scholarly journals Determination of the bifenazate insecticide in apples and cucumbers by high performance liquid chromatography

2019 ◽  
Vol 55 (4) ◽  
pp. 422-428
Author(s):  
M. F. Zayats ◽  
S. M. Leschev
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Diode Array ◽  
The European Union ◽  
Optimal Conditions ◽  
Plant Materials ◽  
Ultraviolet Detection ◽  
Maximum Residue Level ◽  
Distribution Constants

Based on the distribution constants of biphenazate, obtained experimentally and also calculated from literature data on the solubility of biphenazate in water and organic solvents, as well as experimental data on the extraction of biphenazate from plant matrices by various extractants, we selected the optimal conditions for extracting biphenazate from apples and cucumbers. The conditions for the purification of the extracts were also selected. Acetonitrile in the presence of ammonium sulfate and hexane was used for extraction of the pesticide. Purification of extracts of plant materials was carried out by partitioning between hexane and water-acetonitrile mixture. The samples obtained after this treatment were pure enough to determine the residual amounts of biphenazate in them at the maximum residue level determined in Belarus and the countries of the European Union, or lower using widespread liquid chromatography with diode-array (ultraviolet) detection.

scholarly journals The development of methods for the determination of residues of the insecticide pymetrozine in water, soil, cucumber and rape

2019 ◽  
pp. 79-87
Author(s):  
Mikhail F. Zayats ◽  
Sergey M. Leschev
Keyword(s):  
Experimental Data ◽  
Orthophosphoric Acid ◽  
Residue Level ◽  
Inorganic Salts ◽  
Diode Array ◽  
The European Union ◽  
Optimal Conditions ◽  
Ultraviolet Detection ◽  
Maximum Residue Level

Based on the literature data on the solubility of pymetrozine in water and organic solvents, as well as experimental data on the extraction of pymetrozine from water, soil and plant matrices, the optimal conditions for the extraction of pymetrozine from water; soil; cucumber; rape seeds, oil and green pods were selected. The conditions for cleaning extracts were selected as well. At the first stage, acetonitrile, a mixture of dichloromethane – isopropanol, or a mixture of dichloromethane – methanol in the presence or absence of inorganic salts were used for extraction of the pesticide. Pymetrozine was found to be a highly hydrophilic substance. For the purification of extracts of pymetrozine from plant matrices the extraction systems hexane – 0.02 mol/L aqueous solution of orthophosphoric acid, hexane or chloroform – aqueous solutions of ammonium sulfate were successfully used. The samples, obtained after this treatment, were pure enough to determine the residual amounts of pymetrozine in them at the maximum residue level (MRL), determined in Russia and the countries of the European Union, or lower using widespread liquid chromatography with diode-array (ultraviolet) detection.

Deproteinizing methods evaluated for determination of uric acid in serum by reversed-phase liquid chromatography with ultraviolet detection.

1987 ◽  
Vol 33 (8) ◽  
pp. 1427-1430 ◽  
Author(s):  
R Sakuma ◽  
T Nishina ◽  
M Kitamura
Keyword(s):  
Uric Acid ◽  
Liquid Chromatography ◽  
Perchloric Acid ◽  
High Performance ◽  
Reversed Phase ◽  
Precipitation Method ◽  
Zinc Hydroxide ◽  
Good Precision ◽  
Ultraviolet Detection

Abstract We evaluated six deproteinizing methods for determination of uric acid in serum by "high-performance" liquid chromatography with ultraviolet detection: those involving zinc hydroxide, sodium tungstate, trichloroacetic acid, perchloric acid, acetonitrile, and centrifugal ultrafiltration (with Amicon MPS-1 devices). We used a Toyosoda ODS-120A reversed-phase column. The mobile phase was sodium phosphate buffer (40 mmol/L, pH 2.2) containing 20 mL of methanol per liter. Absorbance of the eluate was monitored at 284 nm. The precipitation method with perchloric acid gave high recoveries of uric acid and good precision, and results agreed with those by the uricase-catalase method of Kageyama (Clin Chim Acta 1971;31:421-6).

Determination of fexofenadine in Hank's balanced salt solution by high-performance liquid chromatography with ultraviolet detection: application to Caco-2 cell permeability studies

2014 ◽  
Vol 29 (4) ◽  
pp. 537-544 ◽  
Author(s):  
Marco Antônio dos. Reis Júnior ◽  
Ana Cláudia Miranda de Faria ◽  
Eudes da. Silva Velozo ◽  
Teresa Dalla Costa ◽  
Frank Pereira de Andrade ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Salt Solution ◽  
High Performance ◽  
Cell Permeability ◽  
Ultraviolet Detection ◽  
Permeability Studies
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