title: Evaluation of the impact of matrix effect on quantification of pesticides in foods by gas chromatography-mass spectrometry using isotope-labeled internal standards.
abstract: The impact of the matrix effect in GC-MS quantification of pesticides in food using the corresponding isotope-labeled internal standards was evaluated. A spike-and-recovery study of nine target pesticides was first conducted using paste samples of corn, green soybean, carrot, and pumpkin. The observed analytical values using isotope-labeled internal standards were more accurate for most target pesticides than that obtained using the external calibration method, but were still biased from the spiked concentrations when a matrix-free calibration solution was used for calibration. The respective calibration curves for each target pesticide were also prepared using matrix-free calibration solutions and matrix-matched calibration solutions with blank soybean extract. The intensity ratio of the peaks of most target pesticides to that of the corresponding isotope-labeled internal standards was influenced by the presence of the matrix in the calibration solution; therefore, the observed slope varied. The ratio was also influenced by the type of injection method (splitless or on-column). These results indicated that matrix-matching of the calibration solution is required for very accurate quantification, even if isotope-labeled internal standards were used for calibration.
authors.affiliation: National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 3, Umezono, Tsukuba, Ibaraki 305-8563, Japan. Electronic address: t-yarita@aist.go.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yarita
authors.affiliation: National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 3, Umezono, Tsukuba, Ibaraki 305-8563, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Aoyagi
authors.affiliation: National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 3, Umezono, Tsukuba, Ibaraki 305-8563, Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Otake
mesh_terms: D002138:Calibration; D005504:Food Analysis / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods / Q000592:standards; D007553:Isotope Labeling; D010573:Pesticide Residues / Q000032:analysis*; D014675:Vegetables / Q000737:chemistry
chemical_list: D010573:Pesticide Residues
keywords: Calibration curve; Deuterium-labeled internal standard; Isotope-dilution mass spectrometry; Matrix effect; Matrix matching; Pesticide