Use of dodecyl sulfate as an esterase inhibitor before gas-chromatographic determination of labile beta-adrenoceptor blocking drugs.

Sodium dodecyl sulfate (SDS) was introduced as an esterase inhibitor in the determination of two extremely labile, ultrashort-acting beta-blockers-esmolol and flumolol--in whole blood. SDS was much more efficient than previously used agents in preventing hydrolysis. The assay comprises solvent extraction, perfluoroacylation, and capillary gas-chromatography with electron-capture detection. The limit of detection (the concentration at which the coefficient of variation is 10-15%) for the drugs is 5 nmol/L of whole blood.