title: [Determination of streptomycin and dihydrostreptomycin residues in tomato ketchup by UPLC-MS/MS].
abstract: OBJECTIVE
  To develop a method for simultaneous determination of streptomycin and dihydrostreptomycin residues in tomato ketchup by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).
  
  
  METHODS
  The sample was dissolved with phosphorus solution (pH 2) and extracted by ultrasonic. The pigment was removed with n-hexane. Then, the sample was cleaned up by HLB SPE. The HILIC chromatographic column (100 mm x 2.1 mm, 1.7 μm) was used to complete the separation under gradient elution. The mixed solution of 0.1% formic acid solution and acetonitrile was used as mobile phase. The detection of streptomycin and dihydrostreptomycin were carried out by MS/MS under multiple reaction monitoring (MRM) mode. The external standard method was used for quantitative analysis.
  
  
  RESULTS
  The calibration curves for streptomycin and dihydrostreptomycin were indicated in the range of 0.005 - 0.100 mg/kg, and the detection limits were both 0.005 mg/kg. The recoveries of streptomycin and dihydrostreptomycin were ranged from 79.5% to 93.9% with relative standard deviations no more than 10%.
  
  
  CONCLUSIONS
  The method is simple and accurate to meet the requirements for determination of streptomycin and dihydrostreptomycin residues in tomato ketchup.
authors.forename: Tingting
authors.initials: T
authors.lastname: Liu
authors.forename: Shanliang
authors.initials: S
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Jiali
authors.initials: J
authors.lastname: Cheng
authors.forename: Shi
authors.initials: S
authors.lastname: Shen
authors.forename: Zhu
authors.initials: Z
authors.lastname: Wang
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004096:Dihydrostreptomycin Sulfate / Q000032:analysis*; D004350:Drug Residues / Q000032:analysis; D005502:Food; D005506:Food Contamination / Q000032:analysis*; D006586:Hexanes; D018551:Solanum lycopersicum / Q000737:chemistry*; D052616:Solid Phase Extraction; D013307:Streptomycin / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D006586:Hexanes; C026385:n-hexane; D004096:Dihydrostreptomycin Sulfate; D013307:Streptomycin