Optimized EPA 8270D Calibration on State-of-the-Art Instrumentation Reduces Operating Costs

Overcoming Legacy Obstacles with Innovative Approaches
Oral Presentation

Presented by D. Walker
Prepared by M. Churley
Agilent Technologies, Inc., 5301 Stevens Creek Blvd, Building 3U, Pillar B6, CA, Santa Clara, United States


Contact Information: [email protected]; 408-553-7827


ABSTRACT

Calibration criteria for 8270D are rigorous in terms of the diverse mix of target compound classes and the wide desired calibration range. Initial calibration results are indicative of how long the continuing calibration will last and, thus, the length of time that samples may be analyzed without intervention by the operator, which lowers the cost of operation.

In order to evaluate the legacy method on modern instrumentation, a study was undertaken in which several Agilent GCMS systems were calibrated according to 8270D but under various sets of conditions. Each 7890B or Intuvo GC was equipped with a SSL inlet and 30m x 250Ám x 0.25Ám DB-UI 8270D column. The 5977B MSD with Inert Plus source and 7010 Triple Quadrupole GC/MS/MS systems were evaluated. The following variables were tested: 1) Injection: Pulsed splitless, pulsed split, ramped flow (splitless); 2) Liners: Dual taper; low pressure drop split liner with wool; and single taper, glass wool, Ultra Inert; 3) DFTPP vs. Autotune and Etune (extractor tune); and 4) Ion source draw out lens diameter: 3 mm (standard), 6 mm, and 9 mm. Ten calibration levels were prepared from 0.05 to 160 ppm using a 77-compound mix and six ISTDs. The split ratio was adjusted to meet isomer resolution requirements and the detector gain was adjusted to maximize linearity, which is critical to the analysis.

The study showed that the variables that produced the maximum number of compounds passing criteria were, in order of significance: Ion source draw out lens diameter of 9mm (Inert Plus source); injection technique of 3:1 pulsed split followed by ramped flow; low pressure drop split liner with wool followed by single taper, glass wool, Ultra Inert; and either DFTPP tune or Atune. Specific recommendations are provided.