scholarly journals Liquid Chromatographic Determination of Fosthiazate Residues in Environmental Samples and Application of the Method to a Fosthiazate Field Dissipation Study

2005 ◽  
Vol 88 (6) ◽  
pp. 1827-1833 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Dimitrios T Likas ◽  
Dimitrios G Karpouzas
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Physicochemical Characteristics ◽  
Reversed Phase ◽  
Subsequent Elution ◽  
Water And Soil Samples ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method was developed and validated for the determination of residues of the organophosphorus nematicide fosthiazate in soil and water by using reversed-phase liquid chromatography with UV detection. Good recoveries (>85%) of fosthiazate residues were obtained from water samples (drinking water, groundwater, and liquid chromatography water) after passage of 0.5–2 L water through solid-phase extraction (SPE) C-18 cartridges and subsequent elution with ethyl acetate. Residues in soil were extracted with methanol–water (75 + 25, v/v) on a wrist-action shaker, and the extract was cleaned up on C-18 SPE cartridges before analysis. The method was validated by analysis of a range of soils with different physicochemical characteristics; recoveries exceeded 87% at fortification levels ranging from 0.02 to 5.0 mg/kg. The precision values obtained for the method, expressed as repeatability and reproducibility, were satisfactory (<11%). Fosthiazate detection limits were 0.025 μg/L and 0.005 mg/kg for water and soil samples, respectively. The decline in the levels of fosthiazate residues in soil was measured after application of fosthiazate to protected tomato cultivation. The dissipation of fosthiazate residues followed first-order kinetics with a calculated half-life of 21 days.

Liquid-chromatographic determination of 4-hydroxyproline in urine.

1986 ◽  
Vol 32 (6) ◽  
pp. 1002-1004 ◽  
Author(s):  
H Hughes ◽  
L Hagen ◽  
R A Sutton
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Present Method ◽  
High Performance ◽  
Protein Hydrolysate ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract In this method for 4-hydroxyproline in urine, hydroxyproline is derivatized with 4-chloro-7-nitrobenzofurazan, with subsequent estimation by reversed-phase "high-performance" liquid chromatography. The ranges for excretion of free and total hydroxyproline while the subjects were ingesting unrestricted diets were 2-29 and 122-374 mumol/24 h (n = 21), respectively, with no significant sex-related difference. A comparison with results by colorimetry indicated no significant differences: mean (n = 18) concentrations (mumol/L) of hydroxyproline in urine were 180 (SD 149) by the present method, 163 (SD 166) by colorimetry. For protein hydrolysate the respective values were 5.9 (SD 2.7) and 6.7 (SD 2.9).

scholarly journals Liquid Chromatographic Determination of Triasulfuron in Soil

2000 ◽  
Vol 83 (5) ◽  
pp. 1076-1081 ◽  
Author(s):  
Mara Gennari ◽  
Lucia Ferraris ◽  
Michèle Nègre ◽  
Alessandro Cignetti
Keyword(s):  
Solid Phase ◽  
Chromatographic Determination ◽  
Physicochemical Characteristics ◽  
Extraction Methods ◽  
Determination Limit ◽  
Average Recovery ◽  
Field Samples ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Two extraction methods were developed for the determination of triasulfuron in soil. Method I included extraction with methanol–phosphate buffer at pH 7 (2 + 1, v/v), liquid–liquid partition with dichloromethane, and cleanup on a liquid chromatographic Si adsorption solid-phase extraction tube. In Method II, Extrelut was added and the sample was then extracted with acetonitrile. In both cases, the extracts were analyzed by liquid chromatography (LC) with UV detection and the LC peak was confirmed by LC/mass spectrometry (MS). The 2 methods were tested on 3 soils having different physicochemical characteristics. Method I gave 83% average recovery and a determination limit of 0.4 μg/kg soil. Method II gave 67% average recovery and a determination limit of 2 μg/kg soil. Examples of application of Method I to field samples are reported.

Liquid-chromatographic determination of ethylene glycol in plasma.

1982 ◽  
Vol 28 (1) ◽  
pp. 32-33 ◽  
Author(s):  
R N Gupta ◽  
F Eng ◽  
M L Gupta
Keyword(s):  
Liquid Chromatography ◽  
Ethylene Glycol ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Standard Curve ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract In this novel procedure for determining ethylene glycol in plasma by liquid chromatography, benzoyl esters of ethylene glycol and of benzyl alcohol (used as the internal standard) are prepared directly in plasma. The benzoyl esters, highly ultraviolet-absorbing chromogens, are ideal compounds for analysis by reversed-phase liquid chromatography with methanol/water as the mobile phase. The benzoyl derivative of ethylene glycol is well separated from the derivative of the internal standard and from plasma constituents. The standard curve is linear to 400 mg of ethylene glycol per liter. As little as 10 mg of ethylene glycol per liter of plasma can be measured. Other commonly ingested alcohols do not interfere.

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