title: Measurement of ethyl methanesulfonate in human plasma and breast milk samples using high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.
abstract: Ethyl methanesulfonate (EMS) is a mesylate ester, which is known to be a potent mutagen, teratogen, and possibly carcinogen. Mesylate esters have been found in pharmaceuticals as contaminants formed during the manufacturing process and may potentially pose an exposure hazard to humans. We have developed and validated a method for detection of trace amounts (ng/ml levels) of EMS in human plasma and breast milk. The samples were extracted by matrix solid-phase dispersion with ethyl acetate using Hydromatrix and the ASE 200 Accelerated Solvent Extractor. The extracts were separated by high-performance liquid chromatography (HPLC) using a HILIC column. The detection was performed with a triple quadrupole mass spectrometer (TSQ Quantum Ultra, Thermo Electron Corporation) using atmospheric pressure chemical ionization in negative-ion mode and multiple reaction monitoring. The use of a surrogate internal standard in combination with HPLC-MS/MS provided a high degree of accuracy and precision. The extraction efficiency was greater than 70%. Repeated analyses of plasma and breast milk samples spiked with high (100 ng/ml), medium (50 ng/ml) and low (5 ng/ml) concentrations of the analytes gave relative standard deviations of less than 12%. The limits of detection were in the range of 0.5-0.9 ng/ml for both matrices.
authors.affiliation: Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, Atlanta, GA 30341, USA.
authors.forename: M Angela
authors.initials: MA
authors.lastname: Montesano
authors.forename: Ralph D
authors.initials: RD
authors.lastname: Whitehead
authors.forename: Nayana K
authors.initials: NK
authors.lastname: Jayatilaka
authors.forename: Peter
authors.initials: P
authors.lastname: Kuklenyik
authors.forename: Mark D
authors.initials: MD
authors.lastname: Davis
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Dana Boyd
authors.initials: DB
authors.lastname: Barr
mesh_terms: D001274:Atmospheric Pressure; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005020:Ethyl Methanesulfonate / Q000097:blood* / Q000737:chemistry; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008895:Milk, Human / Q000737:chemistry*; D015394:Molecular Structure; D008970:Molecular Weight; D009153:Mutagens / Q000032:analysis*; D011247:Pregnancy; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D009153:Mutagens; D005020:Ethyl Methanesulfonate