Determination of agrochemical combinations in spiked soil samples

1998 ◽  
Vol 37 (8) ◽  
pp. 243-250 ◽  
Author(s):  
Sandra Babic ◽  
Marija Kastelan-Macan ◽  
Mira Petrovic
Keyword(s):  
Phase Composition ◽  
Mobile Phase ◽  
Soil Samples ◽  
Computer Assisted ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
Spiked Soil ◽  
Layer Chromatography ◽  
Slit Scanning

Quantitative determination of combinations of the agrochemicals: atrazine, propham, chlorpropham, diflubenzuron, α-cypermethrin and tetramethrin from spiked soil is reported. Method involves ultrasonic extraction of agrochemicals with acetone, separation of samples by means of reverse-phase thin-layer chromatography and quantification by slit-scanning densitometry. Computer-assisted optimisation was used to select the optimum mobile phase composition. Apparent recoveries of agrochemicals from spiked soil were: 90.3±8.5 for chlorpropham, 79.3±10.3 for propham, 102±2.4 for atrazine, 100.6±5.4 for α-cypermethrin, 103.0±4.1 for tetramethrin and 98.3±4.9 for diflubenzuron.

MAGIC-LC/FT-IR Spectrometry: Preliminary Studies

1988 ◽  
Vol 42 (8) ◽  
pp. 1365-1368 ◽  
Author(s):  
R. M. Robertson ◽  
J. A. De Haseth ◽  
J. D. Kirk ◽  
R. F. Browner
Keyword(s):  
Phase Composition ◽  
Mobile Phase ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
Ir Spectrometry ◽  
Aerosol Generation ◽  
Mobile Phases ◽  
Ft Ir ◽  
Effluent Stream ◽  
Phase Water

A new solvent elimination interface based on the Monodisperse Aerosol Generation Interface for Combining Liquid Chromatography with Fourier transform infrared (MAGIC-LC/FT-IR) spectrometry is described. The solvent elimination efficiency of MAGIC-LC/FT-IR was studied by varying the mobile-phase composition from 100% methanol to 100% water. As the mobile-phase composition was varied, erythrosin B was injected into the interface and deposited on a KBr window after the solvent removal. Spectra were obtained which compared favorably with reference spectra, even as the mobile-phase water content was increased. A reverse-phase separation was completed to demonstrate that readily identifiable spectra can be obtained from mobile phases containing high percentages of water, without heating of the effluent stream.

scholarly journals Retention Behaviour in Micellar Liquid Chromatography

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Maria Rambla-Alegre
Keyword(s):  
Liquid Chromatography ◽  
Phase Composition ◽  
Mobile Phase ◽  
A Priori ◽  
Great Accuracy ◽  
Micellar Liquid Chromatography ◽  
Computer Assisted ◽  
Mobile Phase Composition ◽  
Mobile Phases ◽  
Sequential Strategy

Retention in micellar liquid chromatography is highly reproducible and can be modelled using empirical or mechanistic models with great accuracy to predict the retention changes when the mobile phase composition varies (surfactant and organic solvent concentrations), thus facilitating the optimisation of separation conditions. In addition, the different equilibria inside the column among the solute, the mobile phase, and the modified stationary phase by monomers of surfactant have been exhaustively studied. In a sequential strategy, the retention of the solutes is not known a priori, and each set of mobile phases is designed by taking into account the retention observed with previous eluents. By contrast, in an interpretative strategy, the experiments are designed before the optimization process and used to fit a model that will allow the prediction of the retention of each solute. This strategy is more efficient and reliable. The sequential strategy will be inadequate when several local and/or secondary maxima exist, as frequently occurs in chromatography, and may not give the best maximum, that is to say, the optimum. More often than not, the complexity of the mixtures of compounds studied and the relevant modification of their chromatographic behaviour when changing the mobile phase composition requires the use of computer-assisted simulations in MLC to follow the modifications in the chromatograms in detail. These simulations can be done with sound reliability thanks to the use of chemometrics tools.

scholarly journals A SIMPLE AND FAST RP-UHPLC-PDA METHOD FOR DETERMINATION OF ISRADIPINE FROM POLYMERIC NANOCAPSULES

2020 ◽  
pp. 225-229
Author(s):  
Fernanda Malaquias Barbosa ◽  
Guilherme dos Anjos Camargo ◽  
Amanda Martinez Lyra ◽  
Jessica Mendes Nadal ◽  
Paulo Vitor Farago
Keyword(s):  
High Performance Liquid Chromatography ◽  
Phase Composition ◽  
Flow Rate ◽  
Mobile Phase ◽  
High Performance ◽  
Experimental Basis ◽  
Mobile Phase Composition ◽  
Polymeric Systems ◽  
Polymeric Nanocapsules

A simple and fast analytical method of ultra-high performance liquid chromatography (UHPLC) was developed and validated in order to assay isradipine in poly(ε-caprolactone) (PCL)/polyethylene glycol (PEG) nanocapsules. Experiments were performed by UHPLC on a C18 chromatographic column at 25°C using a mobile phase composed by methanol and water (85:15 v/v) with a flow rate of 0.5 mL.min−1 and UV detection at 327nm for achieving a total run time of 1.5 min. The UHPLC method was validated according to the guidelines set on The International Conference on Harmonisation. It proved to be selective, linear (r = 0.99962), precise (RSD < 4.1%), and accurate (recovery rates between 95.24 and 96.53%) at the range from 10 to 40 µg.mL−1. The performance was robust when slight changes in the flow rate, wavelength of detection, and mobile phase composition were tested. It was successfully applied to quantify isradipine from nanoparticulate polymeric systems, showing high loading efficiency rates, greater than 98.55%. These results provided an experimental basis to use this method for quantifying isradipine with reliable results, besides being very fast, easy to perform and cheaper.

scholarly journals Quantitative estimation of trimazolin hydrochloride in pharmaceutical preparation by RP-HPLC method

2009 ◽  
Vol 63 (2) ◽  
pp. 87-93 ◽  
Author(s):  
Ivana Savic ◽  
Goran Nikolic ◽  
Vladimir Bankovic ◽  
Ivan Savic
Keyword(s):  
Phase Composition ◽  
Quantitative Determination ◽  
Mobile Phase ◽  
Quantitative Estimation ◽  
Pharmaceutical Preparation ◽  
Hplc Method ◽  
Mobile Phase Composition ◽  
Rp Hplc ◽  
Ich Guidelines

A sensitive and selective RP-HPLC method was developed and validated for the quantitative determination of trimazolin hydrochloride in nasal drops formulations. The mobile phase composition was water-acetonitrile (50:50, v/v) and the UV detection was carried out at 270 nm. Linearity range in the concentration range of 10 to 110 ?g cm-3. The method was tested and validated for various parameters according to ICH guidelines. The detection and quantization limits were found to be 1.45 and 4.8 ?g cm-3, respectively. The results demonstrated that the procedure for estimation of trimazolin hydrochloride in nasal drops formulations was accurate, precise and reproducible.

scholarly journals Revising Reverse-Phase Chromatographic Behavior for Efficient Differentiation of Both Positional and Geometrical Isomers of Dicaffeoylquinic Acids

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Keabetswe Masike ◽  
Ian Dubery ◽  
Paul Steenkamp ◽  
Elize Smit ◽  
Edwin Madala
Keyword(s):  
Phase Composition ◽  
Uv Irradiation ◽  
Mobile Phase ◽  
Elution Order ◽  
Elution Profile ◽  
Plant Metabolites ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
Geometrical Isomers ◽  
Column Temperature

Dicaffeoylquinic acids (diCQAs) are plant metabolites and undergo trans-cis-isomerization when exposed to UV irradiation. As such, diCQAs exist in both trans- and cis-configurations and amplify the already complex plant metabolome. However, analytical differentiation of these geometrical isomers using mass spectrometry (MS) approaches has proven to be extremely challenging. Exploring the chromatographic space to develop possible conditions that would aid in differentially separating and determining the elution order of these isomers is therefore imperative. In this study, simple chromatographic parameters, such as column chemistry (phenyl versus alkyl), mobile phase composition (methanol or acetonitrile), and column temperature, were investigated to aid in the separation of diCQA geometrical isomers. The high-performance liquid chromatography photodiode array (HPLC-PDA) chromatograms revealed four isomers post UV irradiation of diCQA authentic standards. The elution profile/order was seen to vary on different reverse-phase column chemistries (phenyl versus alkyl) using different mobile phase composition. Here, the elution profile/order on the phenyl-derived column matrices (with methanol as the mobile phase composition) was observed to be relatively reproducible as compared to the alkyl (C18) columns. Chromatographic resolution of diCQA geometrical isomers can be enhanced with an increase in column temperature. Lastly, the study highlights that chromatographic elution order/profile cannot be relied upon to fathom the complexity of isomeric plant metabolites.

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