Stereoselective separation and pharmacokinetic dissipation of the chiral neonicotinoid sulfoxaflor in soil by ultraperformance convergence chromatography/tandem mass spectrometry

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Little data on the enantioselective separation of cyflumetofen exists, despite the fact that such data are essential to the assessment of the fate and potential toxic effects of cyflumetofen enantiomers. To address this issue, a simple and sensitive method for the enantioselective determination of cyflumetofen enantiomers in soil has been established using ultra performance convergence chromatography tandem triple quadrupole mass spectrometry. The effects of the chiral stationary phases, mobile phase, auto backpressure regulator pressure, column temperature, flow rate of the mobile phase, and compensation pump solvent were evaluated. The proposed method was applied to the study of the pharmacokinetic dissipation of cyflumetofen stereoisomers in soil under greenhouse conditions. The estimated half-life of cyflumetofen isomers ranged from 12.2 to 13.6 days, and statistically significant enantioselective degradation was observed. This study not only demonstrates that there is an efficient and sensitive method for cyflumetofen enantioseparation, but also provides the first experimental evidence of the pharmacokinetic dissipation of cyflumetofen stereoisomers in the environment.

Section: Optimization Of Enantioseparation Conditionssupporting

confidence: 90%

Enantioselective separation and pharmacokinetic dissipation of cyflumetofen in field soil by ultra‐performance convergence chromatography with tandem mass spectrometry

Liu

Dong

et al. 2016

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“…The separation parameters of the famoxadone enantiomers including the retention factor ( k′ ), the selectivity factor ( α ) and the resolution (Rs). The specific calculation formula is as follows in Equations :

k^{'} = \frac{t - t_{0}}{t_{0}}

α = k_{2} / k_{1}

Rs = 1 . 177 \times \frac{t_{2} - t_{1}}{w_{1} / 2 + w_{2} / 2}

where t 0 (determined using uracil) is the void time under the aforementioned conditions, t is the retention time, k 1 and k 2 are retention factors of the first and second eluted enantiomers separately, w/2 means the peak width at half height.…”

Section: Methodsmentioning

confidence: 99%

“…The degradation kinetics of the famoxadone enantiomers in tomato, apple, and grape samples were estimated using the first‐order kinetics equation. The degradation rate constants ( K ) and half‐life ( T 1/2 ) were estimated using the following equations :

C = C_{0} e^{- Kt}

T_{1 / 2} = ln 2 / K = 0.693 / K

where C 0 and C indicate the concentrations of the enantiomers at time 0 and time t , respectively. k is the degradation rate constant and ln2 = 0.693.…”

Section: Methodsmentioning

confidence: 99%

“…The enantiomeric fraction (EF) was used to investigate the enantioselectivity of the dissipation of famoxadone enantiomers in tomato, apple, and grape samples. EF was described using the following equations :

EF = \frac{A^{-}}{A^{+} + A^{-}}

where A − and A + represent the concentrations of the R ‐(−)‐famoxadone and S ‐(+)‐famoxadone. The EF values range from 0 to 1, and EF = 0.5 means the racemate.…”

Section: Methodsmentioning

confidence: 99%

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Enantioselective monitoring of chiral fungicide famoxadone enantiomers in tomato, apple, and grape by chiral liquid chromatography with tandem mass spectrometry

Jia

et al. 2018

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Famoxadone is a widely used chiral fungicide on tomato, apple, and grape. But it is still being employed as a racemic mixture without distinguishing the difference between enantiomers, which often leads to its inaccurate risk assessment. In this study, a rapid, sensitive, and reliable chiral analytical method was developed for famoxadone enantiomers by ultra high performance liquid chromatography/tandem mass spectrometry, optimal separation condition was achieved with Lux Amylose-1 column using acetonitrile/water (70:30, v/v) as mobile phase at 0.3 mL/min in 6 min. The average recoveries for two enantiomers in all of the matrices at three spiking levels ranged from 89.8 to 109.4%, with relative standard deviation less than 9.5%. The limits of quantification for all enantiomers in tomato, apple, and grape were not more than 4 μg/kg. And the proposed method was successfully applied to investigate the enantioselective degradation of famoxadone enantiomers in tomato, apple, and grape. The data showed that S-(+)-famoxadone was preferentially degraded comparing to the R-(-)-famoxadone in tomato, apple, and grape. The potential reasons of the enantioselective behavior were also discussed. This study could help in better understanding the environmental fate of famoxadone and the rational use of chiral pesticide in agricultural production.

“…It is our sense that the revival of the PLOT column and the technological developments applied to instrument systems, especially the tendency for miniaturization of chromatographic techniques as well as the various polymeric materials being used as stationary phases, will tend to increase the use of open tubular columns in LC and SFC. As a consequence, an expansion of the applicability range beyond the proteomics area, which has been most explored, is expected .…”

Section: Instrumentationmentioning

confidence: 99%

Unified chromatography: Fundamentals, instrumentation and applications†

Silva

Andrade

Fumes

et al. 2015

The concept of unified chromatography has been in existence for 50 years after the work of Giddings proposing that all modes of chromatography (gas chromatography, liquid chromatography, supercritical fluid chromatography and so on) may be treated together under a single unified theory. His idea was partially fulfilled 23 years later by Ishii, Takeuchi and colleagues, who demonstrated for the first time the possibility to analyze a complex sample containing substances with a wide range of boiling points and polarities in the same instrument and column, just by varying the mobile phase pressure and temperature to change from one chromatographic mode to another. This approach has been demonstrated through application to the separation of complex mixtures in several areas including crude oil, edible oils and polymers. Still, unified chromatography has not yet been fully developed. In the present work, we will review the fundamentals, instrumentation and several applications of the technique. Also discussed are the drawbacks that still hinder development, as well as the recent developments and trends in instrumentation and columns that suggest the most feasible ways forward to the full development of unified chromatography.