Multivariate optimization of surfactant-assisted directly suspended droplet microextraction combined with GC for the preconcentration and determination of tramadol in biological samples

Core-shell magnetic covalent organic polymer nanocomposites as an adsorbent for the extraction of flavonoids

A novel 3D magnetic nanocomposite material based on covalent organic polymers was successfully synthesized and utilized as an efficient sorbent for magnetic solid-phase extraction. It exhibited a regular core-shell structure, large specific surface area, superior stability, and paramagnetism. To evaluate its extraction efficiency, six flavonoids were tested, demonstrating maximum adsorption capacities ranging from 90 to 218 mg/g. Additionally, the material exhibited remarkable reusability and mechanical stability, maintaining its original state over eight cycles with consistent recovery. An analytical strategy combining magnetic solid-phase extraction with high performance liquid chromatography and tandem mass spectrometry was developed for the determination of flavonoids in orange, honey, soybean, and Dioscorea bulbifera L. samples. The low limits of detection (0.01-0.1 ng/mL) and limits of quantification (0.05-0.5 ng/mL), as well as satisfactory recovery (80.4-114.8%), were obtained. The linear range started from the limits of quantification to 500 ng/mL with R2 ≥ 0.9929. These results suggest that the prepared adsorbent possesses excellent adsorption capabilities for flavonoids, highlighting its significant potential for detecting these compounds in complex sample matrices.

Application of oxidized multi-walled carbon nanotubes and zeolite nanoparticles for simultaneous preconcentration of codeine and tramadol in saliva prior to HPLC determination

In this work, a dispersive micro-solid phase extraction technique along with high-performance liquid chromatography-UV detection was developed for simultaneous preconcentraion and determination of trace levels of codeine and tramadol in human saliva. This method is based on the adsorption of codeine and tramadol on a mixture of oxidized multi-walled carbon nanotubes and zeolite Y nanoparticles with 1:1 ratio as an efficient nanosorbent. Various analytical parameters influencing the adsorption step including the amount of adsorbent, the pH of the sample solution, the temperature, the stirring rate, the contact time of the sample solution, and the adsorption capacity were investigated. Based on the results, 10 mg adsorbent, sample solutions with pH = 7.6, temperature of 25 °C, stirring rate 750 rpm and contact time 15 min, in the adsorption step shows the best results for both drugs. Then the effective parameters on the analyte desorption stage such as the type of desorption solution, pH of the desorption solution, desorption time and desorption volume were investigated. Studies have shown that water/methanol (50:50 v/v) as desorption solution, pH = 2.0, desorption time of 5 min and desorption volume of 2 ml gives the best results.Chromatographic separation was performed on a RP-Shim-pack CLC-ODS-C18 column (250 mm × 4.6 mm, 5 µm) with isocratic mode. The mobile phase contained of acetonitrile:phosphate buffer (18:82, v/v) at pH = 4.5 and the flow rate was 1 ml.min^-1. The wavelength of UV detector was adjusted at 210 nm and 198 nm for codeine and tramadol, respectively.Under optimum conditions, the extraction efficiencies of 98.5% and 99.2% were achieved for codeine and tramadol respectively. Enrichment factor of 13, detection limit of 0.3 μg L^-1, relative standard deviation of 4.07 for codeine; and an enrichment factor of 15, a detection limit of 0.15 μg L^-1, and standard deviation of 2.06 for tramadol were calculated. The linear range of the procedure for each drug was 1.0 to 1000 μg L^-1. This method was successfully applied for the analysis of codeine and tramadol in saliva samples.

Application of Microextraction-Based Techniques for Screening-Controlled Drugs in Forensic Context-A Review

The analysis of controlled drugs in forensic matrices, i.e., urine, blood, plasma, saliva, and hair, is one of the current hot topics in the clinical and toxicological context. The use of microextraction-based approaches has gained considerable notoriety, mainly due to the great simplicity, cost-benefit, and environmental sustainability. For this reason, the application of these innovative techniques has become more relevant than ever in programs for monitoring priority substances such as the main illicit drugs, e.g., opioids, stimulants, cannabinoids, hallucinogens, dissociative drugs, and related compounds. The present contribution aims to make a comprehensive review on the state-of-the art advantages and future trends on the application of microextraction-based techniques for screening-controlled drugs in the forensic context.

Solid-phase microextraction of ultra-trace amounts of tramadol from human urine by using a carbon nanotube/flower-shaped zinc oxide hollow fiber

A new method is successfully developed for the separation and determination of a very low amount of tramadol in urine using functionalized multiwalled carbon nanotubes/flower-shaped zinc oxide before solid-phase microextraction combined with gas chromatography. Under ultrasonic agitation, a sol of multiwalled carbon nanotubes and flower-shaped zinc oxide were forced into and trapped within the pore structure of the polypropylene and the sol solution immobilized into the hollow fiber. Flower-shaped zinc oxide was synthesized and characterized by Fourier transform infrared spectroscopy. The morphology of the fabricated solid-phase microextraction surface was investigated by scanning electron microscopy and X-ray diffraction. The parameters affecting the extraction efficiencies were investigated and optimized. Under the optimized conditions, the method shows linearity in a wide range of 0.12-7680 ng/mL, and a low detection limit (S/N = 3) of 0.03 ng/mL. The precision of the method was determined and a relative standard deviation of 3.87% was obtained. This method was successfully applied for the separation and determination of tramadol in urine samples. The relative recovery percentage obtained for the spiked urine sample at 1000 ng/mL was 94.2%.

Supramolecular nanosolvent-based hollow fiber liquid phase microextraction as a novel method for simultaneous preconcentration of acidic, basic and amphiprotic pollutants

In this study, for the first time, coextraction of acidic, basic and amphiprotic pollutants was performed using supramolecular nano solvent-based hollow fiber liquid phase microextraction.

Speciation analysis of inorganic arsenic in food and water samples by electrothermal atomic absorption spectrometry after magnetic solid phase extraction by a novel MOF-199/modified magnetite nanoparticle composite

A novel magnetic metal–organic framework (MOF-199/dithiocarbamate modified magnetite nanoparticles composite) was synthesized and utilized for speciation analysis of inorganic arsenic.

Synthesis and application of a novel magnetic metal-organic framework nanocomposite for determination of Cd, Pb, and Zn in baby food samples

This work describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe3O4-2,5-dimercapto-1,3,4-thiadiazole)/Cu3(benzene-1,3,5-tricarboxylate)2] to preconcentrate trace amounts of Cd(II), Pb(II), and Zn(II) ions. A Box–Behnken design was used to find the parameters affecting the preconcentration procedure through response surface methodology. Three variables including sorption time, amount of the magnetic sorbent, and sample pH were selected as affecting factors in the sorption step, and four parameters including type, volume, concentration of the eluent, and elution time were selected in the elution step for the optimization study. These values were 33 mg, 11 min, 5.7 EDTA, 4.3 mL, 0.64 mol L–l EDTA solution, 16 min, for amount of the magnetic sorbent, sorption time, sample pH, type, volume, and concentration of the eluent, and elution time, respectively. Following the sorption and elution steps, the ions were quantified by FAAS. The limits of detection were 0.10, 0.15, and 0.75 ng mL−1 for Cd(II), Zn(II), and Pb(II) ions, respectively. The relative standard deviations (RSD) of the method were less than 8.3% for five separate batch experiments in the determination of 25 μg L−1 of Cd(II), Zn(II), and Pb(II) ions. The sorption capacity of the magnetic MOF nanocomposite was 155 mg g−1 for Cd(II), 173 mg g−1 for Pb(II), and 190 mg g−1 for Zn(II). Finally, the magnetic MOF nanocomposite was successfully applied to rapidly extract trace amounts of heavy metal ions in baby food samples.

Solid phase extraction of heavy metal ions from agricultural samples with the aid of a novel functionalized magnetic metal–organic framework

This work describes synthesis of a novel magnetic metal–organic framework to preconcentrate the trace amounts of heavy metals. (a) Functionalized Fe₃O₄ by ethylenediamine. (b) Synthesis of the magnetic MOF nanocomposite.

Development and validation of a sensitive UHPLC-MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics

The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O-desmethyltramadol, dsmethyl-chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction method using ethyl acetate-diethyl-ether (1:1). Extracted samples were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil-Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3-9.8 and -1.7-4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide.