34 dihydroxy benzoic acid 1 are widespread in the

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Unformatted text preview: trochemical synthesis of dithiocarbamate. Therefore, we have investigated the electrooxidation of 3,4-dyhydroxybenzoic acid in the presence of dithiocarbamate as the nucleophile in aqueous solution, using cyclic voltammetry and controlled -potential coulometry, and describe a facile electrochemical method for the synthesis of some dithiocarbamate in good yield and purity. The oxidation mechanism was deduced from voltammetric data and by coulometry at controlled -potential. The results of this work show that benzoic acid (1) are oxidized to their respective o-benzoquinones (2).The quinones are then attacked by (3), final products are obtained via an EC mechanism, after consumption of only 2e per molecule of (1). According to our results, it seems that the 1,4 - Michael addition of this nucleophile to the o-quinones formed leads to the formation of new dihydroxybenzoic acid derivatives as final products, in good yield and purity. ANA-P11 HIGH PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE DETERMINATION OF SPHINGOSINE AND SPHINGANINE IN BIOLOGICAL FLUIDS USING MONOLITHIC COLUMN 1 Lee Tien Ping, Bahruddin Saad and Baharuddin Salleh 1 2 1 2 School of Chemical Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia School of Biological Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia E-mail: bahrud@usm.my Mycotoxins are produced as secondary metabolites of certain species of fungi. Due to their toxicity, their presence in foodstuff and animal feeds has been of major concern. Some form of early warning system to assess the exposure to mycotoxin is needed. Sphingosine (So) and sphinganine (Sa), chemical marker for fumonisin exposure is developed by using HPLC - fluorescence method with silica based monolithic column. The samples were first extracted using ethyl acetate, and were pre -column derivatized using ortho-phthaldialdehyde in the presence of 2-mercaptoethanol. The liquid chromatographic separation was achieved using a mixture of methanol and water (93:7, v/v) at a flow -1 rate of 1 mL min . The fluorescence excitation and emission were at 335 nm and 440 nm, respectively. The separation time...
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This note was uploaded on 02/17/2011 for the course CHEMISTRY 101 taught by Professor Csr during the Spring '11 term at University of Louisville.

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