New approach to large-volume injection in reversed-phase high performance liquid chromatography: determination of atrazine and hydroxyatrazine in soil samples.
A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow-rate setting accuracy of +/- 1-2% over a flow-rate range from 0.1 mL/min to 10 mL/min and the flow stability is 0.2% or less. Quarternary low pressure gradient pumps are widely available and used, but all their hydraulic lines are seldom utilised. The idea of using one line of a common commercial HPLC quaternary low-pressure pump for direct on-column injection (pumping) of large sample volumes ranging from 1 mL to 100 mL was tested. This approach was evaluated during practical work on the development of an RP-HPLC method of determination of residual atrazine and hydroxyatrazine. In lysimetric environmental experiments hydroxyatrazine was formed in situ in a soil column by hydrolysis of atrazine. The results proved the applicability of this approach not only in experiments with model mixtures of analytes at microg/L levels in solutions. Analysis of 20 mL of soil leachates and extracts of soil samples containing atrazine and hydroxyatrazine at the 10 microg/kg level (in dry soil) revealed that good figures-of-merit were preserved, even in the presence of a large excess of humic substances.
Hutta
Milan
M
Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia. hutta@fns.uniba.sk
Chalányová
Mária
M
Halko
Radoslav
R
Góra
Róbert
R
Rybár
Ivan
I
Pajchl
Marek
M
Dokupilová
Svetlana
S
D001280:Atrazine / Q000031:analogs & derivatives / Q000032:analysis* / Q000592:standards; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D006540:Herbicides / Q000032:analysis / Q000592:standards; D006863:Hydrogen-Ion Concentration; D012015:Reference Standards; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis; D012997:Solvents
D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants; D012997:Solvents; C027881:2-hydroxyatrazine; D001280:Atrazine