Simultaneous determination of phosphorus-containing amino acid-herbicides by nonionic surfactant micellar electrokinetic chromatography with laser-induced fluorescence detection

Molina, Manuel Flores; Silva, Manuel

doi:10.1002/1522-2683()22:6<1175::aid-elps1175>3.0.co;2-8

Cited by 43 publications

(22 citation statements)

References 37 publications

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“…So, for natively fluorescent or labelled analytes absorbing in the UV region, He-Cd laser (325 nm) and frequency-doubled Ar ion laser (257 nm) have been widely employed [7][8][9][10][11][12][13][14][15], using built in-house equipment or coupling laser sources with commercial CE systems. For labelled fluorescent analytes with absorption in the visible region, FITC is the most widely used derivatizating reagent due to its compatibility with commercial air cooled argon ion laser (488 nm) LIF detector [16][17][18][19][20][21]. For labelled fluorescent analytes with absorption in the visible region, FITC is the most widely used derivatizating reagent due to its compatibility with commercial air cooled argon ion laser (488 nm) LIF detector [16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Analytical potential of fluorescein analogues for ultrasensitive determinations of phosphorus-containing amino acid herbicides by micellar electrokinetic chromatography with laser-induced fluorescence detection

Molina

Silva

2002

Electrophoresis

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The analytical potential of three fluorescein analogues, fluorescein isothiocyanate isomer I (FITC), 5-(4,6-dichlorotriazinylamino) fluorescein (DTAF) and 5(6)-carboxyfluorescein N-succinimidyl ester (CFSE), as labelling reagents for the ultrasensitive determination of phosphorus-containing amino acid herbicides (glufosinate and glyphosate) and aminomethylphosphonic acid (the major metabolite of glyphosate) by nonionic surfactant micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection was investigated. Practical aspects related to label chemistry and MEKC separation showed that DTAF is the best choice for the determination of these herbicides; in addition, the most important features of these reagents for the derivatization of amino compounds are discussed. The optimum procedure includes a derivatization step of the herbicides at 40 degrees C with DTAF for 1 h and a 2-fold dilution prior to MEKC analysis, which is conducted within about 10 min using Brij-35 in the running buffer. This nonionic surfactant improves the selectivity and therefore the sensitivity of the method at low analyte concentrations by shifting the interfering peaks of the DTAF excess. The lowest detectable analyte concentration ranged from 0.06 to 0.16 microg/L with a precision of 2.1-3.2%. These results indicate that nonionic surfactant MEKC-LIF is useful as a selective, rapid and sensitive tool for the determination of these herbicides showing a great potential for their analysis in environmental samples without previous enrichment steps. The proposed method surpasses other chromatographic alternatives in terms of limit of detection and sample requirements for the analysis.

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Section: Introductionmentioning

confidence: 99%

Analytical potential of fluorescein analogues for ultrasensitive determinations of phosphorus-containing amino acid herbicides by micellar electrokinetic chromatography with laser-induced fluorescence detection

Molina

Silva

2002

Electrophoresis

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“…Thus, Brij-35 was added to the MRB, because it has been recently reported that nonionic surfactants can significantly improve the separation of closely related anionic analytes without affecting the ionic current during the run and thus avoiding excessive Joule heating [13]. (iii) The use of neutral micelles allowed to achieve a good separation for the amino compound derivatives; however, this pseudostationary phase shows an important inhibitory effect on the labeling reaction.…”

Section: Resultsmentioning

confidence: 99%

“…Among the most frequent excitation sources, the argon ion laser emitting at 488 nm is employed for exciting a wide range of fluorescent derivatives, which are formed by reaction of the analytes with suitable reagents. FITC [9][10][11][12][13] is very popular due to the high-quantum yield of its moiety. Recently, 5-(4,6-dichloro-s-triazin-2-ylamino)fluorescein (DTAF) has been receiving attention as an alternative to FITC due to its faster labeling reaction, higher purity and lower cost [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

In-capillary derivatization and analysis of amino acids, amino phosphonic acid-herbicides and biogenic amines by capillary electrophoresis with laser-induced fluorescence detection

Molina

Silva

2002

Electrophoresis

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This paper describes a general approach for the in-capillary derivatization of amino compounds and the subsequent sensitive determination of the derivatives by micellar electrokinetic chromatography (MEKC) or capillary zone electrophoresis (CZE) with laser-induced fluorescence (LIF) detection. Amino acids, biogenic amines and amino phosphonic acid-herbicides were chosen as model analytes to evaluate the analytical potential of this approach. Fulfilment of the in-capillary reaction of the analytes using LIF detection hinged on the excellent labeling chemistry of 5-(4,6-dichloro-s-triazin-2-ylamino)fluorescein (DTAF) and the good resolution achieved in the separation of derivatized analytes. Careful optimization of the electrophoretic conditions in the mixing step of this protocol allowed the determination of amino acids, biogenic amines and phosphorus-containing amino acid-herbicides with concentration limits of detection at the nug/L level and relative standard deviations from 3.5 to 5.8%. The whole analysis is carried out within 20 min, resulting in a very simple, fast and practical approach for the fully automated analysis of amino acids and related compounds in low-volume and low-concentration samples.

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“…The most commonly used chromatographic separation methods include high-performance liquid chromatography (HPLC) [9,10], gas chromatography (GC) [11], liquid chromatography-tandem mass spectrometry (LC/MS) [12], gas chromatography-tandem mass spectrometry (GC-MS/MS) [13,14], capillary electrophoresis (CE) [15-18], and enzyme-linked immunosorbent assay (ELISA) [2,3,19]. For example, an analytical method has been reported for quantifying dl -glufosinate enantiomers in biological specimens using precolumn derivatization and reversed-phase HPLC with a fluorescence detector.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective hydrolyzation and photolyzation of dufulin in water

Zhang

Zhu

et al. 2013

Chemistry Central Journal

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BackgroundDufulin is a novel, highly effective antiviral agent that activatives systemic acquired resistance of plants. This compound is widely used in China to prevent and control viral diseases in tobacco, vegetable and rice. Dufulin can treat plants infected by the tobacco mosaic virus and the cucumber mosaic virus. However, the achiral analysis and residue determination of dufulin remain underdeveloped because of its high enantioselectivity rates and high control costs. The enantioselectivity of an antiviral compound is an important factor that should be considered when studying the effect of chiral pesticides on the environment. The enantioselective degradation of dufulin in water remains an important objective in pesticide science.ResultsThe configuration of dufulin enantiomers was determined in this study based on its circular dichroism spectra. The S-(+)-dufulin and R-(−)-dufulin enantiomers were separated and identified using an amylose tris-(3,5-dimethylphenylcarbamate) chiral column by normal phase high-performance liquid chromatography. The degradation of the rac-dufulin racemate and its separate enantiomers complied with first-order reaction kinetics and demonstrated acceptable linearity. The enantioselective photolysis of rac-dufulin allowed for the faster degradation of R-(−)-dufulin, as compared with S-(+)-dufulin. However, S-(+)-dufulin was hydrolyzed faster than its antipode.ConclusionThe photolysation and hydrolyzation of dufulin in water samples normally complied with the first-order kinetics and demonstrated acceptable linearity (R2>0.66). A preferential photolysation of the R-(−)-enantiomer was observed in water samples. Moreover, the S-(+)-enantiomer was hydrolyzed faster than its antipode.

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Simultaneous determination of phosphorus-containing amino acid-herbicides by nonionic surfactant micellar electrokinetic chromatography with laser-induced fluorescence detection

Cited by 43 publications

References 37 publications

Analytical potential of fluorescein analogues for ultrasensitive determinations of phosphorus-containing amino acid herbicides by micellar electrokinetic chromatography with laser-induced fluorescence detection

Analytical potential of fluorescein analogues for ultrasensitive determinations of phosphorus-containing amino acid herbicides by micellar electrokinetic chromatography with laser-induced fluorescence detection

In-capillary derivatization and analysis of amino acids, amino phosphonic acid-herbicides and biogenic amines by capillary electrophoresis with laser-induced fluorescence detection

Enantioselective hydrolyzation and photolyzation of dufulin in water

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