4-Methoxy-ortho -phthalaldehyde: a promising derivatizing agent for the fluorimetric evaluation of histamine in seafood

International audienceHistamine, the molecule associated with food poisoning, is nowadays considered as a reliable marker of seafood freshness and therefore its rapid and easy quantification appears critical. Existing method like HPLC or direct fluorimetric analysis employing ortho-phthalaldehyde (OPA) can be time-consuming and tedious. To overcome this problem, we propose in this paper to evaluate the application potential of 4-methoxy-ortho-phthalaldehyde (MO-OPA) for the rapid and easy evaluation of histamine in seafood samples. For this purpose, the histamine com-plexation conditions were studied by molecular fluorescence spectroscopy using MO-OPA as derivatization agent and then compared with the reference compounds: OPA. MOPA proved to be superior to OPA for histamine detection in terms of linearity range (1.10 − 6-1.10 − 4 mol.L − 1 , R 2 > 0.99, n = 10) and detection limit (9.5.10 − 7 mol.L − 1). The optimal conditions were next applied to the analysis of histamine in a mixture of biogenic amines standards and finally on real samples of yellowfin tuna of known histamine concentration

Determination of Agmatine Rate by Spectrofluorimetric Method in Alkaline Medium: Optimization and Application on Shrimp.

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Development of thermochemically induced fluorescence (TIF) method for the determination of insecticide deltamethrin in Senegalese natural waters

International audienceA simple and sensitive thermochemically induced fluorescence (TIF) method was developed to determine deltamethrin, an insecticide which has toxic effects on human beings and animals. After optimisation at different pH, temperature was increased from 25 to 50°C. TIF method is based on the thermolysis transformation of naturally non-fluorescent pesticides into a fluorescent thermoproduct. The thermolysis kinetics reaction investigated in water at optimal pH 12 and after 4 minutes heating at 40°C made it possible to obtain a low mean half-life time (t1/2 = 1.41 ± 0.06 min), which shows that deltamethrin degrades very rapidly due to heat. The obtained calibration curve gave correlation coefficients close to unity. The limit of detection (LOD = 4.4 ng mL−1) and quantification (LOQ = 15 ng mL−1) values were very low, showing the high sensitivity of the TIF method. TIF method was applied to determination of deltamethrin residues in tap and well waters by standard addition procedure, with satisfactory recovery values between 107.6 and 111.4%. The relative standard deviation (RSD) value of the measured concentrations in spiked water samples was less than 6%, which demonstrated good reproducibility of the TIF method