scholarly journals Determination of Pesticides in Water Samples from the Wieprz-Krzna Canal in the czysko-Wodawskie Lake District of Southeastern Poland by Thin-Layer Chromatography with Diode Array Scanning and High-Performance Column Liquid Chromatography with Diode Array Detection

2008 ◽  
Vol 91 (5) ◽  
pp. 1203-1209 ◽  
Author(s):  
Tomasz Tuzimski

Abstract High-performance thin-layer chromatography with diode array scanning (TLC-DAD) and high-performance column liquid chromatography with a diode array detector (HPLC-DAD) were used to screen water samples for pesticides. Atrazine, clofentezine, chlorfenvinphos, hexaflumuron, terbuthylazine, lenacyl, neburon, bitertanol, and metamitron were enriched from canal water samples by solid-phase extraction (SPE) on octadecyl silane (C18)/styrene-divinylbenzene-1, C18, C18 Polar Plus, and cyanopropyl (CN) cartridges. Recovery rates were high for all extraction materials except CN, for which values for all pesticides were lower. SPE was used for both preconcentration and fractionation of the analytes. Analytes were eluted by means of methanol and dichloromethane. Methanol eluates were analyzed by HPLC-DAD and dichloromethane eluates by TLC-DAD. The method was validated for precision, repeatability, and accuracy. Calibration graphs were linear between 0.1 and 50.0 g/mL for all pesticides, and correlation coefficient (r) values were between 0.9994 and 1.000 as determined by HPLC-DAD. Calibration graphs were linear between 0.1 and 1.5 g/spot for all pesticides, and r values were between 0.9899 and 0.9987 as determined by TLC-DAD. The limit of detection was between 0.04 and 0.23 g/spot for TLC-DAD and 0.02 and 0.45 g/mL for HPLC-DAD.

2019 ◽  
Vol 57 (7) ◽  
pp. 592-599
Author(s):  
Marwa A A Ragab ◽  
Mohamed H Abdel-Hay ◽  
Hytham M Ahmed ◽  
Sara M Mohyeldin

Abstract Two chromatographic methods (high performance thin layer chromatography (HPTLC) and high performance liquid chromatography–diode array detector (HPLC-DAD)), were addressed for the analysis of a mixture consisted of phenylephrine hydrochloride and ibuprofen in two forms bulk and their combined dosage form. This binary mixture is considered to be a challenging one as the two drugs differ greatly in their chemical and physical properties. Not only this affects their simultaneous analysis, but also hinders their simultaneous extraction from biological fluids as plasma. That is the reason the literature lacks any report for the simultaneous extraction and analysis of these drugs from biological fluids. The concentration ranges of both drugs were 0.1–2.5 μg/spot and 0.1–100 μg/mL by HPTLC and HPLC, respectively. Not only was the HPLC-DAD method applied to the investigated drugs determination in pharmaceutical preparations, but also in spiked human plasma. Extensive study was conducted to optimize their simultaneous extraction from plasma as it was a crucial step for the in vivo analysis. The results obtained by proposed methods and a reference one were statistically comparable by analysis of variance test. No significant difference was recorded between the mean percent levels determined by the proposed methods and the reference one.


2006 ◽  
Vol 89 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Andrés Navarrete ◽  
Bharathi Avula ◽  
Vaishali C Joshi ◽  
Xiuhong Ji ◽  
Paul Hersh ◽  
...  

Abstract Amphiptherygium adstringens (Anacardiaceae/Julianaceae), local name cuachalalate, is used in folk medicine for the treatment of cholelithiasis, fevers, fresh wounds, hypercholesterolemia, gastritis, gastric ulcers, and cancer of the gastrointestinal tract. The development of column high-performance liquid chromatographyphotodiode array detector (LC-PDA) and high-performance thin-layer chromatography (HPTLC)densitometry methods for the determination of masticadienonic acid and 3-hydroxymasticadienonic acid in cuachalalate preparations is described in this paper. Good separation of the compounds could be achieved by both methods. Either might be preparable depending on the requirements. The LC separation was performed on a Phenomenex Synergi MAX-RP 80A reversed-phase column operated at 40C with detection at 215 nm. The plant materials were extracted with methanol by sonication. The triterpenes present in the plant material and commercial extracts were separated with an acetonitrilewater reagent alcohol isocratic system. The limit of detection was 0.10.2 g/mL. The relative standard deviation values for the determination of triterpenes in plant extracts were less than 1.00%. This is the first report of an analytical method developed for the quantitative analysis of triterpenes from Amphiptherygium adstringens by LC-PDA and HPTLC. The stem bark showed higher amounts of triterpenes, and low amounts in root and stem root. The microscopic description of the crude drug of cuachalalate was also provided.


1981 ◽  
Vol 64 (6) ◽  
pp. 1356-1363 ◽  
Author(s):  
Mary V Howell ◽  
Philip W Taylor

Abstract A sensitive, reliable, and economical method for the determination of 6 mycotoxins in mixed feeds is described. The feed is extracted with chloroform-water and the extract is cleaned up by using a disposable Sep-Pak silica cartridge. The procedure requires less time (15 min from sample extraction to extract preparation) and less solvent (approximately one-tenth) compared with conventional methods and is suitable for a fast, economical screen. Additional cleanup procedures, involving dialysis or extraction into base, are described for samples containing high levels of interfering compounds. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with fluorescence detection are described for identification and estimation of mycotoxins. The method has been applied to a wide range of mixed feeds, including laboratory animal diets, and raw materials. The limit of detection is 1 μg/kg for all mycotoxins measured by HPLC.


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