Related Experiment Videos
Multiresidue HPLC methods for phenyl urea herbicides in water
S R Ruberu1, W M Draper, S K Perera
1Sanitation and Radiation Laboratory, California Department of Health Services, 2151 Berkeley Way, Berkeley, California 94704, USA.
Journal of Agricultural and Food Chemistry
|September 20, 2000
Summary
This study details high-performance liquid chromatography (HPLC) methods for detecting phenyl urea herbicides in water. Solid phase extraction (SPE) and diode array detection (DAD) offer practical utility for trace analysis in various water types.
Area of Science:
- Environmental Chemistry
- Analytical Chemistry
Background:
- Phenyl urea herbicides are widely used, necessitating reliable methods for their detection in water bodies.
- Contamination of water sources by these herbicides poses environmental and health risks.
Purpose of the Study:
- To develop and validate high-performance liquid chromatography (HPLC) methods for the quantitative determination of ten phenyl urea herbicides in water.
- To evaluate the efficacy of solid-phase extraction (SPE) and different detection systems (diode array detector - DAD, postcolumn photolysis and derivatization - PPD) for trace analysis.
Main Methods:
- Water samples were pre-concentrated using automated solid-phase extraction (SPE) with C18 Empore disks or on-line precolumn concentration.
- Herbicides were separated using a C18 reversed-phase column with an acetonitrile-water gradient.
- Detection was performed using either a diode array detector (DAD) at 245 nm or a postcolumn photolysis and derivatization (PPD) system.
Main Results:
- Diode array detection (DAD) showed linearity over three orders of magnitude with instrument detection limits around 0.01 mg/L.
- Solid phase extraction (SPE) efficiencies ranged from 48-70% in laboratory reagent water; accuracy improved with internal standard quantitation.
- Recoveries in Colorado River water spiked at 1 or 50 µg/L ranged from 74-104%, with method detection limits (MDLs) of 4-40 ng/L using DAD.
- Postcolumn photolysis and derivatization (PPD) offered high specificity but resulted in higher MDLs (approximately 5x) compared to DAD.
Conclusions:
- The developed SPE-HPLC methods, particularly with DAD detection, are practical for the trace analysis of phenyl urea herbicides in drinking and surface waters.
- The presence of high total dissolved solids and total organic carbon in surface waters can enhance herbicide recoveries.
- While PPD provides specificity, DAD offers a more sensitive detection method for routine analysis of these contaminants.