In thisstep,weneedtotestwhethertheconcentrationofenzymesolutionmeetsthecleaning
requirement usingAllertestkit(Fig. 3a). Firstly,sample500mLenzymesolution,andthenget5mL
sample intoflaskusingadisposablesyringe.Pleasenotethatbothflaskandsyringeneedtobewashed
using samplespreviously.AddtwodropsofCl-1reagentintoflask,andthesamplewillchangeinto
purple. Then,dropCl-2reagentintoflaskslowlyandshakeitsimultaneouslyuntilthesampleturned
from purpletoyellow.Afterthat,dropCl-3reagentintoflaskslowlyandshakeitsimultaneouslyuntil
the samplechangedfromyellowtopurple,andrecordtheconsumedvolumeofCl-3reagentas V1
(Fig. 3b). Theinitialwaterwasalsotestedaccordingtotheaboveprocess.Theconcentrationofenzyme
solution couldbecalculatedfollowingtheformulabelow: