted, and the data were analyzed using one-way analysis of variance (ANOVA). The recoveries (trueness), repeatability, and intermediate precision obtained using absolute calibration were similar to those obtained using IDMS. Using MIP-SPDE as a pretreatment method for CLB in swine liver and kidney samples yielded comparable results for absolute calibration and IDMS in LC-MS/MS analysis. MIP-SPDE can be used as a pretreatment method to analyze CLB in swine organs with high accuracy.

Investigation of the spatial distribution of airborne polycyclic aromatic hydrocarbons using Rhytidiadelphus squarrosus in Tórshavn, Faroe Islands.

Due to adverse effects of Polycyclic Aromatic Hydrocarbons (PAHs) on human health, it is important to understand how airborne PAHs, are spatially distributed within urban areas. Moss has been shown to be a suitable material for biomonitoring of airborne PAH pollution. In this study, the moss Rhytidiadelphus squarrosus was sampled throughout Tórshavn, Faroe Islands. 53 Rhytidiadelphus squarrosus samples were extracted using a matrix solid-phase dispersive extraction method and analysed for 19 parent PAHs and six groups of alkylated PAHs using gas chromatography mass-spectrometry. All PAHs were quantified in at least one Rhytidiadelphus squarrosus sample, and the sum of the EPA 16 PAHs (ƩPAHEPA16) ranged from 0.90 to 344µgkg-1 dry weight. Higher concentrations were found close to the harbour and the main roads. The spatial correlation was investigated for the ƩPAHEPA16, pyrene, fluoranthene, chrysene, benzo(e)pyrene, benzo(g,h,i)perylene, C1-phenanthrenes/C1-anthracenes, and C2-phenanthrenes/C2-anthracenes using variograms. The effective range of the spatial correlation was between 500 to 700m of all PAHs. The evaluation of diagnostic ratios of fluoranthene to pyrene, and benzo(a)anthracene to chrysene suggest that different pollution sources affect urban areas of different types. To the best of our knowledge, this is the first time airborne PAH pollution patterns were mapped in an Arctic town, and the first time, Rhytidiadelphus squarrosus was used for tracing PAH pollution sources. Rhytidiadelphus squarrosus is suitable for biomonitoring and mapping PAH pollution within urban areas since it is widespread, and suitable for mapping PAHs.

Residual Analysis of Aflatoxin M&lt;sub&gt;1&lt;/sub&gt; in Cheese by HPLC Coupled with Solid Phase Dispersive Extraction and Solid-Phase Fluorescence Derivatization Method, and Its Accuracy Management for Method Validation

Residual Analysis of Aflatoxin M&lt;sub&gt;1&lt;/sub&gt; in Cheese by HPLC Coupled with Solid Phase Dispersive Extraction and Solid-Phase Fluorescence Derivatization Method, and Its Accuracy Management for Method Validation

A simple and reliable isocratic high-performance chromatographic assay for the simultaneous determination of hydrophilic benzophenone-4 and lipophilic octocrylene in sunscreens.

This work aimed to develop a simple HPLC method for the simultaneous quantitative determination of the ultraviolet (UV) filters, hydrophilic benzophenone-4 and lipophilic octocrylene, in the presence of three other commonly used UV filters, avobenzone, octisalate and homosalate. Reverse-phased HPLC was performed on a C18 column. A scouting gradient was initially used to determine the approximate mobile phase composition required for efficient analyte elution and separation before further optimization. The assay was validated with regard to specificity, linearity, intra- and inter-day accuracy and precision, limits of detection and limits of quantification. An ultrasound dispersion extraction method for the UV filters from a commercial sunscreen was developed, and the extraction efficiencies from spiked samples were calculated. An acetonitrile-methanol-water mixture (20:67:13, v/v/v), where the water component contained 0.2% trifluoroacetic acid (v/v), was found to be the optimal mobile phase at a flow rate of 1.0 mL/min. The assay was linear between 1.0-100 μg/mL for both benzophenone-4 and octocrylene (both correlation coefficients were above 0.999). There was no interference from the excipients of the sunscreen nor from the three other UV filters. The intra- and inter-day accuracy was between 90.0-104.6% for both analytes. Extraction recoveries from a spiked commercial sunscreen were between 95.4 ± 2.1% to 98.5 ± 2.1% for benzophenone-4, and between 87.3 ± 2.3% and 98.9 ± 3.1% for octocrylene. All validation parameters were within the acceptance criteria set out in the International Council for Harmonization (ICH) guidelines. The HPLC assay showed the extracted quantities of benzophenone-4 and octocrylene from the commercial sunscreen closely matched claimed quantities. The developed isocratic HPLC method was suitable for simultaneously determining the hydrophilic benzophenone-4 and lipophilic octocrylene in the presence of other commonly used UV filters. Additionally, the extraction method was simple and effective for accurately quantifying the UV filters in a commercial sunscreen.

A novel strategy by combining “magnified” matrix solid phase dispersion extraction with high-speed countercurrent chromatography for the rapid and efficient isolation of flavonoids isomers with anti-inflammatory effect from Lindera aggregata (Sims) Kosterm Leaves

A rapid and efficient isolation strategy by combining matrix solid phase dispersion extraction (MSPD) with high-speed countercurrent chromatography (HSCCC) had been proposed in this study for the separation of four flavonoids with anti-inflammatory effect in high edible value plant food, leaves of Lindera aggregata (Sims) Kosterm (L.aggregata-L). MSPD was firstly developed as an efficient extraction methodology to obtain a “clean” extract for the purpose of further isolation of target compounds. Then, two runs of HSCCC isolation were consecutively performed on MSPD extract to purify the target compounds, in which an environmental-friendly biphasic solvent system composed of ethyl acetate-n-butanol-0.05 mol/L of phosphate buffer (pH 3.16) containing 0.05 mol/L of hydroxypropyl-β-cyclodextrin (HP-β-CD) was established for the successful separation of the flavonoids isomers, for the first time. As a result, 21.3 mg of quercetin-3-O-rhamnopyranoside (purity of 96%), 18.7 mg of kaempferol-7-O-α-l-rhamnopyranoside (purity of 89%), 5.5 mg of quercetin-3-O-β-D-glucoside (purity of 90.3%) and 6.4 mg of quercetin-5-O-β-D-glucoside (purity of 86.4%) were obtained from 5 g plant materials. Further cellular assays (RAW264.7 mouse macrophage cells) revealed that the isomers demonstrated good anti-inflammatory activities, of which quercetin-5-O-β-D-glucoside exhibited better anti-inflammatory effect (330% higher than quercetin-3-O-β-D-glucoside at the concentration of 25 μM) but lower cytotoxicity (50% lower than quercetin-3-O-β-D-glucoside at the concentration of 400 μM). In summary, this research indicated a promising isolation strategy of natural compounds which would provide a solid surport for the subsequent further study and development of L. aggregata-L.