Hyoscyamine and Scopolamine in Honey by HILIC–ESI-MS/MS

Abstract

A simple but effective method was developed for the ultra-trace determination of two tropane alkaloid residues, hyoscyamine and scopolamine, in honey. Honey samples were dissolved in a concentrated aqueous solution of sodium acetate from which the alkaloids were subsequently extracted using acetonitrile. The resulting extract was analyzed using HILIC–ESI-MS/MS without any additional extract cleanup or enrichment steps. Enhanced sensitivity associated with the combination of HILIC and ESI-MS/MS techniques permitted the quantitation of the two tropane alkaloids at concentrations as low as 0.01 µg kg⁻¹. The use of isotopically labelled analogs permitted accuracies ranging from 86.9 to 106.1% for honey samples fortified at 0.02, 0.2 and 2 µg kg⁻¹ with precisions ranging from 0.8 to 6.2%. The estimated method detection limits for hyoscyamine and scopolamine were 0.002 and 0.003 µg kg⁻¹, respectively. Twenty-three samples of honey were analyzed and only two samples were found to contain residues of the tropane alkaloids at concentrations above the limit of quantitation of 0.01 µg kg⁻¹. Hyoscyamine was detected at 0.012 µg kg⁻¹ in two honey samples, one of which also contained 0.012 µg kg⁻¹ of scopolamine.