Anne D. Lucas

Determination of atrazine and simazine in water and soil using polyclonal and monoclonal antibodies in enzyme‐linked immunosorbent assays

An enzyme‐linked immunosorbent assay (ELISA) was developed as a rapid, reproducible and cost‐effective method for routine analysis of atrazine and simazine in environmental samples. Atrazine recoveries from C18 solid phase extractions (SPE) of water spiked from 0.1 ppb to 100 ppb showed good correlations with gas chromatography (GC), [14C] atrazine radioassay and ELISA methods. The C18 cartridges demonstrated very good recovery for extracting and concentrating the herbicide by all three analytical methods. Comparison between ELISA and GC for analysis of 75 well water samples showed no false negatives and a low (5%) occurrence of false positives. Soil extracts from a controlled simazine spill were also analyzed by GC and ELISA, with excellent correlation between the two methods. Characterization of the s‐triazine assay for tolerance to organic solvents and salts demonstrated the method to be resistant to such modifiers. Additionally, comparison of two monoclonal and two polyclonal antibodies raised against...

A multiresidue method by high performance liquid chromatography-based fractionation and gas chromatographic determination of trace levels of pesticides in air and water

A multiresidue analytical method is described for pesticides, transformation products, and related toxicants based upon high performance liquid Chromatographic (HPLC) fractionation of extracted residue on a Partisil® silica gel normal phase column followed by selective-detector gas chromatographic (GC) determination of components in each fraction. The HPLC mobile phase gradient (hexane to methylt-butyl ether) gave good Chromatographic efficiency, resolution, reproducibility and recovery for 61 test compounds, and allowed for collection in four fractions spanning polarities from low polarity organochlorine compounds (fraction 1) to polarN-methylcarbamates and organophosphorus oxons (fraction 4). The multiresidue method was developed for use with air samples collected on XAD-4® and related trapping agents, and water samples extracted with methylene chloride. Detection limits estimated from spiking experiments were generally 0.3–1 ng/m3 for high-volume air samples, and 0.01–0.1 μg/L for one-liter water samples. Applications were made to determination of pesticides in fogwater and air samples.

Development of an ELISA for the N‐dealkylated s‐triazines: Application to environmental and biological samples

A sensitive and rugged ELISA for the detection of the N‐dealkylated metabolites of atrazine and simazine was developed and applied to environmental and biological samples. The limits of detection were approximately 10 ng ml‐1 for water samples, 40 ng ml‐1 for human urine when analyzed without any sample preparation and approximately 45 ng g‐1for solvent‐extracted soil. This assay was tolerant to changes in pH, salt and solvent effects. Comparison of the results from this ELISA with nominal values for a series of tap water samples spiked in a blind fashion resulted in a good correlation coefficient between the values found and those spiked. However, the ELISA systematically underestimated concentrations. Examination of the source of this error revealed that the dealkylated triazine concentrations of the samples declined with time. The assay was used to monitor the presence and loss of dealkylated triazines in a variety of samples. These data indicated that caution must be used in the analysis and interpret...