Meysam Safari

Evaluation of in-tube solid-phase microextraction method for co-extraction of acidic, basic, and neutral drugs

Simultaneous extraction of acidic, basic, and neutral drugs from different biological samples is a considerable and disputable concept in sample preparation strategies. In the present work, a new in-tube solid phase microextraction approach named electrochemically controlled double in-tube solid phase microextraction (EC-DIT-SPME) is introduced for simultaneous extraction of acidic, basic, and neutral drugs from different biological matrices. For this purpose, novel nanostructured coatings based on copolymer of polypyrrole and indole-2-carboxylic acid (PPy-co-PIca) as non-overoxidized and overoxidized forms were electrochemically synthesized on the inner surface of stain-less steel tubes. During the extraction procedure, the PPy-co-PIca and overoxidized PPy-co-PIca coated stain-less steel tubes were used as anode and cathode electrodes, respectively. Extraction of basic and acidic drugs were performed on the surface of overoxidized PPy-co-PIca and PPy-co-PIca, which are connected to the negative and positive potentials, respectively. With regard to the fact that neutral drugs can be absorbed in both electrodes, extraction of neutral drugs will be done in both of them. Satisfactory analytical figures of merit including linear dynamic range and limits of detection in the range of 0.15–500 ng mL−1 and 0.05–1.9 ng mL−1 and good extraction recoveries (38.5–78.6%) were obtained. Finally, the proposed method was successfully applied for simultaneous analysis of acidic, basic, and neutral drugs in some biological samples.

Extraction and preconcentration of formaldehyde in water by polypyrrole‐coated magnetic nanoparticles and determination by high‐performance liquid chromatography

In this study, a simple and rapid extraction method based on the application of polypyrrole-coated Fe3 O4 nanoparticles as a magnetic solid-phase extraction sorbent was successfully developed for the extraction and preconcentration of trace amounts of formaldehyde after derivatization with 2,4-dinitrophenylhydrazine. The analyses were performed by high-performance liquid chromatography followed by UV detection. Several variables affecting the extraction efficiency of the formaldehyde, i.e., sample pH, amount of sorbent, salt concentration, extraction time and desorption conditions were investigated and optimized. The best working conditions were as follows: sample pH, 5; amount of sorbent, 40 mg; NaCl concentration, 20% w/v; sample volume, 20 mL; extraction time, 12 min; and 100 μL of methanol for desorption of the formaldehyde within 3 min. Under the optimal conditions, the performance of the proposed method was studied in terms of linear dynamic range (10-500 μg/L), correlation coefficient (R(2) ≥ 0.998), precision (RSD% ≤ 5.5) and limit of detection (4 μg/L). Finally, the developed method was successfully applied for extraction and determination of formaldehyde in tap, rain and tomato water samples, and satisfactory results were obtained.

Simultaneous determination of steroid drugs in the ointment via magnetic solid phase extraction followed by HPLC-UV

The copper-coated iron oxide nanoparticles with core-shell were produced by deposition of a Cu shell on Fe3O4 NPs through reduction of Cu2+ ions in solution using NaBH4. Subsequently, the organosulfur compound, bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid (b-TMP-DTPA), was used to form self-assembled monolayer in order to modify sorbents surface via covalent bonding between Cu and thiol (–SH) terminal groups. The prepared magnetic nanoparticles were characterized by using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and thermo gravimetric analysis (TGA). Then, the application of this new sorbent was investigated to extract the steroid drugs in ointment samples with the aid of ultrasound. An external magnetic field was applied to collect the magnetic nanoparticles (MNPs). The extracted analytes were desorbed using acetonitrile. The obtained extraction solution was analyzed by HPLC-UV. The main affecting factors on the extraction efficiency including pH, sonication time, amount of sorbent, salt concentration, and desorption conditions were optimized in detail. Under the optimum conditions, good linearity was obtained in the range of 2.5–250.0 µg/ L with reasonable linearity (R2 > 0.99) and the limits of detection (LODs) ranged between 0.5 and 1.0 µg/L (based on S/N = 3). Repeatability (intra-day precision) based on five replicates and preconcentration factors were calculated to be 3.6%–4.7% and 87–116, respectively. Relative recoveries in ointment samples at two spiked levels of the target analytes were obtained in the range of 90.0%–103.2%. The results illustrated that the Fe3O4@Cu@ b-TMP-DTPA NPs have the capability of extraction of steroid drugs from ointment samples.

Supercritical fluid extraction of papaverine and noscapine from poppy capsules followed by preconcentration with magnetic nano Fe3O4@Cu@diphenylthiocarbazone particles

A novel magnetite adsorbent modified with copper and diphenylthiocarbazone was synthesized and used as a sorbent for magnetic solid phase extraction (MSPE) of two opium alkaloids: papaverine and noscapine. Supercritical fluid extraction (SFE) was used to extract the analytes from poppy capsules. The extracts were preconcentrated by magnetic solid phase extraction. Separation and determination of both opium alkaloids were performed using high performance liquid chromatography with an ultra-violet detector. The SFE parameters were optimized through a Taguchi orthogonal array experimental design. Under the optimal conditions, broad linear dynamic ranges of 0.3–180 μg L−1 (0.9981 < R2 < 0.9993) and 0.3–4 mg kg−1 (0.9921 < R2 < 0.9971), favorable limits of detection of 1 μg L−1 and 0.1 mg kg−1, and suitable precisions with RSDs% in the range of 4.3–5.5% and 5.8–7.7% were obtained for MSPE and SFE-MSPE, respectively. The capability of the method was tested by analyzing different real samples including urinary samples and poppy capsules.