BUCHI DuMaster D-480 - Manual (Page 141)

Operation Manual D-480 ©BÜCH Labortechnik AG
7 - Using the instrument 141
Definitions
Routine measuring work comprises the following activities:
 Determination of instrument blank values.
 Instrument conditioning with conditioning samples.
 Determination of daily factors.
Routine measuring work is performed at set intervals or on defined occasions before, during or after a
series of measurements with real samples.
Instrument blank values
Determination of the instrument blank value depends on your needs. The following overview shows
the type and purpose of the determination.
Purpose Sample Blank value Occasion
Checking gas-tightness none N after maintenance work
Blank value determination of
sample additives and packing
materials
 Sample
additive
 Packing
material
N to allow for sample additives or
packing material
For details on determining blank values, cf. Types of blank value determination and their settings
(on page 143).
Conditioning samples
Conditioning samples are measured with standard substances at the start of every series of analyses.
They are used to check...
 ... the correct run of the analysis.
 ... the proper condition of the instrument.
 ... flow and pressure behavior of the gases.
Daily factor determinations
Determination of the daily factor serves...
 ... to fine-tune instrument calibration to room conditions at the time of analysis.
 ... to assess the condition of the instrument by observing daily factor fluctuations and drift trends.
When to perform routine measuring work
Perform routine measuring work...
 ... at least once a day.
 ... additionally when measuring breaks last longer than 2 hours.
If a series of analyses exceeds a duration of 5-6 hours (carousel completely loaded), it is advisable to
determine the daily factor additionally at the end of the series.
Performing routine measuring work
Proceed as follows:
 If desired, perform a blank value determination. For details, see Types of blank value
determination and their settings (on page 143).
 Measure the conditioning sample twice. Use a standard as run-in sample which corresponds
your sample matrix:
 250 mg glutamic acid with method "Standard".
 Measure the following daily factor sample three times and compute the daily factor:
 250 mg glutamic acid with method "Standard".