Hach-Lange LUMISTOX 300 LPV321 User Manual User Manual
Page 38
LUMIStox 300 Operating Manual
Dr. Bruno Lange GmbH
______________________________________________________________________________
______________________________________________________________________________
Page: 38
4.3 Calculation of the GL value in conformity with DIN
Definitions:
Io:
Luminescence of the bacteria suspensions before the sample is added
(initial luminescence)
It:
Luminescence of the tests solutions after the incubation period t (final
luminescence after addition of the sample)
IoK, ItK:
Initial and final luminescence of the control solutions (2% NaCl)
fK:
Correction factor
Ic:
Io of the test solutions, corrected by fK
%inhib.t:
Percentage inhibition of the luminescence after the incubation period t
GL value:
The factor of the test dilution (i.e. the G-value) with which %inhib.t <20 is
reached.
1.
Calculating fK:
fK = ItK/IoK
2.
Calculating Ic:
Ic = fK x Io
3.
Calculating %inhib. t:
%inhib.t = (Ic - It) x 100 / Ic