Hach DR/850, Procedures Manual, Page: 434 / 460

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laundry bleach. Pour the test container contents and test
containers into the bleach solution. Allow 10-15 minutes of
contact time with the bleach solution. Then pour the liquid
down the drain and wash the reaction tubes for re-use.
Summary of Method
Resazurin is a redox-active dye, which changes from pink to blue
when it is reduced. Bacterial respiration occurring in the sample
reduces resazurin. If toxic substances are present, they inhibit the
rate of resazurin reduction. The sample color is compared to a
toxin-free control tube to determine how toxic the sample is to an
indigenous culture or a culture of
E. coli . A chemical accelerant
reduces the reaction time of the procedure.
REQUIRED REAGENTS
Description Cat. No.
ToxTrak Reagent Set (25 tests)..................................................................................... 25972-00
Includes: (1) 25607-66, (1) 25608-36, (1) 22777-00, (1) 24092-32
Quantity Required
Description Per Test Unit Cat. No.
Aqua QC–Stiks, Escherichia Coli................................. 1...................3 cultures.......... 27063-03
Sodium Thiosulfate Standard Solution ..................... varies ..................100 mL.......... 24092-32
ToxTrak Reagent Powder Pillows ...........................1 pillow ................. 50/pkg.......... 25607-66
ToxTrak Accelerator Solution.................................. 2 drops....... 15 mL SCDB.......... 25608-36
Tryptic Soy Broth Tubes............................................... 1....................... 15/pkg.......... 22777-00
Tube, culture, with cap.................................................. 1....................... 10/pkg.......... 20962-08
Water, deionized........................................................ varies ..................200 mL.............. 272-29
REQUIRED APPARATUS
Cap, White .................................................................... 1......................... 6/pkg.......... 22411-06
Clippers, to open powder pillows ................................. 1........................... each.............. 936-00
COD/TNT Adapter ....................................................... 1........................... each.......... 48464-00
Dropper Pipet, 1 mL ................................................. varies ................... 10/pkg.......... 21247-20
Forceps, flat square tip.................................................. 1........................... each.......... 14537-00
Pipet, volumetric, 5.00 mL, Class A............................. 1........................... each.......... 14515-37
Pipet Filler, Safety Bulb................................................ 1........................... each.......... 14651-00
Vial, Test ‘N Tube......................................................... 1......................... 6/pkg.......... 25831-25
TOXTRAK TOXICITY TEST,
continued