environmental monitoring Flashcards
what do particle counts determine and not determine
do: particle size
dont: viability
whats the principal behind the detection and sizing of particles?
a vaccumm pumps the particles through the sensor and the lasar beam.
light from the lasar is detected and converted into an electrical pulse.
pulses are counted and sized by the electronics within the particle counter
about settle plates
contains growth media
inexpensive and easy
volume of air being sampled unknown
about impaction methods (impingers)
uses liquid medium
drawn by a suction pump through a narrow tube into a small flask containing the medium
about impaction methods (impactor)
uses a solid/adhesive medium
media is incubated to enumerate viable microorganisms
about surface sampling (contact plates)
plates pressed against any flat surface.
incubated
colonies counted
small surface area
unsuitable for uneven surfaces
about surface sampling (swab method)
more quantitative than qualitative
bioluminescence methods
biotrace swabs
based on ATP
amount of the microbial biomass is directly proprtional to the amount of ATP
reacts with luciferis in the presence of the catalyst- luciferase wnzyme. light emitted and recorded by luminometer
