In the present study, graphene oxide reinforced two-phase electromembrane extraction (EME) coupled with gas chromatography was applied for the determination of methamphetamine as a model analyte in biological samples. The presence of graphene oxide in the hollow fiber wall can increase the effective surface area, interactions with analyte and polarity of support liquid membrane that leads to an enhancement in the analyte migration. To investigate the influence of the presence of graphene oxide in the support liquid membrane on the extraction efficiency, a comparative study was performed between graphene oxide and graphene oxide/EME methods. The extraction parameters such as type of organic solvent, pH of the donor phase, stirring speed, time, voltage, salt addition and the concentration of graphene oxide were optimized. Under the optimum conditions, the proposed microextraction technique provided low limit of detection (2.4 ng/mL), high preconcentration factor (195-198) and high relative recovery (95-98.5%). Finally, the method was successfully employed for the determination of methamphetamine in urine and hair samples.

An electrochemical sensor was prepared to detect nicotine by depositing copper nanoparticles (Cu NPs) on the surface of a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWNTs). The modified electrode was characterized by scanning electron microscopy and cyclic voltammetry. The novel-modified sensor exhibited effective electrocatalytic activities toward anodic oxidation of nicotine. Calibration plot showed two linear regions with different sensitivity, 1.121 (r 2 = 0.982) in the range from 1 9 10 -6 to 9 9 10 -5 M and 0.164 (r 2 = 0.982) from 1 9 10 -4 M up to 1 9 10 -3 M. The detection limit was 1 lM. For six parallel detections of 1 mM nicotine, the relative standard deviation was 5.68 %, suggesting that the film-modified electrode had good reproducibility. Experimental parameters affecting the sensor response such as pH, modifier concentration and electrodeposition scan rate were found to be optimum at 7.0, 2 mg mL -1 and 80 mV s -1 , respectively.

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Four native Papaver species of Iran, i. e. P. glaucum, P. tenuifolium, P. dubium and P. fugax, were collected from their natural habitat and subjected to HPLC analysis for determination of their morphine, codeine and thebaine content. P. dubium and P. glaucum contained all of the three mentioned narcotic alkaloids, while morphine was not found in P. fugax, and P. tenuifolium was free from codeine.

An Efficient Diastereoselective Synthesis of Spiro Pyrido[2,1-b][1,3]oxazines via a Novel Pyridine-Based Three-Component Reaction. -(ESMAEILI*, A. A.; VESALIPOOR, H.; HOSSEINABADI, R.; ZAVAREH, A. F.; NASERI, M. A.; GHIAMATI, E.; Tetrahedron Lett. 52 (2011) 38, 4865-4867, http://dx.