Chemistry Reference
In-Depth Information
2.3.3.5 uv detector Wavelength Accuracy and linearity
To assess UV detector wavelength accuracy, a National Institute of Standards (NIST)
traceable standard of erbium perchlorate is often used. Absorbances at three wave-
lengths (255, 379, and 522 nm) are measured and compared against vendor specifica-
tions, taking into account the additive effects of detector and standard variability (as
much as 1.5 nm combined). Some detectors are equipped to handle cuvettes; others
can simply be flushed with the required solution using a syringe. A sample detector
start-up diagnostics and wavelength accuracy result form is shown in Table 2.4.
Linearity is assessed by either flushing the cell or filling a cuvette with a known
concentration of a standard (e.g., propylparaben 5, 10, 20, 25, and 30 mg/mL), and
calculating response factors at multiple levels (minimum of five). The response factor
%RSD is then compared against a predetermined or vendor-supplied specification. A
sample detector linearity result form is shown in Table 2.5.
2.3.4 P
erformAnce
Q
uAlIfIcAtIon
(PQ)
Per Figure 2.1, once an IQ and an OQ have been performed, PQ testing is conducted.
PQ testing should be performed under the actual running conditions across the
anticipated working range. It should be repeated at regular intervals; the frequency
tAble 2.4
sample detector start-up diagnostics and Wavelength Accuracy result Form
Detector Serial Number
Solution ID/Lot Number
Expiration Date
Start-up Diagnostics
Pass (Initials)
Fail (Initials)
Test Apparatus
Flow Cell (Initials)
Cuvettes (Initials)
Wavelength Accuracy
measured peak value (nm)
expected peak value (nm)
pass (Initials)
Fail (Initials)
255 (±2.0 nm)
255 (±2.0 nm)
379 (±2.0 nm)
522 (±2.0 nm)
Comments
Certification
The Performer as signed below attests that the test was performed according to the prescribed
procedure and that the results above are accurate and complete.
Performer
Signature
Date
The Reviewer as signed below attests that the test was performed according to the prescribed
procedure and that the results above are accurate and complete.
Reviewer
Signature
Date
