Comparison of different sorbents for on-line liquid-solid extraction followed by high-performance liquid chromatographic determination of nitrogen-containing pesticides.
LiChrolut EN [poly(styrene-divinylbenzene), PSDVB], Carbograph (graphitized carbon black, GCB), Isolute CN (cyanopropylsilica), Isolute C2 (ethylsilica), and LiChrospher RP18 (octadecylsilica) were studied for on-line solid-phase extraction of twelve nitrogen containing pesticides from water. Determination (UV 210 nm) was performed with a Spherisorb C8 analytical column and an acetonitrile-water gradient. The mean recoveries from 50 ml ranged from 83% for RP18 to 44% for GCB, and decreased in the following order: RP18, CN, LiChrolut EN, C2, and GCB. GCB showed poor recoveries due to incomplete desorption with the acetonitrile-water gradient used, and memory effects were detected. Backflush was needed to elute selected pesticides from GCB and from LiChrolut EN. Breakthrough volumes were 50-100 ml for most selected pesticides with silica-based phases, whereas LiChrolut EN allowed larger sample volumes without observable losses.
Soriano
J M
JM
Laboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Burjassot, Spain.
Jiménez
B
B
Redondo
M J
MJ
Moltó
J C
JC
D002244:Carbon; D002851:Chromatography, High Pressure Liquid; D007202:Indicators and Reagents; D009584:Nitrogen / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis* / Q000737:chemistry; D011137:Polystyrenes; D012822:Silicon Dioxide; D013056:Spectrophotometry, Ultraviolet; D014753:Vinyl Compounds
D007202:Indicators and Reagents; D010575:Pesticides; D011137:Polystyrenes; D014753:Vinyl Compounds; D002244:Carbon; D012822:Silicon Dioxide; C004985:divinyl benzene; D009584:Nitrogen