Enzyme Substrate Quantification Sealing Machine: Consisting of a programmable quantitative sealing machine, 51- or 97-well detection plates, 100mL quantitative bottles, and enzyme substrate detection reagents. Water sample detection scope: drinking water, source water, bottled water, reclaimed water, secondary water supply, pipeline water, wastewater, food processing water, livestock water, medical water, etc.

This detection method utilizes Escherichia coli to produce β-galactosidase, which breaks down the chromogenic substrate ONPG (Ortho-nitrophenyl-β-D-galactopyranoside), causing the culture medium to turn yellow. It utilizes the principle that Escherichia coli produces β-glucuronidase to degrade MUG, causing the culture medium to fluoresce under 366 nm UV light. This enables the qualitative and quantitative detection of total coliform bacteria, fecal coliform bacteria (thermotolerant coliform bacteria), and Escherichia coli in water.

Accessory Components:

Equipment procured according to the enzyme substrate detection principle. Uses as follows:

Programmable quantitative sealer: For sealing quantitative detection plates.

Enzyme substrate detection reagents: For selective detection of target bacteria in water.

51-well or 97-well quantitative plates: Used to determine the quantity of target microorganisms.

100-milliliter quantitative bottles/sampling bottles: Provide a specialized dissolution environment for water samples and reagents.

Handheld UV analyzer with darkroom: Used to observe fluorescence in the darkroom during Escherichia coli detection.

Procedure:

Step 1: Add water sample to 100 ml sampling bottle. Add enzyme substrate detection reagent, screw on cap, and shake until completely dissolved.

Step 2: Dispense sample into quantitative detection plate.

Step 3: Use a programmable sealing machine to dispense samples and seal the quantitative detection plate.

Step 4: Incubate the sealed plate at 36±1°C. For fecal coliform (thermotolerant coliform) testing, set the incubator to 44.5°C and incubate for 24 hours.

Step 5: Count the number of positive (yellow or fluorescent) wells against the color chart. Consult the 51-well or 97-well MPN table based on the plate type used to determine the coliform count per 100 mL. Record data according to the MPN table.

Step 6: Calculate the final result based on the dilution factor using the formula:

Coliform bacteria (cfu/L) = MPN value × dilution factor × 1000 mL/100 mL