Skip to content

N. P. Cassells

Government of the United Kingdom

2 papers in the library · 57 citations · publishing 1996

Papers

The Analysis of Lysergide (LSD): The Development of Novel Enzyme Immunoassay and Immunoaffinity Extraction Procedures Together with an HPLC-MS Confirmation Procedure

Journal of Forensic Sciences November 1, 1996 Kenneth S. Webb, Pb Baker, N. P. Cassells et al. 42 citations

A forensic procedure for detecting lysergide (LSD) in urine uses a novel enzyme immunoassay (EIA) and immunoaffinity extraction alongside an established radioimmunoassay (RIA). Initial screening is followed by quantitative estimation via high-performance liquid chromatography with fluorescence detection after solid phase extraction. Final confirmation and quantitation, without derivatization, uses HPLC with electrospray ionization mass spectrometry and methysergide as an internal standard. The detection limit is 0.5 ng/mL. A blind trial confirmed the results. The study discusses internal standard choice, LSD's photo-sensitivity, and shows no interferants among a wide range of compounds tested. Comparisons are made between extraction and screening methods.

Development and Validation of a Nonisotopic Immunoassay for the Detection of LSD in Human Urine

Journal of Analytical Toxicology October 1, 1996 N. P. Cassells, Derek H. Craston, C. W. Hand et al. 15 citations

A new microplate enzyme immunoassay (EIA) detects lysergic acid diethylamide (LSD) in human urine by having LSD in the sample compete with immobilized LSD for binding to rabbit anti-LSD antibodies. The assay requires only 25 microliters of urine and three incubation periods at room temperature. It showed no cross-reaction with other drugs, including ergot alkaloids at up to 100,000 ng/mL, and only slight cross-reactivity with ergonovine (0.0008%). Nor-LSD cross-reacted between 16% and 28%. At a qualitative cutoff of 0.5 ng/mL, precision testing gave a coefficient of variation of 6%.