[Determination of streptomycin and dihydrostreptomycin in pollens by high performance liquid chromatography-tandem mass spectrometry].

A method was established for the determination of streptomycin (STR) and dihydrostreptomycin (DHS) in pollens based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted and cleaned-up by a C18 solid phase extraction cartridge. The separation was carried out on a Protemix WCX-NP5 column (100 mm x 2.1 mm, 5 microm) with a gradient elution using 5% (v/v) formic acid, 20 mmol/L ammonium acetate and methanol as mobile phases. The analysis of streptomycin and dihydrostreptomycin was performed under electrospray positive ionization mode. The limits of detection (LOD, S/N = 3) and limits of quantification (LOQ, S/N = 10) for the both were 5 microg/kg and 10 microg/kg, respectively. Good linearities (r > 0.99) were achieved for the target compounds over the range of 10-200 microg/L. The recoveries at three spiked levels (10, 20, 50 microg/kg) in the blank matrices, such as pollen pini, corn pollen, camellia pollen, sunflower pollen, rape pollen and bee pollen, were from 76.8% to 100.3% with the relative standard deviations varied from 3.70% to 12.6%. The method is accurate, practical, and can be applied to most of the contaminated matrices. With this method, heptafluorobutyric acid is not required as mobile phase which is harmful to MS spectrometer.