OWML: QA/QC

Quality Assurance/Quality Control Manual: Ohio Water Microbiology Laboratory

Centrifuges
There are three types of centrifuges that are used to perform separation of particles by centrifugal force. The refrigerated floor centrifuge is used to concentrate Cryptosporidium oocysts and Giardia cysts by USEPA Method 1623, for DNA extraction, and to process concentrated samples. The ultracentrifuge is used to isolate virus particles eluted from water samples and for concentrating bacterial spores. Two microcentrifuges are used for processing bacterial extractions, purifications, concentrations, and phase separations.

Refrigerated floor centrifuge

• The temperature is monitored quarterly with the digital thermometer (acceptance criteria is 4+ 3ºC).
• The buckets are disinfected with dilute bleach and dechlorinated quarterly.
• Rotors and adapters are checked for deterioration, as needed.
• Lubrication is done annually, or as needed.
• All maintenance is recorded in the LIMS.

Ultracentrifuge

• Each run of the centrifuge is recorded in the centrifuge log book.
• The rotor and buckets are disinfected with dilute bleach and dechlorinated quarterly.
• Lubrication of the O-ring with vacuum grease, and lubrication of the buckets and cap mating surfaces with Spinkote lubricant are done quarterly.
• The O-rings on the buckets are replaced twice a year.
• The vacuum pump oil is changed every 2 years.
• All maintenance is recorded in the LIMS.

Microcentrifuge (2)

• The chamber and the rotor are cleaned with soap and water quarterly.
• The air intake and exhaust vents are cleared from obstructions quarterly.
• Lubrication of the drive shaft and threads and O-ring with vacuum grease is done quarterly.
• All maintenance is recorded in the LIMS.