Laixin Luo

China Agricultural University, College of Agriculture and Biotechnology, Faculty Member

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Address: Beijing, Beijing, China

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ABDALLA ELBASHIR

University of Khartoum

EDUARDO RAPHAEL MARTINEZ MOSCOSO

UNSA - Universidad Nacional de San Agustin de Arequipa

Xiwu Gao

晓芸梅

MDPI

Daniela Soares da Cruz

nura hidayah

Universitas setia budi surakarta

M. Ganjali

Roberto Ramírez Bravo

Wolfgang Gries

Miren de Alda

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Ion-pairing high-performance liquid chromatography determination of amitrole in apple after solid-phase extraction and precolumn derivatization

Analytical and Bioanalytical Chemistry, 2009

A novel method based on solid-phase extraction was studied for the extraction of amitrole (3-amin... more A novel method based on solid-phase extraction was studied for the extraction of amitrole (3-amino-1,2,4-triazole), and its residue determination in apples has been developed. The samples were derivatized with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF). The derivatization conditions and the influence of elution composition on the separation were investigated. In pH 9.5 H3BO3–Na2B4O7 media, the reaction of amitrole with CNBF was complete at 60°C after 30 min. The separation of derivatized amitrole was achieved at room temperature within 13 min by gradient elution mode with cetyltrimethylammonium bromide in mobile phase as ion-pair reagent. The method correlation coefficient was 0.9996, in concentrations ranging from 1.66 to 415 mg L−1. The calculated recoveries of the proposed method were from 94.17% to 105.67%, and relative standard deviations were 1.57% to 6.44% in the application to the quantitative determination of amitrole in apples. The detection limit of amitrole was 0.10 mg L−1 with a signal-to-noise ratio of 3. Figure Residue determination of amitrole in apple by ion-pairing high-performance liquid chromatography

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Determination of tobramycin in soil by HPLC with ultrasonic-assisted extraction and solid-phase extraction

Journal of Chromatography B-analytical Technologies in The Biomedical and Life Sciences, 2011

Pharmaceuticals residues in the environment have become a growing scientific interest worldwide. ... more Pharmaceuticals residues in the environment have become a growing scientific interest worldwide. In the light of the possible harmful effects of tobramycin, a rapid and sensitive analytical method for determination of tobramycin in soil was developed. The extraction and purification methods, derivatization conditions, and chromatographic conditions in the determination of tobramycin in soil have been fully investigated. Extraction was carried out by a combination of vortex mixer and ultrasonic oscillation using acetone/water as the extraction agent. The extract was concentrated to 1 mL and passed through the C 18 SPE cartridge rinsed with water (3 mL), methanol (3 mL). The derivatization procedure was followed by the reaction of tobramycin with 4-Chloro-3,5-dinitrobenzotrifluoride at 60 • C for 10 min in pH 9.0 H 3 BO 3 -Na 2 B 4 O 7 medium. The labeled tobramycin was determined by high performance liquid chromatography at 245 nm. Separation was accomplished within 15 min in gradient elution mode with trifluoroacetic acid in mobile phase as ion-pair reagent. The correlation coefficient for the method was 0.9999 in concentrations ranging from 0.10 to 100.0 g/g. The limit of detection was 0.02 g/g for tobramycin in soil at a signal-to-noise ratio of 3. The calculated recoveries of the proposed method were from 78.0 to 91.0% and RSDs were 3.38-9.79% in the application to the quantitative determination of tobramycin in all types of soil. The method will help to establish adequate monitoring of tobramycin residue in soil and make the contribution to environmental behavior evaluation.

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Development and validation of a HPLC method for determination of levonorgestrel and quinestrol in rat plasma

Biomedical Chromatography, 2009

Levonorgestrel and quinestrol, commonly known as EP-1, has long been used in the control of wild ... more Levonorgestrel and quinestrol, commonly known as EP-1, has long been used in the control of wild rodents. Up to the present time, however, no method for simultaneous quantification of levonorgestrel and quinestrol in rat plasma has been reported. In the present study, a sensitive reverse-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) method for quantification of levonorgestrel and quinestrol in rat plasma has been developed. It uses a Kromasil ODS C18 column and acetonitrile-0.1% formic acid (85 : 15, v/v) mobile phase at ambient temperature. The plasma sample was prepared by hexane–isoamyl alcohol extraction (90 : 10, v/v). The flow rate and detection wavelength were 1.0 mL/min and 230 nm. The correlation coefficients were greater than 0.9995 within 0.08–50 μg/mL for levonorgestrel and 0.12–50 μg/mL for quinestrol, and the limits of detection were 0.02 and 0.05 μg/mL for levonorgestrel and quinestrol, respectively. Average recovery ranged from 92.5 to 96.3% and inter-day RSDs were less than 7.56%. This method can be applied to the further pharmacokinetic study of levonorgestrel and quinestrol in rat plasma. Copyright © 2009 John Wiley & Sons, Ltd.

Ion-pairing high-performance liquid chromatography determination of amitrole in apple after solid-phase extraction and precolumn derivatization

Analytical and Bioanalytical Chemistry, 2009

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Determination of tobramycin in soil by HPLC with ultrasonic-assisted extraction and solid-phase extraction

Journal of Chromatography B-analytical Technologies in The Biomedical and Life Sciences, 2011

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Development and validation of a HPLC method for determination of levonorgestrel and quinestrol in rat plasma

Biomedical Chromatography, 2009

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