Solid-phase extraction and residue determination of glyphosate in apple by ion-pairing reverse-phase liquid chromatography with pre-column derivatization

2009 ◽  
Vol 32 (14) ◽  
pp. 2394-2400 ◽  
Author(s):  
Kun Qian ◽  
Tao Tang ◽  
Tianyu Shi ◽  
Pingliang Li ◽  
Jianqiang Li ◽  
...  
2004 ◽  
Vol 87 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Matthew J Gramse ◽  
Paul E Jacobson ◽  
James C Selkirk

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.


1995 ◽  
Vol 78 (5) ◽  
pp. 1286-1293
Author(s):  
Gregory C Mattern ◽  
Gilbert D Parker ◽  
Debra L Green ◽  
Gregory L Yeutter

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.


2008 ◽  
Vol 1 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Y. Kawamoto ◽  
S. Bandoh ◽  
K. Higashihara ◽  
H. Miyagawa ◽  
T. Goto

Patulin contamination is known in various fruit products, including apple products. In this study, a solid phase extraction clean-up method was developed and validated for patulin in various fruit juices. Patulin was extracted from samples with ethyl acetate and then diluted with hexane. Patulin was isolated with a silica gel cartridge column, then analysed by reverse phase liquid chromatography with UV detection. The detection and quantitation limits were 0.06 and 0.15 ng, respectively. Recoveries within a day, and between days, were determined. Within day recoveries of patulin (n=6) at 5.0 and 50.0 µg/kg were 96-105% and 89-95%, respectively, with relative standard deviations (RSD) of 2.4-6.9 and 0.7-1.7%, respectively. Between day recoveries at 5.0 and 50.0 µg/kg were 96-108% and 92-94%, respectively, with RSDs of 7.1-12.1 and 2.3-4.1%, respectively. Average recoveries of patulin in the range from 2.0 to 80.0 µg/kg were 114 to 93%.


1993 ◽  
Vol 76 (5) ◽  
pp. 956-961 ◽  
Author(s):  
Robert E Sapp ◽  
Sandra Davidson

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.


1994 ◽  
Vol 77 (2) ◽  
pp. 331-333 ◽  
Author(s):  
Wayne Chan ◽  
Geoff C Gerhardt ◽  
Craig D C Salisbury

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.


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