Biotek 405 LS, Operator'S Manual

Page: 98 / 240

78 | Chapter 3: Operation
Sensitivity: Verify Sensor vs. Absorbance Reader
While the 405 LS's Verify™ ultrasonic level sensor is a reliable tool for quickly
determining the current state of the wash manifold, it has greater measurement
variability than a typical absorbance reader.
The Verify sensor is an excellent maintenance tool, but BioTek recommends using
the more precise measurements obtained with a microplate reader for qualifying
the 405 LS's performance on a monthly basis. Additionally, BioTek recommends
performing an annual qualification of the Verify sensor itself, to ensure it is
meeting its performance specifications.
Qualify the Verify™ Technology Sensor on page
167
.
The Verify measurement variability is determined this way:
CV % =
Verify
σ
V
Verify %CV accuracy is determined from the sigma measurement error and mean
volume measurement error. The sensor’s performance specification is σ
measurement
<
9 μL, (also typically σ
measurement
> 3 μL). Typical volume error is +/- 14 μL.
%CV reported by the level sensor is highest when σ
measurement
is high and mean
volume measurement error is low, and vice versa.
1
1
The error contribution of sigma measurement is found by summing the actual well volume variance and
the measurement variance:
σ σ actual σ mea urement error = +
2 2
.
405™ Microplate Washer LS