The objective of this study was to see if the overall performance of the analysis could be improved by selecting specific
consumables for the instrument and incorporating a surge pressure splitless injection to lower the
Detection Limits (MDLs) for U.S. Environmental Protection Agency (USEPA) Method 525.2. U.S. Environmental Protection Agency
(USEPA) Method 525.2 is a general purpose method for the analysis of organic compounds in finished drinking
water, source water, or drinking water in any stage of treatment. A one liter sample is prepared by solid phase
extraction, generating a final extract in ethyl acetate. All calibration standards are made in ethyl acetate to avoid
any adverse effects caused by calibration in a different solvent from that of the extracts. The injection method
was surge pressure splitless at an injection volume of 1 µL. The mass spectrometer was set up for EI full scan
from m/z 45 to 450. The column was programmed to elute all compounds in less than 25 minutes. The
calibration curve was run at the following concentrations: 0.1, 0.5, 1, 2, 5, and 10 µg/mL. The replicates for
MDLs were run at 0.5 µg/mL. The instrument system used was the DSQ II, TRACE GC Ultra, and AS 3000
autosampler.
After an initial evaluation of various inlet liners and column phases, the preferred liner (5 mm Splitless liner) and
column (TR 525 0.25 mm x 30 meter, 0.25 µm) were selected for the study. The liner was selected based on
producing the lowest endrin breakdown. The column phase was selected which showed the best linearity at
levels below 0.50 µg/mL, indicating minimal irreversible adsorption. The study of the preferred liner and column
showed excellent sensitivity and met the tuning criteria for DFTPP easily from run to run. The calibration curve
met all of the QC criteria for a linear fit by average percent relative standard deviation and by least square fit for
a few of the problem compounds listed in the method. In order to illustrate the performance of the system, the
Quality Control criteria method tested in this study is discussed as follows: Critical Time affects GC/MS Performance;
Meeting the Calibration Curve Criteria; and,
Determination of MDLs or Instrument Detection Limits (IDLs).
| Edition : | Vol. - No. |
| File Size : | 1
file
, 93 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 1 |
| Published : | 11/01/2007 |
