Range:≤0.02, 0.05, 0.1, 0.2, 0.5, 1, 2mg/l

Method:4-Pyridinecarboxylic Acid

Reaction Time:5min

Quantity(pcs/box):40

Interferences

Standard colors were determined from standard solutions. However, coexisting substances will

cause inaccurate results. The list below reports ion concentrations under which ones interferences

are insignificant:

≤ 1000 mg/L : Al3+, As3+, B3+, Ba2+, Ca2+, Cd2+, Cl-, F-, K+, Mg2+, Mn2+, Na+, NH4

+, NO3

-, Pb2+,

PO4

3-, SO4

2-, Zn2+, Phenol

≤ 500 mg/L : Ni2+

≤ 100 mg/L : Co2+, Cr3+, Fe2+, Sn2+

≤ 50 mg/L : Cu2+, Fe3+

≤ 10 mg/L : NO2

-

≤ 5 mg/L : Cr6+, V5+, Residual chlorine

Sub-ppm level : Hg2+, I-, SO3

2-, SCN-, some kinds of ethylene amine

Almost all the coexistence substances may weaken the color development of CN-. It is admitted

that thiocyanide and some kinds of ethylene amin (tetraethylene-pentamine,

pentaethylene-hexamine) may show stronger color development.

Oxidative and reductive substances may also influence to developed color.

The Cyanide (free) PACKTEST is not suitable for sea water samples.

For the industrial waste water samples in which interfering substances are expected, a

pretreatment like distillation method or aeration method is required before the measurement.

Cyanide complex ions bonding with various metal ions can not be detected as free cyanide. These

complex ions should be measured using the measurement kit for Total cyanide ion, ref: WA-CNT.

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