How Can I Determine the Quality of Sodium Hypochlorite

This procedure describes how to use a filter system as an aid to easily determine the clarity of sodium hypochlorite solutions.  For more information about the importance of sodium hypochlorite quality, see Sodium Hypochlorite Decomposition.

Simplified Suspended Solids Test

The sodium hypochlorite filter equipment used in this test is inexpensive and is available from Powell. The test is designed for use at the customer's site.  For laboratory-quality equipment and procedures to achieve accurate and repeatable results, please refer to the "Suspended Solids Quality Test for Bleach Using Vacuum Filtration."

Apparatus (see Figure 1 below)

1.  Nalgene™ 180 PVC Vacuum Tubing

2.  Barnant Portable Air/Vacuum Pressure Stations

3.  Nalgene™ Brand Polypropylene Flask with Angled Tabulation

4.  Nalgene™ Vacuum Filter Holder

5.  Millipore™ Filters, AA type, 0.8 uM pore size

6.  1000 ml graduated cylinders or beakers

Figure 1:  Field Bleach Vacuum Test Kit (Powell Item #: 935-05586-001)

Field Bleach Vacuum Test Kit 935-05586-001

Procedure

Note:  All apparatus should be kept clean and dust free

1.  Assemble filter.  Use forceps to place one filter on plastic support base.  Put filter funnel and clamp in place.

2.  Shake sample bottle.  Fill graduated cylinder or beaker to the 1000 ml mark with solution.

3.  Start Vacuum.

4.  Slowly pour the 1000 ml into the top of the vacuum holder.  When sample has filtered through completely, record the time to filter.

Note:  Bleach that has not been filtered with submicron filtration will take approximately 6 to 8 times longer than filtered product.  Typically 1000 ml of high clarity bleach will take less than three minutes at 20" Hg vacuum.

After filtration, the filter paper should be near white with virtually no retained particles.  Discolored filter paper typically indicates the presences of iron.

Five Samples of Bleach Were Tested