Determination of Caffeine in Human Urine Samples Free of the Interference of its Metabolites by Reversed-Phase Liquid Chromatography Using Solid-Phase Extraction from Sample Clean-Up

1993 ◽  
Vol 16 (6) ◽  
pp. 1297-1314 ◽  
Author(s):  
Pilar Campíns-Falcó ◽  
Rosa Herráz-Hernández ◽  
Adela Sevillano-Cabeza
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Human Urine ◽  
Solid Phase ◽  
Reversed Phase ◽  
Urine Samples ◽  
Phase Extraction ◽  
Reversed Phase Liquid Chromatography ◽  
Phase Liquid

Determination of Roxarsone in Feeds Using Solid Phase Extraction and Liquid Chromatography With Ultraviolet Detection

1993 ◽  
Vol 76 (5) ◽  
pp. 956-961 ◽  
Author(s):  
Robert E Sapp ◽  
Sandra Davidson
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Poultry Feed ◽  
Phase Extraction ◽  
Reversed Phase Liquid Chromatography ◽  
Field Samples ◽  
Phase Liquid

Abstract A method is presented for detection and quantitation of Roxarsone in poultry feed by liquid chromatography. The drug is extracted by phosphate buffer and determined by solid phase extraction and reversed-phase liquid chromatography. Recoveries of the sample spikes and fortified field samples agree closely with those obtained by the standard spectrophotometric method.

Determination of Tylosin and Tilmicosin Residues in Animal Tissues by Reversed-Phase Liquid Chromatography

1994 ◽  
Vol 77 (2) ◽  
pp. 331-333 ◽  
Author(s):  
Wayne Chan ◽  
Geoff C Gerhardt ◽  
Craig D C Salisbury
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Animal Tissues ◽  
Reversed Phase Liquid Chromatography ◽  
Tissue Extracts ◽  
Phase Liquid

Abstract A method for the simultaneous determination of ty-losin and tilmicosin residues in animal tissues is reported. Solid-phase extraction columns are used to isolate the drugs from tissue extracts. Determination is accomplished by reversed-phase liquid chromatography with UV detection at 287 nm. Mean recoveries from spiked tissues were 79.9% (coefficient of variation [CV], 8.1%) for tylosin and 92.6% (CV, 8.7%) for tilmicosin. Detection limits for tylosin and tilmicosin were 0.020 and 0.010 ppm, respectively.

Spherical Clay Conglomerates:  A Novel Stationary Phase for Solid-Phase Extraction and “Reversed-Phase” Liquid Chromatography

1999 ◽  
Vol 71 (11) ◽  
pp. 2171-2178 ◽  
Author(s):  
Thomas D. Bucheli ◽  
Stephan R. Müller ◽  
Patrick Reichmuth ◽  
Stefan B. Haderlein ◽  
René P. Schwarzenbach
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Stationary Phase ◽  
Solid Phase ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Reversed Phase Liquid Chromatography ◽  
Phase Liquid

scholarly journals Determination of Tylosin in Feeds by Liquid Chromatography with Solid-Phase Extraction

2004 ◽  
Vol 87 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Matthew J Gramse ◽  
Paul E Jacobson ◽  
James C Selkirk
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Column Temperature ◽  
Solid Phase Extraction Cartridge ◽  
Relative Standard ◽  
Phase Liquid

Abstract A method was developed for the determination of tylosin in feeds. The method involves extraction of tylosin with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex C18 solid-phase extraction cartridge. Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography and UV absorbance at 285 nm with a reference wavelength of 320 nm with column temperature of 45°C. Average spike recoveries for samples prepared at 4 spiking levels (22.7, 181, 907, and 1000 g/ton) were 111.0, 94.9, 96.2, and 98.6%, respectively. The overall method precision at each of the 4 spiking levels was ≤ 7.85% relative standard deviation. The limits of detection and quantitation (g/ton) were 2.16 and 7.20 g/ton, respectively.

Determination of Phenol Sulfone, Phenol Sulfoxide, and Phenol Sulfonic Acid Metabolites of Fenamiphos in Soil by Liquid Chromatography

1995 ◽  
Vol 78 (5) ◽  
pp. 1286-1293
Author(s):  
Gregory C Mattern ◽  
Gilbert D Parker ◽  
Debra L Green ◽  
Gregory L Yeutter
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Sulfonic Acid ◽  
Solid Phase ◽  
Reversed Phase ◽  
Uv Detection ◽  
Phase Extraction ◽  
Soil Matrix ◽  
Phase Liquid

Abstract An analytical method has been developed to quantitate fenamiphos phenol sulfone, phenol sulfoxide, and phenol sulfonic acid in soil. Both control and analyte-fortified soil samples from Fresno, CA, were extracted with methanol–water (2 + 1) and partitioned with ethyl acetate. Fenamiphos phenol sulfone and phenol sulfoxide were determined by re-versed-phase liquid chromatography (LC) with UV detection at 240 nm after cleanup by silica solid-phase extraction. Fenamiphos phenol sulfonic acid was determined by reversed-phase ion-pairing LC with UV detection at 240 nm after cleanup by amino solid-phase extraction. Recoveries of fenamiphos phenol sulfoxide ranged from 88.2 to 111.0%, with an average of 97.4%. Recoveries of fenamiphos phenol sulfone ranged from 101.6 to 107.0%, with an average of 104.6%. Recoveries of fenamiphos phenol sulfonic acid ranged from 76.0 to 99.9%, with an average of 86.0%. Responses for analysis of analytes in both solvent and soil matrix were linear over the tested range of 10 to 500 ppb. Limits of determination of each analyte in soil were less than 10 ppb.

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