Biotek ELx808, Operator'S Manual

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| Chapter 4: Instrument Qualification
Perform Liquid Test 1
1. Using freshly prepared stock solution A or B (the concentrated solution),
prepare a 1:2 dilution using DI water (one part stock, one part DI water; the
resulting solution is a 1:2 dilution).
2. Pipette 200 µL of the concentrated solution into Column 1 of the plate.
3. Pipette 200 µL of the diluted solution into Column 2 of the plate.
™
After pipetting the diluted test solution into the microplate and
before reading the plate, we strongly recommend shaking the plate
for four minutes. This will allow any air bubbles in the solution to
settle and the meniscus to stabilize. If a plate shaker is not
available, wait 20 minutes after pipetting the diluted test solution
before reading the plate.
4. Read the microplate five times at 405 nm using the Normal Read Mode,
single wavelength, no blanking (“Normal” plate position).
5. Without delay, rotate the microplate 180° so that well A1 is now in the H12
position. Read the plate five more times (“Turnaround” plate position).
6. Print the ten sets of raw data, or export the data to an Excel spreadsheet
using Gen5. The mathematical computations described below may then be
performed and the template kept for future tests.
Calculations:
7. Calculate the mean OD value for each well location in columns 1 and 2 for
the five plates read in the Normal position, and then again for the five
plates read in the Turnaround position. This will result in 32 mean values.
8. Perform a mathematical comparison of the mean values for each microwell
in its Normal and Turnaround positions (that is, compare A1 to H12, B1 to
G12, H1 to A12, and so on). To pass this test, the differences in the
compared mean values must be within the accuracy specification for the
instrument. For example:
If the mean value for well A1 in the Normal position is 1.902, where the
specified accuracy is ± 1.0% ± 0.010 OD, then the expected range for the
mean of the same well in its Turnaround (H12) position is 1.873 to 1.931
OD. 1.902 * 0.010 + 0.010 = 0.029; 1.902 – 0.029 =
1.873
; 1.902 + 0.029 =
1.931
BioTek Instruments, Inc.