Determination of Streptomycin and Dihydrostreptomycin in Honey by Liquid Chromatography–Electrospray Mass Spectrometry

A simple and reliable method using liquid chromatography–electrospray ionization‐mass spectrometry (LC/ESI‐MS) has been developed for the determination of aminoglycoside antibiotics, streptomycin (SM), and dihydrostreptomycin (DSM) in honey. The LC separation was performed on a TSK‐gel Super ODS column (100 × 2 mm i.d.) using 5 mM heptafluoro‐n‐butyric acid (HFBA)–acetonitrile (88:12) as the mobile phase at a flow rate of 0.18 mL/min. The positive ionization produced the typical (M + H)+ molecular ions of both drugs (SM m/z 582.3; DSM m/z 584.3). The calibration graphs for SM and DSM were rectilinear from 0.05 to 10 ng with selected ion monitoring (SIM). The drugs were extracted with water, and the extracts were cleaned up on an Oasis HLB cartridge (60 mg). The recoveries of both drugs from honey fortified at a level of 0.1 µg/g was 85.8–89.1%, with high precision. The limits of quantification of the drugs in honey were 0.01 µg/g (signal‐to‐noise ratio >10).