Quanti-Tray® & Quanti-Tray®/2000Takes the Guesswork out of Bacterial Counts The IDEXX Quanti-Tray and Quanti-Tray/2000 provide easy, rapid and accurate counts of coliforms, E. coli and enterococci. The IDEXX Quanti-Tray and Quanti-Tray/2000 are semi-automated quantification methods based on the Standard Methods Most Probable Number (MPN) model. The Quanti-Tray® Sealer automatically distributes the sample/reagent mixture into separate wells. After incubation, the number of positive wells can be converted to an MPN. Quanti-Tray provides counts from one to 200/100 mL. Quanti-Tray/2000 counts from one to 2,419/100 mL. Total hands-on time is less than one minute per test.
The MPN Generator Program makes calculating and recording your test results even easier.
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Quanti-Tray® & Quanti-Tray®/2000 are easy, rapid and accurate
Easy
Rapid
Accurate
Cost Effective
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Quanti-Tray: compared to membrane filtration
Quanti-Tray/2000: compared to multiple tube fermentation |
Scientific Basis: How Quanti-Tray® Works
Quanti-Tray Scientific Basis
By dividing the 100 mL sample into 51 wells, Quanti-Tray uses the Standard Method Most Probable Number (MPN) approach to determine the number of bacteria in the original sample. Automation minimizes hands-on time and maximizes throughput (up to four samples per minute). The relatively large number of wells provides a high counting range (200/100 mL without dilutions), and very tight 95% confidence limits.
Quanti-Tray/2000-Scientific Basis
IDEXX's Quanti-Tray/2000 is based on the same statistical model as the traditional 15-tube serial dilution. In the serial dilution method, varied amounts of sample are distributed into tubes. Dilution water is then added as necessary to fill the tubes and cover the durham tubes. With the Quanti-Tray/2000, the sample is automatically divided into the proper portions by the Quanti-Tray® Sealer, without test tubes, durham tubes, measuring or dilution water. By automatically distributing the sample into 97 wells of two different sizes, Quanti-Tray/2000 yields a counting range of one to 2,419 with a far better 95% confidence limit than a 15-tube serial dilution.
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15-Tube Serial Dilution vs. Quanti-Tray/2000 | |
How to Use Quanti-Tray® and Quanti-Tray®/2000
Quanti-Tray Questions and Answers
Are Quanti-Tray and Quanti-Tray/2000 U.S. EPA-approved? Yes. U.S. Environmental Protection Agency (EPA) has stated in writing that Quanti-Tray and Quanti-Tray/2000 can be used for compliance testing. Quanti-Tray approval letters from U.S. EPA are available on request. How do Quanti-Tray and Quanti-Tray/2000 compare to other standard methods? Quanti-Tray provides a wider counting range than and comparable accuracy to membrane filtration (MF).
Are Quanti-Tray and Quanti-Tray/2000 trays sterile? Yes, the trays are gas sterilized using ethylene oxide. A certificate indicating sterility is included with each box. What is the shelf life of Quanti-Tray and Quanti-Tray/2000? The shelf life of Quanti-Tray and Quanti-Tray/2000 is up to three years from date of manufacture. When storing opened bags of trays, fold over the opened end of the bag and seal with tape. Does the temperature of the sealer affect the organisms that may be in the water sample? No, the short time period that the tray is in the sealer will not harm the bacteria. The temperature in the wells will not increase more than 5°C during sealing. Empty wells do not affect the test interpretation as long as the entire sample is in the tray. The effect on the Most Probable Number (MPN) table is statistically insignificant. An empty or partially filled well is interpreted the same way as a full well. Can the trays be stacked in the incubator? Yes. Quanti-Trays can be stacked as high as desired. Use caution not to block the airflow in the incubator. How is Quanti-Tray interpreted when using Colilert® or Colilert®-18? Use the Quanti-Tray® Comparator (#WQTC) or Quanti-Tray®/2000 Comparator (#WQT2KC) as a reference. Any color or fluorescence equal to or greater than the comparator is considered positive. Color intensity is a reflection of the different metabolic rates and final concentrations of the coliforms and E. coli in the different wells. Any yellow color or fluorescence in the sample well equal to or greater than the Quanti-Tray or Quanti-Tray/2000 Comparator is considered positive. How do you interpret fluorescent wells that are not yellow when using Colilert or Colilert-18? To determined the presence of E. coli, wells must be yellow and fluoresce. A fluorescent well, which is not yellow, is not an E. coli positive well. |
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Resource Library for Quanti-Tray® and Quanti-Tray®/2000
General • Procedure • Technical • U.S. EPA Approvals • Approvals • MSDS
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