Hach Eclox, User Manual

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11.2 Accuracy
The error or standard deviation of the test is the sum of the error introduced to the
test by all components, the ambient and all manipulations. The higher the degree of
variation, the higher the total error.
A Luminescent Bacteria Toxicity Test done strictly according to ISO 11348 has a
better precision (lower CV (coefficient of variation)) than a simplified screening test
under field conditions.
The total error for the test is typically lower than 20%.
11.3 Thermostat and PC software requirements
ISO 11348 states that the measuring luminometer must have a 15 °C temperature
controlled measuring well. The Eclox does not have a temperature controlled
measuring cell.
According to ISO 11348 optional accessories that should be used in the lab include:
• LTV053 LUMIStherm, 230V, thermostat to 15 °C
• LZV093 LUMISsoft 4 PC software
11.4 Reagent description
The Luminescent Bacteria Toxicity Test reagent contains living luminescent bacteria
that have been grown under optimal conditions, harvested and lyophilized
(freeze-dried). The reagent is a freeze-dried preparation of a specially selected
strain of the marine bacterium Vibrio fischeri (formerly known as Photobacterium
phosphoreum, NRRL number B-11177). A vial of reagent contains roughly one
hundred million test organisms.
Refer to section Appendix A, Luminescent bacteria risks on page 121 for bacteria
risk information.
The standards stipulate that certain validity criteria must be complied with for the
reagent. Accordingly, a test is done for each batch of bacteria that is prepared
in-house or bought in. The quality certificate delivered with each package of
luminescent bacteria reagent by HACH-LANGE GmbH guarantees compliance with
the stipulated validity criteria.
To make sure that the test operates correctly on site, do control measurements with
the standard solutions (refer to the ISO standard procedure). The necessary
information about standard substances, test concentrations and sources of supply is
contained in the quality certificate that comes with every box of luminescent bacteria
reagent.