Dispersive Solid-liquid Microextraction Research Articles

Ultrasound-assisted dispersive solid-liquid microextraction with eutectic solvents for the determination of cannabinoids in different hemp products

The wide range of applications of hemp products, together with the environmental benefits that come from hemp cultivation are driving up the market demand for Cannabis sativa L. plant. One of the main restrictions for hemp cultivation and marketing concerns the content of delta-9-tetrahydrocannabidiol (Δ9-THC), which is known to have psychotomimetic effect. If the recent growing of hemp market is beneficial by an economic and environmental point of view, it is necessary to develop reliable analytical methods for the chemical characterization of hemp products, to guarantee the safety of use for the customers.This study aimed to develop a simple ultrasound-assisted dispersive solid-liquid microextraction (UA-DSLME) method for the extraction of cannabinoids in hemp products, using eutectic solvents (ESs) as extraction material. Two types of ESs were compared: one prepared with a [Ch+][Br-]-modified salts as hydrogen bond acceptor and one based on natural terpenoids. The ultrasound-assisted dispersive solid-liquid microextraction method was optimized to be applied for the analysis of aerial parts of hemp collected before flowering, hemp inflorescences and a commercial sample called CBD oil, and proved to be robust and versatile. Under optimal conditions, only 100 µL of ES and 2 mL of water as co-solvent were used in the US-assisted extraction, before the analysis in the UHPLC-PDA system. The developed approach allowed to obtain the same chemical profile of conventional methods, while improving the greenness of the method and the enrichment of the marker analytes. To overcome the strong matrix effect for cannabinoids, a matrix-matched calibration was used. Blank matrices of the samples under study were easily obtained by performing an exhaustive extraction of the marker analytes in the hemp samples. These matrices were successfully used for validation, achieving accuracy values between 82% and 118%.

Development of an Environmentally Friendly Extraction Method Using Smartphone-Based Digital Images for the Determination of Total Sulfonamides in Meat Samples

Sulfonamides (SAs) are low-cost synthetic antimicrobials widely used in veterinary and human medicine to treat diseases and prevent infections. However, long periods of exposure to sulfonamides can cause adverse effects such as allergic reactions. This work aims to study dispersive solid-liquid microextraction as an alternative method for extracting total SAs in meat samples. The procedure uses a colorimetric reaction based on the formation of a pink compound (imine salt) to determine total sulfonamides (sulfamethazine, sulfadimethoxine, sulfathiazole) with digital measurements. A linear response was observed between 33-233 μg kg-1 for total sulfonamides, and the coefficient of variation (n = 11; 67 μg kg-1 of total SAs) and the limit of detection were estimated to be 0.63% and 10 μg kg-1, respectively. For a 750 mg meat sample, 0.11 mg of 4-dimethylaminocinnamaldehyde, 2.60 mg of sodium dodecyl sulfate, and 275 μL of 1-butanol were consumed per sample, and consequently, generating only 335 μL of residue. Besides this, addition-recovery tests were performed, resulting in a 71-100% recovery range, indicating the trueness of the proposed method.

Development of a dispersive solid-liquid microextraction method using natural eutectic solvents for a greener extraction of phytochemicals from fiber-type Cannabis sp

The use of plant materials as natural resources has become fundamental for several applications, in perspective of a sustainable growth. Cannabis sp. crop perfectly fits this purpose, thanks to its rich phytocomplex, that can be exploited in pharmaceutical and cosmetic industry. At the same time, the increasing demand for innovative technologies, energy saving and greener solvents makes necessary the development of new extraction methods to obtain the metabolites of interest. In this study, a dispersive solid-liquid microextraction (DSLME) method, using natural eutectic solvents (ESs), was first optimized and validated for the extraction of the non-volatile fraction of the aerial parts of hemp collected before flowering. The DSLME was directly carried out on the freeze-dried powder of the plant, without the need of a pre-extraction with harmful organic solvents. The optimized method is fast and easy to perform compared to conventional procedures, and only requires 100 µL of ES and 2 mL of water. The ES easily formed the dispersion in water after 30 s of vortex, and no dispersive solvent was added. After 10 min of sonication, the enriched phase was simply recollected after centrifugation and solubilized in 500 µL of methanol/water (70:30, v/v) before the injection in the UHPLC-PDA system. Several natural compounds (menthol, linalool, terpinen-4-ol, eugenol, carvacrol, thymol) were combined and the influence of the two components of the ES, on the performance of extraction, was also evaluated. The proposed solvents showed a higher enrichment of cannabinoid compounds compared to the more polar flavonoids, thanks to the hydrophobic features of the proposed ESs.

Dispersive Solid–Liquid Microextraction Based on the Poly(HDDA)/Graphene Sorbent Followed by ICP-MS for the Determination of Rare Earth Elements in Coal Fly Ash Leachate

A dispersive solid-phase microextraction (DSPME) sorbent consisting of poly(1,6-hexanediol diacrylate)-based polymer microspheres, with embedded graphene microparticles (poly(HDDA)/graphene), was synthesized by microfluidic emulsification/photopolymerization and characterized by optical microscopy and X-ray fluorescence spectrometry. This sorbent was applied for simple, fast, and sensitive vortex-assisted DSPME of rare earth elements (RREs) in coal fly ash (CFA) leachate, prior to their quantification by inductively coupled plasma mass spectrometry (ICP-MS). Among nine DSPME variables, the Plackett–Burman screening design (PBD), followed by the central composite optimization design (CCD) using the Derringer desirability function (D), identified the eluent type as the most influencing DSPME variable. The optimum conditions with maximum D (0.65) for the chelating agent di-(2-ethylhexyl) phosphoric acid (D2EHPA) amount, the sorbent amount, the eluting solvent, the extraction temperature, the centrifuge speed, the vortexing time, the elution time, the centrifugation time, and pH, were set to 60 μL, 30 mg, 2 M HNO3, 25 °C, 6000 rpm, 1 min, 1 min, 5 min, and 4.2, respectively. Analytical validation of the DSPME method for 16 REEs (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in CFA leachate samples estimated the detection limits at the low ppt level, the recovery range 43–112%, and relative standard deviation within ± 22%. This method was applied to a water extraction procedure (EP) and acetic acid toxicity characteristic leaching procedure (TCLP) for leachate of CFA, from five different coal-fired thermoelectric power plants. The most abundant REEs in leachate (20 ÷ 1 solid-to-liquid ratio) are Ce, Y, and La, which were found in the range of 22–194 ng/L, 35–105 ng/L, 48–95 ng/L, and 9.6–51 μg/L, 7.3–22 μg/L, 2.4–17 μg/L, for EP and TCLP leachate, respectively. The least present REE in TCLP leachate was Lu (42–125 ng/L), which was not detected in EP leachate.

Volcanic ashes as a source for nitrated and oxygenated polycyclic aromatic hydrocarbon pollution.

In this study, a novel, simple, and highly sensitive analytical procedure for the quantitative evaluation of oxygenated and nitrated polycyclic aromatic hydrocarbons in volcanic ash samples based on dispersive solid-liquid microextraction (DSLME) coupled to ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. Diverse chemometric tools were applied to optimize DSLME working conditions. Thus, a linear calibration curve for all the target analytes in the concentration range from 0.01 to 100μgg-1 (r2> 0.994) was obtained. The limits of detection for all the compounds were between 14.6 and 56.0pgg-1, with high reproducibility (relative standard deviation (RSD) was below 8.1% for all the analytes). Additionally, recoveries ranged from 94.2 to 100%. The applicability of the method was evaluated and the feasibility of the existence of nitrated and oxygenated-PAHs in volcanic ashes at ultra-trace levels was demonstrated, which reveals an unknown source of distribution of these pollutants to the environment. Graphical Abstract.

Determination of heterocyclic aromatic amines in ashes from biomass burning by UHPLC-MS/MS after ultrasound-assisted dispersive solid-liquid microextraction

A simple, rapid and efficient methodology was developed for the extraction and determination of heterocyclic aromatic amines (HAAs) in cigarette and forest fire ash samples based on a novel Ultrasound-Assisted Dispersive Solid-liquid Microextraction (UA-DSLME) coupled to polyurethane foam (PUF) mini-column as a clean-up strategy and on-line determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimal working conditions were found by (i) application of two-level full factorial designs and (ii) implementation of a response surface methodology based on the second-order design as central composite designs. Under optimal experimental conditions, good linearity was obtained for concentrations ranging from 8.3 to 500 ng g−1, with correlation coefficients (r2) varying from 0.995 to 0.999 for all HAAs investigated. The limits of detection and quantification resulted to be between 2.1 and 10.7 ng g−1 and 8.3–16.9 ng g−1, respectively. The recoveries from 92.2 to 100.6% were reached and the relative standard deviations (RSDs) were lower than 9.2%. The developed method was successfully applied to the determination of HAAs in ashes generated by cigarette and forest fire combustion.

Fe3O4@MCM-41-(SO3−)[ZrO2] Magnetic Mesoporous Nanocomposite: Dispersive Solid-Liquid Micro Extraction of Pb2+ Ions

In the present study, Fe3O4@MCM-41-(SO3−)[ZrO2] magnetic nano-particles (MNPs) as a new, effective and selective solid phase is reported for the preconcentration of lead ions by using of dispersive solid-liquid micro extraction (DSLME) as a rapid method. The Fe3O4@MCM-41 nanocomposite with charged sulfonate groups can be synthesized by the formation of sulfonic functionalized organic-inorganic MCM-41 mesoporous structure on the surface of magnetite nanoparticles. The encapsulated ZrO2 nanoparticles into network of Fe3O4@MCM-41─SO3H MNPs fabricated by covalently bound with implanted of charged sulfonate groups (-SO3−). The structure and morphology of the prepared sorbent were characterized by FT-IR, XRD, VSM, BET and TEM techniques in order to show that they comprised of both magnetite silica mesoporous structures with incorporated sulfonate groups and encapsulated ZrO2 nanoparticles. The synthesized solid phase was utilized for the preconcentration of lead ions prior to determination by atomic absorption spectrophotometry. The calibration graph was obtained under the optimized conditions with linear dynamic range of 1.0–300 μg L−1 and correlation coefficient (r2) of 0.998. The detection limits of this method was 0.03 ng mL−1. The obtained results showed that, the method can be successfully applied to the selective extraction and determination of the lead ionsin different samples of water.

Simultaneous determination of neonicotinoid insecticides and metabolites in rice by dispersive solid-liquid microextraction based on an in situ acid-base effervescent reaction and solidification of a floating organic droplet.

A sensitive and rapid method named dispersive solid-liquid microextraction combining in situ acid-base reaction-based effervescence and solidification of a floating organic droplet was developed for the simultaneous determination of eight neonicotinoid insecticides and two metabolites in rice by ultra-performance liquid chromatography-tandem mass spectrometry. The samples were extracted with sodium citrate monobasic-modified acetonitrile by vortexing and purified by primary secondary amine, and then a mixture of 1-undecanol and sodium carbonate aqueous solution was rapidly injected. An acid-base reaction and carbon dioxide bubbles were generated in situ, which promoted the dispersion of 1-undecanol droplets and subsequent transfer of the analytes from the acidified acetonitrile extract to 1-undecanol. The 1-undecanol phase was easily retrieved by centrifugation and solidification in an ice bath. This novel dispersive solid-liquid microextraction fully utilized the advantages of the effervescent reaction and floating droplet solidification, which was carried out in a tube and did not require stepwise analysis for a solid matrix. Under the optimized conditions, the average recoveries of the analytes ranged from 77.8 to 97.1% with relative standard deviations less than 7.3. Thelimits of detection varied between 0.01 and 0.1μgkg-1, and enrichment factors were 42-55. The proposed method provides a quantitative, sensitive, and convenient analytical tool applicable for routine monitoring of neonicotinoids in rice. Graphical abstract ᅟ.

In-Tube Ultrasound Assisted Dispersive Solid–Liquid Microextraction Based on Self-Assembly and Solidification of an Alkanol-Based Floating Organic Droplet for Determination of Pyrethroid Insecticides in Chrysanthemum

A new in-tube pretreatment method based on ultrasound assisted dispersive solid–liquid microextraction using self-assembly and solidification of an alkanol-based floating organic droplet was developed for the determination of eight pyrethroid insecticides in chrysanthemum by gas chromatography with electron capture detection. This method fully utilized the restricted access property of a 1-decanol/acetonitrile mixture for effective extraction of the analytes from chrysanthemum under ultrasonication, and the self-assembly and coacervation process of 1-decanol by adding water. The 1-decanol phase aggregated and floated on the surface, solidified in an ice bath, and thus was easily collected. For the first time, extraction, separation and preconcentration were combined in a tube, not requiring stepwise preparation for a solid matrix. The recoveries ranged from 75 to 104% with the relative standard deviations of < 8%. The limits of quantification were in the range of 0.15–1.5 µg kg− 1 up to 52-fold compared with the conventional QuEChERS-based, SPE, and solid–liquid dispersive microextraction methods. The results demonstrated that the proposed method was time-saving, sensitive, and environmentally friendly for pyrethroids analysis in chrysanthemum.

Modified dispersive solid-liquid microextraction coupled to HPLC and application of experimental design methodology to determine the trace amount of levothyroxine in human real samples

A simple, efficient and green microextraction method namely ultrasound assisted-dispersive solid-liquid microextraction based on solidification of floating organic droplet (UA-DSLME-SFOD) coupled to HPLC and UV detector was developed for preconcentration and determination of levothyroxine in human urine and serum samples. The effects of different variables on the extraction efficiency such as pH, volume of extraction solvent, amount of solid disperser, ionic strength and time of ultra-sonication were studied and optimized simultaneously using response surface methodology. For validation of the technique, its accuracy, precision, limit of detection, linearity, and sensitivity were evaluated. The calibration graph of the proposed method was linear in the range of 0.5–2000.0ngmL−1 with the determination coefficient (R2) of 0.9986. The relative standard deviations for 6 replicates were 1.76–3.32% (n=6). This method provided high sensitivity, using of low toxic organic solvents, and simplicity of the extraction processes. The proposed method was successfully applied for determination of levothyroxine in human urine and serum samples.

A new green switchable hydrophobic–hydrophilic transition dispersive solid–liquid microextraction of selenium in water samples

A novel switchable hydrophobic–hydrophilic transition dispersive solid–liquid microextraction (SHT-DSLME) method has been used for the first time as a dispersive/extractive method for the removal of total selenium from real samples.