Chapter 6: Maintenance and Adjustments
SPD-M20A Service Manual
65
< Linearity Check Procedure >
1) Attach the standard cell.
2) Use a syringe to inject 1 mL of methanol into the cell.
3) Open the PDA Utility "Utility "Absorbance Linearity Check/Stray Light Correction".
4) Select [Setting] --> [Check Settings…], and perform the settings shown in the table
below.
Time Constant (response):
5) Press [Function] --> [Linearity Check] to perform linearity check.
6) Proceed through <Contents> --> <Necessary Parts> --> <Preparation for the
measurement absorbance linearity> --> <Background Compensation>.
7) After confirming that the baseline is stable, press [Next] and proceed to
<Measurement of absorbance for approx 0.5AU>.
8) Use a syringe to inject 1 mL of caffeine 0.5 AU solution into the cell.
9) After confirming that the baseline is stable, press [Next]. The absorbance
measurement result for the 0.5AU solution is displayed.
10) Press [Next] and proceed to < Measurement of absorbance for approx 2.0AU>.
11) Use a syringe to inject 1 mL of caffeine 2.0 AU solution into the cell.
12) After confirming that the baseline is stable, press [Next]. The absorbance
measurement result for the 2.0 AU solution is displayed.
13) Press [Next] to display the check results. Record these results.
*The linearity error calculation formula and criterion are shown below.
2.0 AU solution absorbance value: (A)
0.5 AU solution absorbance value: (B)
Linearity error: E = (A/B 1/4) 100% Criterion: E is 4% or less
14) If the error does not satisfy the criterion, repeat the linearity correction procedure.
・ If the error (E) is +4% or more, narrow the light measurement wavelength
bandwidth setting to 10 to 14 nm, and repeat the linearity correction procedure.
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