Ultrasonic-assisted Dispersive Solid-phase Research Articles

Cellulose-based nanocomposite for ultrasonic assisted dispersive solid phase microextraction of triazole fungicides from water, fruits, and vegetables samples

Herein, an ultrasound-assisted dispersive solid phase microextraction (UA-DSPME) approach has been described for trace level analysis of triazole fungicides in real samples. For this purpose, a new nanosorbent was prepared through modification of carboxymethylcellulose biopolymer with zinc-based metal–organic framework and graphene oxide, and fully characterized. Then, the effect of extraction parameters on extraction efficiency was optimized for the microextraction process. Finally, desorbed triazole fungicides with ethanol were determined using gas chromatography equipped with flame ionization detector. This technique provided good linearity (R2 > 0.99), low detection limits (0.3–1.5 ng mL−1), high preconcentration factors (419–426), good relative recoveries (91.6–102 %), and high repeatability (RSD < 4.1 %) at optimized conditions (amount of sorbent: 15 mg; pH of solution: 7.0; and extraction time; 4 min). Ultimately, this approach was applied to determine triazole fungicides in different water and food samples.

A hybrid imprinted polymer based on magnetic graphene oxide and carbon dots for ultrasonic assisted dispersive solid-phase microextraction of oxycodone

To promote the development of molecular imprinting technique in the separation and analysis of oxycodone, molecularly imprinted polymer based on the magnetic graphene oxide and carbon dots nanoparticles (MIP@MGO/CDs NPs) was developed using ultrasonic-assisted dispersive solid-phase microextraction (UA-DSPME) and high performance liquid chromatography (HPLC). The morphology and structure characterization of synthesized nanoparticles are assessed by scanning electron microscope (SEM), Brunauer-Emmett-Teller analysis (BET), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The adsorption isotherms of MIPs followed the Langmuir model with the maximum adsorption capacity of 99 mg/g and imprinting factor of 3.39. Under optimized conditions, which achieved by central composite design under response surface methodology, the detection limit (S/N = 3) was obtained 0.80 ng/mL in the linear range of 1–2000 ng/mL. The average recoveries of oxycodone were calculated from 92.50 to 103.20% in human urine samples with RSD less than 3.65%.

Ultrasound Assisted Dispersive Solid Phase Microextraction of Thymol and Carvacrol in Pharmaceutical Products Using Graphene Oxide as an Adsorbent Prior to Analysis by High Performance Liquid Chromatography

Background: Thymol and carvacrol are the most important dietary constituents in thyme species. These two active compounds are used for the standardization of pharmaceutical compounds. Objective: In this work, a simple and reliable ultrasonic assisted dispersive solid phase microextraction method (USA-DSPME) coupled with high performance liquid chromatography-ultra violet detection system was developed to determine thymol and carvacrol in pharmaceutical syrups. The efficiency of SPME sorbent was examined through several sorbents and finally Graphene Oxide (GO) was applied for extraction of the analytes. Method: The efficiency of GO was compared with three reduced forms of GO adsorbents as well. Several effective factors on the extraction performance were investigated. Results: Under the optimized conditions for the GO sorbent, inter and intra-day relative standard deviations (RSDs, n = 3) and the Limits of Detections (LODs) were lower than 5.0% and 0.02 μg/ml, respectively. Moreover, good linear ranges were observed in wide concentration ranges with R-squared larger than 0.9961 for both thymol and carvacrol. Conclusion: The present method is reliable and simple for determination of carvacrol and thymol in pharmaceutical products.

Graphene oxide/ layered double hydroxides@ sulfonated polyaniline: A sorbent for ultrasonic assisted dispersive solid phase extraction of phthalates in distilled herbal beverages

In this study, the ultrasonic-assisted dispersive solid phase extraction (UA-d-SPE) method coupled to gas chromatography-mass spectrometry (GC–MS) was applied for the analysis of phthalate esters in drinking water and distilled herbal beverages (Rosa, Mentha, Cichorium). A new nanocomposite based on layered double hydroxide supported on graphene oxide was synthesized and modified by sulfonated polyaniline via a simple one-pot in-situ polymerization method. The structure and morphology of the nanocomposite was confirmed by means of complementary techniques: Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The effects of key parameters including adsorbent mass, type and amount of back extraction solvent, extraction and desorption time, pH of the solution and ionic strength were optimized and good precision and sensitivity were achieved. Under the optimum conditions, the limits of detection were between 0.06–0.3 ng mL−1 in aqueous solutions. The hybrid nanomaterial exhibited good adsorption ability toward phthalates in drinking water and distilled herbal beverages. The relative standard deviations (RSD%) for beverage samples varied from 0.1% to 9.9% (n = 3). The relative recoveries varied from 54.5% to 112.6%.

Ultrasound-assisted dispersive solid-phase microextraction of capecitabine by multi-stimuli responsive molecularly imprinted polymer modified with chitosan nanoparticles followed byHPLC analysis.

An ultrasonic-assisted dispersive solid-phase microextraction was developed by a multi-stimuli responsive molecularly imprinted polymer based on chain transfer agent-modified chitosan nanoparticles for enrichment and separation of trace capecitabine in a real sample. The synthesized particles were carefully characterized and it wasfound that a uniform pH-sensitive imprinted polymeric shell isobtained on the surface of Fe3O4@chitosan core with enough saturation magnetization (29emug-1). Desirable adsorption capacity (91mgg-1) and high imprinting factor (IF = 3.6) toward capecitabine were exhibited by the Langmuir isotherm model. Under optimized conditions, which wereachieved by experimental design, the detection limit (S/N = 3) was 1.9ngmL-1. The obtained relative mean recoveries of capecitabine using high-performance liquid chromatography were in the range of 93 to 102% in a human plasma sample with RSD less than 5.5%. Graphical abstract Schematic representation of ultrasonic-assisted dispersive solid-phase microextraction by multi-stimuli responsive molecularly imprinted polymer based on chain transfer agent-modified chitosan nanoparticles and high-performance liquid chromatography for enrichment and separation of capecitabine in the real sample.

A mesoporous nanosorbent composed of silica, graphene, and palladium (II) for ultrasound-assisted dispersive solid-phase extraction of organophosphorus pesticides prior to their quantitation by ion mobility spectrometry.

A new ultrasonic-assisted dispersive solid-phase extraction method using mesoporous nanosorbent composed of silica, graphene, and palladium (II) (M S/G@-SH@Pd (II)), coupled with corona discharge ion mobility spectrometry, was developed for trace determination of organophosphorus pesticides. Initially, the M S/G@-SH@Pd (II) nanosorbent was synthesized and characterized. Then, the nanosorbent was used for the sorption and extraction of organophosphorus pesticides. Under the optimized conditions (pH = 7.0, 15 mgof sorbent, 3 minextraction time, ethanol asdesorption agent, 3 mincentrifuge time), the proposed technique provided good linearity (R2 > 0.994), repeatability (RSD < 4.6%), low limits of detection (0.15-0.30ngmL-1), excellent preconcentration factor (PF = 472-478), and high recoveries (93-94%). Themethod was applied tothe determination of organophosphorus pesticides in real water samples. The sorbent was reused in 5 cycles without any considerable loss of activity. Graphical abstract Schematic presentation of design and synthesis of mesoporous nanosorbent composed of silica, graphene, and palladium (II) for ultrasound-assisted dispersive solid-phase extraction of organophosphorus pesticides prior to their quantitation by ion mobility spectrometry.

Silane Coupling Agents Modified Silica and Graphene Oxide Materials for Determination of Sulfamerazine and Sulfameter in Milk by HPLC

Silica and graphene oxide were separately modified by using three different kinds of silane coupling agents, including (3-chloropropyl)-trimethoxysilane (NQ54), 3-methacryloxypropyltrimethoxysilane (KH570), and (3-aminopropyl) triethoxysilane (KH550). The characterization of obtained materials was tested by Fourier transform infrared spectroscopy and scanning electron microscopy, and the electronegativity was determined by Zetasizer Nano ZSP. The obtained materials were used to determine the sulfamerazine and sulfameter by ultrasonic-assisted dispersive solid-phase extraction. The static sorption experiment showed that the graphene oxide modified by NQ54 had a good sorption ability for two targets. Under the optimal condition, a reliable analytical method was developed for high recognition towards two targets in milk by NQ54-modified graphene oxide with satisfactory extraction recoveries (sulfamerazine 96.75% and sulfameter 94.08%, respectively). The recoveries of proposed method at three spiked levels were 92.16–101.71% and 92.95–103.81%, respectively, with the relative standard deviation less than 3.20%. It was indicated that graphene oxide modified by NQ-54 showed better performance for two targets, and the proposed method had been successfully applied for the determination of sulfonamides sample in milk.

The conjunction of a new ultrasonic-assisted dispersive solid-phase extraction method with HPLC-DAD for the trace determination of diazinon in biological and water media

Herein, a new ultrasonic-assisted dispersive solid-phase extraction method was successfully developed for the trace detection of diazinon.

A multi-walled carbon nanotube-based magnetic molecularly imprinted polymer as a highly selective sorbent for ultrasonic-assisted dispersive solid-phase microextraction of sotalol in biological fluids.

A modified multiwalled carbon nanotube-based magnetic molecularly imprinted polymer (MWCNT-MMIP) was synthesized and applied for selective extraction and preconcentration of sotalol (SOT) in biological fluid samples by using ultrasonic-assisted dispersive solid-phase microextraction (UA-DSPME). The synthetic particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The screening of UA-DSPME was preliminarily performed by Plackett-Burman design (PBD) and, subsequently, central composite design (CCD) under response surface methodology (RSM) was used individually for evaluation of the significant factors and their possible interaction effects on the adsorption process. Batch mode adsorption studies were performed to evaluate the adsorption kinetics, adsorption isotherms, and selective recognition of MWCNT-MMIPs. The adsorption equilibrium of SOT using MWCNT-MMIPs could be well-defined with the Langmuir isotherm model and the maximum adsorption capacity was calculated to be 79.36 mg g-1. Under optimized conditions, the SOT was selectively and effectively extracted in real biological samples and good linearity was obtained with correlation coefficients (R2) over 0.996 and the detection limit (S/N = 3) was 0.31 ng mL-1. The average recoveries of the spiked human urine and plasma samples at four concentration levels of SOT ranged from 94.60-102.50 and 97.40-101.60 percent, respectively, and the relative standard deviation was found to be lower than 4.50%. The results illustrated that the proposed MWCNT-MMIPs@UA-DSPME extraction method coupled with HPLC-UV determination could be applied for sensitive and selective analysis of trace SOT in biological fluid samples.

A novel method based on combining ultrasonic-assisted dispersive solid-phase extraction and low-density solvent dispersive liquid–liquid microextraction (UA-DSPE-LDS-DLLME) for the determination of organophosphorus pesticides in soil

A new method of UA-DSPE-LDS-DLLME combining with GC-PFPD was developed to measure OPPs in soil.