scholarly journals Determination of Benzoylurea Insecticides in Apples and Pears by Solid-Phase Extraction Cleanup and Liquid Chromatography with UV Detection

1999 ◽  
Vol 82 (1) ◽  
pp. 213-216 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Pipina G Aplada-Sarlis ◽  
George E Miliadis
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Benzoylurea Insecticides ◽  
Preliminary Extraction ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed and statistically validated for simultaneous determination of 5 benzoylurea insecticides (di-flubenzuron, triflumuron, teflubenzuron, flufenoxuron, and lufenuron) in apples and pears. It involves preliminary extraction with ethyl acetate–sodium sulfate and cleanup on silica solid-phase extraction cartridges using dichloromethane–2-propanol (9 + 1) as eluant. The eluate is dried under nitrogen and redissolved in methanol. Benzoylurea insecticides are determined by reversed-phase LC with gradient elution at 42°C and UV diode array detection. Recoveries from samples fortified with the 5 insecticides at 0.02–0.5 mg/kg ranged from 83 to 102% for apples and from 75 to 99% for pears. Relative standard deviations were 0–12%. Limits of detection were 0.01 mg/kg for apples and 0.02 mg/kg for pears.

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

2005 ◽  
Vol 88 (3) ◽  
pp. 679-683 ◽  
Author(s):  
Matthew J Gramse ◽  
Paul E Jacobson
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Penicillin G ◽  
Phase Extraction ◽  
Solid Phase Extraction Cartridge ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for the determination of penicillin G in feeds. The method involves extraction of penicillin G with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex Strata-X solid-phase extraction cartridge. Analyte separation and quantification were achieved by gradient reversed-phase liquid chromatography and ultraviolet absorbance at 230 nm. Average spike recoveries for samples prepared at 3 spiking levels (25, 50, and 200 g/ton) were 96.3, 92.1, and 88.6%, respectively. The overall method precision at each of the 3 spiking levels was ≤5.39% relative standard deviation. The limits of detection and quantititation (g/ton formulation) were 3.89 and 13.0 g/ton, respectively.

scholarly journals Determination of Amoxicillin in Trout by Liquid Chromatography with UV Detection after Derivatization

1999 ◽  
Vol 82 (6) ◽  
pp. 1345-1352 ◽  
Author(s):  
Lambert K Sørensen ◽  
Heļga Hansen ◽  
Lena Snor
Keyword(s):  
Solid Phase Extraction ◽  
Muscle Tissue ◽  
Solid Phase ◽  
Reversed Phase ◽  
Uv Detection ◽  
Phase Extraction ◽  
Phase Gradient ◽  
Repeatability Standard Deviation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method based on solid-phase extraction was developed for determination of amoxicillin in muscle tissue of rainbow trout. The compound was extracted in an aqueous solution by precipitation of organic material with a mixture of sulfuric acid and sodium tungstate. The extract was processed by solid-phase extraction on an end-capped phenyl sorbent, and concentrated on a divinylbenzene-co-ΛN-vinylpyrrolidone polymeric sorbent. The extract was derivatized and analyzed by reversed-phase gradient LC on a C18 column with UV detection at 323 nm. The method detection limit was 2.9 μg/kg. Mean recovery in muscle was 80.5% (range 10-200 μg/kg). The method was applied to fillets from trout offered feed containing amoxicillin in an aquaculture pilot plant. Amoxicillin was detected in muscle tissue shortly after administration but not 3 weeks later. The relative repeatability standard deviation for incurred residues in muscle tissue was 6.4% (range 11-143 μg/kg).

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.

scholarly journals Solid phase extraction and a spectrophotometric method for the determination of trace amounts of gold with 4-rhodanineazo benzoic acid

2009 ◽  
Vol 74 (10) ◽  
pp. 1133-1142 ◽  
Author(s):  
Jie Huang ◽  
Guo Wang ◽  
Jun Zhang
Keyword(s):  
Benzoic Acid ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Molar Ratio ◽  
Fast Method ◽  
Phase Extraction ◽  
Colored Complex ◽  
Relative Standard

The synthesis and application of 4-rhodanineazo benzoic acid (4-BARA) as a new chromogenic reagent for the determination of gold is described. A highly sensitive, selective, and fast method for the determination of gold based on its rapid reaction with 4-rhodanineazo benzoic acid and the solid phase extraction of the colored complex on a reversed phase Clean-up? C5 cartridge was developed. In the presence of 0.02-0.2 mol/L phosphoric acid solution and a polyoxyethylene nonylphenol ether (emulsifier-OP) medium, 4-rhodanineazo benzoic acid reacted with gold to form a colored complex with a gold-to-4-BARA molar ratio of 1:2. The complex was enriched by solid phase extraction with a reversed phase Clean-up? C5 cartridge. The complex was eluted from the cartridge with ethanol and an enrichment factor of 50 was achieved. In ethanol medium, the molar absorptivity of the complex was 2.39?105 L mol-1 cm-1 at 505 nm. The Beer Law was obeyed in the concentration range 0.01-~1.2 ?g/mL. The relative standard deviation for eleven replicate samples at the 0.001 ?g/mL level was 2.3%. In the original sample, the detection limit was 8.0?10-5 ?g/mL. This method was applied to the determination of trace amounts of gold in ore samples with good result.

scholarly journals Mixed-Mode Solid-Phase Extraction and Cleanup Procedures for the Liquid Chromatographic Determination of Thiabendazole and Carbendazim in Fruit Juices

2001 ◽  
Vol 84 (2) ◽  
pp. 556-562 ◽  
Author(s):  
Michael S Young ◽  
Dorothy J Phillips ◽  
Pamela C Iraneta ◽  
Jim Krol
Keyword(s):  
Solid Phase Extraction ◽  
Cation Exchange ◽  
Mixed Mode ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Grape Juices ◽  
Liquid Chromatographic

Abstract Solid-phase extraction (SPE) procedures were developed for rapid cleanup and determination of thiabendazole and carbendazim in orange, apple, and grape juices. Samples were prepared by using an SPE cartridge containing a mixed-mode sorbent with both reversed-phase and strong cation-exchange chemistries. Analysis was by liquid chromatography with photodiode-array UV detection. Orange juice was analyzed by mixed-mode cation-exchange extraction with reversed-phase cleanup; the other juices were analyzed by reversed-phase extraction with cation-exchange cleanup. Recoveries >80% for carbendazim and >90% for thiabendazole. Quantitation limits were 20 μg/L for both analytes.

scholarly journals Solid phase extraction and spectrophotometric determination of palladium with 2-(2-quinolylazo)-5-diethylaminobenzoic acid

2006 ◽  
Vol 71 (7) ◽  
pp. 821-828 ◽  
Author(s):  
Weizu Yang ◽  
Qiufen Hu ◽  
Zhangjie Huang ◽  
Jiayuan Yin ◽  
Gang Xie ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Molar Absorptivity ◽  
Minimal Amount ◽  
Phase Extraction ◽  
Relative Standard ◽  
Alcohol Medium ◽  
Isopentyl Alcohol

A sensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II) with 2-(2-quinolylazo)-5-diethylaminobenzoic acid (QADEAB) and the solid phase extraction of the Pd(II) -QADEAB chelate with a reversed phase polymer-based C18 cartridge was developed. In the presence of 0.05 - 0.5 mol/L of hydrochloric acid solution and cetyl trimethylammonium bromide (CTAB) medium QADEAB reacts with palladium(II) to form a violet complex with a mole ratio 1:2 (palladium to QADEAB). The chelate was enriched by solid phase extraction with a reversed phase polymer-based C18 cartridge. An enrichment factor of 200 was obtained by elution of the chelate form the cartridge with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate in the isopentyl alcohol medium was 1.43?105 L mol-1 cm-1 at 628 nm. Beer?s law was obeyed in the range of 0.01-1.2 ?g/mL. The relative standard deviation for eleven replicate samples at the 0.2 ?g/L level was 2.18 %. The attained detection limit amounted to 0.02 ?g/L in the original samples. This method was applied to the determination of palladium in environmental samples with good results.

Determination of Ticarcillin and Clavulanic Acid in Serum by Liquid Chromatography

1992 ◽  
Vol 75 (1) ◽  
pp. 30-33 ◽  
Author(s):  
Jennifer C Wright ◽  
Carl N Durham ◽  
Jacob R Dunbar
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Clavulanic Acid ◽  
Solid Phase ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc ◽  
Ml Detection

Abstract A liquid chromatographic (LC) method using solidphase extraction for the determination of clavulanic acid and ticarcillin in human serum has been developed. Clavulanic acid and ticarcillin were extracted separately from 1 mL serum using C18 solid-phase extraction cartridges. Eluates were analyzed by the same reversed-phase LC system. The overall mean recovery of clavulanic acid from serum was 99.7 ±2.3%; the lowest level validated in serum was 0.5 μg/mL. The overall mean recovery of ticarcillin from serum was 101.5 ±3%; the lowest level validated in serum was 12.5 μg/mL. Detection limits for clavulanic acid and ticarcillin were 0.117 and 0.749 μg/mL, respectively.

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