CheckLite 250 Plus is a kit for microbial biomass assay and hygiene monitoring based on the ATP measuring method. It can detect the amount of ATP that is equal to over 10,000 cells of E. coli/ml.
It contains thermostable firefly luciferase. The bioluminescence reagent contains firefly luciferin and luciferase. This Luciferase enzyme catalyses the reaction where luminescence is observed due to ATP and luciferin’s interaction. The amount of bioluminescence produced in the reaction is directly proportional to the amount of ATP in the sample.
Scope of delivery
| Article Number
| Test duration
|| 20-40 mins including calibration curve
|| 2 - 8 °C, DO NOT FREEZE
|| Luciferin-luciferase reagent
|| Lyophilised powder
|| Reconstitution Buffer
|| 5,5 mL
|| 5 Vials
|| ATP releasing reagent
|| 5,5 mL
|| 5 Bottles
Preparation of Bioluminescence reagent
- Luciferin-luciferase reagent is kept under vacuum in a green-labeled vial.
- Pour the reconstitution buffer from the pink- labeled vial into the opened green-labeled vial and leave it at room temperature for a few minutes. (A slight sediment may form in the reconstitution buffer during storage. This will not interfere with test results.)
- Stir the vial gently so as not to produce foam until the contents are completely dissolved.
- Do not touch the rim of the vial or the top of the rubber plug directly with your hands, since this will sometimes raise the blank value of the reagent.
- One vial of luciferin-luciferase reagent can be used for more than 50 assays under normal condition.
- The concentration of ATP in living cells changes rapidly. Therefore, extract ATP from cells or freeze the cells immediately after sampling. Even in the case of extraction, the inhibition or destruction of ATP-degrading enzymes may be necessary to prevent enzymes from decreasing the concentration of ATP.
- Solid samples:
- Treat the sample with a stomacher or a homogenizer and then use the supernatant for the following measurement.
- Liquid samples:
- When the sample solution is turbid, colored, or contains inhibitory ions, such as Cl-, dilute the sample as necessary
- Pour 100 µl of the sample that has been handled as described above into a test tube for measurement and add 100 µl of the ATP releasing reagent solution to the test tube.
- Leave it at room temperature for 10-60 seconds to extract ATP from the microbial cells. The time required for extraction varies according to the species of the microorganisms. For example, it takes 10-20 seconds to extract ATP from bacterial cells and 60 seconds are needed for yeast cells.
- Immediately after extraction, add 100 µl of the luciferin-luciferase reagent solution and measure the amount of bioluminescence with a luminometer, such as Lumitester C-110 (ID No. 1 002 647).
- To plot a calibration curve, measure the amount of bioluminescence from incremental dilutions of ATP standard solution using the method described above.
- The number of microbial cells (Colony Forming Units, CFU) can be obtained based on the correlation between the amount of ATP and the number of CFU counted in advance using to the traditional colony counting method.