PerkinElmer QuantaSmart 1694267

CHAPTER 9
168 PerkinElmer Life and Analytical Sciences
Low Carbon-14 Figure of Merit
1. Verify that the previous efficiency measurement is within ± 2% when using the
same standard. If not, clean the outside of the vials and rerun.
2. Check that the Carbon-14 background and efficiency values are within
specification (when using unquenched standards). If so, the integrity of the
IPA standards is suspect.
Low Chi-Square
 Check for electronic noise. This typically creates spurious pulses of uniform
rate. Use a separate power line for the instrument, or call PerkinElmer
Technical Service.
Note: A properly performing instrument may exceed the 7.63 to
36.19% limit 2% of the time. This is a result of the statistical
nature of the Chi-Square test.
Low Tritium Efficiency
1. Verify that the instrument has been calibrated. If not, perform an SNC
calibration.
2. Confirm that the correct standard (unquenched and purged of oxygen) is being
used.
3. Confirm that the tSIE value of the standard is in the range of 950-1050. If not,
check the expiration date of the standard.
4. Confirm that the efficiency is ± 2% of the previous measurement using the
same standard. If not, clean the outside of the vial and rerun.
Low Tritium Figure of Merit
1. Verify that the previous efficiency measurement is within ± 2% when using the
same standard. If not, clean the outside of the vials and rerun.
2. Check that the tritium background and efficiency values are within specification
(when using unquenched standards). If so, the integrity of the IPA™ standards
is suspect.