Products

Phosphate (reactive, ortho)

Visual Kits

Range

 MDL

Method

Kit Catalog No.

Refill Catalog No.

0-1 & 1-10 ppm

0.05 ppm

Stannous Chloride

CMK8510

CMR8510

2-30 ppm

2 ppm

Vanadomolybdophosphoric Acid

CMK8530

CMR8530

10-150 ppm

10 ppm

Vanadomolybdophosphoric Acid

CMK8515

CMR8515 

0-30 & 30-300 ppm

5 ppm

Stannous Chloride

CMK8515D

CMR8515D

0-60 & 60-600 ppm

10 ppm

Stannous Chloride

CMK8515A

CMR8515A

0-120 & 120-1200 ppm

20 ppm

Stannous Chloride

CMK8515B

CMR8515B

0-1200 & 1200-12,000 ppm

200 ppm

Stannous Chloride

CMK8515C

CMR8515C

  

Instrumental Kits

Range

Method

Kit Catalog No.

V-2000: 0.30-8.00 ppm / Spec: 0.20-5.00 ppm

Vanadomolybdophosphoric Acid

CMK8513

5.0-80.0 ppm

Vanadomolybdophosphoric Acid

CMK8503

 

Methods

Phosphorus occurs naturally in rock formations in the earth's crust, usually as phosphate. High phosphate concentrations in surface waters may indicate fertilizer runoff, domestic waste discharge, or the presence of industrial effluents or detergents. Although phosphates from these sources are usually poly-phosphates or organically bound, all will degrade to ortho or reactive phosphates with time.

Phosphate measurement is used to control scale and corrosion inhibitor levels in boilers and cooling towers. Both methods described below measure reactive phosphate, which will give a positive reaction prior to hydrolysis, and is usually termed ortho-phosphate.

The Vanadomolybdophosphoric Acid Method

References: ASTM D 515-82, Phosphorous in Water, Test Method C. APHA Standard Methods, 21st ed.,Method 4500-P C (2005).

In test kits employing the vanadomolybdophosphoric acid method, phosphate reacts with ammonium molybdate under acid conditions and in the presence of vanadium to form a yellow-colored product. Results are expressed as ppm (mg/L) PO4.

The Stannous Chloride Method

References: APHA Standard Methods, 21st ed., Method 4500-P D (2005).

Test kits employing this chemistry utilize a stannous chloride reduction. Phosphate reacts with ammonium molybdate and is then reduced by stannous chloride to form a blue complex. Results are expressed as ppm (mg/L) PO4.
 


 


 

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