Thermo-Assisted Deep Eutectic Solvent Based on Dispersive Liquid-Liquid Microextraction for Preconcentration of Phthalate Esters in Water Samples and Determination by Gas Chromatography With Flame Ionization Detection.

A thermo-assisted deep eutectic solvent (DES) based on dispersive liquid-liquid microextraction followed by gas chromatography with flame ionization detection was developed for the analysis of five phthalate esters in different water samples. In the procedure involved, a DES composed of lidocaine, an amphiphilic amine, and oleic acid, was mixed with the sample assisted by ultrasound, and phase separation was achieved with increasing temperature. The heating of the extraction system induced the change of acid-base properties of the DES components. Thus, the formation of microdroplets of DES in the sample was provided, and two phases were separated. The structure of the upper hydrophobic layer was characterized by Fourier-transform infrared spectroscopy. Also, the amount of water in the DES phase was analyzed by mass spectrometer and Karl Fischer titration. Some critical variables on the extraction yield were assessed. The proposed method achieved 1.2-1.3 and 4.1-4.3 µg/L for limits of detection and limits of quantification, respectively. The intra-day and inter-day percentage relative standard deviations (n = 5) were determined to be in the range of 4.2-6.2% and 5.1-7.2%, respectively. Ultimately, this method analyzed the five phthalate esters in different water samples with high recoveries.

Effervescent tablet-assisted demulsified dispersive liquid-liquid microextraction based on solidification of floating organic droplet for determination of methadone in water and biological samples prior to GC-flame ionization and GC-MS.

A novel effervescent tablet-assisted demulsified dispersive liquid-liquid microextraction based on the solidification of floating organic droplet was developed to determine methadone prior to gas chromatography with flame ionization detection and gas chromatography with mass spectrometry. In this method, a tablet composed of citric acid, sodium carbonate, and 1-undecanol was utilized. The resulting effervescent tablet generated carbon dioxide in situ to disperse 1-undecanol in the sample. Thus, the dispersive and extraction processes were performed in one synchronous step. An aliquot of acetonitrile as the demulsifier solvent was used for the separation of two phases instead of centrifugation. Under optimal conditions, the developed method was linear up to 50 000 µg/L with correlation coefficients higher than 0.99. Moreover, limits of detection and limits of the quantification were in the range of 3-10  and 7-30 µg/L in water and biological samples, respectively. Intra- and interday precisions (n = 6) of the spiked methadone at a concentration level of 50 µg/L were over ranges of 5.1-6.8% and 5.7-7.1%, respectively. The preconcentration factors and recovery values were obtained in the range of 140-145 and 98.1 to 101.6% in real samples, respectively.

Deep Eutectic Solvent Based Air Assisted Ligandless Emulsification Liquid-Liquid Microextraction for Preconcentration of Some Heavy Metals in Biological and Environmental Samples.

In this study, a deep eutectic solvent (DES) based on air-assisted ligandless emulsification liquid-liquid microextraction method (DES-AA-LL-ELLME) was considered for preconcentration and extraction of some metals (Cd, Ni, Pb and Cu). A 1:1 mixture of the synthesized DES and triethylamine was added as an extractant to extract metal ions in the absence of chelating agent. Tetrahydrofuran as the aprotic solvent provided a turbid state. To disperse the aggregated DES droplets into the aqueous phase, air-assisted was performed. The influence of several effective parameters was monitored. Under optimum conditions, limits of detection were found in the range of 0.31-0.99 µg L-1 with preconcentration factor from 67 to 69. The relative standard deviation (n = 10) was in the range of 2.1%-3.1% for all analytes. This procedure was applied to determine some metals in both biological and environmental samples with appropriate recoveries about 98.7%-106%.

Dispersion of magnetic graphene oxide nanoparticles coated with a deep eutectic solvent using ultrasound assistance for preconcentration of methadone in biological and water samples followed by GC-FID and GC-MS.

Magnetic graphene nanoparticles coated with a new deep eutectic solvent (Fe3O4@GO-DES) were developed for efficient preconcentration of methadone. The extracted methadone was then analyzed by gas chromatography-flame ionization detection (GC-FID) or gas chromatography-mass spectrometry (GC-MS). Fe3O4@GO-DES were characterized by Fourier transform IR and X-ray diffraction techniques. Ultrasound was used to enhance the dispersion of the sorbent, with a high extraction recovery. Some parameters affecting the extraction recovery, such as pH, type of deep eutectic solvent, sample volume, amount of sorbent, extraction time, and type of eluent, were investigated. Under optimum conditions, the method developed was linear in the concentration range from 3 to 45,000 µg L-1 for GC-FID and from 0.1 to 500 µg L-1 for GC-MS, with a detection limit of 0.8 µg L-1 for GC-FID and 0.03 µg L-1 for GC-MS. The relative standard deviations (n = 6) as the intraday and interday precisions of the methadone spike at a concentration of 100 µg L-1 were 5.8% and 8.4% respectively for GC-FID. The preconcentration factor was 250. Relative recoveries from spiked plasma, urine, and water samples ranged from 95.1% to 101.5%.

Evaluation of plasma concentrations of homocysteine, IL-6, TNF-alpha, hs-CRP, and total antioxidant capacity in patients with end-stage renal failure.

It has been proved that hyperhomocysteinemia has a high prevalence in patients with end-stage renal disease (ESRD), which may contribute to the high cardiovascular risk in these patients. Cardiovascular disease is the first cause of high mortality rate in ESRD patients. The aim of the present study was to assess five important factors in patients with ESRD (the amount of homocysteine, IL-6, TNF-alpha, hs-CRP, and Total Antioxidant Capacity). These factors were surveyed in ESRD patients to compare with healthy subjects. In a cross-sectional study, we enrolled 80 patients on maintenance hemodialysis and measured the inflammatory and oxidative stress indicators. The plasma samples were assayed for five above mentioned variables using standard protocols. Two-hour post hemodialysis plasma samples were also assayed for TAC. Plasma levels of inflammation markers, IL-6 and hs-CRP, homocysteine were significantly increased in ESRD group versus control group. This increase was also found in TNF-α levels as compared to the controls, but the differences were not statistically significant. Also, the post dialysis samples had significantly lower levels of TAC as compared to predialysis ones.

Synthesis, in vitro cytotoxicity and radiosensitizing activity of novel 3-[(2,4-dinitrophenylamino)alkyl] derivatives of 5-fluorouracil.

Previously, it was reported that 3[3-(2,4-dinitrophenylamino)-propyl]-5-fluorouracil 8c unlike its components 5-fluorouracil (5-FU) 6 and 2,4-dinitroaniline 2 in HT-29 cells under aerobic conditions had no cytotoxicity but showed radiosensitizing activity. In this study several analogues of 8c differing in the number of linking methylene groups were prepared and tested for in vitro cytotoxicity and radiosensitizing activity under both aerobic and hypoxic conditions. Tethered compound 8a was prepared in one pot by the reaction of 5-FU 6 with paraformaldehyde and 2,4-dinitroaniline 2 in the presence of the concentrated hydrochloric acid, and compounds 8b-f were prepared by the reaction of N-(bromoalkyl)-2,4-dinitrobenzeneamines 5b-f with 1-(t-butoxycarbonyl)-5-fluorouracil 7 followed by hydrolysis of the protecting group. The cytotoxicity of the tested compounds were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and propidium iodide (PI)-digitonin assays and values of sensitization enhancement ratio (SER) as a measure of the radiosensitizing activity were measured from radiation survival curves in the absence and presence of each sensitizer for 37% survival respectively. Results showed that tethered compounds 8a-f induced time- and concentration-dependent cytotoxicity under hypoxia but had no significant effect under aerobic conditions. These compounds also showed selective and concentration-dependent radiocytotoxicity under hypoxic conditions.

Synthesis, in vitro aerobic and hypoxic cytotoxicity and radiosensitizing activity of novel metronidazole tethered 5-fluorouracil.

BACKGROUND AND THE PURPOSE OF THE STUDY: Several 2, 4-dinitrophenyl and 2,4-dinitrophenylamine tethered 5-FU (5-fluorouracil) compared to their components have shown minimal or no cytotoxicity to HT-29 cell line under aerobic conditions but high cytotoxicity and radiosensitizing effects under hypoxic conditions. In the present study the cytotoxicity and radiation potentiation of three novel analogues of these compounds by replacing 2,4-dinitrophenyl moiety with 2-methyl-5-nitroimidazole, a known radiosensitizer and cytotoxic agent was investigated. METHODS: Tethered compounds 7-9 were prepared by the reaction of 1-(t-butoxycarbonyl)-5-fluorouracil 6 with metronidazole esters 2-4 followed by removal of the t-butoxycarbonyl protecting group. Cytotoxicity of compounds in HT-29 cells with or without radiation were determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), propidium iodide (PI)-digitonin and clonogenic assays. RESULTS: Tethered compounds 7-9 induced time-and concentration-dependent cytotoxicity under hypoxia but had no significant effect under aerobic conditions. These compounds also showed selective and concentration- dependent radiosensitization effects under hypoxic conditions. CONCLUSION: Tethered compounds 7-9 compared to 5-FU 5 showed minimal cytotoxicities under aerobic and selective radiosensitizing activities under hypoxic conditions. Also effects of these compounds were higher than those of metronidazole 1 which is a known cytotoxin and radiosensitizer under hypoxic conditions.

Determination of Metal Content in Crocus sativus L. Corms in Dormancy and Waking Stages.

More than 30 mineral elements have been found with different key functions in helping plants and animals to survive and live healthy. As a direct result, they have always attracted the attention of scientists. The quest is to find some efficient analytical and quantitative procedures in this study to determine some mineral and trace elements of Iranian Crocus sativus L. corms. Several studies have been made using distinct methods and eventually, to achieve this purpose, three analytical methods were used as follows: Neutron Activation Analysis (NAA), Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and Atomic Absorption Spectrophotometry (AAS). Seventeen mineral and trace elements (Mg, Na, Ca, K, Mn, Zn, Cu, Pb, Hg, Ni, Fe, Co, Cd, Sr, Rb, Sc, and Br) were determined in Crocus sativus L. corms in two different physiological stages. The mineral elements content in saffron corms showed a wide variability and their concentrations in dormancy stage were higher than waking. Despite of the fact that K concentration was the highest among all mineral elements studied in both samples, it was nil for Sc, Co, Hg, Pb and Cd.

Synthesis and in-vitro cytotoxicity of poly-functionalized 4-(2-arylthiazol-4-yl)-4H-chromenes.

A new series of 4-aryl-4H-chromenes bearing a 2-arylthiazol-4-yl moiety at the 4-position were prepared as potential cytotoxic agents. The in-vitro cytotoxic activity of the synthesized 4-aryl-4H-chromenes was investigated in comparison with etoposide, a well-known anticancer drug, using MTT colorimetric assay. Among them, the 2-(2-chlorophenyl)thiazol-4-yl analog 4b showed the most potent activity against nasopharyngeal epidermoid carcinoma KB, medulloblastoma DAOY, and astrocytoma 1321N1, and compound 4d bearing a 2-(4-chlorophenyl)thiazol-4-yl moiety at the 4-position of the chromene ring exhibited the best inhibitory activity against breast cancer cells MCF-7, lung cancer cells A549, and colon adenocarcinoma cells SW480 with IC(50 )values less than 5 microM. The ability of compound 4b to induce apoptosis was confirmed in a nuclear morphological assay by DAPI staining in the KB and MCF-7 cells.