| The important factor influencing the determination of antibiotics issample matrix.Recently, screening of antibiotics by direct injection analysis in samples with complicated matrixhas attracted much attention.In this study, we chose honey for the model sample that are rich in sugar and fatty acid. And a rapid screening method of the simultaneous analysis at trace level ofchloramphenicol(CAP), sulfadiazine(SD), sulfapyridine(SPD), Sulfathiazole(ST), Sulfamerazine(SMI), Sulfadimidine(SM2), Sulfadimethoxine(SDM) wasdeveloped by Directly Analysis Real Timetandem mass spectrometry(DART-MS/MS), although a method of liquid chromatogram tandem mass spectrometry(LC-MS/MS) was developed for confirmation.The differences of two kinds of analysis techniques in instrument method, sample pretreatment, matrix effect and quantification were studied. The main results are as follows:1. In the multi-reaction monitoring(MRM) mode, weoptimizedthe temperature of carrier gas, sample solvent, declustering potential, injection mode and sample transmission speed. The methodof 5 μL of sample solvent on DIP-it tube quantitatively droppingby pipettewill meet the demandsona rapid screening of antibiotics.2. Takingdeionized water as the extractant for desugarization inpretreatmentcould reduce the matrix effect of DART-MS/MS. The detection limits of CAP is 0.2 μg/kg. The experimental samples were obtained by spiking sulfonadimes in blank honey.The effects of the pretreatment conditions such as acid hydrolysis solution, acid hydrolysis time, acid hydrolysis temperature and extraction method on the recovery of the sulfonadimes were studied.The detection limits of 6 kinds of sulfonamides were 0.1 ~ 0.5 μg/kg.3. 52 kinds of honey which was obtained in the markets were screenedto confirm the DART-MS/MS method in our study. The accuracy rate of the positive honey sample was 100 %, and only one sample was not detectedbecause the concentration lower than detection limit. |
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