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1.
Histamine is an important compound from a physiological point of view, but it is toxic since the absorption of low amounts of histamine can cause abdominal pains accompanied with vomiting. Why we have developed a new method for histamine analysis in order to improve Lerke and Bell method. From the absorption spectra, we showed that the stoichiometry of the complex histamine-orthophthalaldehyde (OPA) is 1:1. From the emission spectra, it was observed that the complex fluorescence is inhibited in acidic medium. In alkaline medium, an exaltation of fluorescence was observed, but the complex histamine-OPA was unstable. Nevertheless, kinetic study showed that good linear correlations between the fluorescence maxima of the formed complex and the histamine concentration could be obtained in this alkaline medium. 相似文献
2.
An analytical method based on the use of UV irradiation to produce fluorescent derivatives from four non-fluorescent sulfonylurea herbicides, including chlorsulfuron, metsulfuron methyl, 3-rimsulfuron and sulfometuron methyl is described. Their photochemically-induced fluorescence (PIF) properties in several solvents (water, dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), acetonitrile, methanol, ethanol, propan-2-ol and their binary mixtures with water) and micellar solutions of sodium dodecyl sulfate (SDS), and cetyltrimethylammonium chloride (CTAC) are reported. Physicochemical variable influencing the sensitivity of the method have been optimized. A PIF method is developed for the determination of the four herbicides under study. Micellar media are found to provide the best analytical figures of merits. Linear dynamic ranges are established over about two orders of magnitude. The limit of detection (LOD) range from 0.2 to 6 ng ml(-1) according to the compound, with relative standard deviation (RSD) between 1.2 and 3.9%. Examples of applications to the analysis of these herbicides in spiked river water samples are given. The mean recoveries range from 80 to 104%. 相似文献
3.
Fluorimetric Determination of Histamine in Fish Using Micellar Media and Fluorescamine as Labelling Reagent 总被引:1,自引:0,他引:1
Adamou R Coly A Douabalé SE Saleck ML Gaye-Seye MD Tine A 《Journal of fluorescence》2005,15(5):679-688
An analytical method based on the use of fluorescamine to produce a fluorescent derivative with histamine and combined with
micellar-enhanced fluorescence detection of the formed complex is developed for the sensitive and rapid determination of histamine
in fishes. The fluorescence properties of the obtained complex in water and micellar solutions of sodium dodecyl sulfate (SDS),
cetyltrimethylammonium chloride (CTAC) and brij-700 are reported. Physicochemical variables influencing the sensitivity of
the method (pH, micellar, fluorescamine and NaCl relative concentrations) have been optimized. The stability of the formed
complex, as shown by kinetic study, depends on the pH of the solution. Linear calibration curves allowing an effective histamine
determination were established with large linear dynamic range (LDR), and low limits of detection (LOD) between 0.5 and 33
ng mL−1, according to the solvent. Application to the analysis of fish samples (sardines) yielded satisfactory results. The method
seems to be suitable for environmental fish quality control.
Presented in part, at the 39th IUPAC Congress and the 86th Conference of the Canadian Society for Chemistry, August, 10–15,
2003, Ottawa (Canada). 相似文献
4.
Moussa Mbaye Mame Diabou Gaye Seye Atanasse Coly Alphonse Tine Jean-Jacques Aaron 《Analytical and bioanalytical chemistry》2009,394(4):1089-1098
The photochemically induced fluorescence (PIF) spectral properties of α-cypermethrin in organic solvents (hexane, dichloromethane,
acetonitrile, ethanol) and in cyclodextrin aqueous solutions (β-CD and 2-hydroxypropyl-β-CD, 2-HP-β-CD) were investigated.
The photolysis kinetics of α-cypermethrin were evaluated in the various media. The PIF signal was found to be significantly
enhanced in the CD media relative to the organic solvents. The stoichiometry and the formation constants of the α-cypermethrin
inclusion complexes formed with the CDs were determined. The analytical performances of the PIF method were improved in the
presence of HP-β-CD relative to the other media, and a CD-enhanced PIF analytical method was developed. The limits of detection
and limits of quantification ranged, respectively, between 6 and 98 ng/mL and between 24 and 343 ng/mL, depending on the medium.
Application to the analysis of tap water and Senegal natural water samples collected close to agricultural areas and spiked
with α-cypermethrin yielded satisfactory recoveries going from about 77% to 98%. An interference study of foreign species,
including pesticides and inorganic ions likely to be present in natural waters, was also carried out.
Figure Photolysis reaction of α-cypermethrin in presence of HP-β-CD 相似文献
5.
Cyclodextrin-enhanced fluorescence and photochemically-induced fluorescence determination of five aromatic pesticides in water 总被引:1,自引:0,他引:1
The effect of β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) aqueous solutions upon the fluorescence and photochemically-induced fluorescence (PIF) properties of five pesticides, including coumatetralyl, pirimiphos-methyl, chlorpyriphos, deltamethrin and fenvalerate was investigated. A 1:1 stoichiometry was found for the β-CD and HP-β-CD complexes formed with all compounds. Binding constant values, ranging between about 90 and 830 M−1 were calculated using the iterative nonlinear least-squares regression approach. Cyclodextrin-enhanced fluorescence and PIF methods were developed for the determination of these pesticides with linear dynamic ranges over two orders of magnitude, and limits of detection (LOD) between 0.2 and 54 ng ml−1 according to the compound. Application to the analysis of tap water and river water samples yielded satisfactory recoveries (88–116%). The method seems to be suitable for environmental water analysis. 相似文献
6.
P. A. Diaw O. M. A. Mbaye M. D. Gaye-Seye J.-J. Aaron A. Coly A. Tine N. Oturan M. A. Oturan 《Journal of fluorescence》2014,24(4):1319-1330
A photo-induced fluorescence (PIF) method was developed for the determination of two benzoyl- and phenylurea pesticides, namely diflubenzuron (DFB) and fenuron (FEN). The photoconversion under UV irradiation of both pesticides into strongly fluorescent photoproducts was performed in several media (methanol, ethanol, acetonitrile, pH4 aqueous solution and pH4 water–methanol (30:70, v/v) mixture). PIF parameters were optimized. Analytical figures of merit for the PIF determination of DFB and FEN were satisfactory, with rather wide linear dynamic range (LDR) values of one to two orders of magnitude, relatively low limit of detection (LOD) values of, respectively, 9–24 ng/mL for DFB and 1–28 ng/mL for FEN, and limit of quantification (LOQ) values of, respectively, 30–80 ng/mL for DFB and 4–95 ng/mL for FEN, according to the medium. Relative standard deviation (RSD) values were in the range 1.7–5.6 %. PIF was validated by comparing its analytical performances to those of a standard UV absorption spectrophotometric method. The optimized PIF method was applied to the quantitative analysis of both pesticides in various spiked natural water samples collected in a Senegal agricultural area by the standard addition procedure prior to extraction steps in dichloromethane, with satisfactory mean recovery percentage values (97.0–105.3 for DFB and 98.3–102.8 % for FEN). An interference study of foreign species, including pesticides and inorganic ions, likely to be present in natural waters, was also carried out. 相似文献
7.
Mbaye M Gaye Seye MD Aaron JJ Coly A Tine A 《Analytical and bioanalytical chemistry》2011,400(2):403-410
Flow injection analysis combined with photo-induced fluorescence (FIA-PIF) has been applied for the determination of α-cypermethrin
pesticide residues in Senegalese natural waters, using organic solutions and cyclodextrin (β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin)
aqueous media. The α-cypermethrin insecticide has a very weak natural fluorescence, but it is converted into strongly fluorescent
photoproduct(s) by UV irradiation. Cyclodextrins were found to enhance the PIF signal. FIA parameters, including mobile phase
flow rate, injected volume, and reactor length, were optimized. Analytical performances of the FIA-PIF method for the determination
of α-cypermethrin were satisfactory, with concentration linear dynamic ranges over one to two orders of magnitude and with
rather low limits of detection and limits of quantification, in the ng mL−1 range, and relative standard deviations comprised between 1.2% and 3.8%. Application of FIA-PIF for the analysis of fortified
natural water samples collected from Senegal yielded good recovery values (84–112%). Because of its high sampling rate, the
FIA-PIF method constitutes a rapid analytical tool, useful for quantification of α-cypermethrin residues in natural waters. 相似文献
8.
The effects of solvent and of ultraviolet (UV) photolysis on the fluorescence intensity of several aromatic pesticides including bendiocarb, chlorophacinone, coumatetralyl and pirimiphos-methyl were investigated. The type and polarity of solvent (acetonitrile, dimethylsulfoxide, methanol, ethanol and 2-propanol) were shown to play an important role in the limits of detection (LOD) of the method. UV photolysis provoked a decrease of the fluorescence signal more or less marked, depending of the structure of the pesticide. Analytical figures of merit were evaluated for the determination of pesticides under optimal conditions. The method exhibited satisfactory analytical performances. The linear dynamic ranges were obtained over more than two orders of magnitude. The LOD ranged from 0.03 to 20 ng/ml, according to the compound. The relative standard deviations were between 5.5 and 6.1%. Examples of application to the determination of pesticides in technical formulations are presented. The mean recoveries ranged from 86 to 116%. It shows the usefulness of this technique for pesticide analysis. 相似文献
9.
Indolecarboxylic acids belong to the auxins group. They constitute a class of phytohormones, which play an important role in plant growth. This paper deals with the kinetics of six indolecarboxylic acids and their regulation effects on the growth of groundnut (Arachis hypogea) and haricot bean (Phaseolus vulgaris). The results obtained enabled us to establish a relationship between photodegradation rate constants and their regulation properties on the growth of these two plants. The paper shows that the compounds yielding the highest photodegradation rates were efficient growth regulators. In this regard, a few explanations are provided. 相似文献
10.