Liquid chromatography with pre-column dansyl derivatisation and fluorimetric detection applied to the assay of...

A simple method employing pre-column dansylation and liquid chromatography is proposed for a very sensitive and specific assay of morphine in biological samples. Nalorphine is used as an internal standard. The detection limit is 0.2 picomol of injected morphine. In the assay of human sera spiked with 150 nmol/l, the intra- and inter-assay coefficients of variation were 3.7% (n = 10) and 4.5% (n = 10), respectively. No interferences were observed from more than 70 opiate and non-opiate drugs. Urine, plasma and total blood were assayed, using different extraction methods, with negligible interference from coextractives.