Bio-Tek ELx800, Руководство оператора

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Chapter 4: Performance Verification and IQ/OQ/PQ Procedures
Liquid Testing
Conducting Liquid Tests confirms the ELx800’s ability to perform to
specification with liquid samples. Liquid testing differs from testing with the
Absorbance Test Plate in that liquid in the wells has a meniscus, whereas the
test plate’s neutral density glass filters do not. The optics characteristics may
differ in these two cases, thus alerting the operator to different types of
problems. The liquid tests will help to detect optical defects or contamination
that can contribute to errant readings.
•
Liquid Test 1 confirms repeatability and consistency of the reader
when a solution is used in the microplate. If these tests pass, then the
lens placement and system cleanliness are proven.
• Liquid Test 2 can be used to test the linearity, repeatability, and
alignment of the reader if you do not have an Absorbance Test Plate.
Prepare the series of solutions of varying absorbances as described on
page 121.
•
Liquid Test 3 is an optional test, and can only be performed with the
“UV” model. It is offered for those sites that must have proof of
linearity at wavelengths lower than those attainable with the
Absorbance Test Plate. This test is optional since the ELx800™ has good
“front end” linearity throughout the specified wavelength range (see
page 125).
•
Bio-Tek offers a dye solution (PN 7120779, 25 ml; or 7120782, 125 ml)
that may be used in the stock solution formulation for Liquid Tests 1
and 2, or, if you prefer, you may use the dye solution described in
Table 3 (page 121). The purpose of the formulation is to create a
solution that absorbs light at ~ 2.000 OD full strength when dispensed
at 200
µ l in a flat-bottom microplate well.
• Alternatively, any solution that gives a stable color will suffice. (This
includes substrates incubated with an enzyme preparation and then
stopped with an acidic or basic solution.) Some enzyme/substrate
combinations that may be used as alternates to the described dye are
shown in
Table 2.
Table 2
Typical Enzyme-Substrate Combinations and Stopping Solutions
Enzyme Substrate Stopping Solution
Alkaline
Phosphate o-nitrophenyl phosphate 3N sodium hydroxide
beta-
Galactosidase o-nitrophenyl -beta-D galactopyranoside 1M sodium carbonate
Peroxidase 2,2'-Azino di-ethylbenzothiazoline-sulfonic
acid (ABTS)
citrate-phosphate
buffer, pH 2.8
Peroxidase o-phenylenediamine 0.03N sulfuric acid
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