Benzene C6H6 NO.121SL


121LS


Performance

Measuring Range

1 to 20 ppm

20 to 100 ppm

Number of Pump Strokes

5

1

Correction Factor

1

5

Sampling Time

2 minutes per pump stroke

Detecting Limit

0.25 ppm (n=5)

Color Change

White Brownish gray

Reaction Principle

Benzene reduces iodine pentoxide to liberate iodine,
which produces a brownish gray in color

C6H6 + I2O5 + H2S2O7 I2

Coefficient of Variation 20% (for 1 to 5 ppm), 15% (for 5 to 20 ppm)
Shelf Life 3 Years
Corrections for
temperature & humidity
Unnecessary
Store the tubes at cool and dark place.


Possible coexisting substances and their interferences (NOTE)

Substance

Concentration

Interference

Change color by itself

Hexane

50 ppm

No effect

No discoloration

Toluene

100 ppm

No effect

No discoloration

Xylene

150 ppm

No effect

No discoloration

Aromatic hydrocarbons other than benzene are trapped in the brown layer in the pretreatment tube.If the pretreatment reagent is entirely consumed (whole brown layer turns to dark brown),a higher reading will be given.


Calibration gas generation Diffusion tube method


TLV to TWA TLV to STEL Explosive range
0.5ppm 2.5ppm 1.3 to 7.1%


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