All US EPA methods for volatile organic compounds (VOCs) require that specific GCMS tuning criteria be met before running a calibration curve or analyzing actual samples. The GCMS is tuned using the traditional tuning compound, PFTBA (perfluorotributylamine), and the tune is evaluated every 12 hours by injecting BFB (4-bromofluorobenzene) and measuring the relative intensity of key mass fragments. The MS tuning procedures adjust PFTBA ion responses to achieve the desired BFB response ratios. The relative ion abundance of the BFB mass fragments must meet specific criteria established in the methods to ensure that the GCMS instrument operating conditions are adjusted and optimized for analysis of VOCs, and the criteria must be met every 12 hours to guarantee that the instrument performance remains stable enough for continued analysis.
This poster describes tuning conditions for the Shimadzu GCMS-QP2010 SE (Figure 1) developed to meet the BFB relative abundance criteria described in US EPA methods for analysis of VOCs.