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Glossary
limits” that are commonly used. These
include: the instrument detection limit (IDL),
the method detection limit (MDL) and the
limit of quantitation (LOQ).
Even when the same terminology is used,
there can be differences in the LOD, according
to nuances of what definition is used and
what type of noise contributes to the
measurement and calibration.
Most analytical instruments produce a signal
even when a blank (matrix without analyte)
is analyzed. This signal is referred to as the
noise level.
The IDL is the analyte concentration that is
required to produce a signal greater than three
times the standard deviation of the noise level.
Many times there is more to the analytical
method than just doing a reaction or submitting
it to direct analysis. For example it might
be necessary to heat a sample that is to be
analyzed for a particularmetal with the addition
of acid first (this is called digestion). The sample
may also be diluted or concentrated prior to
analysis on an instrument.
Additional steps in an analysis add additional
opportunities for error.
Since detection limits are defined in terms
of error, this will naturally increase the
measured detection limit. This detection
limit (with all steps of the analysis included)
is called the MDL.
Dew Point
The dew point is defined as the temperature
to which air must be cooled in order for
condensation (saturation) to occur. The dew
point is dependent on the concentration
of water vapor present, and therefore, the
relative humidity.
DIN Connector
A circular connector for consumer electronics,
originally standardized by the Deutches
Institut für Normung (DIN) for analog audio
signals.
Direct Potentiometry
Direct Potentiometry is a widely used
method of performing ion analysis with ISEs.
This method is highly effective when the
user must quickly measure large batches
of samples at many concentrations. Hanna
direct reading meters such as the HI 98184
and HI 98185 display concentration of the
unknown sample by a direct reading after
calibrating the instrument with two or more
standards. Ionic strength adjustments are
made to both samples and standards. In some
applications quick and reliablemeasurements
can be made on-site, without taking samples
back to the laboratory.
DiST®
Hanna Dissolved Solids Testers are widely
used for monitoring EC/TDS in water
conditioning, reverseosmosis, cooling towers,
drinking water, wastewater, laboratories,
agriculture, aquaculture and aquariums,
hydroponics and the printing industry.
dKH
Degrees of carbonate hardness.
In case of alkalinity: 1 dKH = 0.36
meq/L = 17.86 mg/L CaCO
3
DO
Dissolved Oxygen. A relative measure of the
amount of oxygen that is dissolved or carried
in a given medium.
DPD
N,N-diethyl-p-phenylenediamine
EBC
European Brewery Convention.
EC
Electrical conductivity is a measure of how
well a material accommodates the transport
of electric charge. Its SI derived unit is the
Siemens per meter, (A2s3m-3kg-1) (named
after Werner von Siemens). It is the ratio
of the current density to the electric field
strength. This applies also to the electrolytic
conductivity of a fluid.
EDTA
Edetic acid; etylenediaminetetraacetic acid
EES
Sodium exchangeable ( in meq/100 g soil)
17
Glossary
17.9
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