Sequential Sampling; Sequential Sampling - How It Works - Cantium Scientific MicroBio MB2 Operating Manual

Sequential Sampling

The Sequential Sampling feature allows sampling onto a single plate over an
extended period of time. This is achieved by taking a sequence of smaller
volumes over a defined amount of time.
This is useful in clean room environments where contamination levels are
normally low, resulting in low counts. Monitoring for short periods could risk
missing potential hazards that may occur during the day. The MicroBio MB2
can now be set up and left to work autonomously, sequential sampling up to
10,000 litres over a 24 hour period.
Sequential Sampling – How it works
A cubic meter of air would normally be sampled in 10 minutes using a
standard MicroBio MB2. Sequential sampling allows the user to configure
the total volume to be sampled, by using an adjustable volume or one of the
user preset volumes, over 5 minutes to 24 hours with optional delayed start if
required.
To illustrate how sequential sampling works, consider a 1,000 litre
sample taken over an 8 hour period (t ), broken into five separate samples
p
(n). These numbers are entered into the MicroBio MB2 following a simple set
of questions. The MicroBio MB2 then calculates how much air needs
s
sampling per sequence (t being the time to take each sample) and the time
i
between the samples (t ), calculated using the equation below:
19