Liquid Testing | 119
ELx800 Operator's Manual
Liquid Test 2
The recommended method of testing the instrument performance is to use the
Absorbance Test Plate to confirm alignment, repeatability, and accuracy, which
will also confirm linearity.
If a Test Plate is not available,
Liquid Test 2 can be used for these tests.
Required Materials:
• New 96-well, flat-bottom microplates (Corning Costar
®
#3590 is
recommended)
• Ten test tubes, numbered consecutively, stored in a rack
• Calibrated hand pipette (Class A volumetric pipette recommended)
• Stock solution A or B (these are the same solutions as for Liquid Test 1)
Preparation of Dilutions:
1
Set up a rack containing 10 tubes, numbered consecutively.
2 If you have not already done so, prepare concentrated stock Test
Solution A or B.
Refer to
Table 3 when executing steps 3 and 4.
Table 3
Test Tube Dilutions
Tube Number 1 2 3 4 5 6 7 8 9 10
Volume of Concentrated
Solution (ml)
20 18
16
14
12
10
8
6 4 2
Volume of 0.05% Tween
Solution (ml)
0 2
4
6
8
10
12
14 16 18
Absorbance expected if
concentrated solution is
2.0 at 200 μl
2.0 1.8
1.6
1.4
1.2
1.0
0.8
0.6 0.4 0.2
3 Create a percentage dilution series, beginning with 100% of the
concentrated stock solution in tube 1, 90% of the concentrated solution
in tube 2, 80% in tube 3, and so on to 10% in tube 10.
4 Dilute using amounts of the remaining 0.05% solution of deionized
water and Tween
®
20, as shown in Table 3.
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