Microtox testing of pentachlorophenol in soil extracts and quantification by capillary electrochromatography (CEC)--a rapid screening approach for contaminated land.

An approach to rapid soil testing which involved the use of simple solvent extraction methods was developed. The analytes of interest were priority pollutants of low water solubility which could not be readily removed from the soil using water. Direct toxicity testing of the soil samples by Microtox showed a high background toxicity which prevented realistic toxicity data from being obtained for the contaminants present. A range of different extraction solutions was used in an attempt to extract the contaminants while eliminating the matrix effects of the soil. It was necessary that the solvents selected for extraction of the soil samples were not of significant toxicity, as this could potentially mask the toxic effects of any compounds extracted from the soil. The extraction efficiencies of solvent systems were evaluated using pentachlorophenol (PCP) as a model compound of known toxicity in the Microtox assay. A rapid and cost-effective method was developed in order to determine the amount of PCP recovered from the soil by the extraction solvents employed. This method consisted of a solid phase extraction (SPE) step followed by quantification using capillary electrochromatography (CEC). Recoveries were greater when a higher proportion of organic solvent (methanol) was used in the extraction process, and lowest when water was used. An extraction based on water could provide information on the potential for leaching of contaminants from the soil into nearby water bodies in an environmental setting. An organic solvent extraction method could indicate how much toxicity soil-dependent organisms might be exposed to through ingestion. Extraction based on 50% (v/v) methanol in water was considered to be the most suitable overall extraction solution for soil screening, given that this permitted extraction of the water-insoluble compound PCP at a level which was clearly toxic in the Microtox assay while also retaining the capability to extract water-soluble contaminants.

The effects of commonly used adulterants on the detection of spiked LSD by an enzyme immunoassay.

The effects of 15 chemicals and household agents on an enzyme immunoassay (EIA) for LSD were investigated. The presence of many of these was detected by pH and specific gravity measurements and by sample inspection. A number of agents caused false positives in the assay at 10% adulteration, but only two produced false positive results at 1%. Adulterated samples spiked with LSD produced no false negatives, demonstrating that none of the adulterants tested were able to conceal the presence of LSD by interfering with the EIA. The assay is shown to be a robust method for the screening of urine for LSD when used in conjunction with sample inspection and a sound confirmatory method.

The analysis of lysergide (LSD): the development of novel enzyme immunoassay and immunoaffinity extraction procedures together with an HPLC-MS confirmation procedure.

A forensic procedure for the screening and confirmation of the presence of lysergide (lysergic acid diethylamide, LSD) in urine is described together with the evaluation of a novel enzyme immunoassay (EIA) and immunoaffinity extraction procedure. Following initial screening using either an established radioimmunoassay (RIA) or a novel EIA procedure, a quantitative estimate is established using a conventional high performance liquid chromatography-fluorescence (HPLC) technique following solid phase extraction. Final confirmation and quantitation, without derivatization, is established using HPLC in combination with electrospray ionization (ESI) mass spectrometry using methysergide as an internal standard. The detection limit of LSD in urine is 0.5 ng/mL. A blind trial confirmed the validity of the results. The choice of internal standard is discussed. Consideration is given to the photosensitivity of LSD solutions. A study of potential interferants in the HPLC-MS confirmation of LSD is presented and shows that for the wide range of compounds studied, there are none that would interfere with this confirmation technique. A comparison is shown between solid phase and immunoaffinity extraction/clean up procedures, and between RIA and EIA screening procedures.

Development and validation of a nonisotopic immunoassay for the detection of LSD in human urine.

A microplate enzyme immunoassay (EIA) for the detection of lysergic acid diethylamide (LSD) in human urine was developed. The assay kit is designed around an LSD derivative coated on the wall of microplate wells with preservatives and stabilizers. Sample and rabbit anti-LSD are added to the microplate well. The immobilized LSD and LSD present in specimens compete for the opportunity to bind to the anti-LSD antibodies. An anti-rabbit antibody labeled with horseradish peroxidase is used to provide the assay signal, which is inversely proportional to the concentration of LSD in the sample. The assay requires a 25-microL urine sample and three consecutive incubation periods of 60, 30, and 30 min at room temperature. The assay was tested with a variety of drugs, including ergot alkaloids spiked into drug-free urine at up to 100,000 ng/mL without cross-reaction. Nor-LSD was shown to cross-react between 16% and 28%, depending on its concentration. Of the other compounds tested, only ergonovine demonstrated slight cross-reactivity at approximately 0.0008%. The assay is designed to be used with a qualitative cutoff of 0.5 ng/mL. Precision testing at 0.5 ng/mL gave a coefficient of variation (CV) of 6% based on 20 replicates. The CV at 0.375 ng/mL (cutoff, -25%) was 5.2% and at 0.625 ng/mL was 6.6%. Precision at other concentrations within the range of the calibration curve gave similar results both intra- and interassay. Clinical performance of the assay was compared with that of a commercial radioimmunoassay (RIA). Comparable performance was observed with both methods, each screening a total of 458 samples as negative and 17 samples as positive relative to a 0.5 ng/mL cutoff. The EIA found an additional three positive samples that were negative by RIA. The EIA is suitable for the screening of urine samples for the presence of LSD. Preliminary indications are that the assay is also suitable for use with whole blood specimens. The assay can be performed manually or be fully automated and without the need for radioactivity; it can be used in any laboratory.