The aim of this work is to develop and validate a multi residue analytical method for a rapid and simple determination of Oxytetracycline, Tetracycline, Chlortetracycline and Doxycycline in bovine meat by HPLC-MS. Solid phase extraction of these antibiotics was made on a C18 cartridge that was first activated with 3 mL of methanol and 6 mL of water. This mixture was then eluted with 2 mL of a hydroalcoholic solution (5 % methanol). The antibiotic mixture was adsorbed on the stationary phase of the activated cartridge and eluted twice with 2.5 mL of methanol. The chromatographic separation was obtained on a RP-C18 Omnisher type column and using water (adjusted at pH 2.7 with a 20 mM solution of TFA) and acetonitrile in a gradient elution mode (20 % for 1 min and from 20 to 100 % with acetonitrile in 8 min). The flow was maintained constant at 0.25 mL/min. Quantitative analysis of antibiotics residues was made by HPLC-MS in SIM detection mode. This method allowed the determination of the four antibiotics with good yields: 81.9 ± 2.5 % for Oxytetracycline, 89.6 ± 1.5 % for Tetracycline, 80.1 ± 1.6 % for Chlortetacyclirte and 69.6 ± 2.9 % for Doxycycline.
S. Barrek, O. Paisse, H. Zarrouk, M.F. Grenier-Loustalot
residue, antibiotics, bovine meat, HPLC-MS
Bis(propargyl) polyoxyethylene ethers were obtained, in good yields, by action of propargylbromide on polyoxyethylene glycol ethers. The reaction occured in basic medium, using tetrabutylammonium hydrogenosulfate (TBAHS) as a catalyst.
A.N. Mekni, A. Baklouti
bis(propargyl) polyoxyethylene ether, propargylbromide, polyoxyethylene glycol ethers
In the last few years, hair analysis has become an important alternative and complement to blood and urine analysis. The principal advantage of this matrix lies in its stability and the possibility of long-term detection. The purpose of this work was to compare the results of urine and hair analysis in a smoking cessation program study, and to develop a routine analytical procedure for the quantification of the two organic biological markers: nicotine (alkaloid of tobacco) and cotinine (its principal metabolite). The techniques used were gas and liquid chromatography coupled with mass spectrometry detector, The main results were concerning the influence of sampling and nicotine-metabolism on the urine analysis, and also the precious additional information gave by hair analysis.
I.E. Hassen, M.M. Flament-Waton, O. Paisse, M.F. Grenier Loustalot, H. Zarrouk
urine, hair, nicotine, cotinine, smoking cessation
The electrochemical oxidation of a serie of substituted epoxydes I was investigated in acetonitrile by cyclic voltammetry and controlled potential electrolysis. The anodic process obeys an ECE type mechanism where the chemical reaction is a cleavage of the carbon-oxygen bond. For all the investigated compounds, the values of the rate constant of the electron transfer in solution k1, and the ratio kk1/k2 are calculated since the determination of the current catalytic values from redox catalysis experiments.
H. Medini, I. Tapsoba, M.L. Benkhoud, K. Boujlel
Epoxydes, homogeneus redox catalysis
Isolation of hydroxytyrosol 4-β -d-glucoside and 3,4-dihydroxyphenylglycol with antioxidant activity from olive mill wastewaters
N. Allouche, M. Feki, M. Damak, S. Sayadi
Allylic bromides 2-(E, Z) undergo smooth nucleophilic displacement with 1,4-diazabicyclo [2.2.2] octane (DABCO) and KCN in aqueous THF under mild conditions, to afford the corresponding 2-alkyl-3- methylbutenedinitriles 3(E, Z) with improved yields.
R. Ouled Saad, H. Amri
Pages 239 - 243
Six known glucosid flavonoids have been isolated for the first time from the acrid part of Daucus maritimus L. Their structures were elucidated by spectroscopic methods and some correction of NMR's chemical shifts were reported. The 2,2-diphenyl-1-picryl hydrazyl radical (DPPH') scavenging activity of four compounds was realised.
S. Miladi, R. Jarraya, M. Damak
Daucus maritimus, Umbelliferae, glucosid flavonoids, antioxydant activity
Three methods were used in the diphenylether (DPE) acylation reaction by the coumalic acid (2-pyrone-5-carboxylic) in order to obtain a new bisdiene of the bispyrone type. The first one consists in a Friedel and Crafts acylation in the presence of a Lewis acid. In the second way we used the Eaton reagent (mixture: CH3SO3,H/P2O5). Finally use of the mixture: trifluormethanesulfonic (triflic) acid/P2O5 alone or added to the methanesulfonic acid was described in the third part. The bispyrone obtained with a yield varying from 70 to 90% was analyzed by proton and 13C NMR and by HPLC/MS.
O. Mzani, H. Ben Romdhane, R. Mercier, M. Baklouti
bispyrones, acylation, Eaton reagent, trifluoromethanesulfonic acid
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