Coefficient ofVariation20% (for5 to 40 ppm), 15% (for 40 to 120 ppm)ShelfLife3YearsCorrectionsfor
temperature & humidityUnnecessaryStore the tubes at cool and darkplace. Possible coexisting substances and theirinterferences(NOTE)
Substance
Concentration
Interference
Change color by itself
Hexane
100 ppm
No effect
No discoloration
Toluene
200 ppm
No effect
No discoloration
Xylene
300 ppm
No effect
No discoloration
Aromatichydrocarbons other than benzene are trapped in the brown layer inthe pretreatment tube.If the pretreatment reagent is entirelyconsumed (whole brown layer turns to dark brown),ahigher reading will be given.