Chapter 2 Overview
Page 2-4 MAN 0384
Making measurements
There are two ways to make a measurement; making a manual measurement or
using a Standard Operating Procedure (SOP).
SOPs
SOPs are user-defined procedures that are easily programmed into the software to
allow the same type of sample to be measured in a consistent way. Here all the dif-
ficult decisions on measurement strategy have already been made.
When the SOP is run, it automatically runs through the defined measurement pro-
cedure, prompting the operator to perform tasks (such as adding the sample). The
SOP takes full control of the dispersion unit (except any manual unit), making all
adjustments and settings (such as pump speed and ultrasonic power). This is the
recommended method of operation and is suited to beginners or when routinely
measuring the same type of sample.
Creating an SOP is very easy. The operator selects Configure-New SOP and the
software runs the SOP Wizard. This wizard asks a series of questions, such as:
what are the optical properties of the sample?
what is it suspended in?
how fast should the stirrer be?
how much ultrasonic dispersion is required?
should any additives be added to the sample to aid dispersion?
how is the result to be calculated and displayed?
These all combine to define the measurement procedure.
Manual measurements
But how does a user know how to answer the questions? This information is found
by referring to the advice which is available at all stages of SOP creation, as well as
by experimentation; making a few preliminary measurements and observing the
results. This is the primary function of a manual measurement. Manual meas-
urements can be used to make “one-off” measurements or used to “get a feel” for a
sample prior to defining an SOP.
More details on making measurements can be found in Chapter 4.
MAN0384-1.0 Mastersizer 2000.book Page 4 Tuesday, March 20, 2007 8:56 AM
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