Determination of rotenone residues in raw honey by solid-phase extraction and high-performance liquid chromatography

A method for determining residues of the insecticide rotenone in raw-honey by high-performance liquid chromatography (HPLC) is described. To extract t he residues, organic solvents such as ethyl acetate, n-hexane/dichlorometha ne and solid-phase extraction with octadecylsilane cartridges or Florisil p acked columns were tested. Determination was carried out by reversed-phase HPLC using acetonitrile-buffer phosphate (pH 7) (60:40, v/v) as mobile phas e and detection at 210 nm. Although the data showed that the two extraction methods were able to isolate the pesticide residues, the extraction on oct adecylsilane cartridges was preferred due to its simplicity and higher reco very. Recoveries depended strongly on the fortification level for the two e xtraction procedures. Practical determination limits of 0.015 mg/kg were ob tained. In the analysis of honeys, from beehives treated with rotenone at t herapeutical doses for 1 month, residual amounts below 0.2 mg/kg were found . (C) 2000 Elsevier Science B.V. All rights reserved.