Mohamed Zaki

Novel and effective electrochemical sensor for the determination of morphine (MO) in 0.04 mol L-1 universal buffer solution (pH 7.4) is introduced using gold nanoparticles electrodeposited on a Nafion modified carbon paste electrode. The effect of various experimental parameters including pH, scan rate and accumulation time on the voltammetric response of MO was investigated. At the optimum conditions, the concentration of MO was determined using differential pulse voltammetry (DPV) in a linear range of 2.0 x 10-7 to 2.6 x 10-4 mol L-1 with a correlation coefficient of 0.999, and a detection limit of 13.3 x 10-10 mol L-1, respectively. The effect of common interferences on the current response of morphine namely ascorbic acid (AA) and uric acid (UA) is studied. The modified electrode can be used for the determination of MO spiked into urine samples, and excellent recovery results were obtained.

A mixture of polyphenol components was isolated from the fruits of C. annuum L. cv. Cupra, C. annuum L. cv. Orange glory, and C. annuum L. cv. ST4712 (CLST), via 70% methanol extraction followed by column chromatography over silica gel. The polyphenol components of the mixture were analyzed via HPLC-MS/MS and compared with the reported data. Three cinnamic acid derivatives and five flavonoid components in the fruits of the three varieties were identified for the first time in this study. The antioxidant activity and anticancer effect of the polyphenol mixtures of the three fruits were determined. The antioxidant and anticancer activities of CLST were substantially higher than those of C. annuum L. cv. Cupra and C. annuum L. cv. Orange glory. The high activities of CLST were attributed to the much higher concentration of quercetin derivatives in CLST.

Spinetoram is a second-generation member of the spinosyn class, all members of which have been shown to be effective in insect control via a novel mode of action. Spinetoram is a mixture of 3'-O-ethyl-5, 6-dihydro spinosyn J (XDE-175-J) and 3'-O-ethyl spinosyn L (XDE-175-L). In order to establish a determination method for the analysis of spinetoram residues in crops, commercial product (5% suspension concentrate spinetoram) was applied to two leafy vegetables (Garland chrysanthemum and Aster scaber) on different spraying schedules. The analytical method used herein was based on a reversed-phase separation on a C(18) column, isocratic elution and UV detection. The analytes were confirmed via tandem mass spectrometry. The method was linear over a concentration range of 0.05-10 ppm with a correlation coefficient in excess of 0.9998. The recoveries of XDE-175-J and XDE-175-L from the two vegetables ranged between 86.04 and 98.87% at spiking levels of 1 and 5 ppm. The relative standard deviations were no more than 7% for all recovery tests conducted herein. The calculated limits of detection and quantification were 0.01 and 0.03 ppm for both XDE-175-J and XDE-175-L. The levels of residues in two vegetables treated under a fixed schedule in the greenhouse were 6.21-0.55 ppm (maximum residue limit (MRL) = 7 ppm). In sum, this method constitutes an easy and reliable technique for the determination of spinetoram in leafy vegetables.

A hexane extract of the flower-heads of Euryops pectinatus L. (Cass.) was formulated into local anti-inflammatory implantation patches with controlled release. Cross-linked sodium hyaluronate patches (F1-F3) and chitosan patches (F4-F6) were prepared by a casting/solvent evaporation technique. Morphological and mechanical characterizations including the components ratio, surfactant and the loaded amount of the hexane extract (50, 100, and 200 mg/kg b.wt.) were investigated. Release studies were performed during 24 h using a diffusion cell. Films with optimum in vitro release rate have been investigated for testing the anti-inflammatory activity and the sustaining effect of the formulations. The sustained anti-inflammatory effect of the hexane extract of E. pectinatus flower-heads from the selected films was studied by inducing paw edema in rats with 1% (w/v) carrageenan solution. The results indicated the compatibility of hexane extract with both sodium hyaluronate and chitosan patches forming yellowish transparent films. Based on variations in drug release profiles throughout the 24-h among the formulations (F1-F6) studies, F3 and F6 were selected for further investigation. When the films were applied 1 h before the subplantar injection of carrageenan in the hind paw of male Albino rats, formulation (F3) provided its maximum inhibition of paw edema in rats (91.3%) 4 h after edema induction whereas, formulation (F6) showed less inhibition after 4 h (70.6%). The previous two formulations (F3 and F6) produced potent results (95.3 and 89.5%, respectively) after 24 h when compared with a local market preparation containing 25% ?-sitosterol used as positive control. Histophathological investigation was conducted for 1, 4, and 12 weeks to study the tissue response for the two formulations (F3 and F6) at the implantation site. Chemical investigation of the hexane extract was achieved for both unsaponifiable matter (USM) and fatty acid methyl esters (FAME) using gas liquid chromatography (GLC). The USM was dominated by n-pentacosane (14.40%), phytosterols (Cholesterol, Campesterol, Stigmasterol, ?-sitosterol, ?-amyrin) reached 33.44% and the FAME was dominated by Linoleinic (49.97%). Quality control of the local implantation was evaluated by GLC using cholesterol as an analytical marker and phytosterols as an active marker compared to the plain extract.

In this study, a multiresidue analytical method for the detection of 37 pesticides in a soil matrix was developed and validated. The soil sample was fortified with a known quantity of pesticides at two different concentration levels (0.1 and 0.01 µg/g) and the analytes were extracted via a liquid–solid extraction method. The pesticides were separated on an HP5 capillary column and were analyzed with a gas chromatograph coupled to a nitrogen–phosphorous detector (GC-NPD). Method validation was accomplished with good linearity (r2 = 0.994–0.999) within a considerable range of concentrations. Satisfactory recoveries (70.5–110.4%) were obtained with 32 pesticides at both spiking concentration levels, whereas five pesticides—dimepiperate, buprofezin, prometryn, pirimicarb, and fludioxonil—were recovered at relatively low levels (43.6–61.8%). The applicability of the method was demonstrated by analyzing field samples collected from 24 different sites around Yeongsan and Sumjin rivers in the Republic of Korea. No residues of the selected pesticides were detected in any of the samples. The developed method could be employed as a simple and cost-effective method for the routine detection and analysis of 37 pesticides in soil samples.

The acidic herbicides are an important class of chemical compounds that are used to control a variety of weeds that threaten many crops. Owing to their low microbial activity levels, the acidic herbicides exhibit a residual activity remaining for periods of up to several months in soils and water. The principal objective of this study was to develop an analytical method based on liquid–liquid and solid-phase extraction followed by HPLC, for the determination of 2,4-D in paddy field water. The residues were verified via tandem mass spectrometry (MS/MS) in negative-ion electrospray ionization (ESI) mode. Linearity was good over a concentration range of 1–100 µg/L with a correlation coefficient (r2) of 0.999. The mean recovery rates of triplicate results ranged from 85.2 to 90.85%. The limits of detection and quantitation were 0.4 and 1.0 µg/L, respectively. The method proposed herein was applied to field samples acquired from Hampyung and Sunchang counties, Republic of Korea. The analyte was detected at a concentration range of 6.8–12.8 and 3.55–24.0 µg/L, respectively.